The Intersil ISL324xE devices are 2.7V to 3.6V 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 POS systems,

and notebook and laptop computers 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 0.5µA 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.

ISL324xE are 3 driver, 5 receiver devices that, coupled with the

5x5 QFN package, provide the industry’s smallest, lowest

power complete serial port. The 5x5 QFN requires 60 less

board area than a 28 Ld TSSOP, and is nearly 20 thinner.

These devices also include a noninverting always-active

receiver for “wake-up” capability.

The ISL3243E features an automatic powerdown 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.

The ISL324xE feature a VL pin that adjusts the logic pin (see

“Pin Descriptions” on page 2) output levels and input

thresholds to values compatible with the VCC powering the

external logic (e.g., a UART).

Table 1 summarizes the features of the ISL324xE.

Features

• VL Pin for Compatibility in Mixed Voltage Systems Adjusts

Logic Output Levels and Input Thresholds for Compatibility

with Lower Supply Voltage Logic

• Parameters Specified for 10 Tolerance Supplies and Full

Industrial Temp Range

• Pb-free Small QFN (5mmx5mm) Package is 60 Smaller

than a 28 Lead 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

• Receiver Hysteresis for Improved Noise Immunity

• Guaranteed Minimum Data Rate. . . . . . . . . . . . . . . . 250kbps

• Low Supply Current in Power-down State . . . . . . . . . . . 0.5µA

• Pb-Free (RoHS compliant)

Applications

• Any Space Constrained System Requiring RS-232 Ports

- Battery Powered, Hand-Held, and Portable Equipment

- POS Systems and Scanners

- Laptop Computers, Notebooks

- GPS Receivers

• Mixed Voltage Serial Ports