The ICL3221E, ICL3222E, ICL3223E, ICL3232E, ICL3241E, and ICL3243E 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. Additionally, 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 notebook and laptop computers in which the low operational power consumption and even lower standby power consumption is critical. Efficient on-chip charge pumps, coupled with manual and automatic power-down functions (except for the ICL3232E), 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 ICL324XE are 3-driver, 5-receiver devices that provide a complete serial port suitable for laptop or notebook computers. Both devices also include noninverting always-active receivers for "wake-up" capability. The ICL3221E, ICL3223E, and ICL3243E feature an automatic power-down function that powers down the on-chip power supply and driver circuits. Power-down occurs when an attached peripheral device is shut off or the RS-232 cable is removed, which conserves system power automatically without changes to the hardware or operating system. These devices power up again when a valid RS-232 voltage is applied to any receiver input.