Dual Switching Diode
MAXIMUM RATINGS (TA = 25°C)
Rating Symbol Max Unit
Reverse Voltage VR70 Vdc
Forward Current IF200 mAdc
Peak Forward Surge Current IFM(surge) 500 mAdc
THERMAL CHARACTERISTICS
Characteristic Symbol Max Unit
Total Device Dissipation FR–5 Board(1)
TA = 25°C
Derate above 25°C
PD200
1.6
mW
mW/°C
Thermal Resistance, Junction to Ambient RJA 0.625 °C/W
Total Device Dissipation
Alumina Substrate(2) TA = 25°C
Derate above 25°C
PD300
2.4
mW
mW/°C
Thermal Resistance, Junction to Ambient RJA 417 °C/W
Junction and Storage Temperature TJ, Tstg –55 to +150 °C
DEVICE MARKING
BAW56WT1 = A1
ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted)
Characteristic Symbol Min Max Unit
OFF CHARACTERISTICS
Reverse Breakdown Voltage
(I(BR) = 100 µAdc) V(BR) 70 — Vdc
Reverse Voltage Leakage Current
(VR = 25 Vdc, TJ = 150°C)
(VR = 70 Vdc)
(VR = 70 Vdc, TJ = 150°C)
IR—
—
—
30
2.5
50
µAdc
Diode Capacitance
(VR = 0, f = 1.0 MHz) CD— 2.0 pF
Forward Voltage
(IF = 1.0 mAdc)
(IF = 10 mAdc)
(IF = 60 mAdc)
(IF = 150 mAdc)
VF—
—
—
—
715
855
1000
1250
mVdc
Reverse Recovery Time
(IF = IR = 10 mAdc, RL = 100 Ω, IR(REC) = 1.0 mAdc) (Figure 1) trr — 6.0 ns
1. FR–5 = 1.0 0.75 0.062 in.
2. Alumina = 0.4 0.3 0.024 in. 99.5% alumina.
Preferred devices are ON Semiconductor recommended choices for future use and best overall value.
ON Semiconductor
Semiconductor Components Industries, LLC, 2001
March, 2001 – Rev. 1 1Publication Order Number:
BAW56WT1/D
BAW56WT1
ON Semiconductor Preferred Device
CASE 419–04, STYLE 4
SC–70/SOT–323
12
3
3
ANODE
CATHODE
1
2
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Notes: 1. A 2.0 kΩ variable resistor adjusted for a Forward Current (IF) of 10 mA.
Notes: 2. Input pulse is adjusted so IR(peak) is equal to 10 mA.
Notes: 3. tp » trr
+10 V 2.0 k
820 Ω
0.1 µF
DUT
VR
100 µH
0.1 µF
50 Ω OUTPUT
PULSE
GENERATOR
50 Ω INPUT
SAMPLING
OSCILLOSCOPE
trtpt
10%
90%
IF
IR
trr t
iR(REC) = 1.0 mA
OUTPUT PULSE
(IF = IR = 10 mA; MEASURED
at iR(REC) = 1.0 mA)
IF
INPUT SIGNAL
Figure 1. Recovery Time Equivalent Test Circuit
100
0.2 0.4
VF, FORWARD VOLTAGE (VOLTS)
0.6 0.8 1.0 1.2
10
1.0
0.1
TA = 85°C
10
0
VR, REVERSE VOLTAGE (VOLTS)
1.0
0.1
0.01
0.001
10 20 30 40 50
1.75
0
VR, REVERSE VOLTAGE (VOLTS)
1.5
1.25
1.0
0.75
CD, DIODE CAPACITANCE (pF)
246 8
IF, FORWARD CURRENT (mA)
Figure 2. Forward Voltage Figure 3. Leakage Current
Figure 4. Capacitance
TA = -40°C
TA = 25°C
TA = 150°C
TA = 125°C
TA = 85°C
TA = 55°C
TA = 25°C
IR, REVERSE CURRENT (µA)
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MINIMUM RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONS
Surface mount board layout is a critical portion of the total
design. The footprint for the semiconductor packages must
be the correct size to insure proper solder connection
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
mm
inches
0.035
0.9
0.075
0.7
1.9
0.028
0.65
0.025
0.65
0.025
SC-70/SOT-323 POWER DISSIPATION
The power dissipation of the SC-70/SOT-323 is a function
of the collector pad size. This can vary from the minimum
pad size for soldering to the pad size given for maximum
power dissipation. Power dissipation for a surface mount
device is determined by TJ(max), the maximum rated
junction temperature of the die, RθJA, the thermal resistance
from the device junction to ambient; and the operating
temperature, TA. Using the values provided on the data
sheet, PD can be calculated as
follows.
PD = TJ(max) – TA
RθJA
The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values into
the equation for an ambient temperature TA of 25°C, one can
calculate the power dissipation of the device which in this
case is 200
milliwatts.
