XCL209 Series

400mA Inductor Built-in Step-Down “micro DC/DC” Converters

The XCL209 series is a synchronous step-down micro DC/DC converter which integrates an inductor and a control IC in one tiny package (2.5mm×2.15mm, h=1.05mm). A stable power supply with an output current of 400mA is configured using only two capacitors connected externally.

An internal coil simplifies the circuit and enables minimization of noise and other operational trouble due to the circuit wiring.

A wide operating voltage range of 1.8V (2.0V) to 6.0V enables support for applications that require an alkaline battery (2-cell) or AC adapter (5V) power supply. An internally fixed output voltage (0.8V to 4.0V) or an externally set output voltage can be selected.

The XCL209 series uses synchronous rectification at an operating frequency of 3MHz.

The XCL209 series achieves high efficiency while holding down output ripple across the full range of loads, from light to heavy, enabling the extension of battery operation time.

Soft start and on/off functions with CL discharge are provided, and the IC can be put in the standby state by inputting a Low level signal into the CE pin.

Your news

Apr 24, 2012
Product News
400mA "micro DC/DC" Converter with Integrated Coil XCL208/XCL209 Series

Typical Application Circuit


Input Voltage Range 1.8V~6.0V(TypeF)
Output Voltage Range 0.8V~4.0V(±2.0%)(Fixed)
High Efficiency 90%(VIN=4.2V,VOUT=3.3V)
Output Current 400mA
Oscillation Frequency 3.0MHz(±15%)
CE Function Active High
Soft-start Circuit Built-in
CL High Speed Auto Discharge
Protection Circuits Current Limiter Built-in(Constant Current & Latching)
Control Methods PWM/PFM Auto
Operating Ambient Temperature -40℃~+85℃
Environmentally Friendly EU RoHS compliant, Pb free



Technical Document

Quality Reports


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.