TRSF3221ECPWR

The TRSF3221E contains one line driver, one line receiver, and a dual charge pump circuit with pin-to-pin (serial port connection pins, including GND) ±15kV IEC ESD protection. The TRSF3221E provides an electrical interface between asynchronous communication controllers and serial port connectors. The charge pump and four small external capacitors support a single supply voltage of 3V to 5.5V. The TRSF3221E operates at data signaling rates up to 1Mbit/s, with driver output slew rates of 24V/μs to 150V/μs.

Flexible power management control options are available when the serial port is inactive. The auto-powerdown feature is enabled when FORCEON is low and FORCEOFF is high. In this operating mode, if the TRSF3221E detects no valid RS-232 signal at the receiver input, the driver outputs are disabled. If FORCEOFF is set low and the enable (EN) input is high, both the driver and receiver are shut down, and supply current is reduced to 1μA. Disconnecting the serial port or powering down a peripheral driver causes an auto-powerdown condition. Auto-powerdown can be disabled by setting both FORCEON and FORCEOFF high. With auto-powerdown enabled, the device automatically activates when a valid signal is applied to the receiver input. The INVALID output notifies the user whether an RS-232 signal is present at the receiver input. INVALID is high (valid data) if the receiver input voltage is greater than 2.7V or less than -2.7V, or remains between -0.3V and 0.3V for less than 30μs. INVALID is low (invalid data) if the receiver input voltage remains between -0.3V and 0.3V for more than 30μs.