LINER LT1789IS8-10

LT1789-1/LT1789-10
Micropower,
Single Supply Rail-to-Rail
Output Instrumentation Amplifiers
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FEATURES
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DESCRIPTIO
The LT ®1789-1/LT1789-10 are micropower, precision instrumentation amplifiers that are optimized for single supply
operation from 2.2V to 36V. The quiescent current is 95µA
max, the inputs common mode to ground and the output
swings within 110mV of ground. The gain is set with a single
external resistor for a gain range of 1 to 1000 for the LT17891 and 10 to 1000 for the LT1789-10.
The high accuracy of the LT1789-1 (40ppm maximum
nonlinearity and 0.25% max gain error) is unmatched by
other micropower instrumentation amplifiers. The LT1789-10
maximizes both the input common mode range and dynamic
output range when an amplification of 10 or greater is
required, allowing precise signal processing where other
instrumentation amplifiers fail to operate. The LT1789-1/
LT1789-10 are laser trimmed for very low input offset
voltage, low input offset voltage drift, high CMRR and high
PSRR. The output can handle capacitive loads up to 400pF
(LT1789-1), 1000pF (LT1789-10) in any gain configuration
while the inputs are ESD protected up to 10kV (human body).
The LT1789-1/LT1789-10 are offered in the 8-pin SO package, requiring significantly less PC board area than discrete
multi op amp and resistor designs.
Micropower: 95µA Supply Current Max
Low Input Offset Voltage: 100µV Max
Low Input Offset Voltage Drift: 0.5µV/°C Max
Single Gain Set Resistor:
G = 1 to 1000 (LT1789-1)
G = 10 to 1000 (LT1789-10)
Inputs Common Mode to V –
Wide Supply Range: 2.2V to 36V Total Supply
CMRR at G = 10: 96dB Min
Gain Error: G = 10, 0.25% Max
Gain Nonlinearity: G = 10, 40ppm Max
Input Bias Current: 40nA Max
PSRR at G = 10: 100dB Min
1kHz Voltage Noise: 48nV/√Hz
0.1Hz to 10Hz Noise: 1.5µVP-P
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APPLICATIO S
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Portable Instrumentation
Bridge Amplifiers
Strain Gauge Amplifiers
Thermocouple Amplifiers
Differential to Single-Ended Converters
Medical Instrumentation
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATIO
0.5A to 4A Voltage Controlled Current Source
C1
4700pF
R1
90.9k
VIN
R2
10k
VS
C3
0.1µF
VS
2
3
–
+
7
VS = 3.3V TO 32V
VIN
RSENSE • 10
= 1A PER VOLT AS SHOWN
ILOAD =
RISE TIME ≈ 250µs, 10% TO 90%,
1A TO 2A OUTPUT STEP INTO 0.25Ω LOAD
TIP127*
7
C2
3300pF
* ENSURE ADEQUATE POWER
DISSIPATION CAPABILITY AT
HIGHER VOLTAGES,
CURRENTS AND DUTY CYCLES
VS
5
4
R4
10k
120Ω
R3
100Ω
6
LT1636
8k
+
3
3
8
6
1
LT1789-1
REF
2
1
5
–
4
RSENSE*
0.1Ω ILOAD
4
2
RLOAD*
1789 TA01
1789f
1
LT1789-1/LT1789-10
W W
W
AXI U
U
ABSOLUTE
RATI GS
U
U
W
PACKAGE/ORDER I FOR ATIO
(Note 1)
Supply Voltage (V+ to V–) ........................................ 36V
Input Differential Voltage ......................................... 36V
Input Current (Note 3) ........................................ ±20mA
Output Short-Circuit Duration .......................... Indefinite
Operating Temperature Range ................ – 40°C to 85°C
Specified Temperature Range (Note 4)
LT1789C-1, LT1789C-10 .................... – 40°C to 85°C
LT1789I-1, LT1789I-10 ...................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
TOP VIEW
RG 1
8 RG
–IN 2
7 +VS
+IN 3
6 OUT
–VS 4
5 REF
LT1789CS8-1
LT1789IS8-1
LT1789CS8-10
LT1789IS8-10
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
17891
1789I1
178910
789I10
TJMAX = 150°C, θJA = 190°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
3V and 5V ELECTRICAL CHARACTERISTICS
VS = 3V, 0V; VS = 5V, 0V; R L = 20k, VCM = VREF = half supply, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
G
LT1789-1, G = 1 + (200k/RG)
LT1789-10, G = 10 • [1+ (200k/RG)]
Gain Range
Gain Error (Note 6)
Gain Nonlinearity (Note 6)
MIN
LT1789-1
TYP
MAX
1
MIN
LT1789-10
TYP
MAX
UNITS
1000
10
G = 1, VO = 0.1V to (+VS) – 1V
0.02
0.20
LT1789-1, VO = 0.1V to (+VS) – 0.3V
LT1789-10, VO = 0.2V to (+VS) – 0.3V
G = 10, (Note 2)
G = 100, (Note 2)
G = 1000, (Note 2)
0.06
0.06
0.13
0.25
0.27
G = 1, VO = 0.1V to (+VS) – 1V
35
100
LT1789-1, VO = 0.1V to (+VS) – 0.3V
LT1789-10, VO = 0.2V to 4.7V, VS = 5V
(Note 8)
G = 10
G = 100
G = 1000
12
18
90
