STMicroelectronics ISO808A-1, DualHigh Side, High Side Power Switch IC 36-Pin, PowerSO-36

Galvanic isolated octal high-side power solid state relay with SPI interface for high inductive loads

The ISO808A, ISO808A-1 (PowerSO-36) and ISO808AQ, ISO808AQ-1 (TFQFPN32) 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.

All features

• V_CC(AMR) = 45 V


• Wide process side op. range V_CC = 9.2 to 36 V


• R_DS(on) = 0.125 Ω per channel (TYP)


• Fast demagnetization of inductive loads V_DEMAG(TYP) = VCC - 54 V


• Per channel process side op. current


• ISO808A/ISO808AQ I_OUT < 0.7 A


• ISO808A-1/ISO808AQ-1 I_OUT < 1 A


• Low process and logic sides supply current


• Under-voltage shut down with auto restart and hysteresis


• Logic side 5 V and 3.3 V TTL/CMOS and MCU compatible I/Os


• Logic side SPI interface


• Common output enable/disable pin


• Reset function for IC outputs disable


• High common mode transient immunity


• Short circuit protection on output channels


• ISO808A/ISO808AQ I_LIM(MIN) = 0.7 A


• ISO808A-1/ISO808AQ-1 I_LIM(MIN) = 1 A


• Per-channel over-temperature protection with thermal independence of separate channels


• Case over-temperature protection


• Over-voltage protection (V_CC clamping)


• Loss of GND and V_CC protections


• Common fault open drain diagnostic


• V_CC Power Good open drain diagnostic for 24 V applications


• Designed to meet IEC 61000-4-2, IEC 61000- 4-4, IEC 61000-4-5 and IEC 61000-4-8


• UL1577 and UL508 certified


• PowerSO-36 and TFQFPN32 Package

Datasheet - ISO808A-1