Description

The ISO808A, ISO808A-1, are galvanic isolated 8-channel drivers featuring a low supply current. Each driver

contains 2 independent galvanic isolated voltage domains (VCC and VDD for the Process and Control Logic

stages, respectively). The ICs are intended for driving any kind of load with one side connected to ground.

The Control Logic Stage features an 8-bit Output Status Register (where the MCU sets the ON/OFF status of

the output channels in the Process Stage), daisy chaining is allowed. The two stages communicate through the

galvanic isolation channel by an ST proprietary protocol.

Active channel current limitation (OVL) combined with thermal shutdown (OVT), independent for each channel,

protects the device against overload.

Built-in thermal shut down protects each channel from over-temperature and overload: each overheated channel

automatically turns OFF after its junction temperature triggers the protection threshold (TJSD). The channel turns

back ON if its junction temperature decreases lower than restart threshold (TJR).

An additional case temperature sensor protects the whole chip against over-temperature (OVC event): if the case

temperature triggers the TCSD threshold then overloaded channels are turned OFF and will restart only when case

temperature decreased down to the reset threshold (TCR). Non overloaded channels continue to operate normally.

Other embedded functions are loss of ground protection, VCC and VDD UVLOs (with hysteresis), watchdog and

VCC Power GOOD.

An internal circuit provides an OR-wired not latched common FAULT indicator signaling the channel OVT. The

PGOOD diagnostic pin is activated if VCC goes below the power good threshold. Both FAULT and PGOOD pins

are open drain, active low, fault indication pins.

ISO808A, ISO808A-1

DS14170 - Rev 1

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