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
Internal PWM current control
Motor lead short-to-ground
protection
Internal 5 V regulator
Fault diagnostic output
Thermal shutdown
Undervoltage protectionSpecificationsLoad Supply Voltage, VBB .............................................50 V
VREG (Transient) ...........................................................15 V
Logic Input Voltage Range, VIN ......0.3 V to VLCAP +0.3 V
Sense Voltage, VSENSE ................................ 5 V to 1.5 V
Pins: SA, SB, SC.................................................5 V to 50 V
Pins: GHA, GHB, GHC.............................. 5 V to VBB + 17 V
Pins: CA, CB, CC .........................................SA/SB/SC + 17 V
Operating Temperature Range
Ambient Temperature, TA.........................20°C to +85°C
Junction Temperature, TJ.........................................+150°C
Storage Temperature, TS ......................55°C to +150°C
Thermal Impedance (Typical), at TA = +25ºC;
measured on a JEDEC-standard "High-K" PCB
A3938EQ, RJA .......................................................37°C/W
A3938LD, RJA .......................................................38°C/W
A3938LQ, RJA........................................................44°C/WDescriptionThe A3938 is a three-phase, brushless DC motor controller. It has a high-current gate drive capability that allows driving of a wide range of power MOSFETs and can support motor supply voltages to 50V. The A3938 integrates a bootstrapped high-side driver to minimize the external 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 selection of an input reference voltage and external sensing resistor. A userselected 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 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 configured for 120-degree spacing. The Hall input pins are pulled-up to an internally-generated 5V 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 lead (Pb) free, with 100% matte tin plated leadframe.
A3938 Data Sheet
