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.
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 = 0.1F; 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
-
-
2.0
-
-
3.5
-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
-
R
L
= 3k, C
L
= 1000pF, Measured from +3V to
-3V or -3V to +3V, (Note 2) 1 Transmitter Switching
Transmitter Outputs, 3k 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)
Human Body Model
3
TYP
5
-
-
15
0.1
4.6
-
5.0
1.2
1.7
0.5
0.5
20
MAX
10
0.8
-
200
0.4
-
+30
7.0
-
2.4
1.0
10
45
UNITS
mA
V
V
A
V
V
V
k
V
V
V
s
V/s
LOGIC AND TRANSMITTER INPUTS, RECEIVER OUTPUTS
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
)
5
300
-
-
-
-
-
9
-
10
15
8
15
2
10
-
-
-
-
-
-
V
mA
kV
kV
kV
kV
All Other Pins
NOTES:
2. Guaranteed by design.
3. Meets level 4.
FN4316 Rev 1.00
March 13, 2006
Page 3 of 10
HIN232A
Test Circuits (HIN232A)
+4.5V TO
+5.5V INPUT
0.1F
C3
0.1F
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
3k
T1 OUTPUT
RS-232
30V
INPUT
TTL/CMOS OUTPUT
TTL/CMOS INPUT
TTL/CMOS INPUT
TTL/CMOS OUTPUT
2 V+
3 C1-
4 C2+
5 C2-
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
-
0.1F +
C2
-
0.1F C4
3k
T2
OUTPUT
RS-232
30V
INPUT
FIGURE 1. GENERAL TEST CIRCUIT
V
CC
+
-
GND
S3
C1-
C1
S4
+
-
C3
V
CC
RC
OSCILLATOR
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 voltage doubler section
FN4316 Rev 1.00
March 13, 2006
-
+
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
+
-
GND
S7
C2-
S8
C2
+
-
C4
V- = - (V+)
FIGURE 3. CHARGE PUMP
(V+) is approximately 200, and the output impedance of the
voltage inverter section (V-) is approximately 450. A typical
application uses 0.1F 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 400k 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 3k minimum load impedance, V
CC
=
4.5V, and maximum allowable operating temperature. The
Page 4 of 10
HIN232A
transmitters have an internally limited output slew rate which is
less than 30V/s. The outputs are short circuit protected and can
be shorted to ground indefinitely. The powered down output
impedance is a minimum of 300 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 3k to 7k 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
400k
T
XIN
GND < T
XIN
< V
CC
V-
300
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 presented
represent typical interface configurations.
A simple duplex RS-232 port with CTS/RTS handshaking is
illustrated in Figure 7. Fixed output signals such as DTR (data
terminal ready) and DSRS (data signaling rate select) is
generated by driving them through a 5k resistor connected to
V+.
In applications requiring four RS-232 inputs and outputs
(Figure 8), 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.
FIGURE 4. TRANSMITTER
V
CC
R
XIN
-30V < R
XIN
< +30V
GND
5k
R
OUT
GND < V
ROUT
< V
CC
FIGURE 5. RECEIVER
+5V
16
-
+
1
3
4
5
11
10
12
9
R2
R1
T1
T2
14
7
13
8
CTR (20) DATA
TERMINAL READY
DSRS (24) DATA
SIGNALING RATE
SELECT
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)
C1 +
0.1F -
C2 +
0.1F -
TD
INPUTS
OUTPUTS
TTL/CMOS
RTS
RD
CTS
HIN232A
6
-
+
15
FIGURE 7. SIMPLE DUPLEX RS-232 PORT WITH CTS/RTS HANDSHAKING
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