1
LT1638/LT1639
16389fd
APPLICATIO S
U
DESCRIPTIO
U
FEATURES
TYPICAL APPLICATIO
U
1.2MHz, 0.4V/μs
Over-The-Top Micropower
Rail-to-Rail Input and Output
Op Amps
■
Operates with Inputs Above V
+
■
Rail-to-Rail Input and Output
■
Low Power: 230
μ
A per Amplifier Max
■
Gain Bandwidth Product: 1.2MHz
■
Slew Rate: 0.4V/μs
■
High Output Current: 25mA Min
■
Specified on 3V, 5V and ±15V Supplies
■
Reverse Battery Protection to 18V
■
No Supply Sequencing Problems
■
High Voltage Gain: 1500V/mV
■
Single Supply Input Range: –0.4V to 44V
■
High CMRR: 98dB
■
No Phase Reversal
■
Available in 14-Lead SO, 8-Lead MSOP and DFN
Packages
■
Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
■
Supply Current Sensing
■
Battery Monitoring
■
Micropower Active Filters
■
4mA to 20mA Transmitters
V
CC
V
CC
V1
V2
V0
–
+A
1/2 LT1638
–
+B
1/2 LT1638
V
CC
1M
1M
1M
10k
10k
V
CC
= 5V, V
CM
= 0V TO 44V, t
PD
= 27μs
1638/39 TA01
1M
Over-The-Top
®
Comparator with
100mV Hysteresis Centered at 0mV
Output Voltage vs Input Voltage
5V
0V
The LT
®
1638 is a low power dual rail-to-rail input and output
operational amplifier available in the standard 8-pin PDIP and
SO packages as well as the 8-lead MSOP package. The
LT1639 is a low power quad rail-to-rail input and output
operational amplifier offered in the standard 14-pin PDIP and
surface mount packages. For space limited applications the
LT1638 is available in a 3mm x 3mm x 0.8mm dual fine pitch
leadless package (DFN).
The LT1638/LT1639 op amps operate on all single and
split supplies with a total voltage of 2.5V to 44V drawing
only 170μA of quiescent current per amplifier. These
amplifiers are reverse battery protected and draw no
current for reverse supply up to 18V.
The input range of the LT1638/LT1639 includes both
supplies, and a unique feature of this device is its capability
to operate over the top with either or both of its inputs
above V
+
. The inputs handle 44V, both differential and
common mode, independent of supply voltage. The input
stage incorporates phase reversal protection to prevent
false outputs from occurring when the inputs are below
the negative supply. Protective resistors are included in
the input leads so that current does not become excessive
when the inputs are forced below the negative supply. The
LT1638/LT1639 can drive loads up to 25mA and still
maintain rail-to-rail capability. The op amps are unity-gain
stable and drive all capacitive loads up to 1000pF when
optional output compensation is used.
1638/39 TA02
20mV/DIV
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Over-The-Top is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
2
LT1638/LT1639
16389fd
ABSOLUTE MAXIMUM RATINGS
W
WW
U
Specified Temperature Range (Note 4)
LT1638C/LT1639C ............................. – 40°C to 85°C
LT1638I/LT1639I................................ – 40°C to 85°C
LT1638H/LT1639H ........................... –40°C to 125°C
Junction Temperature........................................... 150°C
DD Package ...................................................... 125°C
Storage Temperature Range ................. –65°C to 150°C
DD Package ...................................... –65°C to 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Total Supply Voltage (V
+
to V
–
) .............................. 44V
Input Differential Voltage ......................................... 44V
Input Current ...................................................... ±25mA
Output Short-Circuit Duration (Note 2) .........Continuous
Operating Temperature Range (Note 3)
LT1638C/LT1639C ............................. – 40°C to 85°C
LT1638I/LT1639I................................ – 40°C to 85°C
LT1638H/LT1639H ........................... –40°C to 125°C
PACKAGE/ORDER INFORMATION
W
UU
ORDER
PART NUMBER
ORDER
PART NUMBER
LT1638CMS8