PD = 150°C – 25°C
0.625°C/W = 200 milliwatts
The 0.625°C/W assumes the use of the recommended
footprint on a glass epoxy printed circuit board to achieve a
power dissipation of 200 milliwatts. Another alternative
would be to use a ceramic substrate or an aluminum core
board such as Thermal Clad. Using a board material such
as Thermal Clad, a power dissipation of 300 milliwatts can
be achieved using the same footprint.
SOLDERING PRECAUTIONS
The melting temperature of solder is higher than the rated
temperature of the device. When the entire device is heated
to a high temperature, failure to complete soldering within
a short time could result in device failure. Therefore, the
following items should always be observed in order to
minimize the thermal stress to which the devices are
subjected.
•Always preheat the device.
•The delta temperature between the preheat and
soldering should be 100°C or less.*
•When preheating and soldering, the temperature of the
leads and the case must not exceed the maximum
temperature ratings as shown on the data sheet. When
using infrared heating with the reflow soldering
method, the difference should be a maximum of 10°C.
•The soldering temperature and time should not exceed
260°C for more than 10 seconds.
•When shifting from preheating to soldering, the
maximum temperature gradient should be 5°C or less.
•After soldering has been completed, the device should
be allowed to cool naturally for at least three minutes.
Gradual cooling should be used as the use of forced
cooling will increase the temperature gradient and
result in latent failure due to mechanical stress.
•Mechanical stress or shock should not be applied
during cooling
* Soldering a device without preheating can cause
excessive thermal shock and stress which can result in
damage to the device.
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SOLDER STENCIL GUIDELINES
Prior to placing surface mount components onto a printed
circuit board, solder paste must be applied to the pads. A
solder stencil is required to screen the optimum amount of
solder paste onto the footprint. The stencil is made of brass
or stainless steel with a typical thickness of 0.008 inches.
The stencil opening size for the surface mounted package
should be the same as the pad size on the printed circuit
board, i.e., a 1:1 registration.
TYPICAL SOLDER HEATING PROFILE
For any given circuit board, there will be a group of
control settings that will give the desired heat pattern. The
operator must set temperatures for several heating zones,
and a figure for belt speed. Taken together, these control
settings make up a heating “profile” for that particular
circuit board. On machines controlled by a computer, the
computer remembers these profiles from one operating
session to the next. Figure 5 shows a typical heating profile
for use when soldering a surface mount device to a printed
circuit board. This profile will vary among soldering
systems b u t i t i s a good starting point. Factors that can a ffect
the profile include the type of soldering system in use,
density and types of components on the board, type of solder
used, and the type of board or substrate material being used.
This profile shows temperature versus time. The line on the
graph shows the actual temperature that might be
experienced o n the surface of a test board at or near a central
solder joint. The two profiles are based on a high density an d
a low density board. The Vitronics SMD310
convection/infrared reflow soldering system was used to
generate this profile. The type of solder used was 62/36/2
Tin Lead Silver with a melting point between 177–189°C.
When this type of furnace is used for solder reflow work, the
circuit boards and solder joints tend to heat first. The
components o n the board are then heated by conduction. The
circuit board, because it has a lar ge surface area, absorbs the
thermal ener gy more ef ficiently, then distributes this ener gy
to the components. Because of this effect, the main body of
a component may be up to 30 degrees cooler than the
adjacent solder joints.
STEP 1
PREHEAT
ZONE 1
RAMP"
STEP 2
VENT
SOAK"
STEP 3
HEATING
ZONES 2 & 5
RAMP"
STEP 4
HEATING
ZONES 3 & 6
SOAK"
STEP 5
HEATING
ZONES 4 & 7
SPIKE"
STEP 6
VENT
STEP 7
COOLING
200°C
150°C
100°C
50°C
TIME (3 TO 7 MINUTES TOTAL) TMAX
SOLDER IS LIQUID FOR
40 TO 80 SECONDS
(DEPENDING ON
MASS OF ASSEMBLY)
205° TO 219°C
PEAK AT
SOLDER JOINT
DESIRED CURVE FOR LOW
MASS ASSEMBLIES
100°C
150°C
160°C
140°C
Figure 5. Typical Solder Heating Profile
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
170°C
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PACKAGE DIMENSIONS
CASE 419–04
ISSUE L
SC–70 (SOT–323)
CN
AL
D
G
SB
H
J
K
3
12
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.071 0.087 1.80 2.20
B0.045 0.053 1.15 1.35
C0.032 0.040 0.80 1.00
D0.012 0.016 0.30 0.40
G0.047 0.055 1.20 1.40
H0.000 0.004 0.00 0.10
J0.004 0.010 0.10 0.25
K0.017 REF 0.425 REF
L0.026 BSC 0.650 BSC
N0.028 REF 0.700 REF
S0.079 0.095 2.00 2.40
0.05 (0.002)
STYLE 4:
PIN 1. CATHODE
2. CATHODE
3. ANODE
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Notes
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Notes
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without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular
purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability,
including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or
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BAW56WT1/D
Thermal Clad is a trademark of the Bergquist Company
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