The Intersil ISL3232E and ISL4221E, ISL4223E devices are 2.7V to 5.5V powered RS-232 transmitters/receivers which meet ElA/TIA-232 and V.28/V.24 specifications, even at V_CC = 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 PDAs, Palmtops, and hand-held products 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. Tiny 5mmx5mm Quad Flat No-Lead (QFN) packaging and the use of small, low value capacitors ensure board space savings as well. Data rates greater than 250kbps are guaranteed at worst case load conditions.

The ISL4221E is a 1 driver, 1 receiver device and the ISL3232E and ISL4223E are 2 driver, 2 receiver devices that, coupled with the 5mmx5mm QFN package, provide the industry's smallest, lowest power serial port suitable for PDAs, and hand-held applications. The 5mmx5mm QFN requires 40% less board area than a 20 Ld TSSOP, and is nearly 20% thinner.

The ISL4221E, ISL4223E versions feature an automatic power-down function that powers down the on-chip power supply and driver circuits. This occurs when an attached peripheral device is shut off or the RS-232 cable is removed, conserving system power automatically without changes to the hardware or operating system. It powers up again when a valid RS-232 voltage is applied to any receiver input.

Table 1 summarizes the features of the IC's, while Application Note AN9863 summarizes the features of each device comprising the 3V RS-232 family.

• 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 V_CC = 2.7V
• On-Chip Voltage Converters Require Only Four External 0.1μF Capacitors
• Manual and Automatic Power-down Features (Except ISL3232E)
• Receiver Hysteresis For Improved Noise Immunity
• Guaranteed Minimum Data Rate 250kbps
• Wide Power Supply Range Single +2.7V to +5.5V
• Low Supply Current in Power-down State 150nA
• Pb-Free Available (RoHS Compliant)

• Any Space Constrained System Requiring RS-232 Ports
  • Battery Powered, and Portable Equipment
  • Hand-Held Products (GPS Receivers, Bar Code Scanners, etc.)
  • PDAs and Palmtops, Data Cables
  • Cellular/Mobile Phones, Digital Cameras