Datasheet

UNISONIC TECHNOLOGIES CO., LTD
UT232A
CMOS IC
HIGH PERFORMANCE RS-232
LINE DRIVERS/RECEIVERS

DESCRIPTION
The UTC UT232A has two drivers and two receivers with dual
charge-pump circuit. It meets RS-232D and V.28 specifications. Its
high performance includes increased drive current for longer and
more flexible cable configurations and 10V/µs slew rate, 120kbps
guaranteed transmission rate. For easier use, enhancements include
better ESD protection for RS-232 I/O pins, low power dissipation and
four external small 0.1µF charge pump capacitors.
The UTC UT232A is available in DIP-16 package and SOP-16
package.

FEATURES
* Single power supply: 3.3V~5.5V
* Low power supply current: 10mA
* Multiple drivers and receivers
* Receiver input levels: ±25V
* 3-State outputs of TTL/CMOS receiver
* High output slew rate: 10V/µs under load
* High data rate: 120kbps under load
* Four external small charge pump capacitors: 0.1µF
* Exceeds ±8KV HBM ESD protection for RS-232 I/O pins

ORDERING INFORMATION
Ordering Number
Lead Free
UT232AL-D16-T
-

Halogen Free
UT232AG-D16-T
UT232AG-S16-R
Package
Packing
DIP-16
SOP-16
Tube
Tape Reel
MARKING
DIP-16
www.unisonic.com.tw
Copyright © 2015 Unisonic Technologies Co., Ltd
SOP-16
1 of 6
QW-R502-272.G
UT232A
CMOS IC

PIN CONFIGURATION

PIN DESCRIPTION
PIN NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PIN NAME
C1+
V+
C1C2+
C2VT2OUT
R2IN
R2OUT
T2IN
T1IN
R1OUT
R1IN
T1OUT
GND
VCC
DESCRIPTION
Positive terminal of the voltage doubler Charge-Pump Capacitor
Positive voltage generated by the charge pump
Negative terminal of the voltage doubler Charge-Pump Capacitor
Positive terminal of inverting Charge-Pump Capacitor
Negative terminal of inverting Charge-Pump Capacitor
Negative voltage generated by the charge pump
RS-232 Transmitter Outputs
RS-232 Receiver Inputs
TTL/CMOS Receiver Outputs
TTL/CMOS Transmitter Inputs
TTL/CMOS Transmitter Inputs
TTL/CMOS Receiver Outputs
RS-232 Receiver Inputs
RS-232 Transmitter Outputs
Ground
Power Supply
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QW-R502-272.F
UT232A

CMOS IC
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply voltage range
Positive-output supply voltage range
Negative-output supply voltage range
SYMBOL
RATINGS
UNIT
VCC
-0.3 ~ +6.0
V
V+
-0.3 ~+13.2
V
V+0.3 ~ -13.2
V
-0.3 ~ +6.0
V
TIN
Input Voltages
RIN
-25 ~ +25
V
-13.2 ~ +13.2
V
TOUT
Output Voltages
ROUT
-0.3 ~ (VCC+0.3)
V
Short Circuit Duration
TOUT
Continuous
Power Dissipation
PD
375
mW
Operating Temperature
TOPR
0 ~ +70
°С
Note: 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
2. All voltages are with respect to network GND.

ELECTRICAL CHARACTERISTICS
(VCC=+5.0V; TA=+25°С; 0.1µF charge pump capacitors; TMIN to TMAX unless otherwise specified)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN TYP
TTL INPUT
Logic Threshold
Low
VTL
TIN; EN , SD
High
VTH
TIN; EN , SD
ITH
TIN=0V
CL=2500pF, RL=3kΩ
120
IOUT=1.6mA; VCC=+5.0V
IOUT=-1.0mA
3.5
Logic Pull up Current
Maximum Data Rate
MAX UNIT
0.8
V
200
µA
kbps
0.4
V
V
2.0
V
15
TTL OUTPUT
TTL/CMOS Output Voltage
Low
High
VOL
VOH
RS-232 OUTPUT
Output Voltage Swing
VO(SW)
All transmitter outputs loaded
With 3kΩ to GND
Output Resistance
Output Short Circuit Current
RS-232 INPUT
Voltage Range
RO
IO(SC)
VCC=0V; VOUT=±2.0V
Infinite duration
Voltage Threshold
Low
High
Hysteresis
Resistance
DYNAMIC CHARACTERISTICS
Propagation Delay, RS232 to TTL
VI(SW)
VTHR(L)
VTHR(H)
VHYS
RI
VCC=+5.0V, TA=+25°С
VCC=+5.0V, TA=+25°С
TA=+25°С, -15V≤VIN≤+15V
tPD
Instantaneous Slew Rate
SR
Transition Region Slew Rate
SR
±5.0
±9.0
V
300
10M
±18
Ω
mA
-25
0.8
0.2
3
+25
1.2
1.7
0.5
5
2.4
1.0
8
1.5
CL=220pF, RL=3kΩ-7kΩ; measured
from +3V ~ -3V or -3V ~ +3V
CL=2500pF, RL=3kΩ;measured from
+3V ~ -3V or -3V ~ +3V
V
V
V
V
kΩ
µs
35
10
V/µs
V/µs
POWER REQUIREMENTS
VCC Power Supply Current
ICC
No load, TA=+25°С; VCC=+5.0V
All transmitters RL=3kΩ;TA=+25°С
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
10
25
15
mA
mA
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QW-R502-272.F
UT232A

