A8481 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – Dual Output Boost Regulator Using Single Inductor

A8481
Dual Output Boost Regulator Using Single Inductor
Features and Benefits
▪ Two independently controlled channels for dual display
▪ Output voltage up to 23 V
▪ 2.7 to 9 V input
▪ Output disconnect allows less than 1 μA supply current
during shutdown
▪ Single-pin dimming control for WLED
▪ 1.2 MHz switching frequency
▪ 1.5 A switch current limit
▪ OVP, Pulse-by-Pulse OCP, OTP, and Soft Start
Package: 10 pin MLP/DFN (suffix EJ) with
exposed thermal pad
Description
The A8481 is a step-up dc-to-dc converter in a thermally-
enhanced MLP package. A constant 1.2 MHz switching
frequency, with current-mode control scheme, provides stable
low-noise operation at high load conditions.
The A8481 is a dual output OLED + WLED driver. This device
is suitable for driving OLED bias supply as well as WLEDs
for backlight. For OLED it is capable of delivering 80 mA at
18 V, and can drive five WLEDs at 20 mA.
Independent output control and output disconnect make this
IC ideally suited for battery operated, dual display portable
applications. The IC disconnects input from the output path
during shutdown, allowing shutdown currents less than 1 μA.
The A8481 is available in a 10-pin 3 mm × 3 mm MLP package
that has a nominal height of only 0.75 mm.
Applications include:
▪ Dual-panel cellular phone with OLED and
WLED backlight
▪ Personal Digital Assistant (PDA)
▪ Camcorder, personal stereo, MP3 player, camera
Approximate Scale 1:1
CIN
VSUPPLY
Typical Applications
Additional applications on page 11
L1
1
GND
D1
10
SW
2
FB1
CAP ⁹
3
VIN
A8481
OUT1
8
4 _OUT2
ISET ⁷
5 _ON2
ON1 ⁶
V_OUT
COUT
R1
CIN
VSUPPLY
L1
1
GND
D1
SW ¹⁰
2
FB1
CAP ⁹
3
VIN
A8481
OUT1
8
4 _OUT2
ISET ⁷
5 _ON2
ON1 ⁶
VOUT
COUT
R1
RSET
R2
PWM
RP
Q1
RSET
R2
Figure 1a. Typical application circuit for A8481
driving OLED and three WLEDs
8481-DS, Rev. 2
Figure 1b. OUT2 current dimming with PWM on
ISET pin, with parallel resistor