Page 1
3-1
TM
File Number 4805.2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Corporation. | Copyright © Intersil Corporation 2000
ICL3221 thru ICL3243
1 Microamp Supply-Current, +3V to +5.5V,
250kbps, RS-232 Transmitters/Receivers
The Intersil ICL32XX devices are 3.0V 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. Targeted
applications are PDAs, Palmtops, 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
powerdown functions (except for the ICL3232), reduce the
standby supply current to a 1µA trickle. Small footprint
packaging,and the use of small, low valuecapacitors ensure
board space savings as well. Data rates greater than
250kbps are guaranteed at worst case load conditions. This
family is fully compatible with 3.3V only systems, mixed 3.3V
and 5.0V systems, and 5.0V only systems.
The ICL324X are 3 driver, 5 receiver devices that provide a
complete serial port suitable for laptop or notebook
computers. Both devices also include noninverting alwaysactive receivers for “wake-up” capability.
The ICL3221, ICL3223 and ICL3243, feature an automatic
powerdown function which powers down the on-chip powersupply 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. These devices power up
again when a valid RS-232 voltage is applied to any receiver
input.
Table 1 summarizes the features of the devices represented
by this data sheet, while Application Note AN9863
summarizes the features of each device comprising the
ICL32XX 3V family.
Features
• Drop in Replacements for MAX3221, MAX3222,
MAX3223, MAX3232, MAX3241, MAX3243, SP3243
• ICL3222 is Low Power, Pin Compatible Upgrade for 5V
MAX242, and SP312A
• ICL3232 is Low Power Upgrade for HIN232/ICL232 and
Pin Compatible Competitor Devices
• Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V
• Latch-Up Free
• On-Chip Voltage Converters Require Only Four External
0.1µF Capacitors
• Manual and Automatic Powerdown Features (Except
ICL3232)
• Guaranteed Mouse Driveability
• Receiver Hysteresis For Improved Noise Immunity
• Guaranteed Minimum Data Rate . . . . . . . . . . . . 250kbps
• Guaranteed Minimum Slew Rate . . . . . . . . . . . . . . . 6V/µs
• Wide Power Supply Range. . . . . . . . Single +3V to +5.5V
• Low Supply Current in Powerdown State. . . . . . . . . . 1µA
Applications
• Any System Requiring RS-232 Communication Ports
- Battery Powered, Hand-Held, and Portable Equipment
- Laptop Computers, Notebooks, Palmtops
- Modems, Printers and other Peripherals
- Digital Cameras
- Cellular/Mobile Phones
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
NO.OF
Tx.
NO.OF
Rx.
NO. OF
MONITOR Rx.
(R
OUTB
)
DATA
RATE
(kbps)
Rx. ENABLE
FUNCTION?
READY
OUTPUT?
MANUAL
POWER-
DOWN?
AUTOMATIC
POWERDOWN
FUNCTION?
ICL3221 1 1 0 250 YES NO YES YES
ICL3222 2 2 0 250 YES NO YES NO
ICL3223 2 2 0 250 YES NO YES YES
ICL3232 2 2 0 250 NO NO NO NO
ICL3241 3 5 2 250 YES NO YES NO
ICL3243 3 5 1 250 NO NO YES YES
Data Sheet May 2000
Page 2
3-2
Ordering Information
(NOTE 1)
PART NO.
TEMP.
RANGE (oC) PACKAGE PKG. NO.
ICL3221CA 0 to 70 16 Ld SSOP M16.209
ICL3221CV 0 to 70 16 Ld TSSOP M16.173
ICL3222CA 0 to 70 20 Ld SSOP M20.209
ICL3222CB 0 to 70 18 Ld SOIC M18.3
ICL3222CP 0 to 70 18 Ld PDIP E18.3
ICL3222CV 0 to 70 20 Ld TSSOP M20.173
ICL3223CA 0 to 70 20 Ld SSOP M20.209
ICL3223CP 0 to 70 20 Ld PDIP E20.3
ICL3223CV 0 to 70 20 Ld TSSOP M20.173
ICL3232CA 0 to 70 16 Ld SSOP M16.209
ICL3232CB 0 to 70 16 Ld SOIC M16.3
ICL3232CP 0 to 70 16 Ld PDIP E16.3
ICL3232CV 0 to 70 16 Ld TSSOP M16.173
ICL3241CA 0 to 70 28 Ld SSOP M28.209
ICL3241CB 0 to 70 28 Ld SOIC M28.3
ICL3241CV 0 to 70 28 Ld TSSOP M28.173
ICL3243CA 0 to 70 28 Ld SSOP M28.209
ICL3243CB 0 to 70 28 Ld SOIC M28.3
ICL3243CV 0 to 70 28 Ld TSSOP M28.173
NOTE:
1. Most surface mount devices are available on tape and reel; add
“-T” to suffix.
