ADG5401F datasheet(28/32 Pages) AD

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ADG5401F

Data Sheet

Rev. 0 | Page 28 of 32

OVERVOLTAGE FAULT PROTECTION

When the voltage at the S or SFB input exceeds VDD or VSS

by VT, the switches turn off or, if the device is unpowered, the

switches remain off. Both switch inputs remain high impedance

regardless of the digital input state or the load resistance, and

the output acts as a virtual open circuit. Signal levels up to +60 V

and −60 V are blocked in both the powered and unpowered

condition as long as the +80 V absolute maximum rating

limitation between the S or SFB pin and VDD or VSS pin is

met. For example with a +40 V single supply, the overvoltage

protection is +60 V and −40 V (see Figure 46).

ADG5401F

80V

VDD

VSS

80V

Figure 46. S or SFB to VDD or VSS Maximum Rating

Power-On Protection

To activate the switches, the three following conditions must be

meet:

•

The minimum supply operating conditions in Table 1.

•

The input signal must be between VSS − VT and VDD + VT.

•

The digital logic control input, IN, is on.

When the switches are on, signal levels from VSS up to VDD − 2 V

are passed.

The switches respond to a voltage on either the S pin or the SFB

pin that exceeds VDD or VSS by VT by turning off. The absolute

input voltage limits are −60 V and +60 V, while maintaining an

80 V limit between the S or SFB pin and the supply rails. The

switches remain off until the voltage at the S and SFB pins

return to between VDD and VSS.

When powered by the ±15 V dual supply, the positive overvoltage

response time (tRESPONSE) is typically 230 ns, and tRECOVERY is 11.7 µs.

These values vary with different supply voltage and output load

conditions.

Exceeding ±60 V on either the S or SFB input may damage the

ESD protection circuitry on the ADG5401F.

Power Off Protection

When no power supplies are present, the switches remain in an

off state and the switch inputs are high impedance. This state

ensures that no current flows and prevents damage to the

switches or downstream circuitry. The switch outputs are a

virtual open circuit.

The switches remain off regardless of whether the VDD and VSS

supplies are 0 V or floating. A GND reference must always be

present to ensure proper operation. Signal levels of up to ±60 V

are blocked when powered off.

Overvoltage Interrupt Flag

The voltages on the S and SFB inputs of the ADG5401F are

continuously monitored, and the active low digital output pin,

FF, indicates the fault state.

The voltage on the FF pin indicates if either the S or SFB input

pin is experiencing a fault condition. The FF pin is an open-

drain output that requires an external pull-up resistor. The

output of the FF pin is high when both the S and SFB pins are

within the normal operating range. If either the S or SFB pin

voltage exceeds the supply voltage (VDD or VSS) by VT, the FF

output provides a low impedance path to GND.

ADG5401F Datasheet(PDF) 28 Page - Analog Devices

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