OPA607 datasheet(16/35 Pages) TI

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8.3.3 Input and ESD Protection

When the primary design goal is a linear amplifier with high CMRR, do not exceed the op amp input common-

mode voltage range (VCM). This CMRR is used to set the common-mode input range specifications in Section

7.1. The typical VCM specifications for the OPAx607-Q1 devices are from the negative rail to 1.1 V below

the positive rail. Assuming the op amp is in linear operation, the voltage difference between the input pins

is small (ideally 0 V) and the input common-mode voltage can be analyzed at either input pin; the other

input pin is assumed to be at the same potential. The voltage at VIN+ is easy to evaluate. In a noninverting

configuration (Figure 8-1) the input signal, VIN+, must not exceed the VCM rating. However, in an inverting

amplifier configuration, VIN+ must be connected to the voltage within VCM. The input signal applied at VIN- can be

any voltage, such that the output voltage swings with a headroom of 10 mV from either of the supply rails.

The input voltage limits have fixed headroom to the power rails and track the power-supply voltages. For single

5-V supply, the linear input voltage range is 0 V to 3.9 V and with a 2.2-V supply this range is 0 V to 1.1 V. The

headroom to each power-supply rail is the same in either case: 0 V and 1.1 V. A weak NMOS input pair from

VIN+ to VIN+ – 1.1 V ensures that an output phase reversal issue does not occur when the VCM is violated.

Power-Supply

ESD Cell

VSS

VDD

TVS

VS+

OPAx607-Q1

V6¤

OUT

IN+

IN-

Figure 8-4. Internal ESD Structure

The OPAx607-Q1 devices also incorporate internal electrostatic discharge (ESD) protection circuits on all pins.

For the input and output pins, this protection primarily consists of current-steering diodes connected between

the input and power-supply pins. These ESD protection diodes provides input overdrive protection, as long as

the current is limited with a series resistor to 10 mA, as stated in Section 7.1. Figure 8-1 shows a series input

resistor can be added to the driven input to limit the input current.

OPA607-Q1, OPA2607-Q1

SBOSA38A – FEBRUARY 2021 – REVISED APRIL 2021

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OPA607 Datenblatt(PDF) 16 Page - Texas Instruments