Pinouts
ICL3221 (SSOP, TSSOP)
TOP VIEW
ICL3222 (PDIP, SOIC)
TOP VIEW
EN
C1+
V+
C1-
C2+
C2-
V-
R1
IN
FORCEOFF
GND
T1
OUT
FORCEON
T1
IN
R1
OUT
V
CC
INVALID
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
EN
C1+
V+
C1-
C2+
C2-
V-
T2
OUT
R2
IN
SHDN
GND
T1
OUT
R1
IN
R1
OUT
T2
IN
V
CC
T1
IN
R2
OUT
18
17
16
15
14
13
12
11
10
1
2
3
4
5
6
7
8
9
ICL3221 thru ICL3243
Page 3
3-3
ICL3222 (SSOP, TSSOP)
TOP VIEW
ICL3223 (PDIP, SSOP, TSSOP)
TOP VIEW
ICL3232 (PDIP, SOIC, SSOP, TSSOP)
TOP VIEW
ICL3241 (SOIC, SSOP, TSSOP)
TOP VIEW
ICL3243 (SOIC, SSOP, TSSOP)
TOP VIEW
Pinouts (Continued)
EN
C1+
V+
C1-
C2+
C2-
V-
T2
OUT
R2
IN
SHDN
GND
T1
OUT
R1
IN
R1
OUT
T1
IN
NC
V
CC
NC
T2
IN
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
R2
OUT
EN
C1+
V+
C1-
C2+
C2-
V-
T2
OUT
R2
IN
FORCEOFF
GND
T1
OUT
R1
IN
R1
OUT
T1
IN
INVALID
V
CC
FORCEON
T2
IN
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
R2
OUT
C1+
V+
C1C2+
C2-
V-
T2
OUT
R2
IN
V
CC
T1
OUT
R1
IN
R1
OUT
T1
IN
R2
OUT
GND
T2
IN
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
C2+
C2-
V-
R1
IN
R2
IN
R3
IN
R4
IN
R5
IN
T1
OUT
T3
OUT
T3
IN
T2
IN
T1
IN
C1+
V
CC
GND
C1EN
R1
OUTB
R1
OUT
R2
OUT
R3
OUT
R4
OUT
R5
OUT
V+
SHDN
R2
OUTB
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
T2
OUT
C2+
C2-
V-
R1
IN
R2
IN
R3
IN
R4
IN
R5
IN
T1
OUT
T3
OUT
T3
IN
T2
IN
T1
IN
C1+
V
CC
GND
C1FORCEON
INVALID
R1
OUT
R2
OUT
R3
OUT
R4
OUT
R5
OUT
V+
FORCEOFF
R2
OUTB
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
T2
OUT
ICL3221 thru ICL3243
Page 4
3-4
Pin Descriptions
PIN FUNCTION
V
CC
System power supply input (3.0V to 5.5V).
V+ Internally generated positive transmitter supply (+5.5V).
V- Internally generated negative transmitter supply (-5.5V).
GND Ground connection.
C1+ External capacitor (voltage doubler) is connected to this lead.
C1- External capacitor (voltage doubler) is connected to this lead.
C2+ External capacitor (voltage inverter) is connected to this lead.
C2- External capacitor (voltage inverter) is connected to this lead.
T
IN
TTL/CMOS compatible transmitter Inputs.
T
OUT
RS-232 level (nominally ±5.5V) transmitter outputs.
R
IN
RS-232 compatible receiver inputs.
R
OUT
TTL/CMOS level receiver outputs.
R
OUTB
TTL/CMOS level, noninverting, always enabled receiver outputs.
INVALID Active low output that indicates if no valid RS-232 levels are present on any receiver input.
EN Active low receiver enable control; doesn’t disable R
OUTB
outputs.
SHDN Active low input to shut down transmitters and on-board power supply, to place device in low power mode.
FORCEOFF Active low to shut down transmitters and on-chip power supply.This overridesanyautomatic circuitry and FORCEON (see Table 2).
FORCEON Active high input to override automatic powerdown circuitry thereby keeping transmitters active. (FORCEOFF must be high).
