XC9511_1 Datasheet, PDF (1/35 Pages) Torex Semiconductor – Synchronous Step-Down DC/DC Converter with built-in LDO Regulator in parallel plus Voltage Detector

XC9511 Series
Synchronous Step-Down DC/DC Converter
with Built-In LDO Regulator In Parallel Plus Voltage Detector
ETR1008_001
■GENERAL DESCRIPTION
The XC9511 series consists of a step-down DC/DC converter and a high-speed LDO regulator connected in parallel with the
DC/DC converter's output. A voltage detector is also built-in. Since the input for the LDO voltage regulator block comes
from the input power supply, it is suited for use with various applications.
The DC/DC converter block incorporates a P-channel driver transistor and a synchronous N-channel switching transistor.
With an external coil, diode and two capacitors, the XC9511 can deliver output currents up to 800mA at efficiencies over 90%.
The XC9511 is designed for use with small ceramic capacitors.
A choice of three switching frequencies are available, 300 kHz, 600 kHz, and 1.2 MHz. Output voltage settings for the DC/DC
and VR are set-up internally in 100mV steps within the range of 0.9V to 4.0V (±2.0%). For the VD, the range is of 0.9V to
5.0V (±2.0%). The soft start time of the series is internally set to 5ms. With the built-in U.V.L.O. (Under Voltage Lock Out)
function, the internal P-channel driver transistor is forced OFF when input voltage becomes 1.4 V or lower.
■APPLICATIONS
●CD-R / RW, DVD
●HDD
●PDAs, portable communication modem
●Palmtop computers
●Cellular phones
●Cameras, video recorders
■FEATURES
DC/DC Converter with Built-in LDO and VD Function
Input Voltage Range : 2.4V ~ 6.0V
Low ESR Capacitor : Ceramic capacitor compatible
VD Function
: Three VD sensing Options for either
Package
VDD, DCOUT, or VROUT
: SOP-8
<DC/DC Converter Block>
Output Voltage Range : 0.9V ~ 4.0V (Accuracy ± 2%)
Output Current
: 800mA
Control Method
: PWM or PWM/PFM Selectable
Oscillation Frequency : 300kHz, 600kHz, 1.2MHz
<Regulator Block>
Regulator Input
: Parallel Input to DC/DC converter
Output Voltage Range : 0.9V ~ 4.0V (Accuracy±2%)
Current Limit
: 600mA
Dropout Voltage
: 160mV@IOUT=200mA (VOUT=2.8V)
High Ripple Rejection : 60dB @1kHz (VOUT=2.8V)
■TYPICAL APPLICATION CIRCUIT
■TYPICAL PERFORMANCE
CHARACTERISTICS
XC9511Axxx
VIN=5.0V, Topr=25^oC, L: 4.7μH(CDRH4D28C)
CIN: 4.7μF(ceramic), CL1: 10μF(ceramic), CL2: 4.7μF(ceramic)
SOP-8 (TOP VIEW)
* Please refer to the typical application circuit when
external components are selected.
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