1 Features
• Dual H-Bridge Motor Driver
– Single/Dual Brushed DC
– Stepper
– Solenoids
• 4 to 18V Operating Supply Voltage Range
• Low ON-resistance: HS + LS = 900mΩ (Typical,
25°C)
• High Output Current per H-Bridge
– 2A Maximum Driver Current at 12V and TA =
25°C
– Parallel Mode Available Capable of 4A
Maximum Driver Current at 12V and TA = 25°C
• Device versions:
– DRV8421A (4-wire input): Independent Half
Bridge Control
– DRV8421B (2-wire input): Sleep Mode, Fault
detect
• Similar LV Stepper Drivers:
– DRV8410: 1.65 to 11V (800mΩ RDS(ON))
– DRV8411: 1.65 to 11V (400mΩ RDS(ON))
– DRV8411A: 1.65 to 11V (400mΩ RDS(ON))
• PWM Control Interface
• Low-Current 3μA Sleep Mode (2-wire input version
only)
• Thermally-Enhanced Surface Mount Package
• Protection Features
– VM Undervoltage Lockout (UVLO)
– Overcurrent Protection (OCP)
– Thermal Shutdown (TSD)
– Fault Condition Indication Pin (nFAULT) (2-wire
input version only)

2 Applications
• Household Appliances
– Printers/Scanners
– Refrigerators
– Vacuum Cleaners
– Clothes Dryer
• General Brushed and Stepper Motors

3 Description
The DRV8421 provides a dual H-bridge motor
driver for home appliances and other mechatronic
applications. The device can be used to drive one
or two DC motors, a bipolar stepper motor, or other
loads. A simple PWM interface allows easy interfacing
to controller circuits.
The output block of each H-bridge driver consists
of N-channel power MOSFETs configured as full Hbridges
to drive the motor windings. The DRV8421
is capable of driving a maximum current of 2A from
each output or 4A in parallel mode (with proper heat
sinking, at 12V and TA = 25°C).
The device contains two versions having a 4-wire
input (DRV8421A) or a 2-wire input (DRV8421B). The
2-wire input version (DRV8421B) contains features
like enable and fault detection, while the 4-wire input
version (DRV8421A) can drive four half bridges based
on signals to four input terminals. A low-power sleep
mode is also provided for the 2-wire input version.
It shuts down internal circuitry to achieve very-low
quiescent current draw. This sleep mode can be set
by pulling the enable pin low.
Internal protection functions are provided for UVLO,
OCP, short-circuit protection, and overtemperature.
Fault conditions are indicated by a nFAULT pin in the
DRV8421B, the 2-wire input device.