S-8533 Series
www.sii-ic.com
STEP-DOWN, SYNCHRONOUS PWM CONTROL
SWITCHING REGULATOR CONTROLLER
© Seiko Instruments Inc., 2002-2010 Rev.3.0_00
Seiko Instruments Inc. 1
The S-8533 Series is a synchronous PWM control CMOS step-down switching regulator controller that includes a reference
voltage source, synchronous circuit, oscillation circuit, error amplifier, phase compensation circuit, and PWM controller.
An efficient step-down switching regulator can be realized simply by adding external P-channel and N-channel power MOS
FETs, one coil, and three capacitors.
Since the oscillation frequency is a high 300 kHz, the S-8533 can be used to configure a high efficiency step-down switching
regulator capable of driving high output current using small external parts and a 3 to 10% increase in efficiency is obtained
compared to conventional step-down switching regulators.
The 8-Pin TSSOP package and high oscillation frequency make the S-8533 ideal as the main power supply for portable
devices.
Features
• Synchronous rectification system realizing high efficiency (typ. 94%)
• Use at maximum duty ratio = 100% and use of a battery up to maximum life is possible by using P-channel and N-
channel power MOS FETs externally.
• Oscillation frequency : 300 kHz typ.
• Input voltage : 2.7 to 16.0 V
• Output voltage : 1.25 V
1.3 to 6.0 V, selectable in 0.1 V steps
• Output voltage accuracy : ±2.0%
• Soft-start function set by an external capacitor (CSS)
• Shutdown function
• Lead-free, Sn 100%, halogen-free*1
*1. Refer to “ Product Name Structure” for details.
Applications
• Constant voltage power supply for hard disks and DVD drivers
• Power supplies for portable devices, such as digital cameras, PDAs, electronic organizers, and cellular phones
• Main or sub power supply for notebook PCs and peripherals
• Constant voltage power supply for cameras, video equipment, and communication equipment
Package
• 8-Pin TSSOP
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
2
Block Diagram
VSS
VOUT
L
COUT
Reference voltage
source with soft start
PWM control circuit
P.N feed-through
prevention circuit
Oscillation
circuit
VIN
Tr
Tr
CSS CSS
PDRV
NDRV
VIN CIN
+
−
ON / OFF
+
+
Remark All the diodes in the figure are parasitic diodes.
Figure 1
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 3
Product Name Structure
The output voltage for the S-8533 Series can be selected depending on usage. Refer to “1. Product Name” for the
definition of the product name, “2. Package” regarding the package drawings and “3. Product Name List” for the full
product names.
1. Product Name
S-8533A xx x FT – TB – x
Environmental code
U: Lead-free (Sn 100%), halogen-free
G: Lead-free (for details, please contact our sales office)
IC direction in tape specifications*1
Package name (abbreviation)
FT : 8-Pin TSSOP
Output voltage
A : 1.3 to 6.0 V
5 : 1.25 V
Output voltage
13 to 60
(E.g., when the o utput voltage is 1.5 V, it is expressed as 15.)
The product whose output volt age is 1.25 V expresses 12.
*1. Refer to the tape specif ications.
2. Package
Drawing Code
Package Name Package Tape Reel
Environmental code = G FT008-A-P-SD FT008-E-C-SD FT008-E-R-SD
8-Pin TSSOP Environmental code = U FT008-A-P-SD FT008-E-C-SD FT008-E-R-S1
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
4
3. Product Name List
Output Voltage Product Name
1.25 V S-8533A125FT-T B -x
1.3 V S-8533A13AFT-TB-x
1.4 V S-8533A14AFT-TB-x
1.5 V S-8533A15AFT-TB-x
1.8 V S-8533A18AFT-TB-x
2.5 V S-8533A25AFT-TB-x
2.7 V S-8533A27AFT-TB-x
2.8 V S-8533A28AFT-TB-x
3.0 V S-8533A30AFT-TB-x
3.3 V S-8533A33AFT-TB-x
3.9 V S-8533A39AFT-TB-x
4.1 V S-8533A41AFT-TB-x
4.5 V S-8533A45AFT-TB-x
4.8 V S-8533A48AFT-TB-x
4.9 V S-8533A49AFT-TB-x
5.0 V S-8533A50AFT-TB-x
5.2 V S-8533A52AFT-TB-x
5.5 V S-8533A55AFT-TB-x
6.0 V S-8533A60AFT-TB-x
Remark 1. Contact the SII marketing department for the availability of product samples other than those specified
above.
2. x: G or U
3. Please select products of environmental code = U for Sn 100%, halogen-free products.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 5
Pin Configurations
Table 1
Pin No. Symbol Pin Description
1 NC*1 No connection
2 VOUT Output voltage pin
3 ON/OFF
Shutdown pin
H : Normal operation (step-down operation)
L : Step-down operation stopped (all circuits
deactivated)
4 CSS Soft start capacitor connection pin
5 VSS GND pin
6 NDRV External N-channel connection pin
7 PDRV External P-channel connection pin
3
4
2
1
6
5
7
8-Pin TSSOP
To
p
view
8
Figure 2
8 VIN IC power supply pin
*1. The NC pin is electrically open. Connection of this pin to VIN or VSS is
allowed.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
6
Absolute Maximum Ratings
Table 2
(Ta = 25°C unless otherwise specified)
Parameter Symbol Absolute Maximum Rating Unit
VIN pin voltage VIN VSS − 0.3 to VSS + 18 V
VOUT pin voltage VOUT V
SS − 0.3 to VSS + 18 V
ON/OFF pin voltage VON/OFF V
SS − 0.3 to VSS + 18 V
CSS pin voltage VCSS V
SS − 0.3 to VIN + 0.3 V
NDRV pin voltage VNDRV V
SS − 0.3 to VIN + 0.3 V
PDRV pin voltage VPDRV V
SS − 0.3 to VIN + 0.3 V
NDRV pin current INDRV ±100 mA
PDRV pin current IPDRV ±100 mA
300 (When not mounted on board) mW
Power dissipation PD 700*1 mW
Operating ambient temperature Topr −40 to +85 °C
Storage temperature Tstg −40 to +125 °C
*1. When mounted on board
[Mounted board]
(1) Board size : 114.3 mm × 76.2 mm × t1.6 mm
(2) Board name : JEDEC STANDARD51-7
Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical
damage. These values must therefore not be exceeded under any conditions.
