The ST3243E device consists of three drivers, five receivers, and a dual charge pump circuit. The equipment meets EIA/TIA and V.28/V requirements. Typically used in laptops, sub-laptops, palmtop PCS, battery-powered devices, handheld devices, peripherals and printers.24 communication standards provide high data rate capabilities and enhanced electrostatic discharge (ESD) protection.
Pin configuration
All transmitter outputs and receiver inputs are protected up to ±8 kV using IEC 1000-4-2 contact discharge and ±15 kV using mannequins. Receiver R2 is always active to realize the serial port wake-up function. The ST3243E features a proprietary low-difference transmitter output stage that achieves true RS-232 performance from a 3.0 V to 5.5 V power supply with a dual charge pump.
Application circuits
The device is guaranteed to operate at 250kbps data rate while maintaining RS-232 output level. FORCEON low or FORCEOFF high The function automatically powers off the device. In this mode of operation, if the device does not detect a valid RS-232 signal, the drive output is disabled. If the FORCEOFF setting is low, both the driver and receiver (expert R2B) are turned off and the supply current is reduced to 1µA. Disconnecting the serial port or turning off the peripheral drive will cause the automatic power-off to occur.
Automatic power-off can be disabled when FORCEON and FORCEOFF values are high, and should be performed when driving a serial mouse. With the automatic power off, the device automatically activates when a valid signal is applied to any receiver input.
Timing diagrams
Automatically power off the input level
Automatic power off input timing