Typical Operating Circuits
ICL3221
15
V
CC
T1
OUT
T1
IN
T
1
0.1µF
+
0.1µF
+
0.1µF
11
13
2
4
3
7
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
5
6
R1
OUT
R1
IN
R
1
89
5kΩ
C
1
C
2
+
C
3
C
4
EN
1
GND
+3.3V
+
0.1µF
14
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
FORCEON
FORCEOFF
12
16
V
CC
10
INVALID
TO POWER
CONTROL LOGIC
ICL3221 thru ICL3243
Page 5
3-5
ICL3222
ICL3223
Typical Operating Circuits (Continued)
17
V
CC
T1
OUT
T2
OUT
T1
IN
T2
IN
T
1
T
2
0.1µF
+
0.1µF
+
0.1µF
12
11
15
8
2
4
3
7
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
5
6
R1
OUT
R1
IN
14
5kΩ
R2
OUT
R2
IN
9
10
5kΩ
13
C
1
C
2
+
C
3
C
4
EN
SHDN
1
GND
18
+3.3V
+
0.1µF
16
V
CC
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
R
1
R
2
19
V
CC
T1
OUT
T2
OUT
T1
IN
T2
IN
T
1
T
2
0.1µF
+
0.1µF
+
0.1µF
13
12
17
8
2
4
3
7
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
5
6
R1
OUT
R1
IN
16
5kΩ
R2
OUT
R2
IN
910
5kΩ
15
C
1
C
2
+
C
3
C
4
EN
1
GND
+3.3V
+
0.1µF
18
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
R
1
R
2
FORCEON
FORCEOFF
14
20
V
CC
11
INVALID
TO POWER
CONTROL LOGIC
ICL3221 thru ICL3243
Page 6
3-6
ICL3232
Typical Operating Circuits (Continued)
16
V
CC
T1
OUT
T2
OUT
T1
IN
T2
IN
T
1
T
2
0.1µF
+
0.1µF
+
0.1µF
11
10
14
7
1
3
2
6
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
4
5
R1
OUT
R1
IN
13
5kΩ
R2
OUT
R2
IN
8
9
5kΩ
12
C
1
C
2
+
C
3
C
4
GND
+3.3V
+
0.1µF
15
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
R
1
R
2
ICL3221 thru ICL3243
Page 7
3-7
ICL3241
Typical Operating Circuits (Continued)
26
V
CC
T1
OUT
T2
OUT
T3
OUT
T1
IN
T2
IN
T3
IN
T
1
T
2
T
3
0.1µF
+
0.1µF
+
0.1µF
14
13
9
10
12 11
28
24
27
3
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
1
2
R1
OUT
R1
IN
4
5kΩ
R2
OUT
R2
IN
518
5kΩ
R3
OUT
R3
IN
617
5kΩ
R4
OUT
R4
IN
716
5kΩ
R5
OUT
R5
IN
R
5
815
5kΩ
19
R2
OUTB
C
1
C
2
+
C
3
C
4
EN
SHDN
23
GND
22
+3.3V
+
0.1µF
20
25
V
CC
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
RS-232
LEVELS
R1
OUTB
21
R
1
R
2
R
3
R
4
ICL3221 thru ICL3243
Page 8
3-8
ICL3243
Typical Operating Circuits (Continued)
26
V
CC
T1
OUT
T2
OUT
T3
OUT
T1
IN
T2
IN
T3
IN
T
1
T
2
T
3
0.1µF
+
0.1µF
+
0.1µF
14
13
9
10
12 11
28
24
27
3
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
1
2
R1
OUT
R1
IN
4
5kΩ
R2
OUT
R2
IN
518
5kΩ
R3
OUT
R3
IN
617
5kΩ
R4
OUT
R4
IN
716
5kΩ
R5
OUT
R5
IN
R
5
815
5kΩ
19
R2
OUTB
C
1
C
2
+
C
3
C
4
FORCEON
FORCEOFF
23
GND
22
+3.3V
+
0.1µF
20
25
V
CC
TTL/CMOS
LOGIC LEVELS
RS-232
LEVELS
RS-232
LEVELS
R
1
R
2
R
3
R
4
21
INVALID
TO POWER
CONTROL LOGIC
ICL3221 thru ICL3243
Page 9
3-9
Absolute Maximum Ratings Thermal Information
VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V
V+ to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V
V- to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3V to -7V
V+ to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14V
Input Voltages
TIN, FORCEOFF, FORCEON, EN, SHDN . . . . . . . . . -0.3V to 6V
RIN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25V
Output Voltages
T
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±13.2V
R
OUT
, INVALID. . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VCC +0.3V
Short Circuit Duration
T
OUT
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . 0oC to 70oC
Thermal Resistance (Typical, Note 2) θJA (oC/W)
16 Ld PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . 90
18 Ld PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . 80
20 Ld PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . 77
16 Ld SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . 100
18 Ld SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . 75
28 Ld SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . 75
16 Ld SSOP Package . . . . . . . . . . . . . . . . . . . . . . . 135
20 Ld SSOP Package . . . . . . . . . . . . . . . . . . . . . . . 122
16 Ld TSSOP Package . . . . . . . . . . . . . . . . . . . . . . 145
20 Ld TSSOP Package . . . . . . . . . . . . . . . . . . . . . . 140
28 Ld SSOP and TSSOP Packages . . . . . . . . . . . . 100
Moisture Sensitivity (see Technical Brief TB363)
All Packages Not Listed Below. . . . . . . . . . . . . . . . . . . . . . Level 1
20 Ld TSSOP and 16 Ld SSOP and TSSOP Packages . . Level 2
Maximum Junction Temperature (Plastic Package) . . . . . . . 150oC
Maximum Storage Temperature Range. . . . . . . . . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . 300oC
(SOIC, SSOP, TSSOP - Lead Tips Only)
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
2. θJA is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications Test Conditions: V
CC
= 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified.
