Faster PWM

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I'm looking at the AT90S4433 for an application, but the max PWM output frequency is too slow. I need something up around the 200kHz mark, ideally with 7 or 8 bit resolution. This implies a 25 to 50 MHz clock rate. I could use a CPLD, but the board area & pin-count blows out. CPLDs with enough flipflops start at 24 pin. But 8 pins are more than enough.

Does anyone know of a PWM peripheral, with a fast clock rate, ideally programmed serially?

Cheers,
Mark

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You might want to look at the ATtiny15. This chip has a built in 1.6 MHz oscillator, with a clock PLL that boost this clock up to 25.6 MHz. The fast clock is fed to one of the timers, which uses it to generate very fast PWM outputs. Example speeds are 100kHz @ 8-bit, 200kHz at 7-bit, but you can configure the timer to reset at any count, which opens for any combination of speed and resolution.

The ATtiny15 was designed for switched regulators used in applications like battery chargers and light ballasts. It comes in a very neat 8-pin package.

Regards,
Haakon Skar
Asian Marketing Manager
AVR Microcontrollers
Atmel Corporation

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