Features

• 10mA Max Supply Current
• ESD Protection to IEC 1000-4-2 Level 4 ±15kV Air Gap, ±8kV Contact
• Uses Small Capacitors: 0.1µF
• 120kBaud Operation for R_L = 3k, C_L = 2500pF
• 250kBaud Operation for R_L = 3k, C_L = 1000pF
• Outputs Withstand ±30V Without Damage
• CMOS Comparable Low Power: 40mW
• Operates from a Single 5V Supply
• Rugged Bipolar Design
• Outputs Assume a High Impedance State When Off
  or Powered Down
  
• Meets All RS232 Specifications
• Available With or Without Shutdown
• Absolutely No Latch-up

Typical Application

Description

The LT®1780/LT1781 are dual RS232 driver/receiver pairs with integral charge pump to generate RS232 voltage levels from a single 5V supply. Using only 0.1µF external capacitors, these circuits consume only 40mW of power, and can operate to 120kbaud even while driving heavy capacitive loads. New ESD structures on the chip allow the LT1780/LT1781 to survive ±15kV air gap and ±8kV contact ESD tests per IEC 1000-4-2, eliminating the need for costly TransZorbs® on the RS232 line pins. The LT1780/LT1781 are fully compliant with EIA RS232 standards. Driver outputs are protected from overload, and can be shorted to ground or up to ±30V without damage. During SHUTDOWN or power-off conditions, driver and receiver outputs are in a high impedance state, allowing line sharing. The LT1780/LT1781 are direct upgrades to the LT1180A/LT1181A, LT1280A/LT1281A and LT1381 for applications which require the utmost ESD protection. The LT1781 is available in 16-pin DIP,SO and SW packages. The LT1780 is supplied in 18-pin DIP and SW packages for applications which require SHUTDOWN.