ADR130 Analog Devices, Inc., ADR130 Datasheet - Page 14

• Manufacturer Part Number: ADR130
• Description: Precision Series Sub-band Gap Voltage Reference
• Manufacturer: Analog Devices, Inc.

ADR130
NEGATIVE PRECISION REFERENCE WITHOUT
PRECISION RESISTORS
A negative reference is easily generated by adding an op amp,
A1, and is configured as shown in Figure 36. V
ground and, therefore, the negative reference can be taken
directly from the output of the op amp. The op amp must be
dual-supply, low offset, and rail-to-rail if the negative supply
voltage is close to the reference output.
Figure 36. Negative Reference, −V
+V
DD
–V
REF
1
2
3
NC
GND
V
IN
ADR130
OP291
0.1µF
U2
A1
–V
V–
V+
DD
V
SET
OUT
NC
REF
1kΩ
= −0.5 V
6
5
4
OUT
is at virtual
Rev. 0 | Page 14 of 16
PRECISION CURRENT SOURCE
In low power applications, the need can arise for a precision
current source that can operate on low supply voltages. The
ADR130 can be configured as a precision current source (see
Figure 37). The circuit configuration shown is a floating current
source with a grounded load. The reference output voltage is
bootstrapped across R
load. With this configuration, circuit precision is maintained for
load currents ranging from the reference supply current,
typically 85 μA, to approximately 4 mA.
Figure 37. ADR130 as a Precision Current Source
V
IN
SET
1
2
3
, which sets the output current into the
NC
GND
V
ADR130
IN
V
SET
OUT
NC
6
5
4
R
P1
R
SET
L