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 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.

FEATURES
• Operates from a single 5V power supply
• Two drivers and two receivers
• Meets all EIA RS-232-C specifications
• On-board voltage doubler
• On-board voltage inverter
• + 30V input levels
• + 9V output levels with + 5V supply
• Low-power CMOS
• Pin-compatible with the MAX 232
• Optional 16-pin SOIC surface mount package