40
75
1000
%
0.01
0.09
0.16
0.25
0.30
%
%
%
ppm
15
20
100
100
100
ppm
ppm
ppm
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
15
100
20
160
µV
VOSO
Output Offset Voltage
G = 1 (LT1789-1), G =10 (LT1789-10)
150
750
650
3000
µV
IOS
Input Offset Current
(Note 6)
0.2
4
0.2
4
nA
IB
Input Bias Current
(Note 6)
19
40
19
40
nA
en
Input Noise Voltage,
RTI (Referred to Input)
G = 1, fO = 0.1Hz to 10Hz
G = 10
G = 100, 1000
5.0
1.5
1.0
4.6
1.1
µVP-P
µVP-P
µVP-P
1789f
2
LT1789-1/LT1789-10
3V and 5V ELECTRICAL CHARACTERISTICS
VS = 3V, 0V; VS = 5V, 0V; R L = 20k, VCM = VREF = half supply, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
LT1789-1
TYP
MAX
MIN
LT1789-10
TYP
MAX
UNITS
Total RTI Noise = √eni2 + (eno/G)2
eni
Input Noise Voltage Density,
RTI
fO = 1kHz (Note 7)
48
eno
Output Noise Voltage Density,
RTI
fO = 1kHz (Note 3)
330
270
nV/√Hz
in
Input Noise Current
fO = 0.1Hz to 10Hz
16
16
pAP-P
Input Noise Current Density
fO = 1kHz
62
62
fA/√Hz
RIN
Input Resistance
VIN = 0V to (+VS) – 1V (Note 6)
1.6
GΩ
CIN
Input Capacitance
Differential
Common Mode
1.6
1.6
pF
pF
VCM
Input Voltage Range
CMRR
Common Mode Rejection Ratio 1k Source Imbalance, (Note 6)
LT1789-1,VCM = 0V to (+VS)–1V
LT1789-10, VCM = 0V to (+VS)–1.2V
G=1
G = 10
G = 100
G = 1000
PSRR
Power Supply Rejection Ratio
0.75
1.6
Minimum Supply Voltage
52
0.75
1.6
1.6
0
VS = 2.5V to 12.5V, VCM = VREF = 1V
G=1
G = 10
G = 100
G = 1000
85
+VS – 1
0
90
+VS – 1.2
nV/√Hz
V
79
96
100
100
88
106
114
114
88
98
98
105
113
113
dB
dB
dB
dB
90
100
102
102
100
113
116
116
94
102
102
109
120
120
dB
dB
dB
dB
2.2
2.5
2.2
2.5
V
IS
Supply Current
(Note 7)
67
95
67
95
µA
VOL
Output Voltage Swing LOW
(Note 7)
54
100
62
110
mV
VOH
Output Voltage Swing HIGH
(Note 7)
ISC
Short-Circuit Current
Short to GND
Short to +VS
2.2
8.5
BW
Bandwidth
G=1
G = 10
G = 100
G = 1000
60
30
3
0.2
25
12
1.5
kHz
kHz
kHz
kHz
0.023
0.062
V/µs
240
190
µs
220
220
kΩ
2.7
2.7
µA
1 ±0.0001
1 ±0.0001
SR
Slew Rate
G = 10, VOUT = 0.5V to 4.5V
Settling Time to 0.01%
4V Step
RREFIN
Reference Input Resistance
IREFIN
Reference Input Current
AVREF
Reference Gain to Output
VREF = 0V
+VS – 0.3 +VS – 0.19
+VS – 0.3 +VS – 0.19
2.2
8.5
V
mA
mA
1789f
3
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of
0°C ≤ TA ≤ 70°C. VS = 3V, 0V; VS = 5V, 0V; R L = 20k, VREF = half supply, unless otherwise noted. (Note 4)
SYMBOL PARAMETER
Gain Error (Note 6)
Gain Nonlinearity (Note 6)
CONDITIONS
MIN
LT1789-1
TYP
MAX
G = 1, VO = 0.3V to (+VS) – 1V
●
0.25
VO = 0.3V to (+VS) – 0.5V
G = 10 (Note 2)
G = 100 (Note 2)
●
●
0.53
0.55
G = 1, VO = 0.3V to (+VS) – 1V
●
185
LT1789-1, VO = 0.3V to (+VS) – 0.5V
LT1789-10, VO = 0.3V to 4.7V, VS = 5V
(Note 8)
G = 10
G = 100
●
●
90
120
G < 1000 (Notes 2, 3)
●
LT1789-10
TYP
MAX
0.30
0.53
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
●
VOSIH
Input Offset Voltage Hysteresis
(Notes 3, 5)
●
VOSO
Output Offset Voltage
G = 1 (LT1789-1), G = 10 (LT1789-10)
●
VOSOH
Output Offset Voltage Hysteresis
(Notes 3, 5)
●
50
100
300
VOSI/T
Input Offset Voltage Drift (RTI)
(Note 3)
●
0.2
0.5
0.3
VOSO/T
Output Offset Voltage Drift
(Note 3)
●
1.5
4
7
IOS
Input Offset Current
(Note 6)
●
IOS/T
Input Offset Current Drift
IB
Input Bias Current
IB/T
Input Bias Current Drift
VCM
Input Voltage Range
CMRR
Common Mode Rejection Ratio
Power Supply Rejection Ratio
50
5
150
10
3
950
4.5
3
●
(Note 6)
ppm
ppm
50
ppm/°C
190
µV
10
µV
3700
µV
900
µV
0.7
µV/°C
20
µV/°C
4.5
nA
pA/°C
45
50
●
130
130
3
45
●
50
pA/°C
●
0.2
77
94
98
85
96
dB
dB
dB
VS = 2.5V to 12.5V, VCM = VREF = 1V
G=1
G = 10
G = 100, 1000
88
98
100
92
100
dB
dB
dB
Minimum Supply Voltage
●
2.5
0.2
nA
1k Source Imbalance, (Note 6)
LT1789-1, VCM = 0.2V to (+VS) – 1V
LT1789-10, VCM = 0.2V to (+VS) – 1.5V
●
G=1
G = 10
●
G = 100, 1000
●
●
●
●
(+VS) – 1
%
%
ppm
Gain vs Temperature
3
UNITS
%
G/T
PSRR
5
MIN
(+VS) – 1.5
2.5
V
V
IS
Supply Current
(Note 7)
●
115
115
µA
VOL
Output Voltage Swing LOW
(Note 7)
●
110
120
mV
VOH
Output Voltage Swing HIGH
(Note 7)
●
+VS – 0.38
+VS – 0.38
V
1789f
4
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range
of –40°C ≤ TA ≤ 85°C. VS = 3V, 0V; VS = 5V, 0V; R L = 20k, VREF = half supply, unless otherwise noted. (Note 4)
SYMBOL PARAMETER
Gain Error (Note 6)
Gain Nonlinearity (Note 6)
CONDITIONS
MIN
LT1789-1
TYP
MAX
G = 1, VO = + 0.3V to (+VS) – 1V
