MAX253

19-0226; Rev 0; 1/94 Transformer Driver for Isolated RS-485 Interface _______________General Description The MAX253 is a monolithic oscillator/power-driver, specifically designed to provide isolated power for an isolated RS-485 or RS-232 data interface. It drives a center-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. The MAX253 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-beforemake 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. ____________________________Features o Power-Supply Transformer Driver for Isolated RS-485/RS-232 Data-Interface Applications o Single +5V or +3.3V Supply o Low-Current Shutdown Mode: 0.4µA o Pin-Selectable Frequency: 350kHz or 200kHz o 8-Pin DIP, SO, and µMAX Packages MAX253 ______________Ordering Information PART MAX253CPA MAX253CSA MAX253CUA MAX253C/D MAX253EPA MAX253ESA MAX253EUA MAX253MJA TEMP. RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 8 Plastic DIP 8 SO 8 µMAX Dice* 8 Plastic DIP 8 SO 8 µMAX 8 CERDIP** ________________________Applications Isolated...