1 General description

The 33879 device is an 8-output hardware configurable, high-side/low-side switch with 16-bit serial input control using the Serial Peripheral Interface (SPI). Two of the outputs may be controlled directly via a microcontroller for pulse-width modulation (PWM) applications. The 33879 incorporates SMARTMOS technology, with CMOS logic, bipolar/MOS analog circuitry, and DMOS power MOSFETs. The 33879 controls various inductive, incandescent, or LED loads by directly interfacing with a microcontroller. The circuit’s innovative monitoring and protection features include very low standby currents, cascade fault reporting, internal +45 V clamp voltage for low-side configuration, –20 V high-side configuration, output specific diagnostics, and independent overtemperature protection.

2 Features and benefits

• Designed to operate at 5.5 V < VPWR < 27.5 V

• 16-bit SPI for control and fault reporting, 3.3 V / 5.0 V compatible

• Outputs are current limited (0.6 A to 1.2 A) to drive incandescent lamps

• Output voltage clamp, + 45 V (low side) and –20 V (high side) during inductive switching

• On/Off control of open load detect current (LED application)

• Internal reverse battery protection on VPWR

• Loss of ground or supply will not energize loads or damage IC

• Maximum 5.0 μA IPWR standby current at 13 V VPWR

• RDS(ON) of 0.75 Ω at 25 °C typical

• Short-circuit detect and current limit with automatic retry

• Independent overtemperature protection

5 Applications

• Solenoids

• Relays

• Actuators

• Stepper motors

• Brush DC motors

• Incandescent lamps