Preliminary
RT9902
4 Channel DC/DC Converters IC with High-Efficiency Step-Up
and Step-Down
General Description
The RT9902 is a complete power supply solution for digital
still cameras and other hand-held devices. It integrates a
high-efficiency main step-up DC-DC converter, two high-
efficiency step-down converters, a charge pump, and a
linear controller that drives an external P-MOSFET for linear
regulator. The RT9902 is targeted for applications that use
either two or three AA cells or a single lithiumion battery.
The main step-up DC-DC converter accepts inputs from
1.5V to 5.5V and build in 2.6A Internal switch. The two
step-down DC-DC converters (CH2, CH3) accept inputs
from 1.5V to 5.5V and regulate a resistor adjustable
output from 0.8V to 5.5V. Each DC-DC converter
has
independent shutdown input.
The feature of the charge pump is to deliver few current
to micro-controller when the system operates in the
standby mode. RT9902 includes a linear controller with
0.8V reference voltage. An adjustable operating frequency
(up to 1.4MHz) is utilized to get optimum size, cost, and
efficiency.
RT9902 is available in VQFN-32L 5x5 package.
Features
1.5V to 5.5V Battery Input Voltage Range
Main step-up DC-DC Converter
1.5V to 5.5V Adjustable Output Voltage
Up to 90% Efficiency
2.6A, 0.3Ω Internal Power Switch
Ω
Two Step-Down DC-DC Converters
0.8V to 5.5V Adjustable Output Voltage
94% Efficiency
100% Duty Cycle
Step-up Charge Pump for Micro-Controller
Linear Controller for Linear Regulator
Up to 1.4MHz Switching Frequency
1μA Supply Current in Shutdown Mode
μ
Programmable Soft Start Function
Independent Enable Pin (CH1, CH2, CH3)
External Compensation Network (CH1, CH2, CH3)
Short Circuit Protection (CH1, CH2, CH3)
Over Voltage Protection (CH2)
32-Lead VQFN Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Digital Still Cameras
PDAs
Portable Devices
Ordering Information
RT9902
Package Type
QV : VQFN-32L 5x5 (V-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Pin Configurations
(TOP VIEW)
COMP2
ENM
25
24
23
22
GND
EN3
EN2
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.
COMP3
VDD3
LX3
PGND3
SS
RT
GND
LDO_O
1
2
3
4
5
6
7
8
32 31
30 29 28
27 26
EN1
FB3
FB2
VDD2
VDD2
LX2
LX2
PGND2
LX1
LX1
VDD1
GND
21
20
19
33
18
17
9
10
11 12 13
14 15
16
COMP1
VQFN-32L 5x5
DS9902-10 August 2007
www.richtek.com
1
PGND1
FB1
VDDC
LFB
VDDM
CPFB
CX
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