LT1638IMS8
LT1638CN8
LT1638IN8
LT1638CS8
LT1638IS8
LT1638HS8
MS8 PART
MARKING* S8 PART MARKING
1638
1638I
1638H
1
2
3
4
OUT A
–IN A
+IN A
V–
8
7
6
5
V+
OUT B
–IN B
+IN B
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
A
B
T
JMAX
= 150°C, θ
JA
= 300°C/W (MS8)
T
JMAX
= 150°C, θ
JA
= 150°C/W (N8)
T
JMAX
= 150°C, θ
JA
= 190°C/W (S8)
LTCY
(Note 1)
*The temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
TOP VIEW
S PACKAGE
14-LEAD PLASTIC SO
N PACKAGE
14-LEAD PDIP
1
2
3
4
5
6
7
14
13
12
11
10
9
8
A
BC
OUT A
–IN A
+IN A
V
+
+IN B
–IN B
OUT B
OUT D
–IN D
+IN D
V
–
+IN C
– IN C
OUT C
D
T
JMAX
= 150°C, θ
JA
= 130°C/W (N)
T
JMAX
= 150°C, θ
JA
= 160°C/W (S)
ORDER
PART NUMBER
LT1639CN
LT1639IN
LT1639CS
LT1639IS
LT1639HS
ORDER
PART NUMBER
LT1638CDD
LT1638IDD
T
JMAX
= 125°C, θ
JA
= 160°C/W (NOTE 10)
UNDERSIDE METAL INTERNALLY CONNECTED TO V
–
DD PART MARKING*
LAAL
TOP VIEW
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
5
6
7
8
4
3
2
1OUT A
–IN A
+IN A
V
–
V
+
OUT B
–IN B
+IN B
A
B
1
2
3
4
8
7
6
5
TOP VIEW
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
V+
OUT B
–IN B
+IN B
A
B
OUT A
–IN A
+IN A
V–
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
3
LT1638/LT1639
16389fd
LT1638C/LT1639C, LT1638I/LT1639I
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage LT1638 N, S Packages 200 600 μV
0°C ≤ T
A
≤ 70°C●850 μV
–40°C ≤ T
A
≤ 85°C●950 μV
LT1639 N, S Packages 300 700 μV
0°C ≤ T
A
≤ 70°C●950 μV
–40°C ≤ T
A
≤ 85°C●1050 μV
LT1638 MS8 Package 350 900 μV
0°C ≤ T
A
≤ 70°C●1150 μV
–40°C ≤ T
A
≤ 85°C●1450 μV
LT1638 DD Package 400 1100 μV
0°C ≤ T
A
≤ 70°C●1350 μV
–40°C ≤ T
A
≤ 85°C●1450 μV
Input Offset Voltage Drift LT1638/LT1639 N, S Packages ●26 μV/°C
(Note 9) LT1638MS8, LT1638DD ●2.5 7 μV/°C
I
OS
Input Offset Current ●16 nA
V
CM
= 44V (Note 5) ●2.5 μA
I
B
Input Bias Current ●20 50 nA
V
CM
= 44V (Note 5) ●830 μA
V
S
= 0V 0.1 nA
Input Noise Voltage 0.1Hz to 10Hz 1 μV
P-P
e
n
Input Noise Voltage Density f = 1kHz 20 nV/√Hz
i
n
Input Noise Current Density f = 1kHz 0.3 pA/√Hz
R
IN
Input Resistance Differential 1 2.5 MΩ
Common Mode, V
CM
= 0V to 44V 1.4 5.5 MΩ
C
IN
Input Capacitance 5pF
Input Voltage Range ●044V
CMRR Common Mode Rejection Ratio V
CM
= 0V to V
CC
– 1V ●88 98 dB
V
CM
= 0V to 44V (Note 8) ●80 88 dB
A
VOL
Large-Signal Voltage Gain V
S
= 3V, V
O
= 500mV to 2.5V, R
L
= 10k 200 1500 V/mV
0°C ≤ T
A
≤ 70°C●133 V/mV
–40°C ≤ T
A
≤ 85°C●100 V/mV
V
S
= 5V, V
O
= 500mV to 4.5V, R
L
= 10k 400 1500 V/mV
0°C ≤ T
A
≤ 70°C●250 V/mV
–40°C ≤ T
A
≤ 85°C●200 V/mV
V
OL
Output Voltage Swing Low V
S
= 3V, No Load ●38 mV
V
S
= 3V, I
SINK
= 5mA ●250 450 mV
V
S
= 5V, No Load ●38 mV
V
S
= 5V, I
SINK
= 10mA ●500 700 mV
V
OH
Output Voltage Swing High V
S
= 3V, No Load ●2.94 2.98 V
V
S
= 3V, I
SOURCE
= 5mA ●2.25 2.40 V
V
S
= 5V, No Load ●4.94 4.98 V
V
S
= 5V, I
SOURCE
= 10mA ●3.8 4.0 V
I
SC
Short-Circuit Current (Note 2) V
S
= 3V, Short to GND 10 15 mA
V
S
= 3V, Short to V
CC
15 25 mA
V
S
= 5V, Short to GND 15 20 mA
V
S
= 5V, Short to V
CC
15 25 mA
The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C.
VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply, unless otherwise noted. (Note 4)
ELECTRICAL CHARACTERISTICS
4
LT1638/LT1639
16389fd
LT1638C/LT1639C, LT1638I/LT1639I
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
PSRR Power Supply Rejection Ratio V
S
= 3V to 12.5V, V
CM
= V
O
= 1V ●90 100 dB
Reverse Supply Voltage I
S
= –100μA per Amplifier ●18 27 V
Minimum Operating Supply Voltage ●2.4 2.7 V
I
S
Supply Current per Amplifier 170 230 μA
(Note 6) ●275 μA
GBW Gain Bandwidth Product f = 5kHz 650 1075 kHz
(Note 5) 0°C ≤ T
A
≤ 70°C●550 kHz
–40°C ≤ T
A
≤ 85°C●500 kHz
SR Slew Rate A
V
= –1, R
L
= ∞0.210 0.38 V/μs
(Note 7) 0°C ≤ T
A
≤ 70°C●0.185 V/μs
–40°C ≤ T
A
≤ 85°C●0.170 V/μs
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C.
VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = half supply, unless otherwise noted. (Note 4)
LT1638C/LT1639C, LT1638I/LT1639I
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage LT1638 N, S Packages 250 800 μV
0°C ≤ T
A
≤ 70°C●1000 μV
–40°C ≤ T
A
≤ 85°C●1100 μV
LT1639 N, S Packages 350 900 μV
0°C ≤ T
A
≤ 70°C●1100 μV
–40°C ≤ T
A
≤ 85°C●1200 μV
LT1638 MS8 Package 400 1050 μV
0°C ≤ T
A
≤ 70°C●1250 μV
–40°C ≤ T
A
≤ 85°C●1550 μV
LT1638 DDPackage 450 1250 μV
0°C ≤ T
A
≤ 70°C●1450 μV
–40°C ≤ T
A
≤ 85°C●1550 μV
Input Offset Voltage Drift LT1638/LT1639 N, S Packages ●26 μV/°C
(Note 9) LT1638MS8, LT1638DD ●2.5 7 μV/°C
I
OS
Input Offset Current ●16 nA
I
B
Input Bias Current ●20 50 nA
Input Noise Voltage 0.1Hz to 10Hz 1 μV
P-P
e
n
Input Noise Voltage Density f = 1kHz 20 nV/√Hz
i
n
Input Noise Current Density f = 1kHz 0.3 pA/√Hz
R
IN
Input Resistance Differential 1 2.5 MΩ
Common Mode, V
CM
= –15V to 14V 500 MΩ
C
IN
Input Capacitance 4.5 pF
Input Voltage Range ●–15 29 V
CMRR Common Mode Rejection Ratio V
CM
= –15V to 29V ●80 88 dB
A
VOL
Large-Signal Voltage Gain V
O
= ±14V, R
L
= 10k 200 500 V/mV
0°C ≤ T
A
≤ 70°C●125 V/mV
–40°C ≤ T
A
≤ 85°C●100 V/mV
V
O
Output Voltage Swing No Load ●±14.9 ±14.95 V
I
OUT
= ±10mA ●±13.7 ±14.0 V
The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C.
VS =
±
15V, VCM = 0V, VOUT = 0V, unless otherwise noted. (Note 4)
5
LT1638/LT1639
16389fd
LT1638H/LT1639H
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage LT1638S8 200 650 μV
●3mV
LT1639S 300 750 μV
●3.2 mV
Input Offset Voltage Drift (Note 9) ●15 μV/°C
I
OS
Input Offset Current ●15 nA
V
CM
= 44V (Note 5) ●10 μA
I
B
Input Bias Current ●150 nA
V
CM
= 44V (Note 5) ●100 μA
Input Voltage Range ●0.3 44 V
CMRR Common Mode Rejection Ratio V
CM
= 0.3V to V
CC
– 1V ●76 dB
V
CM
= 0.3V to 44V ●72 dB
A
VOL
Large-Signal Voltage Gain V
S
= 3V, V
O
= 500mV to 2.5V, R
L
= 10k 200 1500 V/mV
●20 V/mV
V
S
= 5V, V
O
= 500mV to 4.5V, R
L
= 10k 400 1500 V/mV
●35 V/mV
V
OL
Output Voltage Swing Low No Load ●15 mV
I
SINK
= 5mA ●900 mV
V
S
= 5V, I
SINK
= 10mA ●1500 mV
V
OH
Output Voltage Swing High V
S
= 3V, No Load ●2.9 V
V
S
= 3V, I
SOURCE
= 5mA ●2V
V
S
= 5V, No Load ●4.9 V
V
S
= 5V, I
SOURCE
= 10mA ●3.5 V
PSRR Power Supply Rejection Ratio V
S
= 3V to 12.5V, V
CM
= V
O
= 1V ●80 dB
Minimum Supply Voltage ●2.7 V
Reverse Supply Voltage I
S
= –100μA●18 V
I
S
Supply Current 170 230 μA
(Note 6) ●450 μA
GBW Gain Bandwidth Product f = 5kHz 650 1075 kHz
(Note 5) ●350 kHz
SR Slew Rate A
V
= –1, R
L
= ∞0.21 0.38 V/μs
(Note 7) ●0.1 V/μs
The ● denotes the specifications which apply over the full operating temperature range of –40°C ≤ TA ≤ 125°C.
VS = 3V, 0V; VS = 5V, 0V; VCM = VOUT = Half Supply unless otherwise specified. (Note 4)
ELECTRICAL CHARACTERISTICS
LT1638C/LT1639C, LT1638I/LT1639I
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
SC
Short-Circuit Current (Note 2) Short to GND 25 40 mA
0°C ≤ T
A
≤ 70°C●20 mA
–40°C ≤ T
A
≤ 85°C●15 mA
PSRR Power Supply Rejection Ratio V
S
= ±1.5V to ±22V ●90 100 dB
I
S
Supply Current per Amplifier 205 280 μA
●350 μA
GBW Gain Bandwidth Product f = 5kHz 750 1200 kHz
0°C ≤ T
A
≤ 70°C●650 kHz
–40°C ≤ T
A
≤ 85°C●600 kHz
SR Slew Rate A
V
= –1, R
L
= ∞, V
O
= ±10V, 0.225 0.4 V/μs
0°C ≤ T
A
≤ 70°C●0.2 V/μs
–40°C ≤ T
A
≤ 85°C●0.18 V/μs
The ● denotes the specifications which apply over the specified temperature
range, otherwise specifications are at TA = 25°C. VS =
±
15V, VCM = 0V, VOUT = 0V, unless otherwise noted. (Note 4)
6
LT1638/LT1639
16389fd
Note 5: V
S
= 5V limits are guaranteed by correlation to V
S
= 3V and
V
S
= ±15V or V
S
= ±22V tests.
