TLV2772AMFKB datasheet(40/65 Pages) TI

40 / 65 page

TLV277x, TLV277xA

FAMILY OF 2.7V HIGHSLEW RATE RAILTORAIL OUTPUT

OPERATIONAL AMPLIFIERS WITH SHUTDOWN

SLOS209G − JANUARY 1998 − REVISED FEBRUARY 2004

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APPLICATION INFORMATION

shutdown function

Three members of the TLV277x family (TLV2770/3/5) have a shutdown terminal for conserving battery life in

portable applications. When the shutdown terminal is tied low, the supply current is reduced to 0.8

µA/channel,

the amplifier is disabled, and the outputs are placed in a high impedance mode. To enable the amplifier, the

shutdown terminal can either be left floating or pulled high. When the shutdown terminal is left floating, care

needs to be taken to ensure that parasitic leakage current at the shutdown terminal does not inadvertently place

the operational amplifier into shutdown. The shutdown terminal threshold is always referenced to VDD/2.

Therefore, when operating the device with split supply voltages (e.g.

±2.5 V), the shutdown terminal needs to

be pulled to VDD− (not GND) to disable the operational amplifier.

The amplifier’s output with a shutdown pulse is shown in Figures 48, 49, and 50. The amplifier is powered with

a single 5-V supply and configured as a noninverting configuration with a gain of 5. The amplifier turnon and

turnoff times are measured from the 50% point of the shutdown pulse to the 50% point of the output waveform.

The times for the single, dual, and quad are listed in the data tables. The bump on the rising edge of the TLV2770

output waveform is due to the start-up circuit on the bias generator. For the dual and quad (TLV2773/5), this

bump is attributed to the bias generator’s start-up circuit as well as the crosstalk between the other channel(s),

which are in shutdown.

Figures 55 and 56 show the amplifier’s forward and reverse isolation in shutdown. The operational amplifier is

±1.35-V supplies and configured as a voltage follower (AV = 1). The isolation performance is plotted

across frequency for both 0.1 VPP and 2.7 VPP input signals. During normal operation, the amplifier would not

be able to handle a 2.7-VPP input signal with a supply voltage of ±1.35 V since it exceeds the common-mode

input voltage range (VICR). However, this curve illustrates that the amplifier remains in shutdown even under

a worst case scenario.

TLV2772AMFKB Datasheet(PDF) 40 Page - Texas Instruments