INTERSIL ICL232

ICL232
TM
+5V Powered, Dual RS-232 Transmitter/Receiver
June 2001
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Features
Description
• Meets All RS-232C and V.28 Specifications
The ICL232 is a dual RS-232 transmitter/receiver interface
circuit that meets all ElA RS-232C and V.28 specifications. It
requires a single +5V power supply, and features two
onboard charge pump voltage converters which generate
+10V and -10V supplies from the 5V supply.
• Requires Only Single +5V Power Supply
• Onboard Voltage Doubler/Inverter
• Low Power Consumption
• 2 Drivers
- ±9V Output Swing for +5V lnput
- 300Ω Power-off Source Impedance
- Output Current Limiting
- TTL/CMOS Compatible
- 30V/µs Maximum Slew Rate
Ordering Information
• 2 Receivers
- ±30V Input Voltage Range
- 3kΩ to 7kΩ Input Impedance
- 0.5V Hysteresis to Improve Noise Rejection
TEMP.
RANGE ( oC)
PART NUMBER
• All Critical Parameters are Guaranteed Over the Entire
Commercial, Industrial and Military Temperature Ranges
Applications
• Any System Requiring RS-232 Communications Port
- Computer - Portable and Mainframe
- Peripheral - Printers and Terminals
- Portable Instrumentation
- Modems
• Dataloggers
Pinout
PKG.
NO.
PACKAGE
ICL232CPE
0 to 70
16 Ld PDIP
E16.3
ICL232CBE
0 to 70
16 Ld SOIC
M16.3
ICL232lPE
-40 to 85
16 Ld PDIP
E16.3
ICL232lBE
-40 to 85
16 Ld SOIC
M16.3
ICL232MJE
-55 to 125
16 Ld CERDIP
F16.3
Functional Diagram
+5V
ICL232 (PDIP, CERDIP, SOIC)
TOP VIEW
C1+
V+
gede
setes
OCEW
f-
The drivers feature true TTL/CMOS input compatibility, slewrate-limited output, and 300Ω power-off source impedance.
The receivers can handle up to +30V, and have a 3kΩ to 7kΩ
input impedance. The receivers also have hysteresis to
improve noise rejection.
1
2
C1- 3
C2+
4
C2- 5
1
16 VCC
1µF
15 GND
+
3
4
14 T1OUT
1µF
+
5
C1+
C1C2+
16
VCC
2
+5V TO 10V
VOLTAGE INVERTER V+
C2-
12 R1OUT
11
+5V
400kΩ
T1
+5V
400kΩ
T2
10
11 T1IN
T2 OUT 7
10 T2IN
9
T1IN
T2IN
+
14
7
12
13
R1OUT
R2OUT
1µF
1µF
T1OUT
T2OUT
R1 IN
5kΩ
R1
R2OUT
+
+10V TO -10V
6
VOLTAGE INVERTER V-
13 R1IN
V- 6
R2IN 8
+
1.0µF
9
8
R2 IN
5kΩ
R2
15
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 Americas Inc. | Copyright © Intersil Americas Inc. 2001
1
File Number
3020.6
ICL232
Absolute Maximum Ratings
Thermal Information
VCC to Ground . . . . . . . . . . . . . . . . . . . . . .(GND -0.3V) < VCC < 6V
V+ to Ground . . . . . . . . . . . . . . . . . . . . . . . (VCC -0.3V) < V+ < 12V
V- to Ground . . . . . . . . . . . . . . . . . . . . . . . -12V < V- < (GND +0.3V)
Input Voltages
T1IN , T2IN . . . . . . . . . . . . . . . . . . . . (V- -0.3V) < VIN < (V+ +0.3V)
R1IN , R2IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±30V
Output Voltages
T1OUT, T2OUT . . . . . . . . . . . . (V- -0.3V) < VTXOUT < (V+ +0.3V)
R1OUT, R2OUT . . . . . . . . .(GND -0.3V) < VRXOUT < (VCC +0.3V)
Short Circuit Duration
T1OUT, T2OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
R1OUT, R2OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
Thermal Resistance (Typical, Note 1)
θJA ( oC/W) θJC (oC/W)
CERDIP Package . . . . . . . . . . . . . . . .
80
18
PDIP Package . . . . . . . . . . . . . . . . . . .
100
N/A
SOIC Package. . . . . . . . . . . . . . . . . . .
