Datasheet

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