Features

• Four RS232 Transceivers or Two RS485 Transceivers on One Chip
• Operates from a Single 5V Supply
• Withstands Repeated ±10kV ESD Pulses
• Uses Small Charge Pump Capacitors: 0.1µF
• Low Supply Current: 8mA Typical
• 10µA Supply Current in Shutdown
• Self-Testing Capability in Loopback Mode
• Power-Up/Down Glitch-Free Outputs
• Driver Maintains High Impedance in Three-State, Shutdown or with Power Off
• Thermal Shutdown Protection
• Receiver Inputs Can Withstand ±25V

Typical Application

Description

The LTC®1334 is a low power CMOS bidirectional transceiver featuring two reconfigurable interface ports. It can be configured as two RS485 differential ports, as two dual RS232 single-ended ports or as one RS485 differential port and one dual RS232 single-ended port. An onboard charge pump requires four 0.1µF capacitors to generate boosted positive and negative supplies, allowing the RS232 drivers to meet the RS232 ±5V output swing requirement with only a single 5V supply. A shutdown mode reduces the I_CC supply current to 10µA. The RS232 transceivers are in full compliance with RS232 specifications. The RS485 transceivers are in full compliance with RS485 and RS422 specifications. All interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver outputs to be forced into high impedance, which is maintained even when the outputs are forced beyond supply rails or power is off. Both driver outputs and receiver inputs feature ±10kV ESD protection. A loopback mode allows the driver outputs to be connected back to the receiver inputs for diagnostic self-test.