(1) When mounted on board (2) When not mounted on board
0 50 100
150
600
400
200
0
Power dissipation (P
D
) [mW]
Ambient temperature (Ta) [°C]
500
300
100
700
800
050 100 150
300
200
100
0
Power dissipation (P
D
) [mW]
Ambient temperature (Ta) [°C]
400
Figure 3 Power Dissipation of Package
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 7
Electrical Characteristics Table 3
VIN = VOUT × 1.5 V, IOUT = VOUT/50 A (In case VOUT ≤ 1.8 V, VIN = 2.7 V) (Ta = 25°C unless otherwise specified)
Parameter Symbol Conditions Min. Typ. Max. Unit
Measurement
Circuit
Output voltage*1 V
OUT(E) − VOUT(S)
× 0.98 VOUT(S) VOUT(S)
× 1.02 V 2
Input voltage VIN − 2.7 − 16.0 V 1
Current consumption 1 ISS1 No external parts, VOUT = VOUT(S) × 0.95
(Duty ratio 100%) − 30 70 μA 1
Current consumption
during power-off ISSS VON/OFF = 0 V − − 1.0 μA 1
IPDRVH No external parts, VOUT = VOUT(S) × 1.5,
VIN = 9.0 V, VPDRV = VIN − 0.2 V −12 −18 − mA 1
PDRV pin output current IPDRVL No external parts, V OUT = VOUT(S) × 0.95,
VIN = 9.0 V, VPDRV = 0.2 V 19 27 − mA 1
INDRVH No external parts, VOUT = VOUT(S) × 1.5,
VIN = 9.0 V, VNDRV = VIN − 0.2 V −10 −14 − mA 1
NDRV pin output current INDRVL No external parts, VOUT = VOUT(S) × 0.95,
VIN = 9.0 V, VNDRV = 0.2 V 35 50 − mA 1
S-8533A125,
S-8533A13A to 29A − VOUT(E)
× 1.0% VOUT(E)
× 2.5% V 2
Line regulation ΔVOUT1 V
IN = VOUT(S) × 1.2 to 16 V*2
S-8533A30A to 60A − VOUT(E)
× 1.0% VOUT(E)
× 2.0% V 2
Load regulation ΔVOUT2 I
OUT = 10 μA to IOUT (see above) × 1.25 − VOUT(E)
× 0.5% VOUT(E)
× 1.0% V 2
Output voltage
temperature coefficient
Δ
Δ
V
Ta V
OUT
OUT
•
Ta = −40 to +85°C − ±100 − ppm/°C−
Oscillation frequency fOSC Measure waveform at the PDRV pin. 255 300 345 kHz 2
Maximum duty ratio MaxDuty The same condition as lSS1. Measure waveform at
the PDRV pin. 100 − − % 1
VOUT pin input current IVOUT V
OUT = 5.0 V 0.01 0.1 4.0 μA 1
VSH The same condition as ISS1.
VIN = 2.7 V and check that PDRV pin = "L". 1.8 − − V 1
ON/OFF pin input
voltage VSL The same condition as ISS1.
VIN = 16.0 V and check that PDRV pin = "H". − − 0.3 V 1
ISH The same condition as ISS1. VON/OFF = VIN −0.1 − 0.1 μA 1
ON/OFF pin input
leakage current ISL The same condition as ISS1. VON/OFF = 0 V −0.1 − 0.1 μA 1
Soft-start time tSS The same condition as ISS1. Measure time until
PDRV pin oscillates. 5.0 8.0 16.0 ms 1
Efficiency EFFI *3, IOUT = 200 to 400 mA, S-8533A33A − 94 − % 3
External parts : Coil : Sumida Corporation CD105 (22 μH)
Diode : Matsushita Electric Industrial Co., Ltd. MA737 (Schottky diode)
Capacitor : Nichicon Corporation F93 (16 V, 47 μF, tantalum) × 2
Transistor : Toshiba Corporation 2SA1213
Base resistance : 1 kΩ
Base capacitor : 2200 pF
C
SS : 4700 pF
C
NDRV : 1000 pF
*1. VOUT(S) : Nominal output voltage value
V
OUT(E) : Actual output voltage value : VIN = VOUT × 1.5 V, IOUT = VOUT/50 A (If VOUT ≤ 1.8 V, VIN = 2.7 V.)
*2. In case VOUT(S) ≤ 2.2 V, VIN = 2.7 to 16 V
*3. External parts Coil : Sumida Corporation CDRH104R (22 μH)
Capacitor : Nichicon Corporation F93 (16 V, 47 μF, tantalum) × 2
P-channel power MOS FET : Sanyo Electric Co., Ltd. CPH6303 (VGS = 10 V max.)
N-channel power MOS FET : Sanyo Electric Co., Ltd. CPH6403 (VGS = 10 V max.)
C
SS : 4700 pF
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
8
Measurement Circuits
1.
VSS
0.1 μF
4700 pF
ON/OFF
CSS PDRV
VOUT
NDRV
VIN
A A
A
A A
Figure 4
2.
