LT1078/LT1079
U
TYPICAL APPLICATIONS
Micropower, 10ppm/°C, ±5V Reference
Gain of 10 Difference Amplifier
2M
10M
9V
LT1034BC-1.2
220k
3V
1M
1M
5.000V
OUT
1M
–IN
+IN
–
OUTPUT
0.0035V TO 2.4V
LT1078/79 • TA04
120k
8
3
2
1/2 LT1078
+
1M
6
5
1
+
–
1/2 LT1078
7
1/2 LT1078
–5.000V
–
OUT
10M
510k
4
+
LT1078/79 • TA03
–9V
510k
1%
BANDWIDTH = 20kHz
OUTPUT OFFSET = 0.7mV
20k
OUTPUT NOISE = µV80 (0.1Hz TO 10Hz)
160k
1%
P-P
RMS
BANDWIDTH
µ2V60 OVER FULL
SUPPLY CURRENT = 9V BATTERY = 115µA
–9V BATTERY = 8µ5A
OUTPUT NOISE = 36µV , 0.1Hz TO 10Hz
THE USEFULNESS OF DIFFERENCE AMPLIFIERS IS LIMITED BY
THE FACT THAT THE INPUT RESISTANCE IS EQUAL TO THE SOURCE
RESISTANCE. THE PICOAMPERE OFFSET CURRENT AND LOW
CURRENT NOISE OF THE LT1078 ALLOWS THE USE OF 1M SOURCE
RESISTORS WITHOUT DEGRADATION IN PERFORMANCE. IN ADDITION,
WITH MEGOHM RESISTORS MICROPOWER OPERATION CAN BE MAINTAINED
P-P
THE LT1078 CONTRIBUTES LESS THAN 3% OF THE TOTAL OUTPUT NOISE AND
DRIFT WITH TIME AND TEMPERATURE. THE ACCURACY OF THE –5V OUTPUT
DEPENDS ON THE MATCHING OF THE TWO 1M RESISTORS
Picoampere Input Current, Triple Op Amp Instrumentation Amplifier with Bias Current Cancellation
3
R2
–IN
+
1M
1
1/4 LT1079
2
R1
1M
–
R3
9.1M
2R
20M
R
G
200k
9
–
R1
6
5
8
OUTPUT
–
1M
1/4 LT1079
4mV TO 8.2V
7
10
LT`1078/79 • TA05
1/4 LT1079
+
R2
1M
+IN
+
R3
9.1M
9V
R
10M
12
13
4
+
2R1 R3
14
2R
20M
GAIN = 1 +
= 100 FOR VALUES SHOWN
1/4 LT1079
(
)
R
R2
G
–
INPUT BIAS CURRENT TYPICALLY < 150pA
11
INPUT RESISTANCE = 3R = 30M FOR VALUES SHOWN
NEGATIVE COMMON MODE LIMIT = (I )(2R) + 20mV ≈ 140mV
B
GAIN BANDWIDTH PRODUCT = 1.8MHz
13
Linear [ Linear ]
