Si9978

The Si9978 is an integrated driver for an n-channel MOSFET H-bridge. The mode control allows operation as either a full H-bridge driver or as two independent half-bridges. The DIR/PWM input configuration allows easy implementation of either sign/magnitude or anti-phase PWM drive schemes for full H-bridges. Schmitt triggers on the inputs provide logic signal compatibility and hysteresis for increased noise immunity. An internal low-voltage regulator allows the device to be powered directly from a system supply of 20 to 40 volts. All n-channel gates are driven directly from low-impedance outputs. The addition of one external capacitor per half-bridge allows internal circuitry to level shift both the power supply and logic signal for the high-side n-channel gate drives. Internal charge pumps replace leakage current lost in the high-side driver circuits to provide "static" (dc) operation in any output condition. Protection features include an undervoltage lockout, cross-conduction prevention logic, and overcurrent monitors.

The Si9978 is available in both standard and lead (Pb)-free, 24-pin wide-body SOIC (surface mount) packages, specified to operate over the industrial (−40 to +85) temperature range.