VSS
0.1 μF
CNDRV
1000 pF
CD105
22 μH
MA737
2SA1213
2200 pF
1 k
Ω
F93
47 μF
F93
47 μF
F93
22 μF × 3
F93
22
μ
F
×
3
+
+
+
+
4700 pF
ON/OFF
CSS PDRV
VOUT
NDRV
VIN
A
Figure 5
3.
VSS
0.1 μF
CDRH104R
22 μH
IOUT
CPH6403
CPH6303
F93
47 μF
F93
47 μF
F93
22 μF + +
+
4700 pF
ON/OFF
CSS PDRV
VOUT
NDRV
VIN
A
Figure 6
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 9
Operation
1. Synchronous PWM Control Step-down DC-DC Converter
1. 1 Synchronous Rectification
A synchronous rectifying DC-DC converter enables a greater reduction in the power consumption of the external
rectifying element compared with a conventional DC-DC converter. In addition, incorporating a P and N feed-
through prevention circuit reduces the feed-through current during operation of external transistors (P-channel and
N-channel), making the operating power consumption extremely low.
1. 2 PWM Control
The S-8533 Series is a DC-DC converter that uses pulse width modulation (PWM) and is characterized by its low
current consumption.
In conventional modulation PFM system DC-DC converters, pulses are skipped when they are operated with a low
output load current, causing variations in the ripple frequency of the output voltage and an increase in the ripple
voltage. Both of these effects constitute inherent drawbacks to those converters.
In the S-8533 Series, the pulse width varies in the range from 0 to 100% according to the load current, yet the ripple
voltage produced by the switching can easily be eliminated by a filter since the switching frequency is always
constant. When the pulse width is 0% (when there is no load or the input voltage is high), current consumption is
low since pulses are skipped.
2. Soft-Start Function
The S-8533 Series has a built-in soft-start circuit.
This circuit enables the output voltage (VOUT) to rise gradually over the specified soft-start time (tSS) to suppress the
overshooting of the output voltage, when the power is switched on or the ON/OFF pin is set “H”.
The soft-start time can be set with an external capacitance (CSS).
The time needed for the output voltage to reach 95% of the set output voltage value is calculated by the following
formula.
tSS [ms] = 0.002 × CSS [pF]
0
10
20
30
40
50
60
0 5000 10000 15000 20000
External c apacitance (CSS) [pF]
S o ft-start time (tSS) [ms]
Figure 7 Soft-Start Time
The value for CSS should be selected to give enough margin to the soft-start time against the power supply rise
time. If the soft-start time is short, possibility for output voltage overshoot, input current rush, and malfunction of the
IC increases.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
10
3. ON/OFF Pin (Shutdown Pin)
This pin is used to activate and deactivate the step-down operation.
When the ON/OFF pin is set to “L”, all the internal circuits stop working, and substantial savings in current
consumption are thus achieved. The voltage of the PDRV pin goes to VIN level and voltage of the NDRV pin goes
to VSS level to shut off the respective transistors.
The ON/OFF pin is configured as shown in Figure 8. Since pull-up or pull-down is not performed internally,
operation where the ON/OFF pin is in a floating state should be avoided. Application of a voltage of 0.3 to 1.8 V to
the pin should also be avoided lest the current consumption increases. When the ON/OFF pin is not used, it should
be connected to the VIN pin.
ON/OFF Pin CR Oscillation
Circuit Output
Voltage
“H” Active Set value
“L” Non-active Open
ON/OFF
VIN
VSS
Figure 8 ON/OFF Pin Structure
4. 100% Duty Cycle
The S-8533 Series operates with a maximum duty cycle of 100%. T he switching transistor can be kept on to supply
current to the load continually, even in cases where the input voltage falls below the preset output voltage value.
The output voltage under these circumstances is equal to the subtraction of the lowering due to the DC resistance
of the coil and the on-resistance of the switching transistor from the input voltage.
5. Back-Flow Current
Since the S-8533 Series performs PWM synchronous rectification under a light load, current flows backward in the
VIN direction. The back-flow current therefore reaches its peak when there is no load (see Figure 9). Pay attention
to the maximum back-flow current value, which can be calculated from the following expressions.
Duty (IOUT = 0) = VOUT/VIN
Example : VIN = 5 V, VOUT = 3 V, Duty = 60%
ΔIL = ΔV/L × ton = (VIN − VOUT) × Duty/(L × fOSC) × 1.2
Example : VIN = 5 V, VOUT = 3 V, fOSC = 300 kHz, L = 22 μH, ΔIL = 218 mA
I
Lmax. = ΔIL/2 = 109 mA, ILmin. = −ΔIL/2 = −109 mA
When there is no load, the current waveform becomes a triangular wave with the maximum, ILmax., and the
minimum, ILmin., which is negative. The negative current, shaded regions in Figure 10, flows backward.
When the output current (IOUT) is approximately 109 mA under the above conditions, the current does not flow
backward since the minimum value (ILmin) of the triangular wave becomes 0 mA.
When an input capacitor (CIN) is installed, back-flow current to the power source is negligible since the back-flow
current is absorbed by the input capacitor. The input capacitor is indispensable to reduce back-flow current to the
power source.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 11
Though the conditions mentioned above are required to prevent back-flow current, they are guidelines. Check the
validity by measuring the prototype or the actual device.
Back-flow current
CIN VIN
Coil
current IL
L
PDRV
NDRV
VOUT
VIN
VSS
+
+
Figure 9 Back-Flow Current
109 mA
I
OUT
218 mA
Coil current when 109 mA
flows as a load
0 mA Back-flow current = 0 mA
ILmin.
ILmax.
ΔIL
IL
Coil current under no load
Back-flow
current
−109 mA
109 mA
ILmin.
ILmax.
