A4937 Abridged Datasheet

A4937
Automotive 3-Phase MOSFET Driver
Description
Features and Benefits
• High current 3-phase gate drive for N-channel MOSFETs
• SPI compatible serial control
• Cross-conduction protection
• Programmable dead time
• 5.5 to 50 V supply voltage range
• TTL inputs compatible with 3.3 V and 5 V logic
• Extensive diagnostics output
• Low current sleep mode
Applications
The A4937 is a 3-phase controller for use with N-channel
external power MOSFETs and is specifically designed for
automotive applications.
A unique charge pump regulator provides full (>10 V) gate
drive for battery voltages down to 7 V and allows the A4937
to operate with a reduced gate drive, down to 5.5 V.
A bootstrap capacitor is used to provide the above battery
supply voltage required for N-channel MOSFETs.
Full control over all six power MOSFETs in the 3-phase bridge
is provided, through an SPI compatible serial interface, allowing
motors to be driven with block or overlap commutation. Power
output can be regulated by one or both of the PWM inputs.
The power MOSFETs are protected from shoot-through by
integrated crossover control and programmable dead time.
• Electronic power steering (EPS, EHPS, EAS)
• Hydraulic pumps
• Gearbox actuator
Integrated diagnostics provide indication of undervoltage,
overtemperature, and power bridge faults, and can be configured
to protect the power MOSFETs under most short circuit
conditions. Detailed diagnostics are available as a serial data
word.
Package: 28-pin TSSOP with Exposed
Thermal Pad (suffix LP)
The A4937 is supplied in a 28-pin TSSOP power package with
with exposed pad for enhanced thermal dissipation (package
type LP). This package is lead (Pb) free, with 100% matte-tin
leadframe plating.
Not to scale
Functional Block Diagram
VBAT
A8450
VBAT
Regulator
SPI
Microcontroller
PWM
Reset
Diagnostics
A4937A-DS
A4937
3-Phase
BLDC
Motor
A4937
Automotive 3-Phase MOSFET Driver
Selection Guide
Part Number
Packing*
A4937KLPTR-A-T
4000 pieces per 13-in. reel
Package
4.4 mm × 9.7 mm, 1.2 mm maximum height TSSOP
with exposed thermal pad
*Contact Allegro™ for additional packing options.
Absolute Maximum Ratings*
Characteristic
Symbol
Notes
Rating
Unit
Load Supply Voltage
VBB
–0.3 to 50
V
Logic Supply Voltage
VDD
–0.3 to 6
V
Terminal VREG
VREG
–0.3 to 16
V
Terminal CP1
VCP1
–0.3 to 16
V
VCP2
VCP1 – 0.3 to
VREG + 0.3
V
–0.3 to 6
V
–0.3 to 6
V
–0.3 to VDD + 0.3
V
Terminal CP2
STRn, SCK, SDI, PWMH, PWML
Logic Inputs
VI
Logic Outputs
VO
Terminal DIAG
VDIAG
–0.3 to VDD + 0.3
V
Terminal VBRG
VBRG
–5 to 55
V
VCx
–0.3 to VREG + 50
V
VGHx
VCx – 16 to
VCx + 0.3
V
VSx
VCx – 16 to
VCx + 0.3
V
Terminals GLA, GLB, GLC
VGLx
VREG – 16 to 18
V
Terminal LSS
VLSS
VREG – 16 to 18
V
–40 to 150
°C
150
°C
175
°C
–55 to 150
°C
Terminals CA, CB, CC
Terminals GHA, GHB, GHC
Terminals SA, SB, SC
Ambient Operating Temperature
Range
TA
Maximum Continuous Junction
Temperature
TJ(max)
Transient Junction Temperature
TtJ
Storage Temperature Range
Tstg
RESETn; can be pulled to VBB with >22 kΩ
SDO
Limited by power dissipation
Overtemperature event not exceeding 10s,
lifetime duration not exceeding 10 hours,
guaranteed by design characterization.
*With respect to GND. Ratings apply when no other circuit operating constraints are present.
Thermal Characteristics may require derating at maximum conditions
Characteristic
Symbol
Package Thermal Resistance (Junction
to Ambient)
RθJA
Package Thermal Resistance (Junction
to Pad)
RθJP
Value
Unit
On 4-layer PCB based on JEDEC standard
Test Conditions*
28
ºC/W
2-layer PCB with 3.8 in.2 of copper area
each side
32
ºC/W
2
ºC/W
*Additional thermal information available on the Allegro website.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
A4937
Automotive 3-Phase MOSFET Driver
Functional Block Diagram
Battery +
CP
VDD
CP1
CP2
VBB
RESETn
Charge
Pump
Regulator
VBAT
VREG
CREG
VBRG
Phase A
CA
PWMH
CBOOTA
PWML
High Side
Drive
Control
Logic
Bootstrap
Monitor
VDS
Monitor
GHA
One of three phases shown
RGATE
SA
VDS
Monitor
VREG
Low Side
Drive
GLA
RGATE
Phase C
Phase B
LSS
STRn
SCK
SDI
SDO
DIAG
Serial
Interface
Diagnostics
and
Protection
GND
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
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