Note 6: V
S
= 3V limits are guaranteed by correlation to V
S
= 5V and
V
S
= ±15V or V
S
= ±22V tests.
Note 7: Guaranteed by correlation to slew rate at V
S
= ±15V, and GBW at
V
S
= 3V and V
S
= ±15V tests.
Note 8: This specification implies a typical input offset voltage of 2mV at
V
CM
= 44V and a maximum input offset voltage of 5mV at V
CM
= 44V.
Note 9: This parameter is not 100% tested.
Note 10: The θ
JA
specified for the DD package is with minimal PCB heat
spreading metal. Using expanded metal area on all layers of a board
reduces this value.
The ● denotes the specifications which apply over the full operating temperature range of –40°C ≤ TA≤125°C, otherwise
specifications are at TA = 25°C. VS = ±15V, VCM = 0V, VOUT = 0V, VSHDN = V– unless otherwise specified. (Note 4)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: A heat sink may be required to keep the junction temperature
below absolute maximum. This depends on the power supply voltage
and how many amplifiers are shorted.
Note 3: The LT1638C/LT1639C and LT1638I/LT1639I are guaranteed
functional over the operating temperature range of –40°C to 85°C. The
LT1638H/LT1639H are guaranteed functional over the operating
temperature range of – 40°C to 125°C.
Note 4:
The LT1638C/LT1639C are guaranteed to meet specified
performance from 0°C to 70°C and are designed, characterized and
expected to meet specified performance from –40°C to 85°C but not
tested or QA sampled at these temperatures. The LT1638I/LT1639I are
guaranteed to meet specified performance from –40°C to 85°C. The
LT1638H/LT1639H are guaranteed to meet specified performance from
–40°C to 125°C.
LT1638H/LT1639H
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage LT1638S8 250 850 μV
●3.4 mV
LT1639S 350 950 μV
●3.6 mV
Input Offset Voltage Drift (Note 9) ●15 μV/°C
I
OS
Input Offset Current ●25 nA
I
B
Input Bias Current ●250 nA
CMRR Common Mode Rejection Ratio V
CM
= –14.7V to 29V ●72 dB
A
VOL
Large-Signal Voltage Gain V
O
= ±14V, R
L
= 10k 200 500 V/mV
●15 V/mV
V
O
Output Voltage Swing No Load ●±14.8 V
I
OUT
= ±5mA ●±14 V
I
OUT
= ±10mA ●±13.4 V
PSRR Power Supply Rejection Ratio V
S
= ±1.5V to ±22V ●84 dB
Minimum Supply Voltage ●±1.35 V
I
S
Supply Current 205 280 μA
●550 μA
GBW Gain Bandwidth Product f = 5kHz 750 1200 kHz
●400 kHz
SR Slew Rate A
V
= –1, R
L
= ∞, V
O
= ±10V, 0.225 0.4 V/μs
Measure at V
O
= ±5V ●0.1 V/μs
ELECTRICAL CHARACTERISTICS
7
LT1638/LT1639
16389fd
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Minimum Supply Voltage
Input Bias Current vs
Common Mode Voltage
Output Saturation Voltage vs
Load Current (Output High)
0.1Hz to 10Hz Noise Voltage
Noise Voltage Density vs
Frequency
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT PER AMPLIFIER (μA)
10 20 25 45
1638/39 G01
300
280
260
240
220
200
180
160
140
120
100 515 30 35 40
TA = 125°C
TA = 25°C
TA = –55°C
Supply Current vs Supply Voltage
TOTAL SUPPLY VOLTAGE (V)
0
CHANGE IN INPUT OFFSET VOLTAGE (μV)
200
400
4
1638/39 G02
0
–200
100
300
–100
–300
–400 1235
T
A
=
125°CT
A
=
–55°C
T
A
=
25°C
COMMON MODE VOLTAGE (V)
4.0
INPUT BIAS CURRENT (nA)
10000
8000
6000
60
40
20
0
–20
–40
5.6
1638/39 G03
4.4 4.8 5.2 44
T
A
=
125°C
T
A
=
–55°C
T
A
=
25°C
V
S
= 5V, 0V
FREQUENCY (Hz)
1
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
10 100 1k
1638/39 G09
70
60
50
40
30
20
10
0
TIME (SEC)
013579
NOISE VOLTAGE (400nV/DIV)
2468
1638/39 G07
10
V
S
= ±2.5
FREQUENCY (Hz)
1
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
10 100 1k
1638/39 G08
INPUT NOISE CURRENT DENSITY (pA/√Hz)
SOURCING LOAD CURRENT (mA)
0.001
0.01
OUTPUT SATURATION VOLTAGE (V)
0.1
1
0.01 0.1 1 10
1638/39 G04
VS = ±2.5V
VOD = 30mV
TA = 125°C
TA = –55°C
TA = 25°C
SINKING LOAD CURRENT (mA)
0.001
0.001
OUTPUT SATURATION VOLTAGE (V)
0.1
0.01
1
0.01 0.1 1 10
1638/39 G05
VS = ±2.5V
VOD = 30mV
TA = 125°C
TA = –55°C
TA = 25°C
INPUT OVERDRIVE (mV)
10
