The ICL3224E, ICL3226E, and ICL3244E 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. They provide ±15kV ESD protection (IEC61000-4-2 Air Gap and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins). Targeted applications are PDAs, Palmtops, and notebook and laptop computers where the low operational power 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 ICL3244E is a 3-driver, 5-receiver device that provides a complete serial port suitable for laptop or notebook computers. It also includes a noninverting always-active receiver for "wake-up" capability. The ICL3224E, ICL3226E, and ICL3244E 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.