OPA186DBVT datasheet(18/48 Pages) TI

18 / 48 page

7.3 Feature Description

The OPAx186 operational amplifier has several integrated features to help maintain a high level of precision

through a variety of applications. These include a rail-to-rail inputs, phase-reversal protection, input bias current

clock feedthrough, EMI rejection, electrical overstress protection and MUX-friendly Inputs.

7.3.1 Rail-to-Rail Inputs

Unlike many chopper amplifiers, the OPAx186 has rail-to-rail inputs that allow the input common-mode voltage

to not only reach, but exceed the supply voltages by 200 mV. This configuration simplifies power-supply

requirements by not requiring headroom over the input signal range.

The OPAx186 is specified for operation from 4.5 V to 24 V (±2.25 V to ±12 V) with rail-to-rail inputs. Many

specifications apply from –40°C to +125°C.

7.3.2 Phase-Reversal Protection

The OPAx186 has internal phase-reversal protection. Some op amps exhibit a phase reversal when the input is

driven beyond the linear common-mode range. This condition is most often encountered in noninverting circuits

when the input is driven beyond the specified common-mode voltage range, causing the output to reverse into

the opposite rail. The OPAx186 input prevents phase reversal with excessive common-mode voltage. Instead,

the output limits into the appropriate rail. Figure 7-1 shows this performance.

Time (100 Ps/div)

VIN (V)

VOUT (V)

Figure 7-1. No Phase Reversal

7.3.3 Input Bias Current Clock Feedthrough

Zero-drift amplifiers such as the OPAx186 use a switching architecture on the inputs to correct for the intrinsic

offset and drift of the amplifier. Charge injection from the integrated switches on the inputs can introduce short

transients in the input bias current of the amplifier. The extremely short duration of these pulses prevents the

pulses from amplifying; however, the pulses can be coupled to the output of the amplifier through the feedback

network. The most effective method to prevent transients in the input bias current from producing additional

noise at the amplifier output is to use a low-pass filter, such as an RC network.

OPA186, OPA2186, OPA4186

SBOS968B – JUNE 2022 – REVISED DECEMBER 2022

www.ti.com

Submit Document Feedback

Product Folder Links: OPA186 OPA2186 OPA4186

OPA186DBVT датащи(PDF) 18 Page - Texas Instruments