TRSF3243

(1) Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device  eliability.
(2) All voltages are with respect to network GND.
(3) Maximum power dissipation is a function of TJ(max), _JA, and T_A. The maximum allowable power dissipation at any allowable ambient temperature is P_D = (T_J(max) T_A)/_JA. Operating at the absolute maximum T_J of 150 can affect reliability.
(4) The package thermal impedance is calculated in accordance with JESD 51-7.

The TRSF3243 consists of three line drivers, five line receivers, and a dual charge-pump circuit with ±15-kV ESD protection pin to pin (serial-port connection pins, including GND). This TRSF3243 provides the electrical interface between an  synchronous communication controller and the serial-port connector. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-V supply. In addition, this TRSF3243 includes an always-active noninverting output (ROUT2B), which allows applications using the ring indicator to transmit data while the device is powered down. The TRSF3243 operates at data signaling rates up to 1 Mbit/s and an increased slew-rate range of 24 V/s to 150 V/s.

Flexible control options of TRSF3243 for power management are available when the serial port is inactive. The auto-powerdown feature functions when FORCEON is low andFORCEOFF is high. During this mode of operation, if the device does not sense a valid RS-232 signal, the driver outputs are disabled. If FORCEOFF is set low, both drivers and receivers (except ROUT2B) are shut off, and the supply current is reduced to 1 A. Disconnecting the serial port or turning off the peripheral drivers of TRSF3243 causes the auto-powerdown condition to occur.

Auto-powerdown of TRSF3243 can be disabled whenFORCEON and FORCEOFF are high and should be done when driving a serial mouse. With auto-powerdown enabled, the TRSF3243 is activated automatically when a valid signal is applied to any receiver input. The INVALID output is used to notify the user if an RS-232 signal is present at any  receiver input. INVALID is high (valid data) if any receiver input voltage is greater than 2.7 V or less than 2.7 V or has been between 0.3 V and 0.3 V for less than 30 s. INVALID is low (invalid data) if all receiver input voltages of TRSF3243 are between 0.3 V and 0.3 V for more than 30 s. Refer to Figure 5 for receiver input levels.