ADR380/ADR381

Rev. C | Page 13 of 16

PRECISION HIGH CURRENT VOLTAGE SOURCE

In some cases, the user may want higher output current delivered

to a load and still achieve better than 0.5% accuracy from the

ADR380/ADR381. The accuracy for a reference is normally

specified on the data sheet with no load. However, the output

voltage changes with load current.

The circuit in Figure 30 provides high current without compromis-

ing the accuracy of the ADR380/ADR381. By op amp action,

equilibrium, the op amp also drives the N-Channel MOSFET

Q1 into saturation to maintain the current needed at different

loads. R2 is optional to prevent oscillation at Q1. In such an

approach, hundreds of milliamps of load current can be achieved,

GND

3

2

1

8V TO 15V

A1

–V

+V

AD820

U1

ADR380/

ADR381

Q1

2N7002

R2

100

Ω

R1

100k

Ω

C1

0.001µF

Figure 30. ADR380/ADR381 for Precision High Current Voltage Source