LT1490/LT1491
Dual and Quad
Micropower Rail-to-Rail
Input and Output Op Amps
FEATURES
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DESCRIPTION
The dual LT
®
1490 and quad LT1491 op amps operate on all
single and split supplies with a total voltage of 2V to 44V
drawing only 40µA of quiescent current per amplifier. These
amplifiers are reverse supply protected; they draw no current
for reverse supply up to 18V. The input range of the LT1490/
LT1491 includes both supplies and the output swings to both
supplies. Unlike most micropower op amps, the LT1490/
LT1491 can drive heavy loads; their rail-to-rail outputs drive
20mA. The LT1490/LT1491 are unity-gain stable and drive all
capacitive loads up to 10,000pF when optional 0.22µF and
150Ω compensation is used.
The LT1490/LT1491 have a unique input stage that oper-
ates and remains high impedance when above the positive
supply. The inputs take 44V both differential and common
mode even when operating on a 3V supply. Built-in resis-
tors protect the inputs for faults below the negative supply
up to 22V. There is no phase reversal of the output for inputs
22V below V
–
or 44V above V
–
, independent of V
+
.
The LT1490 dual op amp is available in the 8-pin SO and
PDIP packages. The quad LT1491 is available in the 14-pin
SO and PDIP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Rail-to-Rail Input and Output
Single Supply Input Range: – 0.4V to 44V
Micropower: 50µA/Amplifier Max
Specified on 3V, 5V and
±15V
Supplies
High Output Current: 20mA
Output Drives 10,000pF with Output Compensation
Reverse Battery Protection to 18V
No Supply Sequencing Problems
High Voltage Gain: 1500V/mV
High CMRR: 98dB
No Phase Reversal
Gain Bandwidth Product: 200kHz
APPLICATIONS
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s
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Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
Supply Current Sensing
Battery Monitoring
Micropower Active Filters
4mA to 20mA Transmitters
TYPICAL APPLICATION
CHARGER
VOLTAGE
R
S
0.2Ω
I
BATT
RA
2k
R
A
'
2k
Battery Monitor
Q1
2N3904
+
–
A
1/4 LT1491
–
C
1/4 LT1491
+
R
B
2k
R
B
'
2k
LOAD
+
–
Q2
2N3904
B
1/4 LT1491
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
+
V
BATT
= 12V
S1
R
G
10k
10k
D
1/4 LT1491
+
–
90.9k
I
BATT
=
V
OUT
V
=
OUT
AMPS
(R
S
)(R
G
/R
A
)(GAIN) GAIN
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
R
A
= R
B
V
S
= 5V, 0V
U
U
U
LOGIC
V
OUT
1490/91 TA01
1
LT1490/LT1491
ABSOLUTE
MAXIMUM
RATINGS
Total Supply Voltage (V
+
to V
–
) .............................. 44V
Input Differential Voltage ......................................... 44V
Input Current ......................................................
±25mA
Output Short-Circuit Duration (Note 1) ......... Continuous
Operating Temperature Range ................ – 40°C to 85°C
Junction Temperature ........................................... 150°C
Specified Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
OUT A
–IN A
+IN A
V
–
1
2
A
3
B
4
5
+IN B
6
–IN B
8
7
V
+
OUT B
ORDER PART
NUMBER
LT1490CMS8
LT1490CN8
LT1490CS8
MS8 PART MARKING
LTBB
S8 PART MARKING
1490
MS8 PACKAGE
N8 PACKAGE
8-LEAD MSOP
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 250°C/ W (MS8)
T
JMAX
= 150°C,
θ
JA
= 130°C/ W (N8)
T
JMAX
= 150°C,
θ
JA
= 190°C/ W (S8)
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
V
S
= 3V, 0V; V
S
= 5V, 0V; V
CM
= V
OUT
= half supply, T
A
= 25
°
C, unless otherwise noted. (Note 2)
CONDITIONS
LT1490 N Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
