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
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 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

Features
• 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)
• 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)

Applications
• 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