100
N/A
Maximum Junction Temperature
Plastic Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150oC
Ceramic Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175oC
Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oC
Operating Conditions
Temperature Ranges
ICL232C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0oC to 70oC
ICL232I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC
ICL232M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC
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:
1. θJA is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications
Test Conditions: VCC = +5V ±10%, TA = Operating Temperature Range. Test Circuit as in Figure 8
Unless Otherwise Specified
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Transmitter Output Voltage Swing, TOUT
T1OUT and T2OUT Loaded with 3kΩ
to Ground
±5
±9
±10
V
Power Supply Current, ICC
Outputs Unloaded, TA = 25oC
-
5
10
mA
TIN , Input Logic Low, VlL
-
-
0.8
V
TIN , Input Logic High, VlH
2.0
-
-
V
-
15
200
µA
-30
-
+30
V
Logic Pullup Current, IP
T1IN , T2IN = 0V
RS-232 Input Voltage Range, VIN
Receiver Input Impedance, RIN
VIN = ±3V
3.0
5.0
7.0
kΩ
Receiver Input Low Threshold, VlN (H-L)
VCC = 5V, TA = 25oC
0.8
1.2
-
V
Receiver Input High Threshold, VIN (L-H)
VCC = 5V, TA = 25oC
-
1.7
2.4
V
0.2
0.5
1.0
V
Receiver Input Hysteresis, VHYST
TTL/CMOS Receiver Output Voltage Low, VOL
IOUT = 3.2mA
-
0.1
0.4
V
TTL/CMOS Receiver Output Voltage High, VOH
IOUT = -1.0mA
3.5
4.6
-
V
Propagation Delay, tPD
RS-232 to TTL
-
0.5
-
µs
Instantaneous Slew Rate, SR
CL = 10pF, RL = 3kΩ, TA = 25oC
(Notes 2, 3)
-
-
30
V/µs
Transition Region Slew Rate, SRT
RL = 3kΩ, CL = 2500pF Measured
from +3V to -3V or -3V to +3V
-
3
-
V/µs
Output Resistance, ROUT
VCC = V+ = V- = 0V, VOUT = ±2V
300
-
-
Ω
RS-232 Output Short Circuit Current, ISC
T1OUT or T2OUT Shorted to GND
-
±10
-
mA
NOTES:
2. Guaranteed by design.
3. See Figure 4 for definition.
2
ICL232
Test Circuits
+4.5V TO
+5.5V INPUT
-
1µF
C3
+
1
C1+
2
V+
VCC 16
1
C1+
2
V+
3
C1-
T1OUT 14
4
C2+
R1 IN 13
5
C2-
R1OUT 12
6
V-
T1IN 11
7
T2 OUT
T2IN 10
8
R2IN
VCC 16
GND 15
+
1µF
C1
-
GND 15
3kΩ
3
1µF +
C2 -
T1OUT 14
C1-
T1 OUTPUT
RS-232
±30V INPUT
TTL/CMOS
OUTPUT
4
C2+
R1IN 13
5
C2-
R1OUT 12
6
V-
T1IN 11
TTL/CMOS
INPUT
7
T2OUT
T2IN 10
TTL/CMOS
INPUT
8
R2IN
9
TTL/CMOS
OUTPUT
1µF C4
-
+
3kΩ
T2 OUTPUT
RS-232
±30V INPUT
R2OUT
R2OUT 9
ROUT = VIN /I
VIN = ±2V
T2OUT
A
T1OUT
FIGURE 1. GENERAL TEST CIRCUIT
FIGURE 2. POWER-OFF SOURCE RESISTANCE
CONFIGURATION
Typical Performance Curves
10
500
9
o
450 TA = 25 C
EXTERNAL SUPPLY LOAD
400 1kΩ BETWEEN V+ + GND
OR V- + GND
350 TRANSMITTER OUTPUT
V- SUPPLY
OUTPUT VOLTAGE (|V|)
V+, V- SUPPLY IMPEDANCES (Ω)
550
OPEN CIRCUIT
300
250
GUARANTEED
OPERATING
RANGE
V+ SUPPLY
V+ (VCC = 5V)
8
V+ (VCC = 4.5V)
7
6
5
TA = 25 oC
4
200
150
V- (VCC = 5V)
V- (VCC = 4.5V)
TRANSMITTER OUTPUTS
OPEN CIRCUIT
3
3
4
5
6
0
1
2
3
4
INPUT SUPPLY VOLTAGE VCC (V)
5
6
7
8
9
10
|ILOAD| (mA)
FIGURE 3. V+, V- OUTPUT IMPEDANCES vs VCC
FIGURE 4. V+, V- OUTPUT VOLTAGES vs LOAD CURRENT
Pin Descriptions
PDIP, CERDIP
SOIC
PIN NAME
DESCRIPTION
1
1
C1+
2
2
V+
Internally generated +10V (typical) supply.
