Preliminary
RT9903
5 Channel DC/DC Converters IC with High-Efficiency Step-Up
General Description
Features
z Two step-up DC-DC Converters (CH1, CH2)
The RT9903 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.
`HV Internal Switches
`50mA Load Current
z One Step-up DC-DC Converter (CH3)
`0.2V Reference Voltage
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-upDC-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.
`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 Step-up Charge Pump (CH5) for CCD Negative
Voltage
`HV Internal Switches
The feature of the charge pump (CH5) is to deliver few
current to CCD negative voltage.
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)
RT9903 is available in VQFN-24L 4x4 package. Each
DC-DC converters have independent shutdown inputs.
Applications
z Digital Still Camera
z Independent Enable Pin to Shutdown Each
Channel
z PDAs
z 24-Lead VQFN Package
z PortableDevice
z RoHS Compliant and 100% Lead (Pb)-Free
Ordering Information
Pin Configurations
RT9903
(TOP VIEW)
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)
24 23 22 21 20 19
1
2
3
4
5
6
18
17
16
15
14
13
CX
INCD
FB_CP
RT
LX1
VDD
PGND
EN4
EN2
EN1
Note :
Richtek Pb-free and Green products are :
`RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
GND
EXT4
CS4
25
10 11 12
7
8
9
`Suitable for use in SnPb or Pb-free soldering processes.
`100% matte tin (Sn) plating.
Marking Information
VQFN-24L 4x4
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area, otherwise visit our website for detail.
DS9903-07 August 2007
www.richtek.com
1