DATASHEET
ICL3224, ICL3226, I CL3238, ICL3244
1 Microamp, +3V to +5.5V, 250kbps, RS-232 Transceivers with Enhanced
Automatic Powerdown
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 enhanced
automatic powerdown functions, reduce the standby supply
current to a 1A trickle. Small footprint 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. This family is fully
compatible with 3.3V only systems, mixed 3.3V and 5.0V
systems, and 5.0V only systems.
The ICL3244 is a 3 driver, 5 receiver device that provides a
complete serial port suitable for laptop or notebook
computers. The ICL3244/38 also include a noninverting
always-active receiver for RING INDICATOR monitoring.
These devices feature an
enhanced automatic
powerdown
function which powers down the on-chip power-
supply and driver circuits. This occurs when all receiver and
transmitter inputs detect no signal transitions for a period of
30sec. These devices power back up, automatically,
whenever they sense a transition on any transmitter or
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.
FN4876
Rev 10.00
March 1, 2006
Features
•
Pb-Free Plus Anneal Available (RoHS Compliant)
•
15kV ESD Protected (Human Body Model)
• Manual and Enhanced Automatic Powerdown Features
• Drop in Replacements for MAX3224, MAX3226,
MAX3238, MAX3244
• Meets EIA/TIA-232 and V.28/V.24 Specifications at 3V
• Latch-Up Free
• RS-232 Compatible with V
CC
= 2.7V
• On-Chip Voltage Converters Require Only Four External
0.1F Capacitors
• Flow-Through Pinout (ICL3238)
• Guaranteed Mouse Driveability (ICL3244)
• “Ready to Transmit” Indicator Output (ICL3224/26)
• Receiver Hysteresis For Improved Noise Immunity
• Guaranteed Minimum Data Rate . . . . . . . . . . . . . 250kbps
• Guaranteed Minimum Slew Rate . . . . . . . . . . . . . . . 6V/s
• Wide Power Supply Range . . . . . . . Single +3V to +5.5V
• Low Supply Current in Powerdown State. . . . . . . . . . .1A
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
- Data Cradles
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
• AN9863, “3V to +5.5V, 250k-1Mbps, RS-232
Transmitters/Receivers”
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
ICL3224
ICL3226
ICL3238
ICL3244
NO. OF NO. OF
Tx.
Rx.
2
1
5
3
2
1
3
5
NO. OF
MONITOR Rx.
(R
OUTB
)
0
0
1
1
DATA
RATE
(kbps)
250
250
250
250
Rx. ENABLE
FUNCTION?
NO
NO
NO
NO
READY
OUTPUT?
YES
YES
NO
NO
MANUAL
POWER-
DOWN?
YES
YES
YES
YES
ENHANCED
AUTOMATIC
POWERDOWN
YES
YES
YES
YES
FN4876 Rev 10.00
March 1, 2006
Page 1 of 18
ICL3224, ICL3226, I CL3238, ICL3244
Pin Descriptions
PIN
V
CC
V+
V-
GND
C1+
C1-
C2+
C2-
T
IN
T
OUT
R
IN
R
OUT
R
OUTB
INVALID
READY
System power supply input (3.0V to 5.5V).
Internally generated positive transmitter supply (+5.5V).
Internally generated negative transmitter supply (-5.5V).
Ground connection.
External capacitor (voltage doubler) is connected to this lead.
External capacitor (voltage doubler) is connected to this lead.
External capacitor (voltage inverter) is connected to this lead.
External capacitor (voltage inverter) is connected to this lead.
TTL/CMOS compatible transmitter Inputs.
RS-232 level (nominally
5.5V)
transmitter outputs.
RS-232 compatible receiver inputs.
TTL/CMOS level receiver outputs.
TTL/CMOS level, noninverting, always enabled receiver outputs.
Active low output that indicates if no valid RS-232 levels are present on any receiver input.
Active high output that indicates when the ICL32XX is ready to transmit (i.e., V-
-4V)
FUNCTION
FORCEOFF Active low to shut down transmitters and on-chip power supply. This overrides any automatic 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
ICL3224
+3.3V
+
0.1F
2
+
4
5
+
6
13
T1
IN
12
TTL/CMOS
LOGIC
LEVELS
T2
IN
15
R1
OUT
10
R2
OUT
1
14
R
2
READY
FORCEON
GND
18
5k
20
11
R
1
5k
9
R2
IN
12
16
R1
IN
C1+
C1-
C2+
C2-
T
1
T
2
+3.3V
19
V
CC
V+
3
+ C
3
0.1F
C
4
0.1F
+
T1
OUT
8
T2
OUT
RS-232
LEVELS
C
1
0.1F
C
2
0.1F
+
0.1F
C1+
C1-
C2+
C2-
T
1
ICL3226
15
V
CC
V+
3
+ C
3
0.1F
C
4
C
1
0.1F
C
2
0.1F
2
+
4
+
6
5
V- 7
17
V- 7
13
+ 0.1F
T1
OUT
11
TTL/CMOS
LOGIC
LEVELS
T1
IN
9
R1
OUT
1
READY
8
R
1
5k
R1
IN
RS-232
LEVELS
FORCEOFF
FORCEON
GND
14
INVALID
16
10
V
CC
TO POWER
CONTROL
LOGIC
FORCEOFF
INVALID
V
CC
TO POWER
CONTROL
LOGIC
FN4876 Rev 10.00
March 1, 2006
Page 4 of 18
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