A3998_16 Datasheet, PDF (1/20 Pages) Allegro MicroSystems – Dual DMOS Full Bridge Motor Driver With Serial Port Control and Dual Regulators

A3998
Dual DMOS Full Bridge Motor Driver
With Serial Port Control and Dual Regulators
Features and Benefits
• 3.3/5 V switching regulator
• 1 to 2.5 V configurable linear regulator output
• Dual DMOS full bridge: drive two DC motors or
a single stepper motor
• ±1.5 A, 50 V output rating per bridge
• 4-bit microstepping capability
• Serial port control
• Configurable mixed, fast, and slow current decay
• Synchronous rectification for low power dissipation
• Internal UVLO and thermal shutdown circuitry
• Crossover-current protection
• OCP protection
Package: 32-contact QFN (suffix ET)
Approximate size
Description
Designed to provide the motor driver and power supply
requirements for printers and office automation equipment.
This integrated power IC incorporates two high current,
high performance, full bridge outputs, capable of 1.5 A at
50 V. Additionally two power supply rails are provided for
microprocessor or DSP supplies. A switching buck regulator
steps the supply down to a low voltage output that is adjustable
from 3.3 to 5 V. This voltage can be used to supply external 5 V
rails, it also feeds back into the part and supplies the integrated
linear regulator which is adjustable from 1 to 2.5 V.
The A3998 serial port provides flexible configuration for
the dual full bridge motor driver. Two full bridges can be
programmed to control one stepper motor or two DC motors.
Both bridges have integrated fixed off-time PWM control with
programmable decay mode selection.
The A3998 is supplied in a low profile, 32-contact QFN,
5 × 5 mm, 0.90 mm nominal height, with exposed thermal pad
(suffix ET). The package is lead (Pb) free with 100% matte-tin
leadframe plating.
Functional Block Diagram
VOUT1
3. 3 to 5V
1A
COUT1
220 μF
0.22 μF
VREG
VREF
Controller
SLEEPn
ENB1
ENB2
DATA
CSTLKB
CLK
PMON
L1
SW1
D1
R1
FB1
R2
Gate Supply
Buffer
D/A
System
Control
Serial
Port
VBB
Monitor
D/A
VBB
VBB
Switcher PWM Control
PCAD
0.1 μF
Charge Pump
VCP
0.1 μF
PWM Control
Full Bridge 1
Full Bridge
1
VBB
OUT1A
OUT1B
Control
Logic
PWM Control
Full Bridge 2
VREG
Full Bridge
2
SENSE 1
RS1
VBB
OUT2A
OUT2B
SENSE 2
VIN
RS2
To VREG
CSN
LDO
GD/VOUT2
FB2
POR
FB1
RST
100 ms FRST
R3
R4
42 V
220 μF
0.22 μF
RCL2
VOUT1
Q1
VOUT2
1 to 2.5 V
500 mA
COUT2
10 μF
A3998-DS