●
0.30
VO = 0.3V to (+VS) – 0.5V
G = 10 (Note 2)
G = 100 (Note 2)
●
●
0.57
0.59
G = 1, VO = 0.3V to (+VS) – 1V
●
250
LT1789-1, VO = 0.3V to (+VS) – 0.5V
LT1789-10, VO = 0.3V to 4.7V, VS = 5V
(Note 8)
G = 10
G = 100
●
●
105
160
G < 1000 (Notes 2, 3)
●
LT1789-10
TYP
MAX
0.35
0.62
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
●
VOSIH
Input Offset Voltage Hysteresis
(Notes 3, 5)
●
VOSO
Output Offset Voltage
G = 1 (LT1789-1), G = 10 (LT1789-10)
●
VOSOH
Output Offset Voltage Hysteresis
(Notes 3, 5)
●
50
100
300
VOSI/T
Input Offset Voltage Drift (RTI)
(Note 3)
●
0.2
0.5
VOSO/T
Output Offset Voltage Drift
(Note 3)
●
1.5
4
IOS
Input Offset Current
(Note 6)
●
IOS/T
Input Offset Current Drift
IB
Input Bias Current
IB/T
Input Bias Current Drift
VCM
Input Voltage Range
CMRR
Common Mode Rejection Ratio
Power Supply Rejection Ratio
50
5
10
ppm/°C
µV
4000
µV
900
µV
0.3
0.7
µV/°C
7
20
µV/°C
5
nA
3
50
pA/°C
50
50
●
50
µV
5
3
ppm
ppm
10
3
1050
●
150
170
205
175
●
(Note 6)
50
0.2
nA
pA/°C
●
0.2
1k Source Imbalance, (Note 6)
LT1789-1 VCM = 0.2V to (+VS) – 1V
LT1789-10 VCM = 0.2V to (+VS) – 1.5V
G=1
G = 10
G = 100, 1000
●
●
●
75
92
96
84
94
dB
dB
dB
VS = 2.5V to 12.5V, VCM = VREF = 1V
G=1
G = 10
G = 100, 1000
●
●
●
86
96
98
90
98
dB
dB
dB
Minimum Supply Voltage
+VS – 1
%
%
ppm
Gain vs Temperature
3
UNITS
%
G/T
PSRR
5
MIN
+VS – 1.5
V
●
2.5
2.5
V
IS
Supply Current
(Note 7)
●
125
125
µA
VOL
Output Voltage Swing LOW
(Note 7)
●
120
130
mV
VOH
Output Voltage Swing HIGH
(Note 7)
● +VS – 0.40
+VS – 0.40
V
1789f
5
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
VS = ±15V, R L = 20k, VCM = VOUT = 0V, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
G
LT1789-1, G = 1 + (200k/RG)
LT1789-10, G = 10 • [1 + (200k/RG)]
Gain Range
Gain Error
Gain Nonlinearity
MIN
LT1789-1
TYP
MAX
1
MIN
LT1789-10
TYP
MAX
1000
10
VO = ±10V
G=1
G = 10 (Note 2)
G = 100 (Note 2)
G = 1000 (Note 2)
VO = ±10V
G=1
G = 10
G = 100
G = 1000
UNITS
1000
0.01
0.04
0.04
0.07
0.10
0.15
0.15
0.20
0.01
0.03
0.03
0.15
0.20
0.25
%
%
%
%
8
1
6
20
20
10
20
100
5
5
25
40
40
160
ppm
ppm
ppm
ppm
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
30
235
30
295
µV
VOSO
Output Offset Voltage
G = 1 (LT1789-1), G = 10 (LT1789-10)
200
1
0.6
3.3
mV
IOS
Input Offset Current
0.2
4
0.2
4
nA
IB
Input Bias Current
17
40
17
40
nA
en
Input Noise Voltage, RTI
fO = 0.1Hz to 10Hz
G=1
G = 10
G = 100, 1000
5.0
1.5
1.0
fO = 1kHz
49
µVP-P
µVP-P
µVP-P
4.6
1.1
Total RTI Noise = √eni2 + (eno/G)2
eni
Input Noise Voltage Density, RTI
eno
Output Noise Voltage Density, RTI fO = 1kHz
Input Noise Current
fO = 0.1Hz to 10Hz
330
19
19
pAP-P
Input Noise Current Density
100
62
pA/√Hz
4.7
GΩ
20
17
pF
pF
in
RIN
Input Resistance
CIN
Input Capacitance
VCM
Input Voltage Range
CMRR
Common Mode Rejection Ratio
PSRR
Power Supply Rejection Ratio
fO = 1kHz
2
Differential
Common Mode
Supply Current
VO
Output Voltage Swing
ISC
Short-Circuit Current
53
2
20
17
–15
95
270
4.7
14
–15
nV/√Hz
nV/√Hz
14
V
1k Source Imbalance, VCM = –15V to 14V
G=1
G = 10
G = 100, 1000
80
98
102
89
108
117
93
102
108
123
dB
dB
dB
LT1789-1, VS = ±1.25V to ±16V
LT1789-10, VS = ±1.50V to ±16V
G=1
G = 10
G = 100, 1000
94
104
106
107
118
121
100
106
115
129
dB
dB
dB
±1.25
Minimum Supply Voltage
IS
90
85
±14.5
Short to – VS
Short to + VS
±14.7
2.2
8.5
130
85
±14.5
±14.7
2.2
8.5
±1.50
V
130
µA
V
mA
mA
1789f
6
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
VS = ±15V, R L = 20k, VCM = VOUT = 0V, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
BW
G=1
G = 10
G = 100
G = 1000
SR
Bandwidth
Slew Rate
VOUT = ±10V
Settling Time to 0.01%
10V Step
RREFIN
Reference Input Resistance
IREFIN
Reference Input Current
AVREF
Reference Gain to Output
MIN
LT1789-1
TYP
MAX
MIN
LT1789-10
TYP
MAX
60
30
3
0.2
0.012
0.026
0.028
UNITS
25
12
1.5
kHz
kHz
kHz
kHz
0.066
V/µs
460
270
µs
220
220
kΩ
2.7
2.7
µA
1 ±0.0001
1 ±0.0001
VREF = 0
The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C. VS = ±15V, R L = 20k, VCM = VREF = 0V,
unless otherwise noted. (Note 4)
SYMBOL PARAMETER
Gain Error
Gain Nonlinearity
CONDITIONS
MIN
LT1789-1
TYP
MAX
MIN
LT1789-10
TYP
MAX
UNITS
VO = ±10V
G=1
G = 10 (Note 2)
G = 100 (Note 2)
G = 1000 (Note 2)
●
●
●
●
0.15
0.38
0.38
0.43
0.20
0.43
0.48
%
%
%
%
VO = ±10V
G=1
G = 10
G = 100
G = 1000
●
●
●
●
25
15
25
120
45
45
180
ppm
ppm
ppm
ppm