Typicals are at TA = 25oC
PARAMETER TEST CONDITIONS
TEMP
(oC) MIN TYP MAX UNITS
DC CHARACTERISTICS
Supply Current, Automatic
Powerdown
All RIN Open, FORCEON = GND, FORCEOFF = V
CC
(ICL3221, ICL3223, ICL3243 Only)
25 - 1.0 10 µA
Supply Current, Powerdown FORCEOFF= SHDN = GND (Except ICL3232) 25 - 1.0 10 µA
Supply Current,
Automatic Powerdown Disabled
All Outputs Unloaded,
FORCEON = FORCEOFF =
SHDN = V
CC
VCC = 3.3V, ICL3221-32 25 - 0.3 1.0 mA
VCC = 3.0V, ICL3241-43 25 - 0.3 1.0 mA
LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low TIN, FORCEON, FORCEOFF, EN, SHDN Full - - 0.8 V
Input Logic Threshold High TIN, FORCEON, FORCEOFF,
EN, SHDN
VCC = 3.3V Full 2.0 - - V
VCC = 5.0V Full 2.4 - - V
Input Leakage Current TIN, FORCEON, FORCEOFF, EN, SHDN Full - ±0.01 ±1.0 µA
Output Leakage Current
(Except ICL3232)
FORCEOFF = GND or EN = V
CC
Full - ±0.05 ±10 µA
Output Voltage Low I
OUT
= 1.6mA Full - - 0.4 V
Output Voltage High I
OUT
= -1.0mA Full VCC-0.6 VCC-0.1 - V
AUTOMATIC POWERDOWN (ICL3221, ICL3223, ICL3243 Only, FORCEON = GND, FORCEOFF = VCC)
Receiver Input Thresholds to
Enable Transmitters
ICL32XX Powers Up (See Figure 6) Full -2.7 - 2.7 V
Receiver Input Thresholds to
Disable Transmitters
ICL32XX Powers Down (See Figure 6) Full -0.3 - 0.3 V
INVALID Output Voltage Low I
OUT
= 1.6mA Full - - 0.4 V
INVALID Output Voltage High I
OUT
= -1.0mA Full VCC-0.6 - - V
Receiver Threshold to Transmitters
Enabled Delay (tWU)
25 - 100 - µs
ICL3221 thru ICL3243
Page 10
3-10
Receiver Positive or Negative
Threshold to INVALID High Delay
(t
INVH
)
25 - 1 - µs
Receiver Positive or Negative
Threshold to INVALID Low Delay
(t
INVL
)
25 - 30 - µs
RECEIVER INPUTS
Input Voltage Range Full -25 - 25 V
Input Threshold Low VCC = 3.3V 25 0.6 1.2 - V
VCC = 5.0V 25 0.8 1.5 - V
Input Threshold High VCC = 3.3V 25 - 1.5 2.4 V
VCC = 5.0V 25 - 1.8 2.4 V
Input Hysteresis 25 - 0.3 - V
Input Resistance 25357kΩ
TRANSMITTER OUTPUTS
Output Voltage Swing All Transmitter Outputs Loaded with 3kΩ to Ground Full ±5.0 ±5.4 - V
Output Resistance VCC= V+ = V- = 0V, Transmitter Output = ±2V Full 300 10M - Ω
Output Short-Circuit Current Full - ±35 ±60 mA
Output Leakage Current
(Except ICL3232)
V
OUT
= ±12V, VCC= 0V or 3V to 5.5V
Automatic Powerdown or FORCEOFF = SHDN = GND
Full - - ±25 µA
MOUSE DRIVEABILITY (ICL324X Only)
Transmitter Output Voltage
(See Figure 9)
T1IN=T2IN= GND, T3IN=VCC,T3
OUT
Loadedwith3kΩto
GND, T1
OUT
and T2
OUT
Loaded with 2.5mA Each
Full ±5- -V
TIMING CHARACTERISTICS
Maximum Data Rate (Note 3) RL=3kΩ, CL= 1000pF, One Transmitter Switching Full 120 500 - kbps
Receiver Propagation Delay Receiver Input to Receiver
Output, CL= 150pF
t
PHL
25 - 0.3 - µs
t
PLH
25 - 0.3 - µs
Receiver Output Enable Time Normal Operation (Except ICL3232) 25 - 200 - ns
Receiver Output Disable Time Normal Operation (Except ICL3232) 25 - 200 - ns
Transmitter Skew t
PHL
- t
PLH
Full - 200 1000 ns
Receiver Skew t
PHL
- t
PLH
Full - 100 500 ns
Transition Region Slew Rate VCC= 3.3V,
RL=3kΩ to 7kΩ,
Measured From 3V to -3V or -3V
to 3V
CL= 200pF to 2500pF 25 4 8.0 30 V/µs
CL= 200pF to 1000pF 25 6 - 30 V/µs
ESD PERFORMANCE
RS-232 Pins (T
OUT
, RIN) Human Body Model ICL3221 - ICL3243 25 - >±8-kV
IEC1000-4-2 Contact Discharge ICL3221 - ICL3243 25 - ±8-kV
IEC1000-4-2 Air Gap Discharge ICL3221 - ICL3232 25 - ±8-kV
ICL3241 - ICL3243 25 - ±6-kV
All Other Pins Human Body Model ICL3221 - ICL3243 25 - ±2.5 - kV
NOTE:
3. All the ICL32XX devices are guaranteed to operate at a minimum data rate of 250kbps. The specification table lists a minimum of 120kbps to
maintain complete compatibility with competitor data sheets.
