
REF01/REF02/REF03
Rev. J | Page 17 of 20
PRECISION BOOSTED OUTPUT REGULATOR
The output current sourcing capability of the REF0x series can
be boosted by using an external op amp and MOSFET, as shown
U2
15V
N1
200
U1
REF01/
REF02/
REF03
VIN
VOUT
TEMP TRIM
GND
V–
V+
OP1177
2N7002
VIN
VO
RL
1F
CL
00
37
5-
04
2
C1
1000pF
00
37
5-
0
43
R2
100
R1
100
Figure 42. Precision Boosted Output Regulator
In this circuit, U2 forces VO to VREF by regulating the current
through N1, thereby sourcing the load current directly from the
input voltage source connected at VIN. Using the components
shown, this circuit can source up to 50 mA with an input volt-
age of 15.0 V. The circuit’s current sourcing capability can be
further increased by replacing N1 with a higher-power MOSFET.
BIPOLAR VOLTAGE REFERENCE
Many applications require both a positive and reference voltage
of the same magnitude. A simple method of generating such a
REF03
VIN
GND
V+
V–
3
4
2
6
7
2
U1
U2
4
6
VOUT
OP97
100k
–2.5V
+2.5V
100k
Figure 43. Bipolar Voltage Reference
In this configuration, the negative rail is generated simply
with an inverting amplifier with a gain of 1. A low offset
op amp should be used to minimize the voltage error at the
negative output.
ADJUSTABLE REFERENCE WITH POSITIVE AND
NEGATIVE SWING
The output voltage of the REF0x references can be readily
adjusted via a simple trim circuit (explained in the
Outputthe negative range of adjustment beyond that obtainable with
the simple trim circuit by employing a precision op amp with
a potentiometer feeding the op amp’s noninverting input.
00
37
5-
04
4
REF03
VIN
GND
V+
2
3
4
6
7
+15V
50k
2
U1
U2
4
6
VOUT
OP97
50k
50k
VOUT
–2.5V TO +2.5V
Figure 44. Negatively Adjustable Reference
The voltage output from the op amp can be adjusted by
changing the value of the potentiometer: as shown, the op
amp outputs +2.5 V when the pot is pulled completely high,
and 2.5V when pulled completely low. In this configuration,
the load current is sourced by the op amp; therefore, a low
offset op amp with a current rating that meets or exceeds the
current requirements of the load should be used.