18V Operation 0.5A Synchronous Step-Down DC/DC Converters
The XC9264 series are 18V operation synchronous step-down DC/DC converter ICs with a built-in P-channel MOS driver transistor and N-channel MOS switching transistor. The XC9264 series has operating voltage range of 3.0V～18.0V and high-efficiency power supply up to an output current of 0.5A. Low ESR capacitors such as ceramic capacitors can be used for the load capacitor (CL).
A 0.75V reference voltage source is incorporated in the IC, and the output voltage can be set to a value from 1.0V to 15.0V using external resistors (RFB1, RFB2).
500kHz or 1.2MHz or 2.2MHz can be selected for the switching frequency. In automatic PWM/PFM control, the IC operates by PFM control when the load is light to achieve high efficiency over the full load range from light to heavy.
The soft-start time is internally set to 1ms (TYP.), but can be adjusted to set a longer time using an external resistor and capacitor.
With the built-in UVLO function, the driver transistor is forced OFF when input voltage becomes 2.7V or lower.
The output state can be monitored using the power good function.
Internal protection circuits include over current protection, short-circuit protection, and thermal shutdown circuits to enable safe use.
Typical Application Circuit
|Input Voltage Range||3.0V～18.0V
(Absolute Maximum Rating:20V)
|Output Voltage Range||1.0V～15.0V(VFB=0.75V±1.5%)|
|Soft-Start||Adjustable by RC|
|Protection Circuits||Over Current Protection
Integral Latch Method
|Capacitor||Low ESR Ceramic|
|Operating Ambient Temperature||-40℃～+105℃|
|Package||SOT-25||Number of Pins||5|
|Pcs/Reel||3,000||Package Size(mm)||2.8 x 2.9 x 1.3|
|Package||USP-6C||Number of Pins||6|
|Pcs/Reel||3,000||Package Size(mm)||1.8 x 2.0 x 0.6|
What is the soft-start function?
The function to soften the rise to prevent the inrush current.
What does the FB product mean?
An IC for which any output voltage can be set by the reference voltage of the FB pins and the external dividing resistor. The output voltage is determined by the RFB1 and RFB2 values, using the following formula: VOUT = Vref × (RFB1 + RFB2)/RFB2
How does UVLO (under voltage lockout) work?
This circuit forcibly turns off the driver transistor when VIN drops below the UVLO voltage. If the input voltage recovers to the value which is equal to the specified value or more, UVLO will be released to resume the switching operation. It is resumed by the soft-start function. The paused state by UVLO is not the shutdown. The pulse output is stopped, but the internal circuit is operating.