XC9503 Series

2ch. Step-Down DC/DC Controller

XC9503 series are PWM controlled, PWM/PFM automatic switching controlled, multi-functional, 2 channel step-down DC/DC controller ICs. With 0.9V (±2.0%) of standard voltage supply internal, and using externally connected components, output voltage can be set freely on both DC/DC controllers between 0.9V to 6V.

With a 300kHz frequency, the size of the external components can be reduced. 180kHz and 500kHz switching frequencies are also available as custom-designed products.

The control of the XC9503 series can be switched between PWM control and PWM/PFM automatic switching control using external signals. Control switches from PWM to PFM during light loads when automatic switching is selected and the series is highly efficient from light loads to large output currents. Noise is easily reduced with PWM control since the switching frequency is fixed. The series gives freedom to select control suited to the application.

Soft-start time is internally set to 10ms and offers protection against in-rush currents when the power is switched on and prevents voltage overshoot.

Typical Application Circuit


Input Voltage Range 2.0V~10V
Power Supply Voltage Range 2.0V~10V
Output Voltage Range 0.9V~6.0V,Can be set freely with 0.9V (+-2.0%) of reference voltage supply and external components.
Oscillation Frequency 300kHz, ±15%,180kHz, 500kHz is available as semi-custom
Output Current ~1000mA(VIN=5.0V,VOUT=3.3V)
Stand-by Current 3.0μA(MAX.)
Soft-Start 10ms(internallyset)



Quality Reports


QuestionWhat does the standby mode mean in the case of the multi channel IC?

It means the state where the entire IC has been turned off. For Torex products, it means that the pin voltages of EN1 and EN2 are both 0V.

QuestionHow does the GO function of DC/DC converters work? Does it work just like a regulator?

Torex regard the PWM/PFM automatic switch control function as Green Operation (GO) in the case of DC/DC. The GO function is defined as the switching operation between the PFM mode for a small output current and the PWM mode for a large output current. The PFM control method controls the output current by increasing and decreasing the fall time according to the output current while keeping a pulse width. The PWM control method controls the output current by adjusting the pulse width of the rise time, which keeps the rise/fall time interval constant and increases the efficiency at a heavy load. By switching between the PFM control for a small output current and the PWM control for a large output current, the quiescent current can be controlled for both of heavy and light loads.

QuestionWhat is the soft-start function?

The function to soften the rise to prevent the inrush current.

QuestionWhat is the standby current?

The current that flows through the IC in the standby mode. The standby mode means the state where the IC has been turned off by the CE function.