OP77

Data Sheet

Rev. G | Page 12 of 16

PRECISION CURRENT SINKS

V+

200Ω

R1

1Ω

1W

RL

IRF520

IO

VIN

OP77

IO =

VIN > 0V

FULL SCALE OF 1V.

IO = 1A/V

VIN

R1

Figure 31. Positive Current Sink

200Ω

RL

R1

IRF520

IO

VIN

V–

OP77

IO =

VIN > 0V

VIN

R1

Figure 32. Positive Current Source

The simple high-current sinks, shown Figure 31 and Figure 32,

require the load to float between the power supply and the sink.

In these circuits, the high gain, high CMRR, and low TCVOS of

the OP77 ensure high accuracy.

The high gain and low TCVOS ensure accurate operation with

inputs from microvolts to volts. In Figure 33, the signal always

appears as a common-mode signal to the op amps. The

OP77EZ CMRR of 1 µV/V ensures errors of less than 2 ppm.

+15V

–15V

1kΩ

1kΩ

R3

2kΩ

C1

30pF

D1

1N4148

7

6

4

2

3

0.1µF

0.1µF

2N4393

VIN

+15V

VOUT

0 < VOUT < 10V

D2

–15V

7

6

4

2

3

0.1µF

0.1µF

OP77E

OP77E

Figure 33. Precision Absolute Value Amplifier

100Ω

VOUT

15V

0.1µF

OP77

100Ω

100Ω

10µF

6

4

REF-01

VO

2

6

4

REF-01

VO

2

6

4

REF-01

VO

2

+

Figure 34. Low Noise Precision Reference