The A3968SA and A3968SLB are designed to bidirectionally control two dc motors. Each device includes two H-bridges capable of continuous output currents of ±650 mA and operating voltages to 30 V. Motor winding current can be controlled by the internal fixed-frequency, pulse-width modulated (PWM), current-control circuitry. The peak load current limit is set by the user's selection of a reference voltage and current-sensing resistors. Except for package style and pinout, the two devices are identical. The fixed-frequency pulse duration is set by a user-selected external RC timing network.
The capacitor in the RC timing network also determines a user-selectable blanking window that prevents false triggering of the PWM current-control circuitry during switching transitions.
To reduce on-chip power dissipation, the H-bridge power outputs have been optimized for low saturation voltages. The sink drivers feature the Allegro® patented Satlington® output structure. The Satlington outputs combine the low voltage drop of a saturated transistor and the high peak current capability of a Darlington.
For each bridge, the INPUTA and INPUTB terminals determine the load current polarity by enabling the appropriate source and sink driver pair. When a logic low is applied to both INPUTs of a bridge, the braking function is enabled. In brake mode, both source drivers are turned OFF and both sink drivers are turned ON, thereby dynamically braking the motor. When a logic high is applied to both INPUTs of a bridge, all output drivers are disabled. Special power-up sequencing is not required. Internal circuit protection includes thermal shutdown with hysteresis, ground-clamp and flyback diodes, and crossover-current protection.
The A3968SA is supplied in a 16-pin dual in-line plastic package. The A3968SLB is supplied in a 16-pin plastic SOIC with copper heat sink tabs. The power tab is at ground potential and nee
Load Supply Voltage, VBB ................... 30 V
Output Current, IOUT (peak) ....... ±750 mA
(continuous) ................................ ±650 mA
Logic Supply Voltage, VCC .................. 7.0 V
Input Voltage, Vin ...... -0.3 V to VCC + 0.3 V
Sense Voltage, VS .............................. 1.0 V
Package Power Dissipation (TA = 25°C), PD
A3968SA .......................................... 1.8 W*
A3968SLB ........................................ 1.4 W*
Operating Temperature Range,
TA ................................... -20°C to +85°C
Junction Temperature,
TJ ................................................. +150°C
Storage Temperature Range,
TS ................................. -55°C to +150°C
Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified current rating or a junction temperature of 150°C.
* Per SEMI G42-88 Specification, Thermal Test Board Standardization for Measuring Junctionto- Ambient Thermal Resistance of Semiconductor Packages.
Required Field 