G < 1000 (Notes 2, 3)
●
50
ppm/°C
325
µV
8
30
µV
G/T
Gain vs Temperature
5
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
●
VOSIH
Input Offset Voltage Hysteresis
(Notes 3, 5)
●
VOSO
Output Offset Voltage
G=1
●
VOSOH
Output Offset Voltage Hysteresis
(Notes 3, 5)
VOSI/T
Input Offset Voltage Drift (RTI)
VOSO/T
Output Offset Voltage Drift
IOS
Input Offset Current
●
IOS/T
Input Offset Current Drift
●
IB
Input Bias Current
●
IB/T
Input Bias Current Drift
●
VCM
Input Voltage Range
G = 1, Other Input Grounded
●
–14.8
CMRR
Common Mode Rejection Ratio
1k Source Imbalance,
VCM = –14.8V to 14V
G=1
G = 10
G = 100, 1000
●
●
●
78
96
100
50
5
285
8
30
4
mV
●
50
120
400
1000
µV
(Note 3)
●
0.2
0.7
0.3
0.8
µV/°C
(Note 3)
●
1.5
5
8
22
µV/°C
4.5
nA
1.2
4.5
2
2
45
pA/°C
45
35
35
14
–14.8
91
100
nA
pA/°C
14
V
dB
dB
dB
1789f
7
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of
0°C ≤ TA ≤ 70°C. VS = ±15V, R L = 20k, VCM = VREF = 0V, unless otherwise noted. (Note 4)
SYMBOL PARAMETER
CONDITIONS
PSRR
LT1789-1, VS = ±1.25V to ±16V
LT1789-10, VS = ±1.50V to ±16V
G=1
G = 10
G = 100, 1000
Power Supply Rejection Ratio
MIN
●
●
●
LT1789-1
TYP
MAX
92
102
104
MIN
LT1789-10
TYP
MAX
UNITS
dB
dB
dB
98
104
Minimum Supply Voltage
●
±1.25
IS
Supply Current
●
150
VO
Output Voltage Swing
● ±14.25
±14.25
V
SR
Slew Rate
0.010
0.026
V/µs
VOUT = ±10V
●
±1.50
V
150
µA
The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C. VS = ±15V, R L = 20k, VCM = VREF = 0V,
unless otherwise noted. (Note 4)
SYMBOL PARAMETER
Gain Error
Gain Nonlinearity
CONDITIONS
MIN
LT1789-1
TYP
MAX
MIN
LT1789-10
TYP
MAX
UNITS
VO = ±10V
G=1
G = 10 (Note 2)
G = 100 (Note 2)
G = 1000 (Note 2)
●
●
●
●
0.20
0.57
0.57
0.62
0.25
0.62
0.67
%
%
%
%
VO = ±10V
G=1
G = 10
G = 100
G = 1000
●
●
●
●
30
20
30
130
50
50
200
ppm
ppm
ppm
ppm
G < 1000 (Notes 2, 3)
●
50
ppm/°C
G/T
Gain vs Temperature
5
50
5
VOST
Total Input Referred Offset Voltage VOST = VOSI + VOSO/G
VOSI
Input Offset Voltage
G = 1000
●
VOSIH
Input Offset Voltage Hysteresis
(Notes 3, 5)
●
VOSO
Output Offset Voltage
G=1
●
VOSOH
Output Offset Voltage Hysteresis
(Notes 3, 5)
●
50
120
400
1000
VOSI/T
Input Offset Voltage Drift (RTI)
(Note 3)
●
0.2
0.7
0.3
0.8
µV/°C
VOSO/T
Output Offset Voltage Drift
(Note 3)
●
1.5
5
8
22
µV/°C
IOS
Input Offset Current
●
5
nA
IOS/T
Input Offset Current Drift
●
IB
Input Bias Current
●
IB/T
Input Bias Current Drift
●
VCM
Input Voltage Range
G = 1, Other Input Grounded
● –14.8
CMRR
Common Mode Rejection Ratio
1k Source Imbalance,
VCM = –14.8V to 14V
G=1
G = 10
G = 100, 1000
●
●
●
305
8
30
8
1.3
5
2
µV
30
µV
4.2
mV
2
50
35
14
–14.8
89
98
µV
pA/°C
50
35
76
94
98
340
nA
pA/°C
14
V
dB
dB
dB
1789f
8
LT1789-1/LT1789-10
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the temperature range of
–40°C ≤ TA ≤ 85°C. VS = ±15V, R L = 20k, VCM = VREF = 0V, unless otherwise noted. (Note 4)
SYMBOL PARAMETER
CONDITIONS
PSRR
LT1789-1, VS = ±1.25V to ±16V
LT1789-10, VS = ±1.50V to ±16V
G=1
G = 10
G = 100, 1000
Power Supply Rejection Ratio
IS
●
●
●
V
Supply Current
●
160
160
µA
VOUT = ±10V
● ±14.15
±14.15
V
0.008
0.024
V/µs
●
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Does not include the effect of the external gain resistor RG.
Note 3: This parameter is not 100% tested.
Note 4: The LT1789C-1/ LT1789C-10 is guaranteed to meet specified
performance from 0°C to 70°C and is designed, characterized and
expected to meet these extended temperature limits, but is not tested at
–40°C and 85°C. The LT1789I-1/ LT1789I-10 is guaranteed to meet the
extended temperature limits.
Note 5: Hysteresis in offset voltage is created by package stress that
differs depending on whether the IC was previously at a higher or lower
temperature. Offset voltage hysteresis is always measured at 25°C, but
the IC is cycled to 85°C I-grade (or 70°C C-grade) or – 40°C I-grade
(0°C C-grade) before successive measurement. 60% of the parts will
pass the typical limit on the data sheet.
Note 6: VS = 5V limits are guaranteed by correlation to VS = 3V and
VS = ±15V tests.
Note 7: VS = 3V limits are guaranteed by correlation to VS = 5V and
VS = ±15V tests.
Note 8: This parameter is not tested at VS = 3V on the LT1789-10 due to
an increase in sensitivity to test system noise. Actual performance is
expected to be similar to performance at VS = 5V.