ΔIL
IL
0 mA
I
OUT
Figure 10 Example for No Back-Flow Current
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
12
External Parts Selection
1. Inductor
The inductance value (L) greatly affects the maximum output current (IOUT) and the efficiency (η).
As the L value is reduced gradually, the peak current (IPK) increases, the stability of the circuit is improved, and IOUT
increases. As the L value is made even smaller, the efficiency is lowered, and IOUT decreases since the current
driveability of the switching transistor is insufficient.
As the L value is increased, the dissipation in the switching transistor due to IPK decreases, and the efficiency
reaches the maximum at a certain L value. As the L value is made even larger, the efficiency degrades since the
dissipation due to the series resistance of the coil increases. IOUT also decreases.
An inductance of 22 μH is recommended for the S-8533 Series.
When choosing an inductor, attention to its allowable current should be paid since the current exceeding the
allowable value will cause magnetic saturation in the inductor, leading to a marked decline in efficiency and the
breakdown of the IC due to large current.
An inductor should therefore be selected so that IPK does not surpass its allowable current. IPK is expressed by the
following equation :
INOSC
OUTINOUT
OUTPK V L f 2 )V (V V
I I ×××
−×
+=
where fOSC (= 300 kHz) is the oscillation frequency.
2. Capacitors (CIN, COUT)
The capacitor (CIN) inserted on the input side serves to lower the power impedance, average input current, and
suppress back-flow current to the power source. Select the CIN value according to the impedance of the power
supplied, and select a capacitor that has low ESR (Equivalent Series Resistance) and large capacitance. It should
be approximately 47 to 100 μF, although the actual value depends on the impedance of the power source used and
load current value. When the input voltage is low and the load is large, the output voltage may become unstable.
In this case, increase the input capacitance.
For the output side capacitor (COUT), select a large capacitance with low ESR (Equivalent Series Resistance) to
smoothen the ripple voltage. When the input voltage is extremely high or the load current is extremely large, the
output voltage may become unstable. In this case, the unstable area will become narrow by selecting a large
capacitance for an output side capacitor. A tantalum electrolytic capacitor is recommended since the unstable area
widens when a capacitor with a large ESR, such as an aluminum electrolytic capacitor, or a capacitor with a small
ESR, such as a ceramic capacitor, is chosen. The range of the capacitance should generally be approximately 47
to 100 μF.
Fully evaluate input and output capacitors under the actual operating conditions to determine the best value.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 13
3. External Transistor
Enhancement (P-channel, N-channel) MOS FETs can be used as external switching transistors for the S-8533
Series.
3. 1 Enhancement (P-channel, N-channel) MOS FET
The PDRV/NDRV pin of the S-8533 Series is capable of directly driving a P-channel or N-channel MOS FET with a
gate capacity around 1000 pF.
When P-channel/N-channel MOS FETs are chosen, efficiency will be 2 to 3% higher than that achieved by a
PNP/NPN bipolar transistor since MOS FET switching speeds are higher than PNP/NPN bipolar transistors and
power dissipation due to the base current is avoided.
The important parameters in selecting MOS FETs include the threshold voltage, breakdown voltage between gate
and source, breakdown voltage between drain and source, total gate capacity, on-resistance, and the current
ratings.
The PDRV and NDRV pins swing from voltage VIN over to voltage VSS. If the input voltage is low, a MOS FET with a
low threshold voltage has to be used so that the MOS FET will turn on as required. If, conversely, the input voltage
is high, select a MOS FET whose gate-source breakdown voltage is higher than the input voltage by at least several
volts.
Immediately after the power is turned on, or when the power is turned off (that is, when the step-down operation is
terminated), the input voltage will be imposed across the drain and the source of the MOS FET. The transistor
therefore needs to have drain-source breakdown voltage that is also several volts higher than the input voltage.
The total gate capacity and the on-resistance affect the efficiency.
The power dissipation for charging and discharging the gate capacity by switching operation will affect the efficiency
especially at low load current region when the total gate capacity becomes larger and the input voltage becomes
higher. If the efficiency under light loads is a matter of particular concern, select a MOS FET with a small total gate
capacity.
In regions where the load current is high, the efficiency is affected by power dissipation caused by the on-resistance
of the MOS FET. If the efficiency under heavy loads is particularly important in the application, choose a MOS FET
with as low an on-resistance as possible.
As for the current rating, select a MOS FET whose maximum continuous drain current rating is higher than IPK.
If an external P-channel MOS FET has much different characteristics (input capacitance, threshold value, etc.) from
an external N-channel MOS FET, they turn ON at the same time, flowing a through current and reducing efficiency.
If a MOS FET with a large input capacitance is used, switching dissipation incr eases and efficiency decreases. If it
is used at several hundreds of mA or more, the dissipation at the MOS FET increases and may exceed the
permissible dissipation of the MOS FET. To select P-channel and N-channel MOS F ET s, evaluate the performance
by testing under the actual condition.
Caution If the load current is large, the P-channel MOS FET dissipation increases and heat is generated.
Pay attention to dissipate heat from the P-channel MOS FET.
Efficiency data using Sanyo Electric Co., Ltd. CPH6303, CPH6403, and Vishay Siliconix Si3441DV and Si3442DV
for applications with an input voltage range of 6 to 8 V or less is included for reference. For applications with an
input voltage range of 6 to 8 V or more, efficiency data using Sanyo Electric Co., Ltd. CPH6302, CHP6402, and
Vishay Siliconix Si3454DV and Si3455DV is included. Refer to “ Reference Data”.
