Convertor, LDO and reset come together

The new XC9508/09 series from Torex Semiconductor marks the company's entry into the fully integrated power IC arena.

The new XC9508/09 series from Torex Semiconductor marks the company's entry into the fully integrated power IC arena.

Cheaper, smaller and more reliable than the discrete alternative, the XC9508/09 is a family of synchronous rectification type DC/DC convertors with built in high-speed, low-noise LDO voltage regulator and an internal comparator for low voltage detection, all in a tiny chip scale USP-10 (2.7 x 2.6 x 0.6mm) package.

The XC9508/09 is an ideal partner for the latest DSPs and microcontrollers which require 1.8V for the memory (taken from the DC/DC portion of the IC) and 1.5V for the core (provided by the LDO portion of the IC).

The DC/DC convertor's low output ripple makes the new device particularly suited to RF applications such as Bluetooth and mobile phones, as well as a host of other handheld and portable designs.

The new device's 0.6ohm P-channel driver transistor and 0.6ohm N-channel switching transistor means that efficiencies over 90% can be achieved without the need for an external Schottky diode.

The XC9508/09 is designed for use with low ESR ceramic capacitors and small chip inductors making it the ideal choice for designs where space is at a premium.

Output current is 600mA (DC/DC convertor) and 200mA (voltage regulator).

Operating voltage range is 2.4 to 6.0V.

In the case of the XC9508 the voltage regulator takes its input from the DC/DC output, while with the XC9509 the voltage regulator input is from the input voltage.

For both types the DC/DC output voltage and the voltage regulator output voltage are factory set in 0.1V steps between 0.9 and 4.0V.

Voltage detector range is 0.9 to 5.0V, again in 0.1V steps.

Three switching frequencies are available: 300kHz, 600kHz or 1.2MHz.

A choice of switching control method is provided: either synchronous-rectified PWM switching control, or synchronous PWM/PFM auto switching, selectable via the XC9508/09's mode pin.

This gives the designer fast response, low ripple output and high efficiency over a broad range of output loads.

The voltage regulator's dropout voltage is 80mV at 100mA (typical) and ripple rejection is 60dB at 1kHz (2.8V output).

Other features include a built-in current limit, an internal soft-start (set to 10ms) and an undervoltage lockout circuit.

The XC9508/09 is available in both MSOP-10 and ultracompact USP-10 (2.7 x 2.6 x 0.6mm) packages.

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