? GENERAL DESCRIPTION

AX3121 consists of step down switching regulator with synchronous PWM converter. These devise include a reference voltage source, oscillation circuit, error amplifier, internal PMOS and NMOS etc.

AX3121 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to the duty ratio linearly form 0 up to 100%. This converter also contains an error amplifier circuit as well as an enable/soft-start circuit that prevents overshoot at startup. An enable function, an over current protect function and short circuit protect function are built inside, and when OCP or SCP happens, the operation frequency will be reduced. Also, an external compensation is easily to system stable.

With the addition of internal PMOS and NMOS, a coil and capacitors externally, these ICs can function as step down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP-8L-EP package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 23V.

? FEATURES

- Input voltage 4.5 V to 23V

- Output voltage VFB to VCC

- Duty ratio 0% to 100% PWM control

- Oscillation frequency 250KHz typ

- Enable/Soft-Start and Current Limit (CL).

- Thermal Shutdown function.

- Short Circuit Protect (SCP).

- Built-in internal SW P-channel and N-channel MOS

- SOP-8L with Exposed Pad Pb-Free package.

- RoHS and Halogen free compliance.