OUTPUT SATURATION VOLTAGE (mV)
30
100
1638/39 G06
1
10
20 100
90
807060
50
40
0
VS = ±2.5V
NO LOAD
OUTPUT HIGH
OUTPUT LOW
Output Saturation Voltage vs
Input Overdrive
Output Saturation Voltage vs
Load Current (Output Low)
Input Noise Current Density
vs Frequency
8
LT1638/LT1639
16389fd
TYPICAL PERFORMANCE CHARACTERISTICS
UW
PSRR vs Frequency
Output Impedance vs Frequency
LOAD RESISTANCE (kΩ)
1
GAIN BANDWIDTH PRODUCT (kHz)
PHASE MARGIN (DEG)
1500
1400
1300
1200
1100
1000
900
800
10 100
1638/39 G17
60
50
40
30
20
10
0
–10
V
S
= ±2.5V
A
V
= –1
R
F
= R
G
= 100k
f = 1kHz
PHASE MARGIN
GAIN BANDWIDTH
PRODUCT
Gain and Phase Shift vs
Frequency
FREQUENCY (kHz)
1
10
GAIN (dB)
PHASE SHIFT (DEG)
20
30
40
50
10 100 1000
1638/39 G12
0
–10
–20
80
60
70
40
50
60
70
80
30
20
10
0
90
100
VS = ±2.5V
PHASE
GAIN
FREQUENCY (kHz)
POWER SUPPLY REJECTION RATIO (dB)
90
80
70
60
50
40
30
20
10
0
–10
1 10 100 1000
1638/39 G16
V
S
= ±2.5V
POSITIVE SUPPLY
NEGATIVE SUPPLY
TEMPERATURE (°C)
–50
SLEW RATE (V/μs)
050 75
1638/39 G14
–25 25 100 125
RISING, VS = ±15V
RISING, VS = ±2.5V
FALLING, VS = ±2.5V
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
FALLING, VS = ±15V
Slew Rate vs Temperature
Gain Bandwidth Product and
Phase Margin vs Supply Voltage
TOTAL SUPPLY VOLTAGE (V)
0
1000
GAIN BANDWIDTH PRODUCT (kHz)
1200
1500
10 20 25 45
1638/39 G15
1100
1400
1300
PHASE MARGIN (DEG)
10
30
60
20
50
40
515 30 35 40
PHASE MARGIN
GAIN BANDWIDTH
Gain Bandwidth Product and
Phase Margin vs Load Resistance
FREQUENCY (kHz)
COMMON MODE REJECTION RATIO (dB)
120
110
100
90
80
70
60
50
40
30
20
1 10 100 1000
1638/39 G18
V
S
= ±15V
CMRR vs Frequency
FREQUENCY (kHz)
0.1
CHANNEL SEPARATION (dB)
130
120
110
100
90
80
70
60
1 10 100
1638/39 G19
V
S
= ±15V
Channel Separation vs Frequency
FREQUENCY (kHz)
OUTPUT IMPEDANCE (Ω)
10k
1k
100
10
1
0.1
0.1 10 100 1000
1638/39 G20
1
A
V
= 1
A
V
= 100
A
V
= 10
V
S
= ±2.5V
TEMPERATURE (°C)
–50
GAIN BANDWIDTH PRODUCT (kHz)
1500
1400
1300
1200
1100
1000
900
800
050 75
1638/39 G13
–25 25 100 125
VS = ±15V
VS = ±2.5V
f = 1kHz
Gain Bandwidth Product vs
Temperature
9
LT1638/LT1639
16389fd
TYPICAL PERFORMANCE CHARACTERISTICS
UW
Settling Time to 0.1% vs
Output Step
Capacitive Load Handling,
Overshoot vs Capacitive Load
SETTLING TIME (μs)
0
–10
OUTPUT STEP (V)
–8
–4
–2
0
10
4
10 20 25
1638/39 G21
–6
6
8
2
515 30 35
AV = –1
AV = –1
AV = 1
AV = 1
VS = ±15V
Undistorted Output Swing
vs Frequency
Total Harmonic Distortion + Noise
vs Frequency
Total Harmonic Distortion + Noise
vs Load Resistance
Total Harmonic Distortion + Noise
vs Output Voltage
Open-Loop Gain Large-Signal Response Small-Signal Response
1638/39 G28 1638/39 G29V
S
= ±15V
A
V
= 1
V
S
= ±15V
A
V
= 1
C
L
= 15pF
OUTPUT VOLTAGE (5V/DIV)
CHANGE IN INPUT OFFSET VOLTAGE (50μV/DIV)
1638/39 G27
–10V–20V 0V 10V 20V
R
L
=
2k
V
S
=
±15V
R
L
=
10k
R
L
=
50k
CAPACITIVE LOAD (pF)
OVERSHOOT (%)
100
90
80
70
60
50
40
30
20
10
010 100 1000 10000
1638/39 G22
A
V
= 1
A
V
= 5
A
V
= 10
V
S
= 5V, 0V
V
CM
= 2.5V
I
SOURCE
= 150μA
FREQUENCY (kHz)
0.1
OUTPUT SWING (V
P-P
)
1 10 100
1638/39 G23
35
30
25
20
15
10
5
0
DISTORTION ≤ 1%
R
L
= 20k
V
S
= ±2.5V
V
S
= ±15V
FREQUENCY (Hz)
THD + NOISE (%)
0.01 1 10 100
1638/39 G24
0.1
10
1
0.1
0.01
0.001
VS = 3V, 0V
VOUT = 2VP-P
VCM = 1.2V
RL = 20k
AV = –1
AV = 1
LOAD RESISTANCE TO GROUND (kΩ)
0.01
THD + NOISE (%)
0.1
1
10
0.1 10 100
1638/39 G25
0.001
1
VS = 3V TOTAL
AV = 1
VIN = 2VP-P AT 1kHz
VS = ±1.5V
VIN = ±1V
VS = 3V, 0V
VIN = 0.5V TO 2.5V
VS = 3V, 0V
VIN = 0.2V TO 2.2V
OUTPUT VOLTAGE (V
P-P
)
THD + NOISE (%)
10
1
0.1
0.01
0.001
023
1638/39 G26
1
R
L
= 10k, f = 1kHz
V
CM
= HALF SUPPLY
A
V
= –1, V
S
= ±1.5V
A
V
= –1, V
S
= 3V, 0V
A
V
= 1, V
S
= ±1.5V
A
V
= 1, V
S
= 3V, 0V
10
LT1638/LT1639
16389fd
APPLICATIONS INFORMATION
WUUU
Supply Voltage
The positive supply pin of the LT1638/LT1639 should be
bypassed with a small capacitor (typically 0.1μF) within an
