TL971 Datasheet, PDF (11/33 Pages) Texas Instruments – OUTPUT RAIL-TO-RAIL VERY-LOW-NOISE OPERATIONAL AMPLIFIERS

www.ti.com
9 Application and Implementation
TL971, TL972, TL974
SLOS467H – OCTOBER 2006 – REVISED JANUARY 2015
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Typical Application
The voltage follower configuration of the operational amplifier is used for applications where a weak signal is
used to drive a relatively high current load. This circuit is also called a buffer amplifier or unity gain amplifier. The
inputs of an operational amplifier have a very high resistance which puts a negligible current load on the voltage
source. The output resistance of the operational amplifier is almost negligible, so it can provide as much current
as necessary to the output load.
12 V
+
VOUT
VIN
Figure 17. Voltage follower schematic
9.1.1 Design Requirements
• Input at positive Terminal
• Output range of 0 V to 12 V
• Input range of 0 V to 12 V
• Short-circuit feedback to negative input for unity gain
9.1.2 Detailed Design Procedure
9.1.2.1 Output Voltage Swing
The output voltage of an operational amplifier is limited by its internal circuitry to some level below the supply
rails. For this amplifier, the output voltage must be within ±12 V.
9.1.2.2 Supply and Input Voltage
For correct operation of the amplifier, neither input must be higher than the recommended positive supply rail
voltage or lower than the recommended negative supply rail voltage. The chosen amplifier must be able to
operate at the supply voltage that accommodates the inputs. Because the input for this application goes up to 12
V, the supply voltage must be 15 V. Using a negative voltage on the lower rail rather than ground, allows the
amplifier to maintain linearity for the full range of inputs.
Copyright © 2006–2015, Texas Instruments Incorporated
Product Folder Links: TL971 TL972 TL974
Submit Documentation Feedback
11