Datasheet REF01, REF02, REF03 (Analog Devices) - 17

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Data Sheet REF01/REF02/REF03 BIPOLAR VOLTAGE REFERENCE ADJUSTABLE REFERENCE WITH POSITIVE AND
Many applications require both a positive and reference voltage
NEGATIVE SWING
of the same magnitude. A simple method of generating such a The output voltage of the REF01/REF02/REF03 references can bipolar reference is shown in Figure 42. be readily adjusted via a simple trim circuit (explained in the
V+
Output Adjustment section). The circuit shown in Figure 43 extends the negative range of adjustment beyond that
U1 2
obtainable with the simple trim circuit by employing a precision
VIN 6 V
op amp with
OUT +2.5V REF03
a potentiometer feeding the op amp’s noninverting input.
100kΩ V+ GND 100kΩ 4 U1 2 50kΩ U2 V 2 7 IN 6 50kΩ 2 +15V 7 6 VOUT OP97 –2.5V 6 VOUT 3 REF03 OP97 3 –2.5V TO +2.5V 4 50kΩ U2
043
4 V– GND
00375- 044
4 –15V
Figure 42. Bipolar Voltage Reference 00375- In this configuration, the negative rail is generated simply Figure 43. Negatively Adjustable Reference with an inverting amplifier with a gain of −1. A low offset The voltage output from the op amp can be adjusted by op amp should be used to minimize the voltage error at the changing the value of the potentiometer: as shown, the op negative output. amp outputs +2.5 V when the pot is pul ed completely high, and −2.5 V 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. Rev. M | Page 17 of 20 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PIN CONFIGURATIONS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS REF01 SPECIFICATIONS REF02 SPECIFICATIONS REF03 SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION INPUT AND OUTPUT CAPACITORS OUTPUT ADJUSTMENT TEMPERATURE MONITORING LONG-TERM STABILITY BURN-IN POWER DISSIPATION APPLICATIONS INFORMATION BASIC REFERENCE APPLICATION LOW COST CURRENT SOURCE PRECISION CURRENT SOURCE WITH ADJUSTABLE OUTPUT PRECISION BOOSTED OUTPUT REGULATOR BIPOLAR VOLTAGE REFERENCE ADJUSTABLE REFERENCE WITH POSITIVE AND NEGATIVE SWING OUTLINE DIMENSIONS REF01 ORDERING GUIDE REF02 ORDERING GUIDE REF03 ORDERING GUIDE