2.7V to 5.5V powered RS-232 transmitters/receivers whichmeet ElA/TIA-232 and V.28/V.24 specifications, even atVCC = 3.0V. Additionally, they provide ±15kV ESD protection(IEC61000-4-2 Air Gap and Human Body Model) ontransmitter outputs and receiver inputs (RS-232 pins). Targeted applications are PDAs, Palmtops, and hand-heldproducts where the low operational, and even lower standby,power consumption is critical. Efficient on-chip charge pumps,coupled with manual and automatic power-down functions,reduce the standby supply current to a 150nA trickle. Tiny5mmx5mm Quad Flat No-Lead (QFN) packaging and theuse of small, low value capacitors ensure board spacesavings as well. Data rates greater than 250kbps areguaranteed at worst case load conditions. The ISL4221E is a 1 driver, 1 receiver device and theISL3232E and ISL4223E are 2 driver, 2 receiver devicesthat, coupled with the 5mmx5mm QFN package, provide theindustry’s smallest, lowest power serial port suitable forPDAs, and hand-held applications. The 5mmx5mm QFNrequires 40% less board area than a 20 Ld TSSOP, and isnearly 20% thinner. The ISL4223E versions feature an automaticpower-down function that powers down the on-chip powersupply and driver circuits. This occurs when an attachedperipheral device is shut off or the RS-232 cable is removed,conserving system power automatically without changes tothe hardware or operating system. It powers up again whena valid RS-232 voltage is applied to any receiver input.
Available in Near Chip Scale QFN (5mmx5mm) Package, which is 40% Smaller than a 20 Ld TSSOP
ESD Protection for RS-232 I/O Pins to ±15kV (IEC61000)
Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V
RS-232 Compatible with VCC = 2.7V
On-Chip Voltage Converters Require Only Four External 0.1µF Capacitors
Manual and Automatic Power-down Features (Except ISL3232E)