LT1490 S Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
LT1491 N Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
LT1490CMS8 Package, LT1491 S Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
0°C
≤
T
A
≤
70°C (Note 6)
V
CM
= 44V (Note 3)
MIN
q
q
I
OS
I
B
Input Offset Voltage Drift
Input Offset Current
Input Bias Current
V
CM
= 44V (Note 3)
V
S
= 0V
e
n
i
n
Input Noise Voltage
Input Noise Voltage Density
Input Noise Current Density
0.1Hz to 10Hz
f = 1kHz
f = 1kHz
2
U
U
W
W W
U
W
TOP VIEW
OUT A
–IN A
+IN A
V
+
1
2
3
4
5
6
7
B
C
A
D
14 OUT D
13 –IN D
12 +IN D
11 V
–
10 +IN C
9
8
– IN C
OUT C
ORDER PART
NUMBER
LT1491CN
LT1491CS
+IN B
–IN B
OUT B
N PACKAGE
S PACKAGE
14-LEAD PDIP 14-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 110°C/ W (N)
T
JMAX
= 150°C,
θ
JA
= 150°C/ W (S)
TYP
220
220
q
q
300
q
q
350
q
q
q
q
q
q
q
MAX
800
1000
1100
950
1200
1300
1100
1350
1450
1450
1650
1750
4
0.8
0.8
8
10
UNITS
µV
µV
µV
µV
µV
µV
µV
µV
µV
µV
µV
µV
µV/°C
nA
µA
nA
µA
nA
µV
P-P
nV/√Hz
pA/√Hz
2
0.2
4
4
0.1
1
50
0.03
LT1490/LT1491
ELECTRICAL CHARACTERISTICS
SYMBOL
R
IN
C
IN
CMRR
A
VOL
PARAMETER
Input Resistance
Input Capacitance
Input Voltage Range
Common Mode Rejection Ratio
(Note 3)
Large-Signal Voltage Gain
q
V
S
= 3V, 0V; V
S
= 5V, 0V; V
CM
= V
OUT
= half supply, T
A
= 25
°
C, unless otherwise noted. (Note 2)
CONDITIONS
Differential
Common Mode, V
CM
= 0V to 44V
MIN
6
4
0
84
80
200
133
100
400
250
200
TYP
17
11
4.6
98
98
1500
MAX
UNITS
MΩ
MΩ
pF
V
dB
dB
V/mV
V/mV
V/mV
V/mV
V/mV
V/mV
mV
mV
mV
mV
mV
V
V
V
V
mA
mA
mA
mA
dB
V
V
µA
µA
kHz
kHz
kHz
V/µs
V/µs
V/µs
44
V
CM
= 0V to V
CC
– 1V
V
CM
= 0V to 44V
V
S
= 3V, V
O
= 500mV to 2.5V, R
L
= 10k
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
V
S
= 5V, V
O
= 500mV to 4.5V, R
L
= 10k
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
V
S
= 3V, No Load
V
S
= 3V, I
SINK
= 5mA
V
S
= 5V, No Load
V
S
= 5V, I
SINK
= 5mA
V
S
= 5V, I
SINK
= 10mA
V
S
= 3V, No Load
V
S
= 3V, I
SOURCE
= 5mA
V
S
= 5V, No Load
V
S
= 5V, I
SOURCE
= 10mA
V
S
= 3V, Short to GND
V
S
= 3V, Short to V
CC
V
S
= 5V, Short to GND
V
S
= 5V, Short to V
CC
V
S
= 2.5V to 12.5V, V
CM
= V
O
= 1V
I
S
= – 100µA per Amplifier
q
q
q
q
q
q
q
q
q
q
q
q
q
q
1500
V
OL
Output Voltage Swing Low
V
OH
Output Voltage Swing High
I
SC
Short-Circuit Current (Note 1)
PSRR
Power Supply Rejection Ratio
Minimum Operating Supply Voltage
Reverse Supply Voltage
Supply Current per Amplifier
(Note 4)
Gain Bandwidth Product
(Note 3)
Slew Rate
(Note 5)
q
q
q
q
2.95
2.55
4.95
4.30
10
10
15
15
84
18
22
250
22
250
330
2.978
2.6
4.978
4.6
15
30
25
30
98
2
27
40
180
50
450
50
500
500
2.5
50
55
I
S
GBW
f = 1kHz
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
A
V
= – 1, R
L
=
∞
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
q
q
q
q
110
100
90
0.035
0.031
0.030
SR
0.06
V
S
=
±
15V, V
CM
= 0V, V
OUT
= 0V, T
A
= 25
°
C, unless otherwise noted. (Note 2)
SYMBOL
V
OS
PARAMETER
Input Offset Voltage
CONDITIONS
LT1490 N, S Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
LT1491 N Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
LT1490CMS8 Package, LT1491 S Package
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
MIN
q
q
TYP
250
MAX
1200
1400
1500
1250
1500
1600
1600
1850
1950
UNITS
µV
µV
µV
µV
µV
µV
µV
µV
µV
350
q
q
400
q
q
3
LT1490/LT1491
ELECTRICAL CHARACTERISTICS
SYMBOL
I
OS
I
B
e
n
i
n
R
IN
C
IN
CMRR
A
VOL
PARAMETER
Input Offset Voltage Drift
Input Offset Current
Input Bias Current
Input Noise Voltage
Input Noise Voltage Density
Input Noise Current Density
Input Resistance
Input Capacitance