3
3
C1-
External capacitor “-” for internal voltage doubler.
4
4
C2+
External capacitor “+” internal voltage inverter.
5
5
C2-
External capacitor “-” internal voltage inverter.
6
6
V-
7
7
T2OUT
8
8
R2IN
RS-232 Receiver 2 input, with internal 5K pulldown resistor to GND.
9
9
R2out
Receiver 2 TTL/CMOS output.
10
10
T2IN
External capacitor “+” for internal voltage doubler.
Internally generated -10V (typical) supply.
RS-232 Transmitter 2 output ±10V (typical).
Transmitter 2 TTL/CMOS input, with internal 400K pullup resistor to VCC .
3
ICL232
Pin Descriptions
(Continued)
PDIP, CERDIP
SOIC
PIN NAME
11
11
T1IN
12
12
R1OUT
13
13
R1IN
14
14
T1OUT
15
15
GND
Supply Ground.
16
16
VCC
Positive Power Supply +5V ±10%
DESCRIPTION
Transmitter 1 TTL/CMOS input, with internal 400K pullup resistor to VCC .
Receiver 1 TTL/CMOS output.
RS-232 Receiver 1 input, with internal 5K pulldown resistor to GND.
RS-232 Transmitter 1 output ±10V (typical).
VOLTAGE DOUBLER
S1
C1+
VOLTAGE INVERTER
S2
V+ = 2VCC
C2+
S5
S6
VCC
GND
+
GND
S3
C1 -
+
C1
-
+
C3
VCC
+
C2
-
C4
GND
S4
C2 -
S7
V- = -(V+)
S8
RC
OSCILLATOR
FIGURE 5. DUAL CHARGE PUMP
Detailed Description
The ICL232 is a dual RS-232 transmitter/receiver powered by
a single +5V power supply which meets all ElA RS232C specifications and features low power consumption. The functional
diagram illustrates the major elements of the ICL232. The circuit is divided into three sections: a voltage doubler/inverter,
dual transmitters, and dual receivers Voltage Converter.
T1IN, T2 IN
90%
10%
T1OUT, T2OUT
tf
VOH
VOL
tr
(0.8) (VOH - VOL) (0.8) (VOL - VOH)
Instantaneous
=
or
Slew Rate (SR)
tr
tf
An equivalent circuit of the dual charge pump is illustrated in
Figure 5.
FIGURE 6. SLEW RATE DEFINITION
The voltage quadrupler contains two charge pumps which use
two phases of an internally generated clock to generate +10V
and -10V. The nominal clock frequency is 16kHz. During
phase one of the clock, capacitor C1 is charged to VCC .
During phase two, the voltage on C1 is added to VCC ,
producing a signal across C2 equal to twice VCC . At the same
time, C3 is also charged to 2VCC , and then during phase one,
it is inverted with respect to ground to produce a signal across
C4 equal to -2VCC . The voltage converter accepts input
voltages up to 5.5V. The output impedance of the doubler (V+)
is approximately 200Ω, and the output impedance of the
inverter (V-) is approximately 450Ω. Typical graphs are
presented which show the voltage converters output vs input
voltage and output voltages vs load characteristics. The test
circuit (Figure 3) uses 1µF capacitors for C1-C4, however, the
value is not critical. Increasing the values of C1 and C2 will
lower the output impedance of the voltage doubler and
inverter, and increasing the values of the reservoir capacitors,
C3 and C4, lowers the ripple on the V+ and V- supplies.
Transmitters
The transmitters are TTL/CMOS compatible inverters which
translate the inputs to RS-232 outputs. The input logic threshold is about 26% of VCC , or 1.3V for VCC = 5V. A logic 1 at
the input results in a voltage of between -5V and V- at the output, and a logic 0 results in a voltage between +5V and (V+
- 0.6V). Each transmitter input has an internal 400kΩ pullup
resistor so any unused input can be left unconnected and its
output remains in its low state. The output voltage swing
meets the RS-232C specification of ±5V minimum with the
worst case conditions of: both transmitters driving 3kΩ minimum load impedance, VCC = 4.5V, and maximum allowable
operating temperature. The transmitters have an internally
limited output slew rate which is less than 30V/µs. The outputs
are short circuit protected and can be shorted to ground indefinitely. The powered down output impedance is a minimum of
4
ICL232
300Ω with ±2V applied to the outputs and VCC = 0V.
connected to V+.
