A3938SEQ Datasheet, PDF (1/11 Pages) Allegro MicroSystems – Three-Phase Power MOSFET Controller

A3938
Three-Phase Power MOSFET Controller
A3938EQ, 32-pin PLCC
A3938LQ, 36-pin QSOP
A3938LD, 38-pin TSSOP
ABSOLUTE MAXIMUM RATINGS
Load Supply Voltage, V ...................................50 V
BB
VREG (Transient) ...............................................15 V
Logic Input Voltage Range, V_IN ...–0.3 V toV_LCAP+0.3 V
Sense Voltage, V_SENSE ........................... –5 V to 1.5 V
Pins: SA, SB, SC................................... –5 V to 50 V
Pins: GHA, GHB, GHC .................. –5 V toV_BB+ 17 V
Pins: CA, CB, CC ...........................SA/SB/SC + 17 V
Operating Temperature Range
Ambient Temperature, T .............–20°C to +85°C
A
Junction Temperature, T_J............................+150°C
Storage Temperature, T_S ..........–55°C to +150°C
Thermal Impedance (Typical), at T_A = +25ºC;
measured on a JEDEC-standard "High-K" PCB
A3938EQ, R_θJA ........................................37°C/W
A3938LD, R_θJA ........................................38°C/W
A3938LQ, R ........................................44°C/W
θJA
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 exter-
nal component count required to drive N-channel MOSFET drivers.
Internal fixed 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 volt-
age and external sensing resistor. A user-selected external RC timing
network sets the fixed off-time pulse duration. For added flexibility, 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 rectification feature. This shorts out
the current path through the power MOSFET reverse body diodes dur-
ing 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 configured for
120-degree spacing. The Hall input pins are pulled-up to an internally-
generated 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 „ Internal PWM current control
„ Low-side synchronous rectification
„ Power MOSFET protection
„ Motor lead short-to-ground
protection
„ Adjustable dead time for cross-con- „ Internal 5 V regulator
„
duction protection
Selectable coast or dynamic brake on
„
Fault diagnostic output
power-down or RESET input
„ Thermal shutdown
„ Fast/slow current decay modes
„ Undervoltage protection
Use the following complete part numbers when ordering:
Part Number
A3938SEQ
A3938SLQ
A3938SLD
A3938SLD-T
Pins
32
36
38
38
Package
PLCC
QSOP
TSSOP
TSSOP, Lead-free