ICL3221, ICL3222, ICL3223, ICL3232, ICL3241, ICL3243

4. Application Information

FN4805 Rev.23.00

Page 14 of 36

Apr.26.19

The resulting new maximum voltages at V+ and V- are listed in Table 4.

4.2

Transmitters

The transmitters are proprietary, low dropout, inverting drivers that translate TTL/CMOS inputs to EIA/TIA-232

output levels. These transmitters are coupled with the on-chip ± 5.5V supplies and deliver true RS-232 levels

across a wide range of single supply system voltages.

Except for the ICL3232, all transmitter outputs disable and assume a high impedance state when the device

enters the powerdown mode (See Table 5 on page 15). These outputs can be driven to ±12V when disabled.

All devices ensure a 250kbps data rate for full load conditions (3kΩ and 1000pF), VCC ≥ 3.0V, with one transmitter

operating at full speed. Under more typical conditions of VCC ≥ 3.3V, RL = 3kΩ, and CL = 250pF, one transmitter

easily operates at 900kbps.

Transmitter inputs float if left unconnected and may cause ICC increases. Connect unused inputs to GND for the

best performance.

4.3

Receivers

All the ICL32xx devices contain standard inverting receivers that three-state (except for the ICL3232) using the

EN or FORCEOFF control lines. Additionally, the two ICL324X products include noninverting (monitor) receivers

(denoted by the ROUTB label) that are always active, regardless of the state of any control lines. All the receivers

convert RS-232 signals to CMOS output levels and accept inputs up to ±25V while presenting the required 3kΩ to

7kΩ input impedance (see Figure 7) even if the power is off (VCC = 0V). The receivers’ Schmitt trigger input stage

uses hysteresis to increase noise immunity and decrease errors due to slow input signal transitions.

Table 3.

V+ and V- Values for Vcc = 4.5V to 5.5V

C1 (μF)

C2, C3, C4 (μF)

Load

T1IN (Logic

State)

V+ (V)

V- (V)

VCC = 4.5V

VCC = 5.5V

VCC = 4.5V

VCC = 5.5V

0.1

0.1

Open

H

7.44

8.48

-6.16

-6.4

L

7.44

8.48

-6.16

-6.44

2.4kbps

7.44

8.48

-6.17

-6.44

3kΩ // 1000pF

H

7.76

8.88

-6.36

-6.72

L

7.08

8

-5.76

-5.76

2.4kbps

7.76

8.84

-6.4

-6.64

0.047

0.33

Open

H

6.44

6.88

-5.8

-5.88

L

6.48

6.88

-5.84

-5.88

2.4kbps

6.44

6.88

-5.8

-5.88

3kΩ // 1000pF

H

6.64

7.28

-5.92

-6.04

L

6.24

6.6

-5.52

-5.52

2.4kbps

6.72

7.16

-5.92

-5.96

1

1

Open

H

6.84

7.6

-5.76

-5.76

L

6.88

7.6

-5.76

-5.76

2.4kbps

6.92

7.56

-5.72

-5.76

3kΩ // 1000pF

H

7.28

8.16

-5.8

-5.92

L

6.44

6.84

-5.64

-6.84

2.4kbps

7.08

7.76

-5.8

-5.8

Table 4.

New Measured Withstanding Voltages

V+, V- to Ground

±13V

V+ to V-

20V