DS1228 DS1228 +5V Powered Dual RS-232 Transmitter/Receiver FEATURES PIN ASSIGNMENT • Operates from a single 5V power supply C1+ 1 16 VCC 2 15 • Meets all EIA RS-232-C specifications V+ GND C1- 3 14 • On-board voltage doubler C2+ 4 13 • On-board voltage inverter C2- 5 12 T1OUT C1+ V+ R1IN C1R1OUT C2+ • Two drivers and two receivers • + 30V input levels • + 9V output levels with + 5V supply • Low-power CMOS VT2OUT R2IN 6 11 7 10 8 T1IN 16 2 15 3 14 13 T1OUT 12 R1OUT T1IN 4 5 6 T2IN T2OUT 7 11 10 R2IN 8 9 R2OUT 9 C2V- 1 16–Pin DIP (300 MIL) VCC GND R1IN T2IN R2OUT 16–Pin SOIC (300 MIL) • Pin-compatible with the MAX 232 • Optional 16-pin SOIC surface mount package PIN DESCRIPTION C1+, C1 C2+, C2 V+, VT1IN, T2IN T1OUT, T2OUT R1IN, R2IN R1OUT, R2OUT VCC GND – – – – – – – – – Capacitor 1 Connections Capacitor 2 Connections + 10 Volts Transmitter In Transmitter Out Receiver In Receiver Out +5 Volts Ground DESCRIPTION The DS1228 is a dual RS-232-C Receiver/Transmitter that meets all EIA specifications while operating from a single, +5 volt supply. The DS1228 has two internal charge pumps. One of the charge pumps is used to generate +10 volts. The other is used to generate -10 volts. The DS1228 also contains four level translators. Two of the level translators are RS-232 transmitters which convert TTL/CMOS inputs into +9V RS-232 outputs. The other two level translators are capable of operating with Copyright 1995 by Dallas Semiconductor Corporation. All Rights Reserved. For important information regarding patents and other intellectual property rights, please refer to Dallas Semiconductor databooks. up to +30V inputs. The DS1228 is suitable for all RS-232 communications and is particularly valuable where higher voltage power supplies for RS-232 drivers are not available. The power supply section of the DS1228 supplies +10 volts from the VCC input. See the DS1229 data sheet for electrical specifications and operation. 021792 1/1