Preliminary
RT9262/A
High Efficiency, Low Supply Current,
Step-up DC/DC Converter
General Description
The RT9262/A is a compact, high efficient, step-up
DC/DC converter with an adaptive current mode
PWM control loop, providing a stable and high
efficient operation over a wide range of load
currents. It operates in both continuous and
discontinuous current modes in stable waveforms
without external compensation.
The low start-up input voltage below 1V makes
RT9262/A suitable for 1 to 4 battery cell applications
providing up to 400mA output current. The 550KHz
high switching rate minimized the size of external
components. Besides, the 17µA low quiescent
current together with high efficiency maintains long
battery lifetime.
The 1.8V to 5V output voltage is set with 2 external
resistors. Both internal 2A switch and driver for
driving external power devices (NMOS or NPN) are
provided.
A 300mA LDO is included in RT9262 to provide a
secondary low noise output as well as an output
current stop in the shutdown mode. Similarly, a 1.8V
to 5V LDO output voltage can be set with 2 external
resistors. For RT9262A, a low battery detector with
0.86V detection voltage is included. RT9262/A are
provided in SOP-8 packages.
Features
1.0V Low Start-up Input Voltage
High Supply Capability to Deliver 3.3V 100mA
with 1V Input Voltage
17µA Quiescent (Switch-off) Supply Current
90% Efficiency
550KHz Fixed Switching Rate
Providing Flexibility for Using Internal and
External Power Switches
Built-in 300mA LDO, also for the Zero-Output-
Current Shutdown Mode (RT9262)
Boost DC-DC Integrating LDO for Up-Down
Regulation (RT9262)
Built-in 0.86V Voltage Detector (RT9262A)
8-Pin SOP Package
Applications
PDA
Portable Instrument
Wireless Equipment
DSC
LCD Back Bias Circuit
RF-Tags
Pin Configurations
Part Number
RT9262CS
(Plastic SOP-8)
Pin Configurations
TOP VIEW
GND
1
EXT
2
LFB
3
8
7
6
5
CE
LX
VDD
FB
Ordering Information
RT9262A
Package type
S : SOP-8
Operating temperature range
C: Commercial standard
A : Include low battery detector
Default : Include LDO
RT9262ACS
(Plastic SOP-8)
LDOO
4
TOP VIEW
GND
1
EXT
2
LBO
3
LBI
4
8
7
6
5
CE
LX
VDD
FB
DS9262/A-04 August 2002
www.richtek.com
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RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
