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.
θ
JA
is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
PARAMETER
SUPPLY CURRENTS
Power Supply Current, I
CC
Input Logic Low, V
lL
Input Logic High, V
lH
Test Conditions: V
CC
= +5V
±10%,
C1-C4 = 0.1µF; T
A
= Operating Temperature Range
TEST CONDITIONS
No Load, T
A
= 25
o
C
T
IN
T
IN
T
IN
= 0V
I
OUT
= 3.2mA
I
OUT
= -1mA
MIN
TYP
MAX
UNITS
-
5
10
mA
LOGIC AND TRANSMITTER INPUTS, RECEIVER OUTPUTS
-
2.0
-
-
3.5
-
-
15
0.1
4.6
0.8
-
200
0.4
-
V
V
µA
V
V
Transmitter Input Pullup Current, I
P
TTL/CMOS Receiver Output Voltage Low, V
OL
TTL/CMOS Receiver Output Voltage High, V
OH
RECEIVER INPUTS
RS-232 Input Voltage Range, V
IN
Receiver Input Impedance, R
IN
Receiver Input Low Threshold, V
IN
(H-L)
Receiver Input High Threshold, V
IN
(L-H)
Receiver Input Hysteresis, V
HYST
TIMING CHARACTERISTICS
Transmitter, Receiver Propagation Delay, t
PD
Transition Region Slew Rate, SR
T
TRANSMITTER OUTPUTS
Output Voltage Swing, T
OUT
Output Resistance, T
OUT
RS-232 Output Short Circuit Current, I
SC
ESD PERFORMANCE
RS-232 Pins
(T
OUT
, R
IN
)
-30
V
IN
=
±3V,
T
A
= 25
o
C
V
CC
= 5V, T
A
= 25
o
C
V
CC
= 5V, T
A
= 25
o
C
V
CC
= 5V
3.0
-
-
0.2
-
5.0
1.2
1.7
0.5
+30
7.0
-
2.4
1.0
V
kΩ
V
V
V
µs
V/µs
-
R
L
= 3kΩ, C
L
= 1000pF, Measured from +3V to
-3V or -3V to +3V, (Note 2) 1 Transmitter Switching
3
0.5
20
10
45
Transmitter Outputs, 3kΩ to Ground
V
CC
= V+ = V- = 0V, V
OUT
=
±2V
T
OUT
Shorted to GND
Human Body Model
IEC1000-4-2 Contact Discharge
IEC1000-4-2 Air Gap (Note 3)
±5
300
-
±9
-
±10
±15
±8
±15
±2
±10
-
-
V
Ω
mA
-
-
-
-
-
-
-
-
kV
kV
kV
kV
All Other Pins
NOTES:
2. Guaranteed by design.
3. Meets level 4.
Human Body Model
3
HIN232A
Test Circuits (HIN232A)
+4.5V TO
+5.5V INPUT
0.1µF
C3
0.1µF
C1
+
-
+
1 C1+
V
CC
16
GND 15
T1
OUT
14
R1
IN
13
R1
OUT
12
T1
IN
11
T2
IN
10
R2
OUT
9
3kΩ
T1 OUTPUT
RS-232
±30V
INPUT
TTL/CMOS OUTPUT
TTL/CMOS INPUT
TTL/CMOS INPUT
TTL/CMOS OUTPUT
2 V+
3 C1-
1 C1+
2 V+
3 C1-
4 C2+
5 C2-
6 V-
7 T2
OUT
8 R2
IN
V
CC
16
GND 15
T1
OUT
14
R1
IN
13
R1
OUT
12
T1
IN
11
T2
IN
10
R2
OUT
9
-
0.1µF +
C2
-
0.1µF C4
3kΩ
T2
OUTPUT
RS-232
±30V
INPUT
4 C2+
5 C2-
FIGURE 1. GENERAL TEST CIRCUIT
V
CC
+
-
GND
S3
RC
OSCILLATOR
C1-
C1
+
-
S4
C3
V
CC
GND
S7
C2-
S8
+
-
C2
+
-
C4
Detailed Description
The HIN232A is a high-speed RS-232 transmitter/receiver
that is powered by a single +5V power supply, features low
power consumption, and meets all ElA RS232C and V.28
specifications. The circuit is divided into three sections: the
charge pump, transmitter, and receiver.
Charge Pump
An equivalent circuit of the charge pump is illustrated in
Figure 3. The charge pump contains two sections: The
voltage doubler and the voltage inverter. Each section is
driven by a two phase, internally generated clock to generate
+10V and -10V. The nominal clock frequency is 125kHz.
During phase one of the clock, capacitor C1 is charged to
V
CC
. During phase two, the voltage on C1 is added to V
CC
,
producing a signal across C3 equal to twice V
CC
. During
phase two, C2 is also charged to 2V
CC
, and then during
phase one, it is inverted with respect to ground to produce a
signal across C4 equal to -2V
CC
. The charge pump accepts
input voltages up to 5.5V. The output impedance of the
4
-
+
6 V-
7 T2
OUT
8 R2
IN
R
OUT
= V
IN
/I
T2
OUT
T1
OUT
V
IN
=
±2V
A
FIGURE 2. POWER-OFF SOURCE RESISTANCE
CONFIGURATION
VOLTAGE DOUBLER
S1
C1+
S2
V+ = 2V
CC
S5
VOLTAGE INVERTER
C2+
S6
GND
V- = - (V+)
FIGURE 3. CHARGE PUMP
voltage doubler section (V+) is approximately 200Ω, and the
output impedance of the voltage inverter section (V-) is
approximately 450Ω. A typical application uses 0.1µF
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, 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 V
CC
, or 1.3V for V
CC
= 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 specifications of
±5V
minimum with the worst case
conditions of: all transmitters driving 3kΩ minimum load
HIN232A
impedance, V
CC
= 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 300Ω with
±2V
applied to the outputs and V
CC
= 0V.
T
IN
OR
R
IN
T
OUT
OR
R
OUT
V
OH
V
OL
t
PHL
t
PLH
t
PHL +
t
PLH
2
Receivers
The receiver inputs accept up to
±30V
while presenting the
required 3kΩ to 7kΩ input impedance even if the power is off
(V
CC
= 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 specifications. The receiver output is 0V to V
CC
.
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 (except during
shutdown) to improve noise rejection.
V+
V
CC
400kΩ
T
XIN
GND < T
XIN
< V
CC
V-
300Ω
T
OUT
V- < V
TOUT
< V+
AVERAGE PROPAGATION DELAY =
FIGURE 6. PROPAGATION DELAY DEFINITION
Application Information
The HIN232A 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
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