Electrical Specifications Test Conditions: V
CC
= 3V to 5.5V, C1 - C4 = 0.1µF; Unless Otherwise Specified.
Typicals are at TA = 25oC (Continued)
PARAMETER TEST CONDITIONS
TEMP
(oC) MIN TYP MAX UNITS
ICL3221 thru ICL3243
Page 11
3-11
Detailed Description
ICL32XX interface ICs operate from a single +3V to +5.5V
supply, guarantee a 250kbps minimum data rate, require
only four small external 0.1µF capacitors, feature low power
consumption, and meet all ElA RS-232C and V.28
specifications. The circuit is divided into three sections: The
charge pump, the transmitters, and the receivers.
Charge-Pump
Intersil’s new ICL32XX family utilizes regulated on-chip dual
charge pumps as voltage doublers, and voltage inverters to
generate ±5.5V transmitter supplies from a V
CC
supply as
low as 3.0V. 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 0.1µF capacitors for the
voltage doubler and inverter functions at V
CC
= 3.3V. 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.
Except for the ICL3232, all transmitter outputs disable and
assume a high impedance state when the device enters the
powerdown mode (see Table 2). These outputs may be
driven to ±12V when disabled.
All devices guarantee a 250kbps data rate for full load
conditions (3kΩ and 1000pF), V
CC
≥ 3.0V, with one
transmitter operating at full speed. Under more typical
conditions of V
CC
≥ 3.3V, RL=3kΩ, and CL= 250pF, one
transmitter easily operates at 900kbps.
Transmitter inputs float if left unconnected, and may cause
I
CC
increases. Connect unused inputs to GND for the best
performance.
Receivers
All the ICL32XX devicescontain standard inverting receivers
that tristate (except for the ICL3232) via the
EN or
FORCEOFF control lines. Additionally, the two ICL324X
products include noninverting (monitor) receivers (denoted
by the R
OUTB
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 1) even if the power is off (V
CC
= 0V). The
receivers’ Schmitt trigger input stage uses hysteresis to
increase noise immunity and decrease errors due to slow
input signal transitions.
The ICL3221/22/23/41 inverting receivers disable only when
EN is driven high. ICL3243 receivers disable during forced
(manual) powerdown, but not during automatic powerdown
(see Table 2).
ICL324X monitor receivers remain active even during
manual powerdown and forced receiver disable, making
them extremely useful for Ring Indicator monitoring.
Standard receivers driving powered down peripherals must
be disabled to prevent current flow through the peripheral’s
protection diodes (see Figures 2 and 3). This renders them
useless for wakeup functions, but the corresponding monitor
receiver can be dedicated to this task as shown in Figure 3.
Powerdown Functionality (Except
ICL3232)
This 3V family of RS-232 interface devices requires a
nominal supply current of 0.3mA during normal operation
(not in powerdown mode). This is considerably less than the
5mA to 11mA current required of 5V RS-232 devices. The
already low current requirement drops significantly when the
device enters powerdown mode. In powerdown, supply
current drops to 1µA, because the on-chip charge pump
turns off (V+ collapses to V
CC
, V- collapses to GND), and
the transmitter outputs tristate. Inverting receiver outputs
may or may not disable in powerdown; refer to Table 2 for
details. This micro-power mode makes these devices ideal
for battery powered and portable applications.
Software Controlled (Manual) Powerdown
Most devices in the ICL32XX family provide pins that allow
the user to force the IC into the low power, standby state.
On the ICL3222 and ICL3241, the powerdown control is via
a simple shutdown (
SHDN) pin. Driving this pin high enables
normal operation, while driving it low forces the IC into it’s
powerdown state. Connect
SHDN to VCC if the powerdown
function isn’t needed. Note that all the receiver outputs
remain enabled during shutdown (see Table 2). For the
lowest power consumption during powerdown, the receivers
should also be disabled by driving the
EN input high (see
next section, and Figures 2 and 3).
The ICL3221, ICL3223, and ICL3243 utilize a two pin
approach where the FORCEON and
FORCEOFF inputs
determine the IC’s mode. For always enabled operation,
FORCEON and
FORCEOFF are both strapped high. To
switchbetweenactiveand powerdownmodes, under logic or
software control, only the
FORCEOFF input need be driven.
R
XOUT
GND ≤ V
ROUT
≤ V
CC
5kΩ
R
XIN
-25V ≤ V
RIN
≤ +25V
GND
V
CC
FIGURE 1. INVERTING RECEIVER CONNECTIONS
ICL3221 thru ICL3243
Page 12
3-12
The FORCEON state isn’t critical, as FORCEOFF
dominates over FORCEON. Nevertheless, if strictly manual
control over powerdown is desired, the user must strap
FORCEON high to disable the automatic powerdown
circuitry. Inverting (standard) receiver outputs also disable
when the device is in powerdown, thereby eliminating the
possible current path through a shutdown peripheral’s input
protection diode (see Figures 2 and 3).