+5V
- C3
+ 1µF
5kΩ
2
V+
VCC
400kΩ
TXIN
C1 +
1µF -
TOUT
GND < TXIN < VCC
5kΩ
3
ICL232
4
V- < VTOUT < V+
C2 +
1µF -
V-
FIGURE 7. TRANSMITTER
TD
Receivers
6
5
T1
11
CTS
RXIN
GND < VROUT < VCC
FIGURE 8. RECEIVER
T1IN, T2 IN
OR
R1 IN, R2IN
VOH
VOL
Average Propagation Delay =
R1
8
C4
1µF RS-232
INPUTS AND OUTPUTS
TD (2) TRANSMIT DATA
RTS (4) REQUEST TO SEND
RD (3) RECEIVE DATA
CTS (5) CLEAR TO SEND
SIGNAL GROUND (7)
In applications requiring four RS-232 inputs and outputs
(Figure 11), note that each circuit requires two charge pump
capacitors (C1 and C2) but can share common reservoir
capacitors (C3 and C4). The benefit of sharing common reservoir capacitors is the elimination of two capacitors and the
reduction of the charge pump source impedance which
effectively increases the output swing of the transmitters.
GND
tPHL
R2
CTR (20) DATA
TERMINAL READY
DSRS (24) DATA
SIGNALING RATE
SELECT
FIGURE 10. SIMPLE DUPLEX RS-232 PORT WITH CTS/RTS
HANDSHAKING
ROUT
5kΩ
7
13
15
VCC
-30V < RXIN < +30V
14
T2
INPUTS
RTS
OUTPUTS
12
TTL/CMOS RD
9
+
10
The receiver inputs accept up to ±30V while presenting the
required 3kΩ to 7kΩ input impedance even it the power is off
(VCC = 0V). The receivers have a typical input threshold of
1.3V which is within the ±3V limits, known as the transition
region, of the RS-232 specification. The receiver output is
0V to VCC . The output will be low whenever the input is
greater than 2.4V and high whenever the input is floating or
driven between +0.8V and -30V. The receivers feature 0.5V
hysteresis to improve noise rejection.
T1OUT, T2 OUT
OR
R1OUT, R2 OUT
16
1
300Ω
tPLH
tPHL + tPLH
2
FIGURE 9. PROPAGATION DELAY DEFINITION
Applications
The ICL232 may be used for all RS-232 data terminal and
communication links. It is particularly useful in applications
where ±12V power supplies are not available for conventional RS-232 interface circuits. The applications presented
represent typical interface configurations.
A simple duplex RS-232 port with CTS/RTS handshaking is
illustrated in Figure 10. Fixed output signals such as DTR
(data terminal ready) and DSRS (data signaling rate select)
is generated by driving them through a 5kΩ resistor
5
1
C1 +
1µF TD
INPUTS
OUTPUTS
TTL/CMOS
RTS
4
ICL232
3
T1
11
-
14
T2
10
+ C2
1µF
5
TD (2) TRANSMIT DATA
7
RTS (4) REQUEST TO SEND
13
12
RD (3) RECEIVE DATA
RD
9
CTS
R2
R1
8
CTS (5) CLEAR TO SEND
15
6
-
2
C3
+
+
C4
V- V+
2µF
6
-
2 µF
2
16
+5V
RS-232
INPUTS AND
OUTPUTS
ICL232
C1 +
1µF DTR
INPUTS
OUTPUTS
TTL/CMOS
DSRS
1
4
3
5
T1
11
14
T2
10
12
7
13
DCD
R1
9
R2
R1
8
15
+ C2
1µF
-
DTR (20) DATA TERMINAL
READY
DSRS (24) DATA SIGNALING
RATE SELECT
DCD (8) DATA CARRIER
DETECT
R1 (22) RING INDICATOR
SIGNAL GROUND (7)
FIGURE 11. COMBINING TWO ICL232s FOR 4 PAIRS OF RS-232 INPUTS AND OUTPUTS
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Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice.
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6
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