General Description
The XC9509 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 XC9509 can deliver output currents up to 600mA at efficiencies over 90%.
The XC9509 is designed for use with small ceramic capacitors.
A choice of three switching frequencies are available, 300kHz, 600kHz, and 1.2MHz. 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. The functions of
the MODE pin can be selected via the external control pin to switch the DC/DC control mode and the disable pin to shut down
either the DC/DC block or the regulator block.
Features
- Input Voltage Range : 2.4V ~ 6.0V
- Low ESR Capacitor : Ceramic capacitor compatible
- VD Function : Sense internally either VDD, DCOUT,
or VROUT.
DC/DC Converter Block
- Output Voltage Range : 0.9V ~ 4.0V (Accuracy±2%)
- Output Current : 600mA (for MSOP-10 package)
400mA (for USP-10 package)
- Oscillation Frequency : 300kHz, 600kHz, 1.2MHz
Regulator Block
- Reglator Output : Parallel Input to DC/DC Converter
- Output Voltage Range : 0.9V ~ 4.0V (Accuracy±2%)
- Current Limit : 300mA
- Dropout Voltage : 80mV @ IOUT=100mA (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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