The
INVALID output always indicates whether or not a valid
RS-232 signal is present at any of the receiver inputs (see
Table 2), giving the user an easy way to determine when the
interface block should power down. In the case of a
disconnected interface cable where all the receiver inputs
are floating (but pulled to GND by the internal receiver pull
down resistors), the
INVALID logic detects the invalid levels
and drives the output low. The power management logic
then uses this indicator to power down the interface block.
Reconnecting the cable restores valid levels at the receiver
inputs,
INVALID switches high, and the power management
logic wakes up the interface block.
INVALID can also be
used to indicate the DTR or RING INDICATOR signal, as
long as the other receiver inputs are floating, or driven to
GND (as in the case of a powered down driver). Connecting
FORCEOFF and FORCEON together disables the
automatic powerdown feature, enabling them to function as
a manual
SHUTDOWN input (see Figure 4).
TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE
RS-232
SIGNAL
PRESENT
AT
RECEIVER
INPUT?
FORCEOFF
OR SHDN
INPUT
FORCEON
INPUTENINPUT
TRANSMITTER
OUTPUTS
RECEIVER
OUTPUTS
(NOTE 4)
R
OUTB
OUTPUTS
INVALID
OUTPUT MODE OF OPERATION
ICL3222, ICL3241
N.A. L N.A. L High-Z Active Active N.A. Manual Powerdown
N.A. L N.A. H High-Z High-Z Active N.A. Manual Powerdown w/Rcvr. Disabled
N.A. H N.A. L Active Active Active N.A. Normal Operation
N.A. H N.A. H Active High-Z Active N.A. Normal Operation w/Rcvr. Disabled
ICL3221, ICL3223
NO H H L Active Active N.A. L Normal Operation
(Auto Powerdown Disabled)
NO H H H Active High-Z N.A. L
YES H L L Active Active N.A. H Normal Operation
(Auto Powerdown Enabled)
YES H L H Active High-Z N.A. H
NO H L L High-Z Active N.A. L Powerdown Due to Auto Powerdown
Logic
NO H L H High-Z High-Z N.A. L
YES L X L High-Z Active N.A. H Manual Powerdown
YES L X H High-Z High-Z N.A. H Manual Powerdown w/Rcvr. Disabled
NO L X L High-Z Active N.A. L Manual Powerdown
NO L X H High-Z High-Z N.A. L Manual Powerdown w/Rcvr. Disabled
ICL3243
NO H H N.A. Active Active Active L Normal Operation
(Auto Powerdown Disabled)
YES H L N.A. Active Active Active H Normal Operation
(Auto Powerdown Enabled)
NO H L N.A. High-Z Active Active L Powerdown Due to Auto Powerdown
Logic
YES L X N.A. High-Z High-Z Active H Manual Powerdown
NO L X N.A. High-Z High-Z Active L Manual Powerdown
NOTE:
4. Applies only to the ICL3241 and ICL3243.
ICL3221 thru ICL3243
Page 13
3-13
With any of the above control schemes, the time required to
exit powerdown, and resume transmission is only 100µs. A
mouse, or other application, may need more time to wakeup
from shutdown. If automatic powerdown is being utilized, the
RS-232 device will reenter powerdown if valid receiver levels
aren’t reestablished within 30µs of the ICL32XX powering
up. Figure 5 illustrates a circuit that keeps the ICL32XX from
initiating automatic powerdown for 100ms after powering up.
This gives the slow-to-wake peripheral circuit time to
reestablish valid RS-232 output levels.
Automatic Powerdown (ICL3221/23/43 Only)
Even greater power savings is availablebyusing the devices
which feature an automatic powerdown function. When no
valid RS-232 voltages (see Figure 6) are sensed on any
receiver input for 30µs, the charge pump and transmitters
powerdown, thereby reducing supply current to 1µA. Invalid
receiver levels occur whenever the driving peripheral’s
outputs are shut off (powered down) or when the RS-232
interface cable is disconnected. The ICL32XX powers back
up whenever it detects a valid RS-232 voltage level on any
receiver input. This automatic powerdown feature provides
additional system power savings without changes to the
existing operating system.
Automatic powerdown operates when the FORCEON input
is low, and the
FORCEOFF input is high. Tying FORCEON
high disables automatic powerdown, but manual powerdown
is always available via the overriding
FORCEOFF input.
Table 2 summarizes the automatic powerdown functionality.