Current flow in the parasitic diode is not allowed in some MOS FETs. In this case, a Schottky diode must be
connected in parallel to the MOS FET. The Schottky diode must have a low forward voltage, a high switching
speed, a reverse-direction withstand voltage of VIN or higher, and a current rating of IPK or higher.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
14
Standard Circuit
• Using MOS FET
L
VIN
Nch Power
MOS FET
COUT
CIN
VOUT
Pch Power
MOS FET
1 8
4 5
CSS
S-8533
V
ON / OFF + +
Figure 11
Caution The above connection diagram does not guarantee correct operation. Perform sufficient evaluation
using the actual application to set the constants.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 15
Precautions
• Install the external capacitors, diode, coil, and other peripheral parts as close to the IC as possible, and make a one-
point grounding.
• Normally, the P-channel and N-channel MOS FETs do not turn ON at the same time. However, if the external P-
channel MOS FET has much different characteristics (input capacitance, Vth, etc.) from the external N-channel MOS
FET, they may turn ON at the same time, flowing a through current. Select P-channel and N-channel transistors with
similar characteristics.
• Characteristics ripple voltage and spike noise occur in IC containing switching regulators. Moreover rush current flows
at the time of a power supply injection. Because these largely depend on the coil, the capacitor and impedance of
power supply used, fully check them using an actually mounted model.
• If the input voltage is high and output current is low, pulses with a low duty ratio may be output, and then the duty ratio
may be 0% for several clocks.
• The PDRV and NDRV oscillation frequencies may be an integer fraction of 300 kHz at some input voltage and load
conditions. In this case, the ripple voltage may increase.
• The through current prevention circuit reduces through current by shifting the P-channel and N-channel transistor on
timing. It does not suppress the through current in the external transistors completely.
• Since PWM synchronous rectification is performed even when the load is light, current flows back to VIN. Check
whether the back-flow occurs and whether it affects the performance. (See “5. Back-Flow Current” in “
Operation”.)
• The PDRV or NDRV oscillation frequency may vary in a voltage range, depending on input voltage.
• When decreasing the power supply voltage slowly, the IC operation may be undefined if the voltage falls below the
minimum operating voltage.
• Make sure that dissipation of the switching transistor especially at high temperature will not surpass the power
dissipation of the package.
• Switching regulator performance varies depending on the design of PCB patterns, peripheral circuits and parts.
Thoroughly evaluate the actual device when setting. When using parts other than those which are recommended,
contact the SII marketing department.
• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in electrostatic
protection circuit.
• SII claims no responsibility for any disputes arising out of or in connection with any infringement by products including
this IC of patents owned by a third party.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
16
Characteristics (Typical Data)
1. Examples of Major Characteristics
(1) Current Consumption 1 (ISS1) vs. Input Voltage (VIN) (2) Oscillation Frequency (fOSC) vs. Input Voltage (VIN)
2 4 6 810 12 14
Ta = 25°C
Ta = −40°C
Ta = 85°C
I
SS1
(μA)
V
IN
(V)
100
90
80
70
60
50
40
30
20
10
0 16
2 4 6 8 10 12 14
f
OSC
(kHz)
V
IN
(V)
360
340
320
300
280
260
240 16
Ta = 25°C
Ta = −40°C
Ta = 85°C
(3) PDRV Pin Output Current “H” (IPDRVH) vs.
Input Voltage (VIN) (4) PDRV Pin Output Current “L” (IPDRVL) vs.
Input Voltage (VIN)
2 4 6 8 10 12 14
IPDRVH
(mA)
VIN (V)
70
60
50
40
30
20
10
0 16
Ta = 85°C
Ta = −40°C
Ta = 25°C
2 4 6 8 10 12 14
I
PDRVL
(mA)
V
IN
(V)
70
60
50
40
30
20
10
016
Ta = −40°C
Ta = 25°C
Ta = 85°C
(5) NDRV Pin Output Current “H” (INDRVH) vs.
Input Voltage (VIN) (6) NDRV Pin Output Current “L” (INDRVL) vs.
Input Voltage (VIN)
2 4 6 8 10 12 14
INDRVH
(mA)
VIN (V)
70
60
50
40
30
20
10
0 16
Ta = 85°C Ta = 25°C
Ta = −40°C
2 4 6 8 10 12 14
I
NDRVL
(mA)
V
IN
(V)
120
100
80
60
40
20
016
Ta = −40°C
Ta = 25°C
Ta = 85°C
(7) ON/OFF Pin Input Voltage “H” (VSH) vs.
Input Voltage (VIN) (8) ON/OFF Pin Input Voltage “L” (VSL) vs.
