GND1

INP

VDD1

4 pF

INN

4 pF

Overvoltage

monitor

100

NŸ

100

NŸ

16 pF

50 k

2.5

NŸ

50

NŸ

2.5 k

GND1

VDD1

VDD1

12

AMC1302

SBAS812 – JUNE 2018

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7.3 Feature Description

7.3.1 Analog Input

The differential amplifier input stage of the AMC1302 feeds a second-order, switched-capacitor, feed-forward ΔΣ

modulator. The modulator converts the analog signal into a bitstream that is transferred over the isolation barrier,

as described in the Isolation Channel Signal Transmission section.

Figure 5 depicts the equivalent input structure of the AMC1302 with the relevant components. The total gain of

the device results from a combination of the gain of the fully-differential input amplifier and the gain of the active

output filter.

Figure 5. Equivalent Analog Input Circuit

There are two restrictions on the analog input signals (INP and INN). First, if the input voltage exceeds the range

GND1 – 6 V to VDD1 + 0.5 V, the input current must be limited to 10 mA because the device input electrostatic

discharge (ESD) diodes turn on. In addition, the linearity and noise performance of the device are ensured only

specifications.