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(LT1789-1, LT1789-10)
Input Bias Current
vs Temperature
Supply Current vs Supply Voltage
0
INPUT BIAS CURRENT (nA)
125°C
90
80
25°C
–55°C
50
40
Input Bias Current
vs Common Mode Input Voltage
–10
VS = 5V, 0V
VCM = 2.5V
–12
–5
INPUT BIAS CURRENT (nA)
120
110
SUPPLY CURRENT (µA)
dB
dB
dB
96
102
±1.50
Output Voltage Swing
–10
–15
–20
30
20
5
10 15 20 25 30 35
TOTAL SUPPLY VOLTAGE (V)
40
1789 G01
–25
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
1789 G02
–55°C
–14
–16
125°C
–18
25°C
–20
85°C
–22
–24
–26
–28
0
UNITS
±1.25
Slew Rate
60
90
100
102
LT1789-10
TYP
MAX
●
SR
70
MIN
Minimum Supply Voltage
VO
100
LT1789-1
TYP
MAX
MIN
VS = 5V, 0V
VREF = 2.5V
–30
–0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
COMMON MODE INPUT VOLTAGE (V)
1789 G03
1789f
9
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Output Voltage Swing
vs Load Current
Slew Rate vs Temperature
Gain vs Frequency
80
1.6
4.4
25°C
1.4
4.2
1.2
VS = 5V, 0V
VREF = 2.5V
4.0
1.0
125°C
0.8
25°C
0.6
0.4
SINK
–55°C
0.2
60
0.1
1
0.01
OUTPUT CURRENT (mA)
G = 1000
50
40
G = 100
30
20
G = 10
10
0
G=1
1k
10k
FREQUENCY (Hz)
100k
VS = 5V, 0V
VREF = 2.5V
G = 10
G = 100, 1000
G=1
80
70
60
50
40
10
100
1k
FREQUENCY (Hz)
10k 20k
NEGATIVE POWER SUPPLY REJECTION RATIO (dB)
COMMON MODE REJECTION RATIO (dB)
120
90
140
120
G = 1000
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
G = 100
100
G = 10
80
G=1
60
40
20
0
10
100
1k
FREQUENCY (Hz)
10k 20k
1879 G07
80
140
G=1
80
60
40
20
0
10
100
1k
FREQUENCY (Hz)
AV = 1
VS = ±15V
RL = 20k
G=1
2
0
–2
–4
–8
AV ≥ 100
10
100
CAPACITIVE LOAD (pF)
4
–6
AV = 10
1
10k 20k
1789 G09
6
40
0
1789 G10
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
G = 10
100
8
50
10
100k
G = 100, 1000
120
10
60
30
125
Settling Time to 0.01% vs Output
Step
70
20
1k
10k
FREQUENCY (Hz)
100
Positive Power Supply Rejection
Ratio vs Frequency
OUTPUT STEP (V)
1k
10
75
50
25
TEMPERATURE (°C)
0
1789 G06
VS = 5V, 0V
VREF = 2.5V
VOUT = 100mVP-P
90
OVERSHOOT (%)
OUTPUT IMPEDANCE (Ω)
100
VS = 5V, 0V
VREF = 2.5V
1
100
0.010
– 50 – 25
Overshoot vs Capacitive Load
100
FALLING
1789 G08
Output Impedance vs Frequency
10k
0.025
Negative Power Supply Rejection
Ratio vs Frequency
Common Mode Rejection Ratio
vs Frequency
100
RISING
0.030
1789 G05
1789 G04
110
0.035
0.015
–20
100
10
VS = 5V, 0V
0.045 VREF = 2.5V
G=1
0.040 RL = 20k
0.020
–10
0
0.001
VS = 5V, 0V
VREF = 2.5V
70
POSITIVE POWER SUPPLY REJECTION RATIO (dB)
SOURCE
0.050
SLEW RATE (V/µs)
125°C
4.6
OUTPUT VOLTAGE SWING—SINKING (V)
–55°C
4.8
GAIN (dB)
5.0
OUTPUT VOLTAGE SWING—SOURCING (V)
(LT1789-1)
1000
1789 G11
–10
0
100
300
400
200
SETTLING TIME (µs)
500
1789 G12
1789f
10
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Voltage Noise Density vs
Frequency
Current Noise Density vs
Frequency
1000
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
CURRENT NOISE DENSITY (fA/√Hz)
VOLTAGE NOISE DENSITY (nV/√Hz)
1000
G=1
G = 10
100
G = 100, 1000
10
10
100
FREQUENCY (Hz)
1
(LT1789-1)
VS = 5V, 0V
VREF = 2.5V
100
RS
LT1789-1
10
1k
10
100
FREQUENCY (Hz)
1
1k
1789 G13
1789 G14
0.1Hz to 10Hz Noise Voltage,
RTI, G = 1000
0.1Hz to 10Hz Noise Voltage,
G=1
0.1Hz to 10Hz Noise Current
VS = 5V, 0V
VREF = 2.5V
VS = 5V, 0V
VREF = 2.5V
1
2
3
4 5 6
TIME (SEC)
7
8
0
9 10
1
3
2
4 5 6
TIME (SEC)
7
8
9 10
1789 G16
1789 G15
0
1
2
3
4 5 6
TIME (SEC)
7
8
9 10
1789 G17
Turn-On Characteristics
1.5
CHANGE IN OUTPUT VOLTAGE (V)
0
NOISE CURRENT (5pA/DIV)
NOISE VOLTAGE (2µV/DIV)
NOISE VOLTAGE (0.5µV/DIV)
VS = 5V, 0V
VREF = 2.5V
VS = 5V, 0V
VREF = 2.5V
VCM = 2.5V
G = 1000
TA = 25°C
0.5
–0.5
–1.5
0
10
20
30
40
TIME (ms)
1789 G18
1789f
11
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Output Voltage Swing
vs Load Current
1.6
25°C
1.4
4.2
1.2
VS = 5V, 0V
VREF = 2.5V
4.0
1.0
125°C
0.8
25°C
0.6
0.4
SINK
–55°C
0.2
0.1
1
0.01
OUTPUT CURRENT (mA)
40
G = 100
30
20
G = 10
10
100
VS = 5V, 0V
VREF = 2.5V
90
80
70
60
50
40
100
1k
FREQUENCY (Hz)
–20
100
1k
10k
FREQUENCY (Hz)
10k 20k
140
G = 1000
120
100
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
G = 100
80
G = 10
60
40
20
0
10
90
80
100
1k
FREQUENCY (Hz)
10k 20k
140
G = 100, 1000
120
G = 10
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
100
80
60
40
20
0
10
100
1k
FREQUENCY (Hz)
10
6
50
40
0
10
VS = ±15V
RL = 20k
G = 10
8
30
G = 1000
4
2
0
–2
–4
–6
G = 100
–8
G = 10
–10
100
CAPACITIVE LOAD (pF)
10k 20k
1789 G26
VS = 5V, 0V
VREF = 2.5V
VOUT = 100mVP-P
60
10
1789 G27
125
Settling Time to 0.01% vs
Output Step
70
20
100k
100
Positive Power Supply Rejection
Ratio vs Frequency
OUTPUT STEP (V)
1k
OVERSHOOT (%)
OUTPUT IMPEDANCE (Ω)
100
1k
10k
FREQUENCY (Hz)
75
50
1789 G25
VS = 5V, 0V
VREF = 2.5V
10
25
TEMPERATURE (°C)
Overshoot vs Capacitive Load
100
0
1789 G23
Output Impedance vs Frequency
1
100
0.04
–50 –25
100k
1789 G22
1789 G24
10k
FALLING
0.07
Negative Power Supply Rejection
Ratio vs Frequency
G = 10
10
0.08
0.05
