5

Detailed Description

The ICL32X7E interface ICs operate from a single +3V to

+5.5V power supply, guarantee a 250kbps minimum data

rate, require only four small external 0.1

µF capacitors,

feature low power consumption, and meet all ElA RS-232C

and V.28 specifications. The circuit is divided into three

sections: charge pump, transmitters and receivers.

Charge-Pump

Intersil’s new ICL32XXE family utilizes regulated on-chip

dual charge pumps as voltage doublers, and voltage

inverters to generate

supply as low as 3V. This allows these devices to maintain

RS-232 compliant output levels over the

±10% tolerance

range of 3.3V powered systems. The efficient on-chip power

supplies require only four small, external 0.1

µF capacitors

See the Capacitor Selection section, and Table 3 for

capacitor recommendations for other operating conditions.

The charge pumps operate discontinuously (i.e., they turn off

as soon as the V+ and V- supplies are pumped up to the

nominal values), resulting in significant power savings.

Transmitters

The transmitters are proprietary, low dropout, inverting

drivers that translate TTL/CMOS inputs to EIA/TIA-232

output levels. Coupled with the on-chip

±5.5V supplies,

these transmitters deliver true RS-232 levels over a wide

range of single supply system voltages.

ICL3217E transmitter outputs disable and assume a high

impedance state when the device enters the automatic

powerdown mode. These outputs may be driven to

±12V

when disabled.

Both devices guarantee a 250kbps data rate for full load

conditions (3k

Ω and 1000pF), V

transmitter operating at full speed. Under more typical

transmitter easily operates at 800kbps.

Transmitter inputs float if left unconnected, and may cause

performance.

Input Hysteresis

25

-

0.3

-

V

Input Resistance

25

357

k

Ω

TRANSMITTER OUTPUTS

Output Voltage Swing

All Transmitter Outputs Loaded with 3k

Ω to Ground

Full

±5.0

±5.4

-

V

Output Resistance

Full

300

10M

-

Ω

Output Short-Circuit Current

Full

-

±35

±60

mA

Output Leakage Current

(ICL3217E Only)

In Automatic Powerdown

Full

-

-

±25

µA

TIMING CHARACTERISTICS

Maximum Data Rate

(One Transmitter Switching)

Full

250

500

-

kbps

Full

250

286

-

kbps

Full

250

310

-

kbps

Receiver Propagation Delay

Receiver Input to Receiver

25

-

0.3

-

µs

25

-

0.3

-

µs

Transmitter Skew

Full

-

200

1000

ns

Receiver Skew

Full

-

100

500

ns

Transition Region Slew Rate

Measured From +3V to -3V or -3V

to +3V

25

4

15

30

V/

µs

25

6

15

30

V/

µs

ESD PERFORMANCE

IEC61000-4-2, Air-Gap Discharge Method

25

-

±15

-

kV

IEC61000-4-2, Contact Discharge Method

25

-

±8-

kV

Human Body Model

25

-

±15

-

kV

All Other Pins

Human Body Model

25

-

±2-

kV

Electrical Specifications

PARAMETER

TEST CONDITIONS

TEMP

(°C)

MIN

TYP

MAX

UNITS

ICL3207E, ICL3217E