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.
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
VDD, DCOUT, or VROUT
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)
Applications
- CD-R / RW, DVD
- HDD
- PDAs, portable communication modem
- Cellular phones
- Palmtop computers
- Cameras, video recorders
Typical Application Circuit

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