RT9907_11 Datasheet, PDF (1/19 Pages) Richtek Technology Corporation – 3 Channel DC/DC Converters IC with High-Efficiency Step-Up and Step-Down

RT9907
3 Channel DC/DC Converters IC with High-Efficiency Step-Up
and Step-Down
General Description
The RT9907 is a three channel power-supply solution for
digital still cameras and other battery-powered devices. It
integrates an asynchronous step-up and two synchronous
step-down DC-DC converters. The RT9907 is targeted for
applications that use two AA cells or a single lithium-ion
battery.
The three DC-DC converters (CH1, CH2, CH3) accept input
voltage from 1.5V to 5.5V. Each DC-DC converter has
better transient response and excellent stability by
providing current-mode control and external compensation
network. With built-in Internal MOSFET and up to 1.4MHz
operating frequency, the RT9907 allows minimum BOM
cost and PCB area.
The step-down DC-DC converters (CH2, CH3) can regulate
output voltage as low as 0.8V. Three operational modes
are available: PWM, PSM, Low-Dropout modes. At PWM
mode, Internal synchronous rectifier with low R_DS(ON)
dramatically reduces conduction loss and achieve 94%
efficiency. It enters Low-Dropout mode when normal PWM
cannot provide regulated output voltage by continuously
turning on the upper P-MOSFET. No external Schottky
diode is required in practical application.
Each DC-DC converter has independent enable input and
soft-start function allowing versatile power sequence
combination. Complete protection functions are
implemented such as short circuit, over-voltage protection.
Features
z 1.5V to 5.5V Battery Input Voltage Range
z 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
z Two Step-Down DC-DC Converters
` 0.8V to 5.5V Adjustable Output Voltage
` 94% Efficiency
` 100% Duty Cycle
z Up to 1.4MHz Switching Frequency
z 1uA Supply Current in Shutdown Mode
z Programmable Soft Start Function
z Independent Enable Pin (CH1, CH2, CH3)
z External Compensation Network (CH1, CH2, CH3)
z Short Circuit Protection (CH1, CH2, CH3)
z Over Voltage Protection (CH2)
z 24-Lead VQFN Package
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Digital Still Camera
z PDAs
z Portable Device
Pin Configurations
(TOP VIEW)
The RT9907 is available in small VQFN-24L 4x4 package.
Ordering Information
RT9907
Package Type
QV : VQFN-24L 4x4 (V-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Richtek 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.
24 23 22 21 20 19
COMP3 1
18 EN1
VDD3 2
17 ENM
LX3 3
PGND3 4
GND
16 VDD2
15 LX2
SS 5
RT 6
14 PGND2
25 _{13 LX1}
7 8 9 10 11 12
VQFN-24L 4x4
DS9907-10 April 2011
www.richtek.com
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