inch of the pin. When driving heavy loads an additional
4.7μF electrolytic capacitor should be used. When using
split supplies, the same is true for the negative supply pin.
The LT1638/LT1639 are protected against reverse battery
voltages up to 18V. In the event a reverse battery condition
occurs, the supply current is less than 1nA.
The LT1638/LT1639 can be shut down by removing V
+
. In
this condition the input bias current is less than 0.1nA,
even if the inputs are 44V above the negative supply.
At temperatures greater than 70°C, when operating the
LT1638/LT1639 on total supplies of 10V or more, the
supply must not be brought up faster than 1V/μs. Increas-
ing the bypass capacitor and/or adding a small resistor in
series with the supply will limit the rise time.
Inputs
The LT1638/LT1639 have two input stages, NPN and PNP
(see the Simplified Schematic), resulting in three distinct
operating regions as shown in the Input Bias Current vs
Common Mode typical performance curve.
For input voltages about 0.8V or more below V
+
, the PNP
input stage is active and the input bias current is typically
–20nA. When the input common mode voltage is within
0.5V of the positive rail, the NPN stage is operating and the
input bias current is typically 40nA. Increases in tempera-
ture will cause the voltage at which operation switches
from the PNP input stage to the NPN input stage to move
towards V
+
. The input offset voltage of the NPN stage is
untrimmed and is typically 600μV.
A Schottky diode in the collector of each NPN transistor
allow the LT1638/LT1639 to operate over the top, with
either or both of its inputs above V
+
. At about 0.3V above
V
+
the NPN input transistor is fully saturated and the input
bias current is typically 8μA at room temperature. The
input offset voltage is typically 2mV when operating above
V
+
. The LT1638/LT1639 will operate with its inputs 44V
above V
–
regardless of V
+
.
The inputs are protected against excursions of 2V below
V
–
by an internal 1k resistor in series with each input and
a diode from the input to the negative supply. If the inputs
can go more than 2V below V
–
, an additional external
resistor is required. A 10k resistor will protect the input
against excursions as much as 10V below V
–
. The input
stage of the LT1638/LT1639 incorporates phase reversal
protection to prevent the output from phase reversing for
inputs below V
–
. There are no clamping diodes between
the inputs and the maximum differential input voltage is
44V.
Output
The output of the LT1638/LT1639 can swing within 20mV
of the positive rail with no load, and within 3mV of the
negative rail with no load. When monitoring voltages
within 20mV of the positive rail or within 3mV of the
negative rail, gain should be taken to keep the output from
clipping. The LT1638/LT1639 are capable of sinking and
sourcing over 40mA on ±15V supplies; sourcing current
capability is reduced to 20mA at 5V total supplies as noted
in the electrical characteristics.
The LT1638/LT1639 are internally compensated to drive
at least 200pF of capacitance under any output loading
conditions. A 0.22μF capacitor in series with a 150Ω
resistor between the output and ground will compensate
these amplifiers for larger capacitive loads, up to 1000pF,
at all output currents.
Optional Output Compensation for
Capacitive Loads Greater than 200pF
–
+
LT1638
V
IN
1000pF
0.22μF
150Ω
Distortion
There are two main contributors of distortion in op amps:
output crossover distortion as the output transitions from
sourcing to sinking current and distortion caused by
11
LT1638/LT1639
16389fd
APPLICATIONS INFORMATION
WUUU
TYPICAL APPLICATIONS
U
With 1.2MHz bandwidth, Over-The-Top capability, re-
verse-battery protection and rail-to-rail input and output
features, the LT1638/LT1639 are ideal candidates for
general purpose applications.
