R1240x Series

Data Sheet / Flyer

The R1240x series are CMOS-based Step-down DC/DC converter with internal Nch high side Tr. (0.35Ω), which can provide the maximum 1.2A output current. The ICs consists of an Oscillator, a PWM control circuit, a Reference Voltage unit, an Error amplifier, phase compensation circuits, a slope circuit, a soft-start circuit, protection circuits, internal voltage regulators, and a switch for boot strap circuit. The ICs can make up a Step-Down DC/DC Converter with the following external components: an inductor, resistors, a diode, and capacitors.

The R1240x series are current mode operating type DC/DC converter which does not require external current sense resistor, and it works high speed response time, high efficiency and compatible with ceramic capacitors. Oscillator frequency is internally set at 1.25MHz.

As a protection function, it has cycle by cycle peak current limit function, short protection function, thermal shutdown function and UVLO.

There are two types for short protection, A version has latch protection function with 2ms delay time, and B version has fold back protection function that keep operating at short condition with lower operating frequency and limiting the Lx current.