Input Voltage Range
Common Mode Rejection Ratio
Large-Signal Voltage Gain
V
CM
= – 15V to 29V
V
O
=
±14V,
R
L
= 10k
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
No Load
I
OUT
=
±5mA
I
OUT
=
±10mA
Short to GND
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
V
S
=
±1.25V
to
±22V
q
q
q
q
q
q
V
S
=
±
15V, V
CM
= 0V, V
OUT
= 0V, T
A
= 25
°
C, unless otherwise noted. (Note 2)
CONDITIONS
0°C
≤
T
A
≤
70°C (Note 6)
q
q
q
MIN
TYP
3
0.2
4
1
50
0.03
17
15000
4.6
MAX
6
0.8
8
UNITS
µV/°C
nA
nA
µV
P-P
nV/√Hz
pA/√Hz
MΩ
MΩ
pF
0.1Hz to 10Hz
f = 1kHz
f = 1kHz
Differential
Common Mode, V
CM
= – 15V to 14V
6
– 15
80
100
75
50
±14.9
±14.5
±14.5
±20
±15
±10
88
98
250
29
V
dB
V/mV
V/mV
V/mV
V
V
V
mA
mA
mA
dB
V
O
Output Voltage Swing
±14.978
±14.750
±14.670
±25
I
SC
Short-Circuit Current (Note 1)
q
q
q
q
PSRR
I
S
GBW
Power Supply Rejection Ratio
Supply Current per Amplifier
Gain Bandwidth Product
98
50
70
85
µA
µA
kHz
kHz
kHz
V/µs
V/µs
V/µs
f = 1kHz
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
A
V
= – 1, R
L
=
∞,
V
O
=
±10V,
Measure at V
O
=
±5V
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
q
q
125
110
100
0.0375
200
SR
Slew Rate
0.07
q
q
0.0330
0.0300
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
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 2:
The LT1490/LT1491 are designed, characterized and expected
to meet these extended temperature limits, but are not tested at – 40°C
and 85°C. Guaranteed I grade parts are available, consult factory.
Note 3:
V
S
= 5V limits are guaranteed by correlation to V
S
= 3V and
V
S
=
±15V
tests.
Note 4:
V
S
= 3V limits are guaranteed by correlation to V
S
= 5V and
V
S
=
±15V
tests.
Note 5:
Guaranteed by correlation to slew rate at V
S
=
±15V
and GBW
at V
S
= 3V and V
S
=
±15V
tests.
Note 6:
This parameter is not 100% tested.
4
LT1490/LT1491
TYPICAL PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
80
CHANGE IN INPUT OFFSET VOLTAGE (µV)
SUPPLY CURRENT PER AMPLIFIER (µA)
70
60
50
40
30
20
10
0
0
5
10 15 20 25 30 35 40
TOTAL SUPPLY VOLTAGE (V)
45
T
A
= 125°C
T
A
= 25°C
200
100
0
–100
–200
–300
T
A
= 125°C
0
1
3
4
2
TOTAL SUPPLY VOLTAGE (V)
5
1490/91 G02
INPUT BIAS CURRENT (nA)
T
A
= –55°C
Output Saturation Voltage
vs Load Current (Output High)
1
OUTPUT SATURATION VOLTAGE (V)
OUTPUT SATURATION VOLTAGE (mV)
OUTPUT SATURATION VOLTAGE (V)
V
S
=
±
2.5V
V
OD
= 30mV
T
A
= 125°C
0.1
T
A
= 25°C
T
A
= – 55°C
0.01
0.001
0.01
0.1
1
SOURCING LOAD CURRENT (mA)
0.1Hz to 10Hz Noise Voltage
INPUT NOISE VOLTAGE DENSITY (nV/√Hz)
V
S
=
±2.5V
80
INPUT NOISE CURRENT DENSITY (pA/√Hz)
NOISE VOLTAGE (400nV/DIV)
0
1
2
3
4 5 6
TIME (SEC)
7
U W
1490/91 G01
Minimum Supply Voltage
400
300
6000
4000
2000
Input Bias Current
vs Common Mode Voltage
V
S
= 5V, 0V
T
A
= 25°C
T
A
= –55°C
30
20
10
0
–10
4.0
T
A
= –55°C
T
A
= 25°C
T
A
= 125°C
4.4
5.2
5.6
4.8
COMMON MODE VOLTAGE (V)
44
1490/91 G03
– 400
Output Saturation Voltage
vs Load Current (Output Low)
1
V
S
=
±
2.5V
V
OD
= 30mV
Output Saturation Voltage
vs Input Overdrive
100
90
80
70
60
50
40
30
20
10
0
0
OUTPUT LOW
10 20 30 40 50 60 70 80 90 100
INPUT OVERDRIVE (mV)
1490/91 G06
V
S
=
±
2.5V
NO LOAD
T
A
= 125°C
0.1
T
A
= 25°C
T
A
= – 55°C
OUTPUT HIGH
10
0.01
0.001
0.01
0.1
1
SINKING LOAD CURRENT (mA)
10
1490/90 G05
1490/90 G04
Noise Voltage Density
vs Frequency
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
1
10
100
FREQUENCY (Hz)
1k
1490/91 G08
Input Noise Current vs Frequency
70
60
50
40
30
8
9
10
1
10
100
FREQUENCY (Hz)
1k
1490/91 G09
1490 G07
5
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