FIGURE 2. POWER DRAIN THROUGH POWEREDDOWN
PERIPHERAL
OLD
V
CC
POWERED
GND
SHDN = GND
V
CC
Rx
Tx
V
CC
CURRENT
V
OUT=VCC
FLOW
RS-232 CHIP
DOWN
UART
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
ICL324X
TRANSITION
R
X
T
X
R2
OUTB
R2
OUT
T1
IN
FORCEOFF = GND
V
CC
V
CC
TO
R2
IN
T1
OUT
V
OUT
= HI-Z
POWERED
OR SHDN = GND, EN = V
CC
DETECTOR
DOWN
UART
WAKE-UP
LOGIC
FIGURE 4. CONNECTIONS FOR MANUALPOWERDOWN
WHEN NO VALID RECEIVER SIGNALS ARE
PRESENT
PWR
FORCEOFF
INVALID
CPU
I/O
FORCEON
ICL3221/23/43
MGT
LOGIC
UART
FIGURE 5. CIRCUIT TO PREVENT AUTOPOWERDOWN FOR
100ms AFTER FORCED POWERUP
ICL3221/23/43
FORCEOFF FORCEON
POWER
MASTER POWERDOWN LINE
1MΩ
0.1µF
MANAGEMENT
UNIT
FIGURE 6. DEFINITION OF VALID RS-232 RECEIVER LEVELS
0.3V
-0.3V
-2.7V
2.7V
INVALID LEVEL - POWERDOWN OCCURS AFTER 30µs
VALID RS-232 LEVEL - ICL32XX IS ACTIVE
VALID RS-232 LEVEL - ICL32XX IS ACTIVE
INDETERMINATE - POWERDOWN MAY OR
INDETERMINATE - POWERDOWN MAY OR
MAY NOT OCCUR
MAY NOT OCCUR
ICL3221 thru ICL3243
Page 14
3-14
Devices with the automatic powerdown feature include an
INVALID output signal, which switches low to indicate that
invalid levels have persisted on all of the receiver inputs for
more than 30µs (see Figure 7).
INVALID switches high 1µs
after detecting a valid RS-232 level on a receiver input.
INVALID operates in all modes (forced or automatic
powerdown, or forced on), so it is also useful for systems
employing manual powerdown circuitry. When automatic
powerdown is utilized,
INVALID = 0 indicates that the
ICL32XX is in powerdown mode.
The time to recover from automatic powerdown mode is
typically 100µs.
Receiver ENABLE Control (ICL3221/22/23/41 Only)
Several devices also feature an EN input to control the
receiver outputs. Driving
EN high disables all the inverting
(standard) receiver outputs placing them in a high
impedance state. This is useful to eliminate supply current,
due to a receiveroutput forwardbiasing the protection diode,
when driving the input of a powered down (V
CC
= GND)
peripheral (see Figure 2). The enable input has no effect on
transmitter nor monitor (R
OUTB
) outputs.
Capacitor Selection
The charge pumps require 0.1µF capacitors for 3.3V
operation. For other supply voltages refer to Table 3 for
capacitor values. Do not use values smaller than those listed
in Table 3. Increasing the capacitor values (by a factor of 2)
reduces ripple on the transmitter outputs and slightly
reduces power consumption. C
2
, C3, and C4 can be
increased without increasing C
1
’s value, however, do not
increase C
1
without also increasing C2, C3, and C4 to
maintain the proper ratios (C
1
to the other capacitors).
When using minimum required capacitor values, make sure
that capacitor values do not degrade excessively with
temperature.If in doubt, use capacitors with a larger nominal
value. The capacitor’s equivalent series resistance (ESR)
usually rises at low temperatures and it influences the
amount of ripple on V+ and V-.
Power Supply Decoupling
In most circumstances a 0.1µF bypass capacitor is
adequate. In applications that are particularly sensitive to
power supply noise, decouple V
CC
to ground with a
capacitor of the same value as the charge-pump capacitor C
1
.
Connect the bypass capacitor as close as possible to the IC.
Transmitter Outputs when Exiting
Powerdown
Figure 8 shows the response of two transmitter outputs
when exiting powerdown mode. As they activate, the two
transmitter outputs properly go to opposite RS-232 levels,
with no glitching, ringing, nor undesirable transients. Each
transmitter is loaded with 3kΩ in parallel with 2500pF. Note
that the transmitters enable only when the magnitude of the
supplies exceed approximately 3V.
Mouse Driveability
The ICL324X have been specifically designed to power a
serial mouse while operating from low voltage supplies.
Figure 9 shows the transmitter output voltages under
increasing load current. The on-chip switching regulator
ensures the transmitters will supply at least
±5V during worst
case conditions (15mA for paralleled V+ transmitters, 7.3mA
for single V- transmitter). The Automatic Powerdown feature
does not work with a mouse, so
FORCEOFF and
FORCEON should be connected to V
CC
.
RECEIVER
INPUTS
TRANSMITTER
OUTPUTS
INVALID
OUTPUT
V+
V
CC
0
V-
V
CC
0
t
INVL
t
INVH
INVALID
REGION
}
FIGURE7. AUTOMATIC POWERDOWN ANDINVALIDTIMING
DIAGRAMS
AUTOPWDN
PWR UP
TABLE 3. REQUIRED CAPACITOR VALUES
V
CC
(V)
C
1
(µF)
C2, C3, C
4
(µF)
3.0 to 3.6 0.1 0.1
4.5 to 5.5 0.047 0.33
3.0 to 5.5 0.1 0.47
TIME (20µs/DIV.)
