RT9903B Datasheet, PDF (1/15 Pages) Richtek Technology Corporation – 4 Channel DC/DC Converters IC with High-Efficiency Step-Up

Preliminary
RT9903B
4 Channel DC/DC Converters IC with High-Efficiency Step-Up
General Description
The RT9903B is a complete power-supply solution for
digital still cameras and other hand-held devices. It
integrates a high-efficiency fours step-up DC-DC
converters and a charge pump.
The two Step-up DC-DC converters (CH1,CH2) accept
inputs from 1.5V to 5.5V and regulate a resistor-
adjustable output up to 17V. One Step-up DC-DC
converter (CH3) can be regarded as white LED Driver,
which reference voltage is 0.2V and have OVP function.
One step-up DC-DC converter (CH4) regulate a resistor-
adjustable output up 5V. An adjustable operating
frequency (up to 1.4MHz) is utilized to get optimum size,
cost, and efficiency.
RT9903B is available in VQFN-24L 4x4 package. Each
DC-DC converters have independent shutdown inputs.
Applications
z Digital Still Camera
z PDAs
z Portable Device
Ordering Information
RT9903B
Package Type
QV : VQFN-24L 4x4 (V-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Note :
Richtek Pb-free and Green products are :
`RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
`100% matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area, otherwise visit our website for detail.
Features
z Two step-up DC-DC Converters (CH1, CH2)
`HV Internal Switches
`50mA Load Current
z One Step-up DC-DC Converter (CH3)
`0.2V Reference Voltage
`HV Internal Switches
`LED Brightness Dimming Control
`Over Voltage Protection
z One Step-up DC-DC Converter (CH4)
`External Switches
`External Current Limit Setting
z Up to 1.4MHz Switching Frequency
z 1μA Supply Current in Shutdown Mode
z External Compensation Network for All Converters
z Programmable Soft Start Function (CH1, CH2, CH3,
CH4)
z Independent Enable Pin to Shutdown Each
Channel
z 24-Lead VQFN Package
z RoHS Compliant and 100% Lead (Pb)-Free
Pin Configurations
(TOP VIEW)
24 23 22 21 20 19
NC 1
18 LX1
PGND 2
17 VDD
PGND 3
RT 4
GND
16 PGND
15 EN4
EXT4 5
CS4 6
14 EN2
25 _{13 EN1}
7 8 9 10 11 12
VQFN-24L 4x4
DS9903B-07 August 2007
www.richtek.com
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