MAX253CSA+T

MAXIM INTEGRATED PRODUCTS  MAX253CSA+T  芯片, 线路驱动器, RS232, RS422/RS485

The is a transformer driver for isolated RS485 interface in 8 pin NSOIC package. It is a monolithic oscillator/power-driver specifically designed to provide isolated power for an isolated RS485 or RS232 data interface. The device drives a centre-tapped transformer primary from a 5V or 3.3V DC power supply. The secondary can be wound to provide any isolated voltage needed at power levels up to 1W. It consists of a CMOS oscillator driving a pair of N-channel power switches. The oscillator runs at double the output frequency, driving a toggle flip flop to ensure 50% duty cycle to each of the switches. Internal delays are arranged to ensure break before make action between the two switches. The SD pin puts the entire device into a low-power shutdown state, disabling both the power switches and oscillator. It is used in high noise-immunity communications interface, isolated and/or high-voltage power supplies and bridge ground differentials.

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Supply voltage range is 2.5V to 6V

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Operating temperature range from 0°C to 70°C

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Shutdown supply current is 0.4µA

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Pin-selectable frequency of 350KHz or 200KHz

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Maximum on-resistance of switch is 4ohm

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Maximum operating supply current is 5mA