5 Volt Only Driver/Receiver with an Integrated Standly Mode

EIA–232–E and CCITT V.28

The MC145705/06/07 are a series of silicon–gate CMOS transceiver ICs that fulfill the electrical specifications of EIA–232–E and CCITT V.28 while operating from a single + 5 V power supply. These transceiver series are high performance and low power consumption devices that are equipped with standby and output enable function.

A voltage doubler and inverter convert the + 5 V to ± 10 V. This is accomplished through an on–board 20 kHz oscillator and four inexpensive external electrolytic capacitors.

The MC145705 is composed of two drivers and three receivers, the MC145706 has three drivers and two receivers, and the MC145707 has three drivers and three receivers. These drivers and receivers are virtually identical to those of the MC145407.

Drivers:

• ± 7.5 Output Swing

• 300 Ω Power–Off Impedance

• Output Current Limiting

• TTL and CMOS Compatible Inputs

• Three–State Outputs During Standby Mode

• Hold Output OFF (MARK) State by TxEN Pin

Receivers:

• ± 25 V Input Range

• 3 to 7 kΩ Input Impedance

• 0.8 V Hysteresis for Enhanced Noise Immunity

• Three–State Outputs During Standby Mode

Charge Pumps:

• + 5 to ± 10 V Dual Charge Pump Architecture

• Supply Outputs Capable of Driving Three Drivers on the MC145403/06 Simultaneously

• Requires Four Inexpensive Electrolytic Capacitors

• On–Chip 20 kHz Oscillators