T1
T2
2V/DIV
5V/DIV
VCC = +3.3V
FORCEOFF
FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING
POWERDOWN
C1 - C4 = 0.1µF
ICL3221 thru ICL3243
Page 15
3-15
High Data Rates
The ICL32XX maintain the RS-232 ±5V minimum transmitter
output voltages even at high data rates. Figure 10 details a
transmitter loopback test circuit, and Figure 11 illustrates the
loopback test result at 120kbps. For this test, all transmitters
were simultaneously driving RS-232 loads in parallel with
1000pF, at 120kbps. Figure 12 shows the loopback results
for a single transmitter driving 1000pF and an RS-232 load
at 250kbps. The static transmitters were also loaded with an
RS-232 receiver.
Interconnection with 3V and 5V Logic
The ICL32XX directly interface with most 5V logic families,
including ACT and HCT CMOS. See Table 4 for more
information on possible combinations of interconnections.
FIGURE 10. TRANSMITTER LOOPBACK TEST CIRCUIT
FIGURE 9. TRANSMITTER OUTPUT VOLTAGE vs LOAD
CURRENT (PER TRANSMITTER, i.e., DOUBLE
CURRENT AXIS FOR TOTAL V
OUT+
CURRENT)
TRANSMITTER OUTPUT VOLTAGE (V)
LOAD CURRENT PER TRANSMITTER (mA)
0246810
-6
-4
-2
0
2
4
6
-5
-3
-1
1
3
5
13579
V
OUT
+
V
OUT
-
V
CC
V
OUT
+
V
OUT
-
T1
T2
T3
V
CC
= 3.0V
ICL3241/43
ICL32XX
V
CC
FORCEOFF
C
1
C
2
C
4
C
3
+
+
+
+
1000pF
V+
V-
5k
T
IN
R
OUT
C1+
C1-
C2+
C2-
R
IN
T
OUT
+
V
CC
0.1µF
V
CC
EN
SHDN OR
FIGURE 11. LOOPBACK TEST AT 120kbps
FIGURE 12. LOOPBACK TEST AT 250kbps
TABLE 4. LOGIC FAMILY COMPATIBILITY WITH VARIOUS
SUPPLY VOLTAGES
SYSTEM
POWER-SUPPLY
VOLTAGE
(V)
V
CC
SUPPLY
VOLTAGE
(V) COMPATIBILITY
3.3 3.3 Compatible with all CMOS
families.
5 5 Compatible with all TTL and
CMOS logic families.
5 3.3 Compatible with ACT and HCT
CMOS, and with TTL.
Incompatible with AC, HC, or
CD4000 CMOS.
T1
IN
T1
OUT
R1
OUT
5µs/DIV.
VCC = +3.3V
5V/DIV.
C1 - C4 = 0.1µF
T1
IN
T1
OUT
R1
OUT
2µs/DIV.
5V/DIV.
VCC = +3.3V
C1 - C4 = 0.1µF
ICL3221 thru ICL3243
Page 16
3-16
Typical Performance Curves V
CC
= 3.3V, TA = 25oC
FIGURE 13. TRANSMITTER OUTPUT VOLTAGE vs LOAD
CAPACITANCE
FIGURE 14. SLEW RATE vs LOAD CAPACITANCE
FIGURE 15. SUPPLYCURRENT vs LOAD CAPACITANCE
WHEN TRANSMITTING DATA
FIGURE 16. SUPPLYCURRENT vs LOAD CAPACITANCE
WHEN TRANSMITTING DATA
FIGURE 17. SUPPLY CURRENT vs SUPPLY VOLTAGE
-7.5
-5.0
-2.5
0
2.5
5.0
7.5
1000 2000 3000 4000 50000
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
1 TRANSMITTER AT 235kbps
V
OUT
+
V
OUT
-
1 OR 2 TRANSMITTERS AT 30kbps
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
0 1000 2000 3000 4000 5000
5
10
15
20
25
+SLEW
-SLEW
0
5
10
15
20
25
30
45
35
40
0 1000 2000 3000 4000 5000
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
20kbps
235kbps
120kbps
ICL3221 - ICL3232
0
5
10
15
20
25
30
45
35
40
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
20kbps
235kbps
120kbps
ICL324X
SUPPLY CURRENT (mA)
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
0
0.5
1.0
1.5
2.0
SUPPLY VOLTAGE (V)
2.5
3.0
3.5
NO LOAD
ALL OUTPUTS STATIC
ICL3221 - ICL3232
ICL324X
ICL324X
ICL3221 thru ICL3243
Page 17
3-17
Die Characteristics
DIE DIMENSIONS:
ICL3221/22/23/32:
100 mils x 100 mils (2540µm x 2540µm)
ICL3241/43:
100 mils x 127 mils (2550µm x 3230µm)
METALLIZATION:
Type: Metal 1: AISi(1%)
Thickness: Metal 1: 8k
Å
Type: Metal 2: AISi (1%)
Thickness: Metal 2: 10k
Å
SUBSTRATE POTENTIAL (POWERED UP):
GND
PASSIVATION:
Type: Silox
Thickness: 13k
Å
TRANSISTOR COUNT:
ICL3221: 286
ICL3222: 338
ICL3223: 357
ICL3232: 296
ICL324X: 464
PROCESS:
Si Gate CMOS
ICL3221 thru ICL3243
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