Input Voltage (VIN)
2 4 6 8 10 12 14
VSH
(V)
VIN (V)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0 16
Ta = 85°C
Ta = 25°C
Ta = −40°C
2 4 6 8 10 12 14
V
SL
(V)
V
IN
(V)
1.7
1.5
1.3
1.1
0.9
0.7
0.5
0.3 16
Ta = −40°C
Ta = 25°C
Ta = 85°C
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 17
(9) Soft-Start Time (tSS) vs. Input Voltage (VIN)
2 4 6 8 10 12 14
tSS
(ms)
VIN (V)
16
14
12
10
8
6
4
2
0 16
Ta = 85°C
Ta = 25°C
Ta = −40°C
(10) Outpu t Vo ltag e (VOUT) vs. Input Voltage (VIN)
(1.5 V : S-8533A15AFT) (11) Output Voltage (VOUT) vs. Input Voltage (VIN)
(3.3 V : S-8533A33AFT)
2 4 6 8 10 12 14
VOUT
(V)
VIN (V)
1.53
1.52
1.51
1.50
1.49
1.48
1.47 16
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 400 mA
2 4 6 8 10 12 14
V
OUT
(V)
V
IN
(V)
3.37
3.35
3.33
3.31
3.29
3.27
3.25
3.23 16
I
OUT
= 0.1 mA
I
OUT
= 100 mA I
OUT
= 400 mA
(12) Outpu t Vo ltag e (VOUT) vs. Input Voltage (VIN)
(5.0 V : S-8533A50AFT)
2 4 6 8 10 12 14
VOUT
(V)
VIN (V)
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92 16
IOUT = 100 mA
IOUT = 0.1 mA
IOUT = 400 mA
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
18
2. Examples of Transient Response Characteristics
(1) Power-on (VIN : 0 V → 2.7 V or 5.0 V or 7.5 V, 0 V → 9.0 V, IOUT : 10 mA)
S-8533A15AFT (VIN : 0 V → 2.7 V) S-8533A15AFT (VIN : 0 V → 9.0 V)
t (2 ms/div)
10 V
0 V
Input voltage
(2.5 V/div)
Output voltage
(1 V/div)
3 V
0 V
t (2 ms/div)
10 V
0 V
Input volt age
(2.5 V/div)
Output voltage
(1 V/div)
3 V
0 V
S-8533A33AFT (VIN : 0 V → 5.0 V) S-8533A33AFT (VIN : 0 V → 9.0 V)
t (2 ms/div)
10 V
0 V
Input voltage
(2.5 V/div)
Output voltage
(1 V/div)
3 V
0 V
t (2 ms/div)
10 V
0 V
Input voltage
(2.5 V/div)
Output voltage
(1 V/div)
3 V
0 V
S-8533A50AFT (VIN : 0 V → 7.5 V) S-8533A50AFT (VIN : 0 V → 9.0 V)
t (2 ms/div)
10 V
0 V
Input volt age
(2.5 V/div)
Output voltage
(1.5 V/div)
4.5 V
0 V
t (2 ms/div)
10 V
0 V
Input voltage
(2.5 V/div)
Output voltage
(1.5 V/div)
4.5 V
0 V
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 19
(2) ON/OFF Pin Response (VON/OFF : 0 V → 1.8 V, IOUT : 10 mA)
S-8533A15AFT (VIN : 2.7 V) S-8533A15AFT (VIN : 9.0 V)
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1 V/div)
3 V
0 V
ON/OFF
pin voltage
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1 V/div)
3 V
0 V
ON/OFF
pin voltage
S-8533A33AFT (VIN : 5.0 V) S-8533A33AFT (VIN : 9.0 V)
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1 V/div)
3 V
0 V
ON/OFF
pin voltage
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1 V/div)
3 V
0 V
ON/OFF
pin voltage
S-8533A50AFT (VIN : 7.5 V) S-8533A50AFT (VIN : 9.0 V)
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1.5 V/div)
4.5 V
0 V
ON/OFF
pin voltage
t (2 ms/div)
4 V
0 V
(1 V/div)
Output voltage
(1.5 V/div)
4.5 V
0 V
ON/OFF
pin voltage
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
20
(3) Load Fluctuations (IOUT : 0.1 mA → 500 mA, 500 mA → 0.1 mA, VIN : 2.7 V or 5.0 V or 7.5 V)
S-8533A15AFT (VIN : 2.7 V) S-8533A15AFT (VIN : 2.7 V)
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output current
0.1 mA
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output current
0.1 mA
S-8533A33AFT (VIN : 5.0 V) S-8533A33AFT (VIN : 5.0 V)
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output cu r rent
0.1 mA
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output current
0.1 mA
S-8533A50AFT (VIN : 7.5 V) S-8533A50AFT (VIN : 7.5 V)
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output cu rr ent
0.1 mA
t (0.1 ms/div)
500 mA
Output voltage
(0.1 V/div)
Output current
0.1 mA
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 21
(4) Input Voltage Fluctuations (VIN : 2.7 V → 9.0 V → 2.7 V, 5.0 V → 9.0 V → 5.0 V, 7.5 V → 9.0 V → 7.5 V)
S-8533A15AFT (IOUT : 10 mA) S-8533A15AFT (IOUT : 500 mA)
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
S-8533A33AFT (IOUT : 10 mA) S-8533A33AFT (IOUT : 500 mA)
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
S-8533A50AFT (IOUT : 10 mA) S-8533A50AFT (IOUT : 500 mA)
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
t (0.5 ms/div)
Output voltage
(0.1 V/div)
Input volta
g
e
10 V
(2.5 V/div)
0 V
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
22
Reference Data
Reference data are intended for use in selecting peripheral parts to the IC. The information therefore provides
characteristic data in which external parts are selected with a view of wide variety of IC applications. All data show typical
values.
1. External Parts for Reference Data
Table 4 External Parts List for Output Current vs. Efficiency Characteristics
No. Product Name
Output
Voltage Inductor Transistor
P-channel Transistor
N-channel Output
Capacitor Input
Capacitor Application Condition
(1) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(2) S-8533A15AFT 1.5 V Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(3) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(4) Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(5) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(6)
S-8533A33AFT 3.3 V
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(7) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(8) S-8533A50AFT 5.0 V
CDRH104R/22 μH
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(9) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(10) S-8533A15AFT 1.5 V Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(11) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(12) Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(13) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(14)
S-8533A33AFT 3.3 V
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(15) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(16) S-8533A50AFT 5.0 V
CDRH104R/47 μH
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(17) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(18) S-8533A15AFT 1.5 V Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(19) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(20) Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(21) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(22)
S-8533A33AFT 3.3 V
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(23) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(24) S-8533A50AFT 5.0 V
CDRH104R/10 μH
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(25) CPH6303 CPH6403 IOUT ≤ 3 A, VIN ≤ 8 V
(26) S-8533A33AFT 3.3 V CDRH125/10 μH CPH6302 CPH6402
47 μF × 2 47 μF, 0.1 μF
IOUT ≤ 3 A, VIN ≤ 16 V
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 23
External Parts List for Ripple Data
Table 5 External Parts for Input Voltage vs. Ripple Voltage Characteristics Data
No. Product Name
Output
Voltage Inductor Transistor
P-channel Transistor
N-channel Output
Capacitor Input
Capacitor Application Condition
(27) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(28) S-8533A15AFT 1.5 V Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(29) CPH6303 CPH6403 IOUT ≤ 2 A, VIN ≤ 8 V
(30) Si3441DV Si3442DV IOUT ≤ 1.4 A, VIN ≤ 6 V
(31) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(32)
S-8533A33AFT 3.3 V
Si3455DV Si3454DV IOUT ≤ 1.6 A, VIN ≤ 16 V
(33) CPH6302 CPH6402 IOUT ≤ 2 A, VIN ≤ 16 V
(34) S-8533A50AFT 5.0 V
CDRH104R/22 μH
Si3455DV Si3454DV
47 μF × 2 47 μF, 0.1 μF
IOUT ≤ 1.6 A, VIN ≤ 16 V
Performance Data for Parts
The following shows the performance of external parts.
