MAX251CSD+

MAX251CSD+ is a 5V, isolated, RS-232 driver/receiver. By combining many functions on two chips, the cost and complexity required for an isolated digital interface is greatly reduced. Four low-cost optocouplers, four capacitors, a diode and a small pot-core type transformer are all that are required to complete a 19.2k baud transceiver. Faster data rates are possible by using high-speed optocouplers. In addition to the driving and receiving circuitry for the optocouplers, the chipset includes a push-pull transformer driver to supply power to the interface's isolated side. Other convenient features include single +5V operation, a low power shutdown mode, and output-enabling control for three-state operation. Applications include bridge ground differentials, data links to analog circuits, high-noise data communications, and industrial communications.

• Isolated data interface, single +5V supply
• Uses low cost optocouplers
• 5µW power shutdown, 2 transmitters and 2 receivers
• Positive supply current is 0.7mA typical
• Negative supply current is 0.45mA typical
• RS-232 output voltage swing is ±7.2V typ, all transmitter outputs loaded with 3kohm to ground
• Transmitter slew rate is 3V/µs min at RL=3kohm, CL=2500pF
• Output source current is -7mA typ at Vout=1.4V, TA=25°C
• 14 lead SO package
• Temperature range from 0°C to +70°C