ADR01/ADR02/ADR03/ADR06

Data Sheet

Rev. R | Page 16 of 20

125

25

50

75

100

0.40

0.80

0.75

0.70

0.65

0.60

0.55

0.50

0.45

–25

0

–50

SAMPLE SIZE = 5

TEMPERATURE (°C)

ΔV

Figure 36. Voltage at TEMP Pin vs. Temperature

The TEMP function is provided as a convenience rather than a

precise feature. Because the voltage at the TEMP node is

acquired from the band gap core, current pulling from this pin

TEMP output with a suitable low bias current op amp, such as

the AD8601, AD820, or OP1177, all of which result in less than

even tens of microamps drawn from the TEMP pin can cause

U2

15V

U1

ADR01/

ADR02/

ADR03/

ADR06

TEMP TRIM

GND

V–

V+

OP1177

1.9mV/°C

Figure 37. Temperature Monitoring

LOW COST CURRENT SOURCE

Unlike most references, the ADR01/ADR02/ADR03/ADR06

employ an NPN Darlington in which the quiescent current

remains constant with respect to the load current, as shown in

Figure 23. As a result, a current source can be configured as

0.55 mA to 0.65 mA, limiting this circuit to general-purpose

applications.

ADR01/

ADR02/

ADR03/

ADR06

GND

Figure 38. Low Cost Current Source

PRECISION CURRENT SOURCE WITH

ADJUSTABLE OUTPUT

Alternatively, a precision current source can be implemented

with the circuit shown in Figure 39. By adding a mechanical or

digital potentiometer, this circuit becomes an adjustable current

source. If a digital potentiometer is used, the load current is

simply the voltage across Terminal B to Terminal W of the

SET

REF

L

R

D

V

I

×

=

(1)

where D is the decimal equivalent of the digital potentiometer

input code.

U2

+12V

–12V

W

B

A

U1

ADR01/

ADR02/

ADR03/

ADR06

TEMP TRIM

GND

V–

V+

OP1177

AD5201

+12V

1kΩ

1kΩ

100k

Ω

Figure 39. Programmable 0 mA to 5 mA Current Source

To optimize the resolution of this circuit, dual-supply op amps

should be used because the ground potential of ADR02 can

potentiometer setting.