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A3938
Three-Phase Power MOSFET Controller

AB SO LUTE MAX I MUM RAT INGS
Load Supply Voltage, VBB ...................................50 V
VREG (Transient) ...............................................15 V
Logic Input Voltage Range, VIN ...�C0.3 V to VLCAP +0.3 V
Sense Voltage, VSENSE ............................�C5 V to 1.5 V
Pins: SA, SB, SC ....................................�C5 V to 50 V
Pins: GHA, GHB, GHC ...................�C5 V to VBB + 17 V
Pins: CA, CB, CC ...........................SA/SB/SC + 17 V
Operating Temperature Range
Ambient Temperature, TA ............�C20��C to +85��C
Junction Temperature, TJ ...........................+150��C
Storage Temperature, TS...........�C55��C to +150��C
Thermal Impedance (Typical), at TA = +25ºC;
measured on a JEDEC-standard "High-K" PCB
A3938EQ, R��JA ........................................37��C/W
A3938LD, R��JA ........................................38��C/W
A3938LQ, R��JA ........................................44��C/W

The A3938 is a three-phase, brushless dc motor controller. The A3938
high-current gate drive capability allows driving of a wide range of
power MOSFETs and can support motor supply voltages to 50 V. The
A3938 integrates a bootstrapped high-side driver to minimize the external
component count required to drive N-channel MOSFET drivers.
Internal fi xed off-time, PWM current-control circuitry can be used to
regulate the maximum load current to a desired value. The peak load
current limit is set by the user��s selection of an input reference voltage
and external sensing resistor. A user-selected external RC timing
network sets the fi xed off-time pulse duration. For added fl exibility, the
PWM input can provide speed/torque control where the internal current
control circuit sets a limit on the maximum current.
The A3938 includes a synchronous rectifi cation feature. This shorts out
the current path through the power MOSFET reverse body diodes during
PWM off-cycle current decay. This can minimize power dissipation
in the MOSFETs, eliminate the need for external power clamp diodes,
and potentially allow a more economical choice for the MOSFET drivers.
The A3938 provides commutation logic for Hall sensors confi gured for
120-degree spacing. The Hall input pins are pulled-up to an internallygenerated
5 V reference. Power MOSFET protection features include:
bootstrap capacitor charging current monitor, regulator undervoltage
monitor, motor lead short-to-ground, and thermal shutdown.
The LD package is available in a lead-free version (100% matte tin
plated leadframe).

FEATURES
􀂄 Drives wide range of N-channel MOSFETs
􀂄 Low-side synchronous rectifi cation
􀂄 Power MOSFET protection
􀂄 Adjustable dead time for cross-conduction
protection
􀂄 Selectable coast or dynamic brake on
power-down or RESET input
􀂄 Fast/slow current decay modes
AB SO LUTE MAX I MUM RAT INGS
􀂄 Internal PWM current control
􀂄 Motor lead short-to-ground
protection
􀂄 Internal 5 V regulator
􀂄 Fault diagnostic output
􀂄 Thermal shutdown
􀂄 Undervoltage protection