CMOS IC
FUNCTION DESCRIPTION
Driver/Transmitter
The drivers are inverting transmitters, which accept TTL or CMOS inputs and output the RS-232 signals with an
inverted sense relative to the input logic levels. Typically the RS-232 output voltage swing is ±9.0V. Even under
worst case loading conditions of 3kΩ and 2500pF, the output is guaranteed to be ±5.0V, which is consistent with the
RS-232 standard specifications. The transmitter outputs are protected against infinite short-circuits to ground without
degradation in reliability.
The instantaneous slew rate of the transmitter output is internally limited to a maximum of 35V/µs. However, the
transition region slew rate of these enhanced products is typically 10V/µs. The smooth transition of the loaded output
from VOL to VOH clearly meets the monotonicity requirements.
Receivers
The receivers convert RS-232 input signals to inverted TTL signals. Since the input is usually from a transmission
line, where long cable lengths and system interference can degrade the signal, the inputs have a typical hysteresis
margin of 0.5V.
This ensures that the receiver is virtually immune to noisy transmission lines. The input thresholds are 0.8V
minimum and 2.4V maximum, again well within the ±3.0V RS-232 requirements. The receiver inputs are also
protected against voltages up to ±25V. Should an input be left unconnected, a 5kΩ pull down resistor to ground will
commit the output of the receiver to a high state.
In actual system applications, it is quite possible for signals to be applied to the receiver inputs before power is
applied to the receiver circuitry.
This occurs, for example, when a PC user attempts to print, only to realize the printer wasn’t turned on. In this
case an RS-232 signal from the PC will appear on the receiver input at the printer. When the printer power is turned
on, the receiver will operate normally. All of these enhanced devices are fully protected.
Charge Pump
The charge pump section of the devices allows the circuit to operate from a single +5.0V power supply by
generating the required operating voltages internal to the devices. The charge pump consists of a voltage doubler
and a voltage inverter. As shown in Figure 1, an internal oscillator triggers the charge accumulation and voltage
inversion. The voltage doubler momentarily stores a charge on capacitor C1 equal to VCC, referenced to ground.
During the next transition of the oscillator this charge is boot-strapped to transfer charge to capacitor C3. The voltage
across C3 is now from VCC to V+.
In the inverter section as shown in Figure 2, the voltage across C3 is transferred to C2 forcing a range of 0V to
V+ across C2. Boot-strapping of C2 will then transfer charge to C4 to generate V-. One of the significant
enhancements over previous products of this type is that the values of the capacitors are no longer critical and have
been decreased in size considerably to 0.1µF. Because the charge pump runs at a much higher frequency, the
0.1uF capacitors are sufficient to transfer and sustain charges to the two transmitters.
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QW-R502-272.F
UT232A

CMOS IC
APPLICATION INFORMATION
To operate from a single +5.0V supply, the UTC UT232A include charge pump voltage converters which can
allow it. To generate the RS-232 output levels these converters convert the +5.0V input power to the ±9V needed.
The current drain due to charge pump operation is considerably reduced with this power supplied externally. The
UTC UT232A can operate over the commercial, industrial and military temperature ranges.
+5V INPUT
+
16
VCC
1 C+
1
0.1µF +
Voltage Doubler V+
0.1µF
2+
Voltage Inverter
6
3 C1
4 C+
2
0.1µF +
V-
0.1µF
+
5 C2
T1IN
TTL/CMOS
INPUTS
T2IN
TTL/CMOS
OUTPUTS
R1OUT
11
10
12
400kΩ
T1
400kΩ
T2
14
7
13
R1
T1OUT
RS-232
OUTPUTS
T2OUT
R1IN
RS-232
INPUTS
5kΩ
R2OUT
9
8
R2
R2IN
5kΩ
GND
15
Connecting the capacitor to VCC (+5.0V) is recommended.
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QW-R502-272.F
UT232A
CH2: 5Vdiv CH1: 2Vdiv
CH2: 5Vdiv CH1: 2Vdiv
TYPICAL CHARACTERISTICS
0
CH1
CH2
0
50
Time (10µs/div)
100
CH1: 2Vdiv
0
CH1=RIN2, CH2=ROUT2
(120kbps)
0
CH2: 2Vdiv
CH1: 2Vdiv
CH1=RIN1, CH2=ROUT1
(120kbps)
CH2: 2Vdiv

CMOS IC
0
CH1
CH2
0
50
Time (10µs/div)
100
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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QW-R502-272.F