Low-Noise Step-Up DC-DC Converters

The MAX1790/MAX8715 boost converters incorporate high-performance (at 1.2MHz), current-mode, fixed-frequency, pulse-width modulation (PWM) circuitry with a built-in 0.21Ω/0.15Ω n-channel MOSFET to provide a highly efficient regulator with fast response.

High switching frequency (640kHz or 1.2MHz selectable) allows easy filtering and faster loop performance. An external compensation pin provides the user flexibility in determining loop dynamics, allowing the use of small, low equivalent-series-resistance (ESR) ceramic output capacitors. The device can produce an output voltage as high as 12V from an input as low as 2.6V.

Soft-start is programmed with an external capacitor, which sets the input-current ramp rate. In shutdown mode, current consumption is reduced to 0.1µA. The MAX1790/MAX8715 are available in a space-saving 8-pin µMAX® package. The ultra-small package and high switching frequency allow the total solution to be less than 1.1mm high.

Applications

* Handheld Devices * LCD Displays * PCMCIA Cards * Portable Applications

* 90% Efficiency

* Adjustable Output from VIN to 12V

* 1.6A, 0.21Ω, 14V Power MOSFET (MAX1790)

* 2.4A, 0.15Ω, 14V Power MOSFET (MAX8715)

* +2.6V to +5.5V Input Range

* Pin-Selectable 640kHz or 1.2MHz Switching Frequency

* 0.1µA Shutdown Current

* Programmable Soft-Start

* Small 8-Pin µMAX Package