A3904 Datasheet, PDF (1/7 Pages) Allegro MicroSystems – Low Voltage Voice Coil Motor Driver

A3904
Low Voltage Voice Coil Motor Driver
Features and Benefits
▪ Fixed I²C logic thresholds
▪ 8-bit D-to-A converter
▪ 500 μA resolution
▪ Low voltage I²C serial interface
▪ Low current-draw sleep mode
▪ 2.4 to 5.5 V operation
▪ 1.1 mm × 0.7 mm, 0.5 mm maximum overall height WLCSP
Package: 6-ball wafer-level chip scale
package (CG)
1.1 mm × 0.7 mm
Description
The A3904 is a voice coil motor (VCM) driver, with an
I²C-compatible serial interface. Designed for camera autofocus
and zoom applications, this high accuracy digital IC is provided
in a WLCSP package ideal for portable devices. Its operating
voltage range is 2.4 to 5.5 V, and its maximum output current
is 127 mA.
Output current is programmed via the I²C interface, in 500 uA
increments, with clock rates up to 400 kHz. I²C inputs set the
internal D-to-A converter output voltage that is the reference
for linear current control via a MOSFET output sink transistor.
To conserve battery power, a logic low signal on the SLEEPZ
input disables the output MOSFET and reduces the supply
current to <0.5 μA.
A3904 internal protection features include thermal shutdown
and undervoltage lockout. Logic input levels are independent
of the supply voltage. The operating temperature range is
–40°C to 85°C.
The A3904 is available in a bumped wafer level chip scale
package (WLCSP) (suffix CG).
Not to scale
Functional Block Diagram
1.8 V
1.8 kΩ
1.8 kΩ
I²C
Master
I²C
Slave
VDD
SDA
SCL
SLEEPZ
Bandgap
Ref
I²C Serial
Interface
8 Bit DAC
EW only
PAD
2.4 to 5.5 V
IOUT
2.4 Ω
GND
3904-DS, Rev. 4