The XC9103/9104/9105 series are PWM; PWM/PFM auto switching/manual switching controlled multi-functional step-up DC/DC controllers. Outputs will be stable no matter which load capacitors are used but should a low ESR capacitor be used, RSENSE of about 0.1Ωwill be required and phase compensation will be achieved. This makes the use of ceramic capacitors much easier and allows for lower output ripple and reduced PCB area requirements. Tantalum and electrolytic capacitors can also be used; in which case, RSENSE becomes unnecessary.

With 0.9V of standard voltage supply internal, and using externally connected components, output voltage can be set up freely within a range of 1.5V to 30V. With 300kHz or 180kHz frequencies, the size of the external components can be reduced. Oscillation frequencies of 100kHz and 500kHz are also available as custom-designed products.

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 maintain 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 an external signal. A current limiter circuit is built in to the IC (except with the 500kHz 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 Votage Range: 1.8V ~ 10V
• Output Voltage Range : 1.5V ~ 30V
• Set up freely with a standard voltage supply
  of 0.9V(±2.0%) & external components
• Oscillation Frequency : 300, 180kHz ±15%
  100, 500kHz available as semi-custom
• Output Current : more than 400mA
  (VIN=1.8V, VOUT=3.3V)
• Controls : PWM (XC9103)
  PWM/PFM auto-switching (XC9104)
  PWM/PFM manual switching (XC9105)
• High Efficiency : 85% (TYP.)
• Stand-by Current : ISTB=1.0μA (MAX.)
• Load Capacitors : Low ESR capacitors compatible
• Current Limiter Function :Operates when ripple voltage=250mV
• Also available without current limiter
  (100kHz and 500kHz types are
  available only without current limiter)