–10
10
NEGATIVE POWER SUPPLY REJECTION RATIO (dB)
COMMON MODE REJECTION RATIO (dB)
110
0.09
0.06
Common Mode Rejection Ratio
vs Frequency
G = 100, 1000
RISING
0
1789 G21
120
0.11
0.10
50
0
0.001
G = 1000
POSITIVE POWER SUPPLY REJECTION RATIO (dB)
SOURCE
60
SLEW RATE (V/µs)
125°C
0.12
VS = 5V, 0V
VREF = 2.5V
70
GAIN (dB)
–55°C
OUTPUT VOLTAGE SWING—SINKING (V)
OUTPUT VOLTAGE SWING—SOURCING (V)
80
4.8
4.4
Slew Rate vs Temperature
Gain vs Frequency
5.0
4.6
(LT1789-10)
1000
1789 G28
0
100
300
400
200
SETTLING TIME (µs)
500
1789 G29
1789f
12
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(LT1789-10)
Current Noise Density vs
Frequency
Voltage Noise Density vs
Frequency
1000
VS = 5V, 0V
VREF = 2.5V
INPUT REFERRED
CURRENT NOISE DENSITY (fA/√Hz)
VOLTAGE NOISE DENSITY (nV/√Hz)
1000
G = 10
100
G = 100
G = 1000
VS = 5V, 0V
VREF = 2.5V
100
RS
LT1789-10
10
10
10
100
FREQUENCY (Hz)
1
10
100
FREQUENCY (Hz)
1
1k
1k
1789 G31
1789 G30
0.1Hz to 10Hz Noise Voltage,
RTI, G = 1000
0.1Hz to 10Hz Noise Voltage,
RTI, G = 10
0.1Hz to 10Hz Noise Current
VS = 5V, 0V
VREF = 2.5V
VS = 5V, 0V
VREF = 2.5V
1
2
3
4 5 6
TIME (SEC)
7
8
0
9 10
1
2
3
4 5 6
TIME (SEC)
7
8
9 10
1789 G33
1789 G32
0
1
2
3
4 5 6
TIME (SEC)
7
8
9 10
1789 G34
Turn-On Characteristics
1.5
CHANGE IN OUTPUT VOLTAGE (V)
0
NOISE CURRENT (5pA/DIV)
NOISE VOLTAGE (2µV/DIV)
NOISE VOLTAGE (0.5µV/DIV)
VS = 5V, 0V
VREF = 2.5V
VS = 5V, 0V
VREF = 2.5V
VCM = 2.5V
G = 1000
TA = 25°C
0.5
–0.5
–1.5
0
10
20
30
40
TIME (ms)
1789 G18
1789f
13
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(LT1789-1)
Large-Signal Transient Response
G = 1000
5V/DIV
5V/DIV
Large-Signal Transient Response
G = 1, 10, 100
VS = ±15V
RL = 20k
CL = 50pF
500µs/DIV
1789-1 G38
VS = ±15V
RL = 20k
CL = 50pF
1789-1 G39
Small-Signal Transient Response
G = 10
20mV/DIV
20mV/DIV
Small-Signal Transient Response
G=1
2ms/DIV
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
100µs/DIV
1789-1 G40
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
100µs/DIV
1789-1 G41
Small-Signal Transient Response
G = 1000
20mV/DIV
20mV/DIV
Small-Signal Transient Response
G = 100
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
200µs/DIV
1789-1 G42
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
2ms/DIV
1789-1 G43
1789f
14
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(LT1789-10)
5V/DIV
Large-Signal Transient Response
G = 1000
5V/DIV
Large-Signal Transient Response
G = 10, 100
VS = ±15V
RL = 20k
CL = 50pF
500µs/DIV
1789-10 G44
VS = ±15V
RL = 20k
CL = 50pF
500µs/DIV
1789-1 0 G45
20mV/DIV
Small-Signal Transient Response
G = 10
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
100µs/DIV
1789-10 G46
Small-Signal Transient Response
G = 1000
20mV/DIV
20mV/DIV
Small-Signal Transient Response
G = 100
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
200µs/DIV
1789-10 G47
VS = 5V, 0V
VREF = 2.5V
RL = 20k
CL = 50pF
2ms/DIV
1789-10 G48
1789f
15
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±15V
3.0
TA = 25°C
G=1
2.5
10
VALID OUTPUT VOLTAGE (V)
VALID OUTPUT VOLTAGE (V)
G≥2
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±2.5V
5
0
–5
–10
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±1.5V
1.5
TA = 25°C
AV = 10
2.0
AV = 1
1.5
VALID OUTPUT VOLTAGE (V)
15
(LT1789-1)
AV = 2
1.0
0.5
0
–0.5
–1.0
–1.5
TA = 25°C
AV = 1
1.0
AV = 2
AV = 10
0.5
0
–0.5
–1.0
–2.0
–15
–15
10
–5
0
5
–10
INPUT COMMON MODE VOLTAGE (V)
–2.5
–2.5
15
–1.5
1.5
–0.5
0.5
INPUT COMMON MODE VOLTAGE (V)
15V
+
VOUT
VCM
REF
–
20K
V–
–15V
VCM
VOUT
REF
–
4
3
G=1
2
G=2
G = 10
0
0
1
3
4
2
INPUT COMMON MODE VOLTAGE (V)
VCM
5
G=1
1
G=2
G = 10
0
0
2.0
0.5
1.5
2.5
1.0
INPUT COMMON MODE VOLTAGE (V)
V–
3.0
3V
V+
VD /2
VOUT
REF
–
1789 G51
TA = 25°C
+
LT1789-1
VD /2
20K
2
V+
VD /2
V–
–1.5V
5V
+
–
3
TA = 25°C
1
REF
Valid Output Voltage vs Input
Common Mode Voltage
VS = 3V
VALID OUTPUT VOLTAGE (V)
VALID OUTPUT VOLTAGE (V)
5
VCM
VD /2
1789 G50
Valid Output Voltage vs Input
Common Mode Voltage
VS = 5V
VOUT
LT1789-1
20K
V–
–2.5V
1789 G49
V+
VD /2
LT1789-1
VD /2
1.5
1.5V
+
V+
VD /2
LT1789-1
VD /2
0
0.5
1.0
–1.0 –0.5
INPUT COMMON MODE VOLTAGE (V)
2.5V
+
V+
VD /2
–1.5
–1.5
2.5
20K
1789 G52
VOUT
LT1789-1
VCM
VD /2
REF
–
V–
20K
1789 G53
1789f
16
LT1789-1/LT1789-10
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±15V
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±2.5V
15
2.5
5
0
–5
–10
Valid Output Voltage vs Input
Common Mode Voltage
VS = ±1.5V
AV = 100
1.5
1.5
TA = 25°C
AV = 10
VALID OUTPUT VOLTAGE (V)
G = 100
2.0
VALID OUTPUT VOLTAGE (V)
10
TA = 25°C
1.0
0.5
0
–0.5
–1.0
–1.5
TA = 25°C
AV = 10
1.0
AV = 100
0.5
0
–0.5
–1.0
–2.0
–15
–15
10
–5
0
5
–10
INPUT COMMON MODE VOLTAGE (V)
–2.5
–2.5
15
–1.5
1.5
–0.5 0 0.5
INPUT COMMON MODE VOLTAGE (V)
15V
+
VOUT
REF
–
0
0.5
1.0
–1.0 –0.5
INPUT COMMON MODE VOLTAGE (V)
V–
20K
VCM
–15V
VOUT
VD /2
VCM
REF
–
–2.5V
Valid Output Voltage vs Input
Common Mode Voltage
VS = 5V
1789 G56
3
TA = 25°C
TA = 25°C
G = 10
