OPA172, OPA2172, OPA4172

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SBOS618H – DECEMBER 2013 – REVISED SEPTEMBER 2015

8.4 Device Functional Modes

8.4.1 Common-Mode Voltage Range

The input common-mode voltage range of the OPAx172 series extends 100 mV below the negative rail and

within 2 V of the top rail for normal operation.

This device can operate with full rail-to-rail input 100 mV beyond the top rail, but with reduced performance within

2 V of the top rail. The typical performance in this range is summarized in Table 3.

PARAMETER

MIN

TYP

MAX

UNIT

Input Common-Mode Voltage

(V+) – 2

(V+) + 0.1

V

Offset voltage

5

mV

10

µV/°C

Common-mode rejection

70

dB

Open-loop gain

60

dB

Gain bandwidth product (GBP)

4

MHz

Slew rate

4

V/µs

Noise at f = 1 kHz

22

nV/

√Hz

8.4.2 Electrical Overstress

Designers often ask questions about the capability of an operational amplifier to withstand electrical overstress.

These questions tend to focus on the device inputs, but may involve the supply voltage terminals or even the

output terminal. Each of these different terminal functions have electrical stress limits determined by the voltage

breakdown characteristics of the particular semiconductor fabrication process and specific circuits connected to

the terminal. Additionally, internal electrostatic discharge (ESD) protection is built into these circuits to protect

them from accidental ESD events both before and during product assembly.

A good understanding of this basic ESD circuitry and its relevance to an electrical overstress event is helpful.

Figure 46 illustrates the ESD circuits contained in the OPAx172 (indicated by the dashed line area). The ESD

protection circuitry involves several current-steering diodes connected from the input and output terminals and

routed back to the internal power-supply lines, where the diodes meet at an absorption device internal to the

operational amplifier. This protection circuitry is intended to remain inactive during normal circuit operation.

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Product Folder Links: OPA172 OPA2172 OPA4172