A8480 Datasheet, PDF (2/17 Pages) Allegro MicroSystems – Boost Regulator for Display Bias or LED Driver

A8480
Boost Regulator for Display Bias or LED Driver
Features and Benefits
▪ Output disconnect during shutdown
▫ 1 μA shutdown current
▪ 2.7 to 9 V input
▫ Operate with 1 or 2 Li+ battery input supply
▪ Output voltage up to 23 V
▪ 1.2 MHz switching frequency
▪ 1.5 A switch current limit
▪ Internal overvoltage and overtemperature protection,
and soft start
Package:
9-pin CSP (suffix CG)
10-pin MLP/DFN (suffix EJ)
with exposed thermal pad
Approximate Scale 1:1
Description
TheA8480 is a 1.2 MHz optimized boost converter with internal
soft-start and compensation to support WLED, flash/torch,
and display bias applications. The input voltage range of
2.7 to 9 V supports either 1 or 2 Li-ion battery applications.
The high voltage integrated double-diffused MOSFET (DMOS)
allows output voltages as high as 23 V with a switch current
limit of 1.5 A, this increases the maximum quantity of LEDs
that can be used in series.
To maximize battery life in the application, the output can be
completely disconnected from the battery voltage to virtually
eliminate leakage current in the system. The disconnect switch
can pass up to 80 mA current. For system protection, the A8480
has internal overtemperature and overvoltage protection.
The A8480 can be used as a general purpose boost converter
by taking power through the CAP pin. In this configuration, it
can provide up to 520 mA at 12 V with 5.5 V input voltage.
The A8480 is available in both 1.6 mm × 1.6 mm, 0.5 mm
nominal height CSP, and 3 mm × 3 mm, 0.75 mm nominal
height MLP/DFN packages.
Applications include:
▪ WLED flash/torch
▪ WLED backlight
▪ OLED bias supplies
▪ LCD bias supplies
▪ General purpose boost converter
Typical Applications
VSUPPLY
2.8 to 5 V
L1
22 μH
MBRA130LT3
VOUT
CIN
1 μF
6.3 V
D1
EJ only
B1[3] A8480
VIN
[1] _[PGND]
SW _A3[10]
B2[2]
FB[FB1]
CAP _A2[9]
RADJ
12.1 kΩ
FBADJ
C1[4]
DIM
C2[5]
OUT1
B3[8]
GND _A1[7]
ON1
C3[6]
48 kΩ
COUT
2.2 μF
16 V
30 Ω
VSUPPLY
L1
D1
EJ only
B1[3] A8480
VIN
[1] _[PGND]
SW _A3[10]
CAP _A2[9]
B2[2]
FB[FB1]
OUT1
B3[8]
FBADJ
C1[4]
GND _A1[7]
CIN
DIM
ON1
C2[5]
C3[6]
VOUT
COUT
R1
R2
Square brackets indicate pin names or numbers used only with the EJ package;
where no brackets are shown with a pin name, name applies to both CG and EJ packages
Square brackets indicate pin names or numbers used only with the EJ package;
where no brackets are shown with a pin name, name applies to both CG and EJ packages
Figure 1. Using the A8480 to drive a flash (100 mA) or
torch (20 mA)
Figure 2. The A8480 used as a general boost
8480-DS, Rev. 4