Sunnyvale, Calif. - Maxim Integrated Products' MAX1997 and MAX1998 power supplies provide the voltages required for active-matrix, thin-film-transistor LCDs. Both combine a step-up regulator with two linear-regulator controllers, input protection switch control and flexible-sequence programming. The MAX-1997 contains two additional linear-regulator controllers and a high-current backplane driver (VCOM buffer).
The MAX1997 and MAX1998 operate from 2.7- to 5.5-volt supplies and feature multiple levels of protection circuitry, making a complete power supply system for displays.
The products' dc/dc converter provides the regulated supply voltage for the display's source-driver ICs. The converter is a high-frequency (up to 1.5 MHz) step-up regulator with an integrated 14-V n-channel MOSFET that allows the use of ultra-small inductors and ceramic capacitors while achieving efficiencies of over 85 percent, Maxim said.
The MAX1997's backplane driver (VCOM buffer) provides peak currents exceeding 400 milliamps. Its two additional linear-regulator controllers can be used to build a gamma reference voltage and a logic supply.
The MAX1997 is available in a 32-pin QFN package and the MAX1998 is available in a 20-pin QFN . Both packages have a maximum 1-mm thickness suitable for ultra-thin LCD panels. Prices start at $4.07 for the MAX1997 and $3.38 for the MAX1998 in quantities over 1,000.
Maxim also launched the MAX1945, a 6-amp, 1 percent accurate, step-down dc/dc regulator that generates I/O supplies for DSPs, FPGAs, ASICs and microprocessors. The small circuit requires 0.76 square inch of board space and delivers an output down to 0.8 V from a 2.6-V to 5.5-V input. If a 3- to 5.5-V bias supply is available, the device can operate from voltages as low as 2.25 V. Its selectable 500-kHz or 1-MHz switching frequency reduces the size and cost of external components.
The MAX1945 models come in thermally enhanced 28-pin TSSOPs with an exposed metal pad. They are specified for the extended industrial temperature range. Prices start at $4.20 in quantities over 1,000.
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