资 源 简 介
The MAX3243 device 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). The device meets therequirements of TIA/EIA-232-F and provides the electrical interface between an asynchronous communicaTIoncontroller and the serial-port connector. This combination of drivers and receivers matches that needed for thetypical serial port used in an IBM PC/AT, or compatible. The charge pump and four small external capacitorsallow operation from a single 3-V to 5.5-V supply. In addition, the device includes an always-active noninvertingoutput (ROUT2B), which allows applications using the ring indicator to transmit data while the device is powereddown. The device operates at data signaling rates up to 250 kbit/s and a maximum of 30-V/ms driver output slewrate.Flexible control options for power management are available when the serial port is inactive. Theauto-powerdown feature functions when FORCEON is low and FORCEOFF is high. During this mode ofoperation, if the device does not sense a valid RS-232 signal, the driver outputs are disabled. If FORCEOFFis set low, both drivers and receivers (except ROUT2B) are shut off, and the supply current is reduced to 1 mA.Disconnecting the serial port or turning off the peripheral drivers causes the auto-powerdown condition to occur.