G = 100
3
2
1
0
1
3
4
2
INPUT COMMON MODE VOLTAGE (V)
5
G = 100
2
1
0
0
2.0
0.5
1.5
2.5
1.0
INPUT COMMON MODE VOLTAGE (V)
5V
+
VCM
VOUT
REF
–
V–
V+
VD /2
LT1789-10
VD /2
3.0
3V
+
V+
VD /2
20K
Valid Output Voltage vs Input
Common Mode Voltage
VS = 3V
4
0
V–
–1.5V
1789 G55
G = 10
VOUT
LT1789-10
20K
V–
1789 G54
5
V+
VD /2
REF
–
1.5
1.5V
+
LT1789-10
VD /2
VALID OUTPUT VOLTAGE (V)
VCM
–1.5
–1.5
V+
VD /2
LT1789-10
VD /2
2.5
2.5V
+
V+
VD /2
VALID OUTPUT VOLTAGE (V)
VALID OUTPUT VOLTAGE (V)
G = 10
(LT1789-10)
20K
1789 G57
VOUT
LT1789-10
VCM
VD /2
REF
–
V–
20K
1789 G58
1789f
17
LT1789-1/LT1789-10
W
BLOCK DIAGRA
V+
V+
100k
V+
5.7k
+IN 3
–
R1
R2
110k/10k* 110k/100k*
RG 1
V–
V–
V+
V+
+
A1
5 REF
VB
V–
+
RG 8
A3
100k
–
5.7k
V+
–IN 2
–
V–
V
+
–
R3
R4
110k/10k* 110k/100k*
A2
6 OUT
7 V+
VB
*LT1789-1/LT1789-10
V–
4 V–
1789 BD
Figure 1. Block Diagram
1789f
18
LT1789-1/LT1789-10
U
W
U U
APPLICATIO S I FOR ATIO
Setting the Gain
The gain of the LT1789-1 and LT1789-10 is set by the
value of resistor RG, applied across pins 1 and 8. For the
LT1789-1, the gain G will be:
G = 1+ 200k/RG
voltage dominates, whereas at low gains the output offset
voltage dominates. The total offset voltage is:
Total input offset voltage (RTI)
= input offset + (output offset/G)
Total output offset voltage (RTO)
= (input offset • G) + output offset
and RG can be calculated from the desired gain by
RG = 200k/(G – 1)
Reference Terminal
For the LT1789-10, the gain G will be
G =10 • (1 + 200k/RG)
and RG can be calculated from the desired gain by
RG = 200k/(0.1 • G – 1)
For the lowest achievable gain, RG may be set to infinity by
leaving Pins 1 and 8 open.
The output voltage of the LT1789-1/LT1789-10 (Pin 6) is
referenced to the voltage on the reference terminal (Pin
5). Resistance in series with the REF pin must be minimized for best common mode rejection. For example, a
22Ω resistance from the REF pin to ground will not only
increase the gain error by 0.02% but will lower the CMRR
to 80dB.
Output Offset Trimming
Input and Output Offset Voltage
The offset voltage of the LT1789-1/LT1789-10 has two
components: the output offset and the input offset. The
total offset voltage referred to the input (RTI) is found by
dividing the output offset by the programmed gain (G) and
adding it to the input offset. At high gains the input offset
–
1
LT1789-1/-10
8
REF
3 +
+IN
5
RG
V+
OUTPUT
6
1
±10mV
ADJUSTMENT RANGE
2
10mV
100Ω
LT1880
+
2
–
–IN
The LT1789-1/LT1789-10 is laser trimmed for low offset
voltage so that no external offset trimming is required for
most applications. In the event that the offset needs to be
adjusted, the circuit in Figure 2 is an example of an optional
offset adjust circuit. The op amp buffer provides a low
impedance to the REF pin where resistance must be kept
to a minimum for best CMRR and lowest gain error.
3
10k
100Ω
–10mV
V–
1789 F02
Figure 2. Optional Trimming of Output Offset Voltage
1789f
19
LT1789-1/LT1789-10
U
W
U U
APPLICATIO S I FOR ATIO
Input Bias Current Return Path
Output Voltage vs Input Common Mode Voltage
The low input bias current of the LT1789-1/LT1789-10
(19nA) and the high input impedance (1.6GΩ) allow the
use of high impedance sources without introducing significant offset voltage errors, even when the full common
mode range is required. However, a path must be provided
for the input bias currents of both inputs when a purely
differential signal is being amplified. Without this path the
inputs will float high and exceed the input common mode
range of the LT1789-1/LT1789-10, resulting in a saturated
input stage. Figure 3 shows three examples of an input
bias current path. The first example is of a purely differential signal source with a 10kΩ input current path to
ground. Since the impedance of the signal source is low,
only one resistor is needed. Two matching resistors are
needed for higher impedance signal sources as shown in
the second example. Balancing the input impedance improves both common mode rejection and DC offset. The
need for input resistors is eliminated if a center tap is
present as shown in the third example.
All instrumentation amplifiers have limiting factors that
can cause an output to be invalid (the output is not equal
to the input differential voltage multiplied by the gain) even
though the output appears to be operating in a linear
region. Limiting factors such as input voltage range and
output swing can be easily measured, however, there are
also internal nodes that can limit. These internal nodes
cannot be measured externally and can lead to erroneous
output readings.
To ensure a valid output for a given input common mode
voltage and input differential voltage, the following four
limiting factors must be taken into consideration (refer to
the block diagram):
1) The input voltage ranges of the input amplifiers A1 and
A2.
2) The output swings of the input amplifiers A1 and A2
(internal nodes).
