7.3.5 Mux-Friendly Inputs

The OPA593 uses a unique input architecture to eliminate the need for input protection diodes but still provides

robust input protection under transient conditions. Conventional input diode protection schemes shown in Figure

7-4 can be activated by fast transient step responses and can introduce signal distortion and settling time

delays because of alternate current paths, as shown in Figure 7-5. For low-gain circuits, these fast-ramping input

signals forward-bias back-to-back diodes that cause an increase in input current, resulting in extended settling

time.

OPA593

81.5 V

~0.7 V

V+

V

Conventional Input Protection Limits Differential Input Range

OPA593 Provides Full 81.5-V Differential Input Range

V+

V

Figure 7-4. OPA593 Input Protection Does Not Limit Differential Input Capability

Input Low-Pass Filter

D

Simplified Mux Model

10 V

–10 V

Buffer Amplifier

1

2

10 V

~–9.3 V

1

VIN+

VIN–

~0.7 V

VOUT

2

–10 V

Figure 7-5. Back-to-Back Diodes Create Settling Issues

The OPA593 a true high-impedance differential input capability for high-voltage applications. This patented

input protection architecture does not introduce additional signal distortion or delayed settling time, making this

device an excellent choice for multichannel, high-switched, input applications. The OPA593 tolerates a maximum

differential swing (voltage between inverting and noninverting pins of the op amp) of up to 85 V, making this

device a great choice for use as a comparator or in applications with fast-ramping or switched input signals.

7.4 Device Functional Modes

The OPA593 has two modes of operation. The first mode is normal operation where the amplifier is enabled,

either by supply a voltage to the enable-disable (E/D) pin that is between 2.5 V and 5 V greater than the E/D

Com pin. The second mode of operation is a lower-power, disabled state where the E/D pin is driven between

0 V and 0.65 V greater than the E/D Com pin. In this state, the amplifier output is disabled and enters a high

output impedance state.

OPA593

SBOS659A – JANUARY 2022 – REVISED MARCH 2022

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