Features: REFERENCE ±800 mA Continuous Output Current Rating
45 V Output Voltage Rating
Internal PWM Current Control, Saturated Sink Drivers
Internally Generated Precision 2.5 V Reference
nternal Transient-Suppression Diodes
Internal Thermal-Shutdown Circuitry
Crossover-Current Protection, UVLO ProtectionPinout
SpecificationsLoad Supply Voltage, VBB . . . . . . . .... . . 45 V
Output Current, IOUT . . . . . . . . ... . ±800 mA*
Logic Supply Voltage, VCC . . . . . . . . .... 7.0 V
Logic Input Voltage Range,
VIN . . . . . . . . . ...... . -0.3 V to VCC + 0.3 V
Sense Voltage, VSENSE . . . . . . . . . . . . 1.0 V
Reference Output Current,
IREF OUT . . . . . . . . . . . . . . . . . ....... . 1.0 mA
Package Power Dissipation,
PD . . . . . . . . . . . . . . . . . . ..... .. See Graph
Operating Temperature Range,
TA . . . . . . . . . . . . . . . . . -20°C to +85°C
Junction Temperature, TJ . . .. . . . . +150°C†
Storage Temperature Range,
TS . . . . . . . . . . . . . . . . -55°C to +150°CDescriptionDesigned for pulse-width modulated (PWM) current control of bipolar stepper motors, the A3961S- is capable of continuous output currents to ±800 mA and operating voltages to 45 V. Internal fixed off-time PWM current-control circuitry can be used to regulate the maximum load current to a desired value. An internal precision voltage reference is provided to improve motor peak current control accuracy. The peak load current limit is set by the user's selection of an external resistor divider and current-sensing resistors.
The fixed off-time pulse duration is set by user-selected external RC timing networks. 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 transi-tions. This eliminates the need for two external RC filter networks on the current-sensing comparator inputs.
For each bridge the PHASE input controls load current polarity by selecting the appropriate source and sink driver pair. For each bridge the ENABLE input, when held high, disables the output drivers. Specia power-up sequencing is not required. Internal circuit protection includes thermal shutdown with hysteresis, transient-suppression diodes, and
crossover-current protection.
The A3961S- is supplied in a choice of two power packages:24-pin dual-in-line plastic package with copper heat-sink tabs and 24-lead plastic SOIC with copper heat-sink tabs. In both packages the power tab is at ground potential and needs no electrical isolation.
3961 Data Sheet
