6-3
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
TC232*
DUAL RS-232 TRANSMITTER/RECEIVER AND POWER SUPPLY
C1
10
F
400 k
400 k
1
3
4
5
11
10
12
9
2
6
14
7
13
8
5 k
5 k
15
RS-232
OUTPUTS
RS-232
INPUTS
C1
+
C2
10
F
TTL/CMOS
INPUTS
TTL/CMOS
OUTPUTS
+5V TO +10V
VOLTAGE DOUBLER
+10V TO 10V
VOLTAGE INVERTER
+5V
+5V
+5V INPUT
+10V
10V
10
F
+
+
16
+
+
R2
R1
T2
T1
C1
C2
+
C2
T2IN
T1IN
R1IN
R2OUT
R2IN
T2OUT
T1OUT
R1OUT
GND
C4
10
F
C3*
+
10
F
+
10
F
C3*
VCC
V
+
V
*NOTE: C3 can be connected between
V+ and VCC for convenience.
FEATURES
s
Meets All RS-232 Specifications
s
Operates From Single 5V Power Supply
s
2 Drivers and 2 Receivers
s
On-Board Voltage Quadrupler
s
Input Levels ......................................................
30V
s
Output Swing With +5V Supply ........................
9V
s
Low Supply Current ........................................ 5 mA
s
Does not require external
12V supplies
APPLICATIONS
s
RS-232C Communication Links
s
Modems, peripherals, computers
s
Battery-powered systems
GENERAL DESCRIPTION
The TC232 is a dual RS-232 transmitter/receiver that
complies with EIA /TIA RS-232E guidelines and is ideal for
all RS-232 communication links. This device operates from
a 5V power supply and contains two charge pump voltage
converters that produce
10V power supplies.
The TC232 has four level translators. Two are RS-232
transmitters that convert TTL/CMOS input levels to 9V
RS-232 outputs. The other two translators are RS-232
receivers that convert RS-232 inputs to 5V TTL/CMOS
output levels. The receivers have a nominal threshold of
1.3V, a typical hysteresis of 0.5V, and can operate with
inputs up to
30V.
ORDERING INFORMATION
Part No.
Package
Temp. Range
TC232COE
16-Pin SOIC (Wide)
0
C to +70
C
TC232CPE
16-Pin Plastic DIP
0
C to +70
C
TC232EOE
16-Pin SOIC (Wide)
40
C to +85
C
TC232EPE
16-Pin Plastic DIP
40
C to +85
C
TC232IJE
16-Pin CerDIP
25
C to +85
C
TC232MJE
16-Pin CerDIP
55
C to +125
C
PIN CONFIGURATIONS (DIP AND SOIC)
TC232COE
TC232EOE
1
2
3
4
16
15
14
13
VCC
T1
5
6
7
12
11
10
9
R1
R2
8
R2
T2
V
+
GND
R1IN
T1IN
OUT
OUT
T2IN
OUT
IN
OUT
V
C
+
1
C
1
C
+
2
C
2
TC232CPE
TC232EPE
TC232IJE
TC232MJE
1
2
3
4
16
15
14
13
VCC
T1
5
6
7
12
11
10
9
R1
R2
8
R2
T2
V
+
GND
R1IN
T1IN
OUT
OUT
T2IN
OUT
IN
OUT
V
C
+
1
C
1
C
+
2
C
2
TYPICAL APPLICATION
*Patented
TC232-6 10/21/96
6-4
TELCOM SEMICONDUCTOR, INC.
ABSOLUTE MAXIMUM RATINGS*
V
CC
............................................................................. +6V
V
+
........................................................................... +12V
V
........................................................................... +12V
Input Voltages
T1
IN
, T2
IN
.................................... 0.3 to (V
CC
+0.3V)
R1
IN
, R2
IN
.........................................................
30V
Output Voltages
T1
OUT
, T2
OUT
...................... (V
+
+0.3V) to (V
0.3V)
R1
OUT
, R2
OUT
.............................. 0.3 to (V
CC
+0.3V)
Short Circuit Duration
V
+
.................................................................... 30sec
V
.................................................................... 30sec
T1
OUT
, T2
OUT
.......................................... Continuous
Storage Temperature Range .................. -65
C to +150
C
Package Power Dissipation (T
A
70
C)
CerDIP ............................................................ 890mW
Derate 9.5 mW/
C Above +70
C
Plastic DIP ...................................................... 840mW
Derate 7 mW/
C Above +70
C
Small Outline (SOIC) ...................................... 760mW
Derate 7 mW/
C Above +70
C
ELECTRICAL CHARACTERISTICS:
V
CC
= 5V
10%, T
A
= operating temperature range, test circuit unless
otherwise noted.
