110V SO-8 CURRENT-MODE PWM CONTROLLERS ELIMINATE OPTOCOUPLER IN ISOLATED POWER SUPPLIES
SUNNYVALE, CA-September 17, 2001-Maxim Integrated Products introduces the MAX5019 and MAX5020 PWM controllers that allow the design of compact, high-performance, isolated or nonisolated power supplies for telecom and networking equipment. An isolated power-supply design using the MAX5019/MAX5020 eliminates the need for an optocoupler and a shunt reference on the secondary side of the transformer, thus reducing power-supply cost.
The MAX5019 and MAX5020 are capable of operating from a wide 12V to 110V input voltage range. Both devices include a high-voltage preregulator for startup. After startup, however, device power is derived from a low-voltage tertiary winding from the transformer. Features include current-mode control, leading-edge blanking, shutdown, soft-start, overcurrent shutdown, undervoltage lockout, and thermal shutdown. Oscillator frequency is internally trimmed to 275kHz, which allows use of all surface-mount components. The MAX5019 operates at 85% maximum duty cycle and is recommended for isolated flyback converters. The MAX5020 operates at 50% maximum duty cycle and is recommended for forward-mode converters.
Both the MAX5019 and MAX5020 are available in an 8-pin SO package and are rated for operation over the extended-industrial temperature range (-40°C to +85°C). Prices start at $0.87 (1000-up, FOB USA).
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