特点
Two RS232 Transceivers or One RS485 Transceiver
Operates from a Single 5V Supply
Guaranteed Receiver Output with Inputs Floating or Shorted to Ground
Logic Selectable Fast/Slow RS485 Driver Slew Rate
Low Supply Current: 7mA Typical
5μA Supply Current in Shutdown
Self-Testing Capability in Loopback Mode
Separate Driver and Receiver Enable Controls
Driver Maintains High Impedance in Three-State,Shutdown or with Power Off
Receiver Inputs Can Withstand ±25V
典型应用
描述
The LTC?1387 is a low power reconfigurable CMOS bidirectional transceiver. It can be configured as an RS485 differential port or as two RS232 single-ended ports. An onboard charge pump uses four 0.1μF capacitors to generate boosted positive and negative supplies, allowing the RS232 drivers to meet ±5V output swing requirements with only a single 5V supply. A shutdown mode reduces the I CC supply current to 5μA.
The RS232 transceivers are in full compliance with RS232 specification. The RS485 transceiver is in full compliance with RS485 and RS422 specifications. The RS485 receiver assumes a known output state when the inputs are floating or shorted to ground. 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 the power is off. A loop back mode allows the driver outputs to be connected back to the receiver inputs for diagnostic self-test.
The LTC1387 is available in 20-pin plastic SSOP and SW packages.