A3985

A3985 Digitally Programmable Dual Full-Bridge MOSFET Driver FEATURES AND BENEFITS ▪ Serial interface for full digital control ▪ Dual full-bridge gate drive for N-channel MOSFETs ▪ Dual 6-bit DAC current reference ▪ Operation over 12 to 50 V supply voltage range ▪ Synchronous rectification ▪ Cross-conduction protection ▪ Adjustable mixed decay ▪ Fixed off-time PWM current control ▪ Low-current idle mode PACKAGE: 38-pin TSSOP (suffix LD) Not to scale DESCRIPTION The A3985 is a flexible dual full-bridge gate driver suitable for driving a wide range of higher power industrial bipolar 2-phase stepper motors or 2-phase brushless dc motors. It can also be used to drive two individual torque motors or solenoid actuators. Motor power is provided by external N-channel power MOSFETs at supply voltages from 12 to 50 V. Full digital control is provided by two serially accessible registers that allow programming of off-time, blank-time, dead-time, mixed decay ratios, synchronous rectification, master clock source selection, and division ratio and idle mode. All internal timings are derived from a master clock that can be generated on-chip or provided by an external clock such as the system clock of the master controller. A programmable divider allows for a wide range of external system clock frequencies. The internal fixed off-time PWM current-control timing is programmed via the serial interface to operate in slow, fast, and mixed current-decay modes. The desired load-current level and ...