TLC271_01 Datasheet, PDF (3/82 Pages) Texas Instruments – LinCMOSE PROGRAMMABLE LOW-POWER OPERATIONAL AMPLIFIERS

TLC271, TLC271A, TLC271B
LinCMOS PROGRAMMABLE LOW-POWER
OPERATIONAL AMPLIFIERS
SLOS090D – NOVEMBER 1987 – REVISED MARCH 2001
bias selection
Bias selection is achieved by connecting the bias select pin to one of three voltage levels (see Figure 1). For
medium-bias applications, it is recommended that the bias select pin be connected to the midpoint between the
supply rails. This procedure is simple in split-supply applications, since this point is ground. In single-supply
applications, the medium-bias mode necessitates using a voltage divider as indicated in Figure 1. The use of
large-value resistors in the voltage divider reduces the current drain of the divider from the supply line. However,
large-value resistors used in conjunction with a large-value capacitor require significant time to charge up to
the supply midpoint after the supply is switched on. A voltage other than the midpoint can be used if it is within
the voltages specified in Figure 1.
VDD
To the Bias
Select Pin
Low
Medium
1 MΩ
High
1 MΩ
0.01 µF
BIAS MODE
Low
Medium
High
BIAS-SELECT VOLTAGE
(single supply)
VDD
1 V to VDD – 1 V
GND
Figure 1. Bias Selection for Single-Supply Applications
high-bias mode
In the high-bias mode, the TLC271 series features low offset voltage drift, high input impedance, and low noise.
Speed in this mode approaches that of BiFET devices but at only a fraction of the power dissipation. Unity-gain
bandwidth is typically greater than 1 MHz.
medium-bias mode
The TLC271 in the medium-bias mode features low offset voltage drift, high input impedance, and low noise.
Speed in this mode is similar to general-purpose bipolar devices but power dissipation is only a fraction of that
consumed by bipolar devices.
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