Parameter
Test Conditions
Min
Typ
Max
Unit
Output Voltage Swing
T1
OUT
, T2
OUT
Loaded With
5
9
10
V
3 k
to Ground
Power Supply Current
--
5
10
mA
Input Logic Threshold Low
T1
IN
, T2
IN
--
--
0.8
V
Input Logic Threshold High
T1
IN
, T2
IN
2
--
--
V
Logic Pull-Up Current
T1
IN
, T2
IN
= 0V
--
15
200
A
RS-232 Input Voltage Operating Range
30
--
+30
V
RS-232 Input Threshold Low
V
CC
= 5V
0.8
1.2
--
V
RS-232 Input Threshold High
V
CC
= 5V
--
1.7
2.4
V
RS-232 Input Hysteresis
0.2
0.5
1
V
RS-232 Input Resistance
T
A
= +25
C, V
CC
= 5V
3
5
7
k
TTL/CMOS Output Voltage Low
I
OUT
= 3.2 mA
--
--
0.4
V
TTL/CMOS Output Voltage High
I
OUT
= 1 mA
3.5
--
--
V
Propagation Delay
RS-232 to TTL or TTL to RS-232
--
0.5
--
sec
Instantaneous Slew Rate
C
L
= 10 pF, R
L
= 3 k
to 7 k
,
--
--
30
V/
sec
T
A
= +25
C (Note 1)
Transition Region Slew Rate
R
L
= 3 k
, C
L
= 2500 pF
--
3
--
V/
sec
Measured From +3V to 3V
or 3V to +3V
Output Resistance
V
CC
= V
+
= V
= 0V, V
OUT
=
2V
300
--
--
RS-232 Output
--
10
--
mA
Short-Circuit Current
NOTE 1. Sample tested.
*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under "Absolute Maximum Ratings" may cause perma-
nent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operation sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
TC232
DUAL RS-232 TRANSMITTER/
RECEIVER AND POWER SUPPLY
6-5
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
1
2
8
DETAILED DESCRIPTION
The TC232 contains a +5V to
10V dual charge pump
voltage converter, a dual transmitter and a dual receiver.
+5V to
10V Dual Charge Pump
Voltage Converter
The TC232 power supply consists of two charge pumps.
One uses external capacitor C1 to double the +5V input to
+10V, with output impedance of about 200
. The other
uses C2 to invert +10V to 10V, with overall output
impedance of 450
(including effects of +5V to +10V
doubler impedance).
The clock in the doubler circuit will start at
4.2V in the
typical part, but external loads may make this point rise to as
high as 4.5V with a load of 2 k
on each of the two output
voltages.
Because of this, use of the doubler and inverter to run
additional external circuits should be limited. The maximum
current should be no more than 2.5 mA from the +10V and
- 10V. in order to guarantee start-up of the doubler clock.
The test circuit employs 22
F capacitors for C1 to C4,
but the value is not critical. These capacitors usually are low-
cost aluminum or tantalum electrolytic capacitors.
Increasing C1 and C2 to 47
F lowers the output
impedance of the +10V doubler and the - 10V inverter by
the change in the ESR of the capacitors.
Increasing C3 and C4 lowers ripple on the
10V out-
puts and 16 kHz ripple on the RS-232 outputs. Where size
is critical, the value of C1 to C4 can be lowered to 1
F. The
use of a low ESR capacitor will help lower the output ripple
and keep the output impedance of the
10V as low as
possible.
Dual Transmitter
TC232 transmitters are CMOS inverters driven by
10V
internally-generated voltages. The input is TTL/CMOS com-
patible, with a logic threshold of about 26% of V
CC
(1.3V for
5V V
CC
). The input of an unused transmitter can be left
unconnected, since an internal 400 k
pull-up resistor
connected between the transmitter input and V
CC
pulls the
input HIGH and forces the unused transmitter output to the
LOW state.
With V
CC
at 5V, the outputs will go from (V+ 0.6V) to
V
with no load and will swing
9V when loaded with 3 k
.
The minimum output voltage swing, with V
CC
at 4.5V and at
maximum ambient temperature, is
5V. This conforms to
RS-232 specifications for "worst-case" conditions.
EIA/TIA RS-232E specs limit the slew rate at output
to less than 30V/
s.
The powered-down output impedance (V
CC
= 0V) is
a minimum of 300
with
2V applied to outputs.
V
+
, V
Output Voltages vs Load Current
TEST CIRCUIT
TC232
1
2
3
4
16
15
14
13
5
6
7
12
11
8
10
9
C1
22 F
22 F
+
+
C2
22 F
22 F
+
+
RS-232
INPUT
30V
RS-232
OUTPUT
+4.5V TO +5.5V
INPUT
3 k
RS-232
OUTPUT
RS-232
INPUT 30V
TTL/CMOS OUTPUT
TTL/CMOS INPUT
TTL/CMOS
INPUT
TTL/CMOS OUTPUT
3 k
V+
V
T2OUT
R2IN
VCC
GND
T1OUT
T1IN
R1OUT
T2IN
R2OUT
IN
R1
C
+
1
C
1
C
+
2
C
2
C3
C4
10
9
8
7
6
5
4
3
0
1
2
3
4
5
6
7
8
9
10
OUTPUT VOLTAGE (|V|)
(V = 4.5V)
CC
(V = 5V)
CC
(V = 4.5V)
CC
(V = 5V)
CC
CONDITIONS:
A) T = +25
C
B) TRANSMITTER OUTPUTS
OPEN CIRCUIT
A
| I | (mA)
LOAD
+
V
V
V
+
V
The outputs are protected and can be short-circuited to
ground indefinitely.
Dual Receiver
TC232 receivers meet RS-232 input specifications.
Input impedance is between 3 k
and 7 k
. Switching
thresholds are within the
3V limits, and the receivers
withstand up to
30V inputs. RS-232 and TTL/CMOS input
compatible, the receivers have 0.8V V
IL
and 2.4V V
IH
with
0.5V hysteresis to reject noise.
The TTL/CMOS compatible receiver output is LOW
when an RS-232 input is greater than 2.4V. It is HIGH
when an input is floating or between +0.8V and 30V.
TC232
DUAL RS-232 TRANSMITTER/
RECEIVER AND POWER SUPPLY
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