lt1012a Linear Technology Corporation, lt1012a Datasheet - Page 12

• Manufacturer Part Number: lt1012a
• Description: Picoamp Input Current, Microvolt Offset, Low Noise Op Amp
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LT1012A/LT1012
*RESISTORS MUST HAVE LOW THERMOELECTRIC
TYPICAL APPLICATIO S
12
100
POTENTIAL
50k
and its Drift with Temperature
Test Circuit for Offset Voltage
*
*
V
2
3
0
= 1000V
–
+
LT1012
–15V
50k
15V
CURRENT INPUT
7
4
*
0S
Q1, Q2, Q3, Q4, RCA CA3146 TRANSISTOR ARRAY.
CALIBRATION: ADJUST R1 FOR FULL-SCALE
DEFLECTION WITH 1 A INPUT CURRENT
AMPMETER MEASURES CURRENTS FROM 100pA
TO 100 A WITHOUT THE USE OF EXPENSIVE
HIGH VALUE RESISTORS. ACCURACY AT 100 A
IS LIMITED BY THE OFFSET VOLTAGE BETWEEN
Q1 AND Q2 AND, AT 100pA, BY THE INVERTING
BIAS CURRENT OF THE LT1012
U
6
U
LT1012A • AI02
V
10k
0
U
W
10k
IN
Follower Feedforward Compensation
2
3
5k
Ampmeter with Six Decade Range
0.1 F
–
+
LT1012
U
–15V
15V
7
4
2
3
0.01 F
–
+
6
LT1012
CA3146
PIN 13
50pF
10k
33k
5
6
Q4
Q1
LT1012A • AI03
Q2
OUT
100 A
METER
RANGE
100 A
100nA
100pA
10 A
10nA
1 A
1nA
Q3
1.2k
549
549
549
549
549
549
R1
2k
Pulse Response of Feedforward
Compensation
LT1004C
10k
Photo
LT1012A • TA03
5 s/DIV
15V
o
sn1012 1012afbs