–
THERMOCOUPLE
–
LT1789-1/
LT1789-10
RG
MICROPHONE,
HYDROPHONE,
ETC
10k
LT1789-1/
LT1789-10
RG
+
–
+
200k
LT1789-1/
LT1789-10
RG
+
200k
CENTER-TAP PROVIDES
BIAS CURRENT RETURN
1789 F03
Figure 3. Providing an Input Common Mode Current Path
1789f
20
LT1789-1/LT1789-10
U
W
U U
APPLICATIO S I FOR ATIO
3) The input voltage range of the output amplifier A3
(internal node).
4) The output swing of the output amplifier A3.
These limits can be determined using the relationships
below.
1)The input voltage range limits can be found in the
electrical tables.
2)The output voltages of the input amplifiers A1 and A2
can be found by the following formulas:
VOUT A1 = (VD/2)(G)(R1/R2) + VCM + 0.6V
VOUT A2 = (–VD/2)(G)(R1/R2) + VCM + 0.6V
Where VD is the input differential voltage and VCM is the
input common mode voltage.
The typical output swing limits for A1 and A2 can be found
in the Output Swing vs Load Current typical performance
curve, using R1 + R2 as the load resistance.
This limitation usually becomes dominant when gain is
taken in the input stage and the common mode input
voltage is close to either supply rail.
The LT1789-10 is less susceptible to this limiting factor
because the gain is taken in the output stage.
3)The voltage on the inputs to the output amplifier A3 can
be determined by the following formula:
VIN A3 = (VOUT A1 – VREF)(R2/(R1 + R2))
The input voltage range of A3 has the same input limits as
the LT1789-1. This limiting factor is more prevalent with
single supplies, where both the reference voltage and
input common mode voltage are near V+. This is also more
of a concern with the LT1789-10 because the ratio of
R1:R2 is 1:10 instead of 1:1.
4)The output voltage swing limits are also found in the
electrical tables.
The Output Voltage vs Input Common Mode Voltage
typical performance curves show the regions of operation
for the three supply voltages specified.
Single Supply Operation
There are usually two types of input signals that need to be
processed; differential signals, like the output of a bridge
or single ended signals, such as the output from a thermistor. Both signals require special consideration when
operating with a single supply.
When processing differential signals , REF (Pin 5) must be
brought above the negative supply (Pin 4) to allow the
output to process both the positive and negative going
input signal. The maximum output operating range is
obtained by setting the voltage on the REF pin to half
supply. This must be done with a low impedance source to
minimize CMRR and gain errors.
For single ended input signals, the REF pin can be at the
same potential as the negative supply provided the output
of the instrumentation amplifier remains inside the specified operating range. This maximizes the output range,
however the smallest input signal that can be processed is
limited by the output swing to the negative supply.
1789f
21
LT1789-1/LT1789-10
U
TYPICAL APPLICATIO S
Single Supply Positive Integrator
VS
3
VIN
+
7
LT1789-1
REF
1
2
–
VS
R1
6 10k
8
5
3
+
C1
100µF
4
+
1
LT1636
R2
10Ω
4
–
VOUT
2
RESET
1789 TA02
VS = 2.7V TO 32V
TIME CONSTANT = (R1)(C1) = 1 SECOND AS SHOWN
Avalanche Photo Diode Module Bias Current Monitor
APD
HIGH VOLTAGE
BIAS INPUT
FOR OPTIONAL “ZERO CURRENT” FEEDBACK TO
APD BIAS REGULATOR, SEE APPENDIX A, APPLICATION NOTE 92
1k*
1%
1µF
100V
100k*
1µF
100V
100k*
VOUT = 20V TO 90V
TO APD
Q1
1N4690
5.6V
1M*
0.2µF
5V
–
10k
A1
LT1789-1
30k
+
Q2
MPSA42
0.2µF
5V
1µF
6
20k
+
2
S2
5
–
20k*
1M* –3.5V
–3.5V
20k
200k*
12
13
OUTPUT
0V TO 1V =
0mA TO 1mA
A2
LT1006
1µF
14
S1
18
5V
5V
3
15
+
* = 0.1% METAL FILM RESISTOR
1µF 100V = TECATE CMC100105MX1825
# CIRCLED NUMBERS = LTC1043 PIN NUMBER
+
S3
–3.5V TO
AMPLIFIERS
22µF
22µF
= 1N4148
= TP0610L
16
17
4
0.056µF
†
FOR MORE INFORMATION REFER TO APPLICATION NOTE 92
5V
AN92 F04
1789f
22
LT1789-1/LT1789-10
U
PACKAGE DESCRIPTION
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
7
6
5
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
3
4
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
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)
.050
(1.270)
BSC
SO8 0303
1789f
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
23
LT1789-1/LT1789-10
U
TYPICAL APPLICATIO S
Voltage Controlled Current Source
3V TO 32V
3
VIN
+
7
8
RG
1
2
6
LT1789-1 REF
5
–
R1
1k
4
IL
LOAD
IL = AV • VIN/R1
1789 TA03
AV = 1 + 200k
RG
10°C to 40°C Thermometer
29.4k
1%
VS+ 4 LT1790 6
–1.25
1 2
3
7
6
LT1789-10
1
2
100k
@ 25°C
+
8
36.5k
0.5%
THERMISTOR
THERMOMETRICS
DC95G104V
VS+
5
–
4
866k
1%
56.2k
1%
VOUT = 2.5V AT 25°C + 50mV/°C
OVER 10°C TO 40°C
LINEARITY = 0.3°C
ACCURACY = 1°C WORST CASE
TOLERANCE STACK-UP
VS+ = 4V TO 18V
1789 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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LT1167
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LT1168
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ISUPPLY = 530µA Max
LTC 1418
14-Bit, Low Power, 200ksps ADC with Serial and Parallel I/O
Single Supply 5V or ±5V Operation, ±1.5LSB INL
and ±1LSB DNL Max
LT1460
Precision Series Reference
Micropower; 2.5V, 5V, 10V Versions; High Precision
LT1468
16-Bit Accurate Op Amp, Low Noise Fast Settling
16-Bit Accuracy at Low and High Frequencies, 90MHz GBW,
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Active RC Filter
Lowpass, Bandpass, Highpass Responses; Low Noise,
Low Distortion, Four 2nd Order Filter Sections
LTC1605
16-Bit, 100ksps, Sampling ADC
Single 5V Supply, Bipolar Input Range: ±10V,
Power Dissipation: 55mW Typ
®
1789f
24
Linear Technology Corporation
LT/TP 0403 2K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
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 LINEAR TECHNOLOGY CORPORATION 2002