Table 6 Performance of External Parts
Parts Product
Name Manufacturer Characteristics
L Value DC Resistance Maximum
Current Diameter Height
CDRH125 10 μH 0.019 Ω 4.0 A
12.0 mm typ.
12.3 mm max.
8.0 mm max.
47 μH 0.095 Ω 1.9 A
22 μH 0.054 Ω 2.5 A
Inductor
CDRH104R
Sumida
Corporation
10 μH 0.026 Ω 3.8 A
10.2 mm typ.
10.5 mm max.
4.0 mm max.
Diode MA737
Matsushita Electric
Industrial Co., Ltd Forward current 1.5 A (@VF = 0.5 V)
Output
Capacity F93 Nichicon
Corporation
CPH6303 VGS = 10 V max., ID = −4 A max., Vth = −0.4 V min.,
Ciss = 820 pF typ., RDS(ON) = 0.090 Ω max. (VGS = −4 V),
CPH6 package
CPH6302
Sanyo
Electric Co., Ltd VGS = 20 V max., ID = −3 A max., Vth = −1.0 V min.,
Ciss = 300 pF typ., RDS(ON) = 0.145 Ω max. (VGS = −10 V),
CPH6 package
Si3441DV VGS = 8 V max., ID = −3.3 A max., Vth = −0.45 V min.,
RDS(ON) = 0.10 Ω max. (VGS = −4.5 V), TSOP-6 package
External
transistor
(P-channel
FET)
Si3455DV
Vishay
Silliconix VGS = 20 V max., ID = −3.5 A max., Vth = −1.0 V min.,
RDS(ON) = 0.100 Ω max. (VGS = −10 V), TSOP-6 package
CPH6403 VGS = 10 V max., ID = 6 A max., Vth = 0.4 V min.,
Ciss = 700 pF typ., RDS(ON) = 0.038 Ω max. (VGS= 4 V),
CPH6 package
CPH6402
Sanyo
Electric Co., Ltd VGS = 24 V max., ID = 4 A max., Vth = 1.0 V min.,
Ciss = 240 pF typ., RDS(ON) = 0.75 Ω max. (VGS= 10 V),
CPH6 package
Si3442DV VGS = 8 V max., ID = 4.0 A max., Vth = 0.6 V min.,
RDS(ON) = 0.07 Ω max. (VGS = 4.5 V), TSOP-6 package
External
transistor
(N-channel
FET)
Si3454DV
Vishay
Silliconix VGS = 20 V max., ID = 4.2 A max., Vth = 1.0 V min.,
RDS(ON) = 0.065 Ω max. (VGS = 10 V), TSOP-6 package
Caution The value of each characteristic in Table 6 depends on the materials prepared by each manufacturer,
however, confirm the specifications by referring to respective materials when using any of the above.
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
24
2. Output Current (IOUT) vs. Efficiency (η) Characteristics
The following shows the actual output current (IOUT) vs. efficiency (η) characteristics when the S-8533 Series is used
under conditions (1) to (26) in Table 4.