The lowpass slope limiting filter in Figure 1 limits the
maximum dV/dT (not frequency) that it passes. When the
input signal differs from the output by one forward diode
drop, D1 or D2 will turn on. With a diode on, the voltage
across R2 will be constant and a fixed current, V
DIODE
/R2,
will flow through capacitor C1, charging it linearly instead
of exponentially. The maximum slope that the circuit will
pass is equal to V
DIODE
divided by (R2)(C1). No matter
how fast the input changes the output will never change
any faster than the dV/dT set by the diodes and (R2)(C).
nonlinear common mode rejection. If the op amp is oper-
ating inverting there is no common mode induced distor-
tion. If the op amp is operating in the PNP input stage
(input is not within 0.8V of V
+
), the CMRR is very good,
typically 98dB. When the LT1638 switches between input
stages there is significant nonlinearity in the CMRR. Lower
load resistance increases the output crossover distortion,
but has no effect on the input stage transition distortion.
For lowest distortion the LT1638/LT1639 should be oper-
ated single supply, with the output always sourcing
current and with the input voltage swing between ground
and (V
+
– 0.8V). See the Typical Performance Character-
istics curves.
Gain
The open-loop gain is almost independent of load when
the output is sourcing current. This optimizes perfor-
mance in single supply applications where the load is
returned to ground. The typical performance curve of
Open-Loop Gain for various loads shows the details.
V
OUT
V
IN
Response of Slope Limiting Filter
Figure 2. Lowpass Slope Limiting Filter with 0 TC
Figure 1. Lowpass Slope Limiting Filter
1638/39 TA02
A modification of this application is shown in Figure 2
using references instead of diodes to set the maximum
slope. By using references, the slope is independent of
temperature. A scope photo shows a 1V
P-P
, 2kHz input
signal with a 2V pulse added to the sine wave; the circuit
passes the 2kHz signal but limits the slope of the pulse.
–
+
1/2 LT1638
C1 V
OUT
1638/39 F01
R2
D2
D1
R1
V
IN
FOR R1 = 10k, R2 = 100k, C1 = 1000pF
V
OUT(MAX)
=
d
dt
V
D
(R2)(C1)
V
OUT(MAX)
= 0.006V/μs
d
dt
–
+
–
+
1/4 LT1639
–
+
1/4 LT1639
1/4 LT1639
D1 D2
V
CC
C1
V
OUT
V
EE
V
IN
R5
100k
R6
100k
1638/39 F02
LT1634-1.2V
R3
100k
R4
100k
R2
R1
1k
D3 D4
LT1634-1.2V
FOR R2 = 50k, C1 = 500pF,
MAXIMUM SLOPE = 0.048V/μs
V
OUT
=
d
dt
1.2V
(R2)(C1)
D1 TO D4 = IN4148
12
LT1638/LT1639
16389fd
TYPICAL APPLICATIONS
U
–
+
1/2 LT1638
5V
V+
200Ω
200Ω
0.2Ω
2k
0V TO 4.3V
1638/39 F03
VOUT = (2Ω)(ILOAD)
Q1
2N3904
LOAD ILOAD
Figure 4. Current Source
Figure 3. Positive Supply Rail Current Sense
SI PLIFIED SCHE ATIC
WW
Q10
D5
Q9
Q1
Q7
R2
1k
R3
1k
R4
8k
Q8
Q5
–IN
+IN
Q11 Q12
D4
ONE AMPLIFIER
D2
Q2
D1
Q6
Q13 Q14
R1
6k
R5
8k
Q4
10μA
+
Q15
Q19
D3
Q3
Q16 Q18
Q22
V+
Q17 Q20
Q21
OUT
V–
1638/39 SS
–
+
1/2 LT1638
R1
1.2V
R1
IOUT =
LT1634-1.2
IOUT
1638/39 F04
VCC VCC
The application in Figure 3 utilizes the Over-The-Top
capabilities of the LT1638. The 0.2Ω resistor senses the
load current while the op amp and NPN transistor form a
closed loop making the collector current of Q1
propor
tional to the load current. As a convenient monitor,
the 2k load resistor converts the current into a voltage. The
positive supply rail, V
+
, is not limited to the 5V supply of
the op amp and could be as high as 44V.
The Figure 4 application uses the LT1638 in conjunction
with the LT1634 micropower shunt reference. The supply
current of the op amp also biases the reference. The drop
across resistor R1 is fixed at 1.2V generating an output
current equal to 1.2V/R1.
