The ICL3224, ICL3226, and ICL3238 (ICL32xx) devices are 3. 0V to 5. 5V powered RS-232 transmitters/receivers that meet ElA/TIA-232 and V. 28/V. 24 specifications, even at VCC = 3. 0V. Targeted applications are PDAs, Palmtops, and notebook and laptop computers where low operational power consumption and even lower standby power consumption are critical. Efficient on-chip charge pumps, coupled with manual and enhanced automatic powerdown functions, reduce the standby supply current to a 1μA trickle. Small footprint packaging, and the use of small, low value capacitors ensure board space savings. Data rates greater than 250kbps are ensured at worst case load conditions. This family is fully compatible with 3. 3V only systems, mixed 3. 3V and 5. 0V systems, and 5. 0V only systems. The ICL3238 is a 5 driver, 3 receiver device that includes a noninverting always-active receiver for Ring Indicator monitoring. The ICL32xx devices feature an enhanced automatic powerdown function that powers down the on -chip power supply and driver circuits. Powerdown occurs when all receiver and transmitter inputs detect no signal transitions for a period of 30s. These devices power back up automatically whenever they sense a transition on any transmitter or receiver input. AN9863 summarizes the features of each device in the ICL32xx 3V family.


  • Pb-free (RoHS compliant)
  • ±15kV ESD protected (human body model)
  • Manual and enhanced automatic powerdown features
  • Drop in replacements for MAX3224, MAX3226, MAX3238
  • Meets EIA/TIA-232 and V.28/V.24 specifications at 3V
  • Latch-up free
  • RS-232 compatible with VCC = 2.7V
  • On-chip voltage converters require only four external 0.1μF capacitors
  • Flow-through pinout (ICL3238)
  • “Ready to transmit” indicator output (ICL3224/26)
  • Receiver hysteresis for improved noise immunity
  • Ensured minimum data rate: 250kbps
  • Ensured minimum slew rate: 6V/μs
  • Wide power supply range: Single +3V to +5.5V
  • Low supply current in powerdown state: 1μA




  • Any System Requiring RS-232 Communication Ports Battery Powered, Hand-Held, and Portable Equipment Laptop Computers, Notebooks, Palmtops Modems, Printers and other Peripherals Digital Cameras Cellular/Mobile Phones Data Cradles


Design & Development