XC9244 Datasheet, PDF (1/24 Pages) Torex Semiconductor – 400mA Synchronous Step-Down DC/DC Converters

XC9244/XC9245 Series
ETR0520-006
400mA Synchronous Step-Down DC/DC Converters
˙GENERAL DESCRIPTION
ˑGreenOperation Compatible
The XC9244/XC9245 series is a group of synchronous-rectification type step-down DC/DC converters with a built-in
0.65Њ
P-channel MOS driver transistor and 0.45Њ N-channel MOS switching transistor, designed to allow the use of
ceramic capacitors. Output current of 400mA (MAX.) to be configured using only a coil and capacitor connected externally.
The output voltage can be set from 0.8V to 4.0V in increments of 0.05V (accuracy: ±2.0%). With an internal switching
frequency of 1.2MHz, small external components can be used. USPN-6 package is suitable for the application which
requires low profile and small-footprint.
The XC9244 series is PWM fixed frequency control, and the XC9245 series is PWM/PFM, which automatically switches
from PWM to PFM during light loads, high efficiency can be achieved over a wide range of load conditions. When
stand-by mode, due to stop all operation, supply current is reduced to 1ЖA or less. The integrated C_L discharge function
which enables the electric charge at the output capacitor C_L to be discharged via the internal discharge switch located
between the V_OUT and V_SS pins. The C_L discharge function prevents malfunction on V_OUT connecting application during
stand-by mode.
The XC9244/XC9245 series has a high speed soft-start as fast as 0.25ms in typical for quick turn-on. Current limiter
circuit (Constant Current & Latching) is built-in for preventing from thermal destruction. With UVLO (Under Voltage Lock
Out) function, the internal P channel driver transistor is forced OFF when input voltage becomes 2.25V or lower.
˙APPLICATIONS
˔Smart phones / Mobile phones
˔Bluetooth
˔Mobile devices / terminals
˔Portable game consoles
˔Digital still cameras / Camcorders
˔Note PCs / Tablet PCs
˙FEATURES
Driver Transistor Built-In
: 0.65Њ P-ch Driver Transistor


0.45Њ N-ch Synchronous Switch Transistor
Input Voltage

: 2.3V ~ 6.0V
Output Voltage Selectable

High Efficiency

: _{0.8V ~ 4.0V (0.05V Increments)}
: 90% (TYP.)^ˎ
Output Current
: 400mA
Oscillation Frequency
: 1.2MHz ±15%
Maximum Duty Cycle
Function




: 100%
: ^{Current Limiter Circuit}
(Constant Current & Latching)
C_L High Speed Discharge
Soft Start Circuit
Capacitor

: Low ESR Ceramic Capacitor
Control Methods
: PWM (XC9244)


PWM/PFM Auto (XC9245)
Operating Ambient Temperature
Package
: -40ˆʙ+85ˆ
: USPN-6
Environmentally Friendly



: EU RoHS Compliant, Pb Free
* The characteristics change with external parts, substrate wiring, etc.
˙TYPICAL APPLICATION CIRCUIT
-
7065
7*/
N"
7*/
-Y
˙TYPICAL PERFORMANCE
CHARACTERISTICS
XC9244/XC9245A33C
C_IN=4.7μF(LMK212BJ475)
100 ^{L=4.7μH(SPM3012),CL=10μF(LMK212BJ106)}
$*/
DFSBNJD
$&
$&
7065
744
$-
DFSBNJD
80
60
V_IN=4.2V
40 V_IN=5.0V
20
PWM Control
V_IN=4.2V
5.0V
0
0.1
1
10
100
1000
Output Current : I_OUT (mA)
1/24