13
LT1638/LT1639
16389fd
PACKAGE DESCRIPTION
U
MSOP (MS8) 0204
0.53 ± 0.152
(.021 ± .006)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.18
(.007)
0.254
(.010)
1.10
(.043)
MAX
0.22 – 0.38
(.009 – .015)
TYP
0.127 ± 0.076
(.005 ± .003)
0.86
(.034)
REF
0.65
(.0256)
BSC
0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
12
34
4.90 ± 0.152
(.193 ± .006)
8765
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
0.52
(.0205)
REF
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ± 0.127
(.035 ± .005)
RECOMMENDED SOLDER PAD LAYOUT
0.42 ± 0.038
(.0165 ± .0015)
TYP
0.65
(.0256)
BSC
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
3.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
0.38 ± 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.115
TYP
2.38 ±0.10
(2 SIDES)
14
85
PIN 1
TOP MARK
(NOTE 6)
0.200 REF
0.00 – 0.05
(DD) DFN 1203
0.25 ± 0.05
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 ±0.05
(2 SIDES)2.15 ±0.05
0.50
BSC
0.675 ±0.05
3.5 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
14
LT1638/LT1639
16389fd
PACKAGE DESCRIPTION
U
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0°– 8° TYP
.008 – .010
(0.203 – 0.254)
SO8 0303
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
1234
.150 – .157
(3.810 – 3.988)
NOTE 3
8765
.189 – .197
(4.801 – 5.004)
NOTE 3
.228 – .244
(5.791 – 6.197)
.245
MIN .160
±
.005
RECOMMENDED SOLDER PAD LAYOUT
.045
±
.005
.050 BSC
.030
±
.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE
MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL
NOT EXCEED .006" (0.15mm)
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
N8 1002
.065
(1.651)
TYP
.045 – .065
(1.143 – 1.651)
.130 ± .005
(3.302 ± 0.127)
.020
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
.120
(3.048)
MIN
12 34
87 65
.255 ± .015*
(6.477 ± 0.381)
.400*
(10.160)
MAX
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
15
LT1638/LT1639
16389fd
PACKAGE DESCRIPTION
U
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
1
N
234
.150 – .157
(3.810 – 3.988)
NOTE 3
14 13
.337 – .344
(8.560 – 8.738)
NOTE 3
.228 – .244
(5.791 – 6.197)
12 11 10 9
567
N/2
8
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0° – 8° TYP
.008 – .010
(0.203 – 0.254)
S14 0502
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
.245
MIN
N
123 N/2
.160 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
.050 BSC
.030 ±.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE
MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS
SHALL NOT EXCEED .006" (0.15mm)
S Package
14-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
N Package
14-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
N14 1103
.020
(0.508)
MIN
.120
(3.048)
MIN
.130 ± .005
(3.302 ± 0.127)
.045 – .065
(1.143 – 1.651)
.065
(1.651)
TYP
.018 ± .003
(0.457 ± 0.076)
.005
(0.127)
MIN
.255 ± .015*
(6.477 ± 0.381)
.770*
(19.558)
MAX
31 24567
8910
11
1213
14
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
()
NOTE:
1. DIMENSIONS ARE INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
16
LT1638/LT1639
16389fd
LT 0707 REV D • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 1998
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
TYPICAL APPLICATION
U
RA, 2k
Q2
2N3904
S1
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
RA = RB
VS = 5V, 0V
10k 90.9k
VOUT
LOGIC
1638/39 F05
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
RG
10k
Q1
2N3904
RS, 0.2Ω
CHARGER
VOLTAGE
RA', 2k
RB', 2k
RB, 2k
VBATT = 12V
IBATT
+
LOAD
VOUT
(RS)(RG/RA)(GAIN)
VOUT
GAIN
IBATT = = AMPS
–
+
A
1/4 LT1639
–
+
B
1/4 LT1639
–
+
C
1/4 LT1639
–
+
D
1/4 LT1639
Figure 5. Battery Monitor
PART NUMBER DESCRIPTION COMMENTS
LT1078/LT1079 Dual/Quad 55μA Max, Single Supply, Precision Op Amps Input/Output Common Mode Includes Ground, 70μV V
OS(MAX)
LT2078/LT2079 and 2.5μV/°C Drift (Max), 200kHz GBW, 0.07V/μs Slew Rate
LT1178/LT1179 Dual/Quad 17μA Max, Single Supply, Precison Op Amps Input/Output Common Mode Includes Ground, 70μV V
OS(MAX)
LT2178/LT2179 and 4μV/°C Drift (Max), 85kHz GBW, 0.04V/μs Slew Rate
LT1366/LT1367 Dual/Quad Precision, Rail-to-Rail Input and Output Op Amps 475μV V
OS(MAX)
, 500V/mV A
VOL(MIN)
, 400kHz GBW
LT1490/LT1491 Dual/Quad Over-The-Top Micropower, Rail-to-Rail Input and Single Supply Input Range: – 0.4V to 44V, Micropower 50μA
Output Op Amps per Amplifier, Rail-to-Rail Input and Output, 200kHz GBW
LT1636 Single Over-The-Top Micropower Rail-to-Rail Input and Output 55μA Supply Current, V
CM
Extends 44V above V
EE
,
Op Amp Independent of V
CC
; MSOP Package, Shutdown Function
RELATED PARTS
The battery monitor in Figure 5 also demonstrates the
LT1638’s ability to operate with its inputs above the
positive rail. In this application, a conventional amplifier
would be limited to a battery voltage between 5V and
ground, but the LT1638 can handle battery voltages as
high as 44V. When the battery is charging, Amp B senses
the voltage drop across RS. The output of Amp B causes
Q2 to drain sufficient current through RB to balance the
input of Amp B. Likewise, Amp A and Q1 form a closed
loop when the battery is discharging. The current through
Q1 or Q2 is proportional to the current in RS and this
current flows into RG and is converted into a voltage. Amp
D buffers and amplifies the voltage across RG. Amp C
compares the output of Amp A and Amp B to determine
the polarity of current through RS. The scale factor for
VOUT with S1 open is 1V/A. With S1 closed the scale factor
is 1V/100mA and currents as low as 500μA can be
measured.
