General Description
The XC9105 series is PWM, PWM/PFM auto switching /manual switching controlled universal step-up
DC/DC converter controllers.
Output will be stable no matter which load capacitors are used but should a low ESR capacitor be used, RSENSE of about 0.1Ω
will be required and phase compensation will be achieved. This allows the use of ceramic capacitors and enables to obtain lower
output ripple and small PCB design. Tantalum and electrolytic capacitors can also be used, in which case, RSENSE becomes
unnecessary.
With 0.9V internal voltage reference and by using externally connected two resistors, output voltage can be set freely within a
range of 1.5V to 30V. The series is available in 300 kHz and 180 kHz frequencies, the size of the external components can be
reduced. 100 kHz and 500 kHz are also available in custom options.
The XC9103 offers PWM operation. The XC9104 offers PWM/PFM automatic switching operation. The PWM operation is shifted to
the PFM operation automatically at light load so that it maintains high efficiency over a wide range of load currents. The XC9105
offers both PWM and PWM/PFM auto switching operations and it can be selected by external signal.
A current limiter circuit is built-in to the IC (except with the 500 kHz version) and monitors the ripple voltage on the FB pin.
Operation is shut down when the ripple voltage is more than 250mV. The operations of the IC can be returned to normal with
a toggle of the CE pin or by turning the power supply back on.
Features
- Input Voltage Range : 0.9V ~ 10V
- Supply Voltage Range : 1.8V ~ 10V
- Output Voltage Range : 1.5V ~ 30V
- Oscillation Frequency : 100, 180, 300, 500kHz (±15%)
- Output Current : more than 400mA (VIN=1.8V, VOUT=3.3V)
Applications
- PDAs
- Cellular phones
- Palmtop computers
- Portable audio systems
- Various multi-function power supplies
Typical Application Circuit
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