A3936 Datasheet, PDF (1/10 Pages) Allegro MicroSystems – DMOS Three-Phase PWM Motor Driver

A3936
DMOS Three-Phase PWM Motor Driver
Features and Benefits
▪ ±3 A, 50 V continuous output rating
▪ Low r_DS(on) outputs (typically 500 mΩ source,
315 mΩ sink)
▪ Configurable mixed-, fast- and slow-current-decay modes
▪ Synchronous rectification for low power dissipation
▪ Internal UVLO and thermal shutdown circuitry
▪ Crossover-current protection
▪ Tachometer output for external speed control loop
Package: 44-pin PLCC (suffix ED)
Description
Designed for pulse-width-modulated (PWM) current control
of three-phase brushless DC motors, the A3936 is capable of
peak output currents to ±3 A and operating voltages to 50 V.
Internal fixed off-time PWM current-control timing circuitry
can be configured to operate in slow-, fast- and mixed-decay
modes.
Internal synchronous rectification control circuitry is provided
to improve power dissipation during PWM operation.
Internal circuit protection includes thermal shutdown with
hysteresis, and crossover current protection. Special power-up
sequencing is not required.
The A3936 is supplied in a 44-pin plastic PLCC with internally
fused leads (three on each side) for enhanced heat dissipation.
These leads are at ground potential and need no electrical
isolation. This device is lead (Pb) free version, with 100%
matte tin leadframe plating.
Not to scale
A3936-DS, Rev. 8
Typical Application
VREG
OSC
Regulator
Osc
CP1 CP2
Charge Pump ^VCP
TSD
VDD
UVLO [V_DD
V_REG V_CP]
3X Half Bridge
VBB1
VBB2
VDD
TACH
HBIAS
SLEEP
DIR
EXT MODE
BRAKE
Control Logic
and Gate Drive
Fixed Off-Time
PWM Current Ctrl.
Blanking Time
Crossover
Current Protection
OUTA
OUTB
OUTC
M
Zero Current Detect
Current Sense
LSS1
LSS2
SENSE
SR
BLANK
Fast, Slow, and
Mixed Decay
HA–
HB–
HC–
PFD1
Sync. Rect.
HA+
PFD2
HB+
HC+
ENABLE
4X
GND GND GND