DC-DC Converters from Torex Semiconductor

The XC9128/29 Series feature a 0.2Ω (typ) N-channel driver transistor and a synchronous 0.2Ω (typ) P-channel switching transistor built-in. The XC9128/29 series from Torex deliver efficiencies up to 93% over the entire load range, and can supply 500mA to a 3.3V load from a 1.8V battery supply. Additionally, the 1.2MHz fixed switching frequency helps minimise design footprint by enabling the use of extremely small inductors and capacitors.

Output voltage can be freely set within a range of 1.8V ~ 5.3V using a reference voltage supply of 0.45V and an external resistor ladder. The input voltage range is 0.8V ~ 5.3V.

With the MODE pin, designers can select the PWM control or PFM/PWM automatic switching control. In the PWM/PFM automatic switching mode, the XC9128/29 Series switch from PWM to PFM to reduce switching loss when load current is small. However, when load current is large, the control switches automatically to PWM so that high efficiency is achievable over a wide range of load conditions.

In addition, the XC9128 Series incorporates an AEN (Adaptor Enable) pin which allows the device to also be used to provide a fast power supply back-up solution when the IC is used together with added power sources such as AC adapters. The AEN pin monitors the external power source and can quickly sense if that power supply fails, providing immediate back-up. The XC9128 Series also features a Flag Output (FO) pin for monitoring the IC’s operation.

The XC9128/29 Series offer a variety of safety features including thermal shutdown and over current limit protection, and soft start that can be set internally to typically 5ms. Specified over the
-40ºC to +85ºC temperature range, the XC9128 Series is available in two compact packages:
MSOP-10 and USP-10B, whereas the XC9129 Series is available in SOP-8.