(1) S-8533A15AFT (CPH6303/CPH6403) (2) S-8533A15AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 10 100 1000 10000
Output current (mA)
Efficiency η (%)
V
IN = 2.7 V
5.0 V
50
55
60
65
70
75
80
85
90
95
100
110 100 1000 10000
Output current (mA)
VIN
=
2.7 V
5.0 V
Efficiency η (%)
(3) S-8533A33AFT (CPH6303/CPH6403) (4) S-8533A33AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
Output current (mA)
10
V
IN = 4.0 V
4.95 V 7.0 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
Output current (mA)
10
VIN
=
4.0 V
4.95 V
Efficiency η (%)
(5) S-8533A33AFT (CPH6302/CPH6402) (6) S-8533A33AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 4.95 V
10 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
Output current
10
VIN
=
4.95 V
10 V
Efficiency η (%)
(7) S-8533A50AFT (CPH6302/CPH6402) (8) S-8533A50AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
10 Output current
VIN = 6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 25
(9) S-8533A15AFT (CPH6303/CPH6403) (10) S-8533A15AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 10 100 1000 10000
Output current (mA)
V IN
5.0 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
110 100 1000 10000
Output current (mA)
V IN
=
2.7 V
5.0 V
Efficiency η (%)
= 2.7 V
(11) S-8533A33AFT (CPH6303/CPH6403) (12) S-8533A33AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
Output current
10
V
IN = 4.0 V
4.95 V
7.0 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
100 1000 10000
Output current (mA)
101
VIN
=
4.0 V
4.95 V
Efficiency η (%)
(13) S-8533A33AFT (CPH6302/CPH6402) (14) S-8533A33AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 4.95 V
10 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
110 100 1000 10000
Output current (mA)
10 V
VIN
=
4.95 V
Efficiency η (%)
(15) S-8533A50AFT (CPH6302/CPH6402) (16) S-8533A50AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
Output current
10
V
IN = 6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
10 Output current
VIN
=
6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
26
(17) S-8533A15AFT (CPH6303/CPH6403) (18) S-8533A15AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
5.0 V
V
IN = 2.7 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
Output current
10
V
IN
=
2.7 V
5.0 V
Efficiency η (%)
(19) S-8533A33AFT (CPH6303/CPH6403) (20) S-8533A33AFT (Si3441DV/Si3442DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 4.0 V
4.95 V 7.0 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA) Output current
10
VIN
=
4.0 V
4.95 V
Efficiency η (%)
(21) S-8533A33AFT (CPH6302/CPH6402) (22) S-8533A33AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 4.95 V
10 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
10 Output current
10 V
VIN
=
4.95 V
Efficiency η (%)
(23) S-8533A50AFT (CPH6302/CPH6402) (24) S-8533A50AFT (Si3454DV/Si3455DV)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
10 Output current
V
IN = 6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
1100 1000 10000
(mA)
10 Output current
VIN
=
6.0 V
16 V
10 V
7.5 V
Efficiency η (%)
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0_00 S-8533 Series
Seiko Instruments Inc. 27
(25) S-8533A33AFT (CPH6303/CPH6403) (26) S-8533A33AFT (CPH6302/CPH6402)
50
55
60
65
70
75
80
85
90
95
100
1 100 1000 10000
(mA)
V
IN = 4.95 V
7.0 V
Output current
10
Efficiency η (%)
50
55
60
65
70
75
80
85
90
95
100
110 100 1000 10000
(mA)
Output current
13 V
VIN
=
10 V
Efficiency η (%)
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series Rev.3.0_00
Seiko Instruments Inc.
28
3. Output Current (IOUT) vs. Ripple Voltage (Vr) Characteristics
The following shows the actual output current (IOUT) vs. ripple voltage (Vr) characteristics when the S-8533 Series is
used under conditions (27) to (34) in Table 5.
(27) S-8533A15AFT (CPH6303/CPH6403) (28) S-8533A15AFT (Si3441DV/Si3442DV)
35
40
45
50
1 10 100 1000 10000
Output current (mA)
V
IN = 2.7 V 5.0 V
0
5
Ripple voltage Vr (mV)
30
15
20
25
10
0
20
25
30
35
40
45
50
110 100 1000 10000
Output current (mA)
Ripple voltage Vr( mV)
15
10
5
VIN
=
2.7 V 5.0 V
(29) S-8533A33AFT (CPH6303/CPH6403) (30) S-8533A33AFT (Si3441DV/Si3442DV)
0
35
40
45
50
110 100 1000 10000
Output current (mA)
5
10
15
20
25
30 VIN
=
4.0 V 4.95 V
Ripple voltage Vr( mV)
0
35
40
45
50
1 10 100 1000 10000
Output current (mA)
30
5
10
15
20
25 V
IN = 4.0 V 7.0 V
4.95 V
Ripple voltage Vr (mV)
(31) S-8533A33AFT (CPH6302/CPH6402) (32) S-8533A33AFT (Si3454DV/Si3455DV)
0
35
40
45
50
110 100 1000 10000
Output current (mA)
30
10
15
25
20
5
VIN
=
4.95 V 10 V
Ripple voltage Vr( mV)
1 10 100 1000 10000
Output current (mA)
0
5
30
35
40
45
50
10
15
25
20
V
IN = 4.95 V 10 V
Ripple voltage Vr (mV)
(33) S-8533A50AFT (CPH6302/CPH6402) (34) S-8533A50AFT (Si3454DV/Si3455DV)
0
5
50
110 100 1000 10000
Output current (mA)
10
15
20
25
30
35
40
45 VIN
=
6.0 V 16 V
7.5 V 10 V
Ripple voltage Vr( mV)
0
5
10
30
40
45
50
1 10 100 1000 10000
Output current (mA)
20
35
25
15
V
IN = 6.0 V 16 V
7.5 V 10 V
Ripple voltage Vr (mV)
No.
TITLE
SCALE
UNIT
Seiko Instruments Inc.
TSSOP8-E-PKG Dimensions
No. FT008-A-P-SD-1.1
FT008-A-P-SD-1.1
0.17±0.05
3.00 +0.3
-0.2
0.65
0.2±0.1
14
5
8
mm
No.
TITLE
SCALE
UNIT
Seiko Instruments Inc.
ø1.55±0.05
2.0±0.05
8.0±0.1 ø1.55 +0.1
-0.05
(4.4)
0.3±0.05
1
45
8
4.0±0.1
Feed direction
TSSOP8-E-Carrier Tape
No. FT008-E-C-SD-1.0
FT008-E-C-SD-1.0
+0.4
-0.2
6.6
mm
No.
TITLE
SCALE
UNIT
Seiko Instruments Inc.
Enlarged drawing in the central part
No. FT008-E-R-SD-1.0
2±0.5
ø13±0.5
ø21±0.8
13.4±1.0
17.5±1.0
3,000
QTY.
TSSOP8-E-Reel
FT008-E-R-SD-1.0
mm
No.
TITLE
SCALE
UNIT
Seiko Instruments Inc.
Enlarged drawing in the central part
2±0.5
ø13±0.5
ø21±0.8
13.4±1.0
17.5±1.0
4,000
QTY.
TSSOP8-E-Reel
FT008-E-R-S1-1.0
mm
No. FT008-E-R-S1-1.0