HIN202A thru HIN241A
Transmitters
The transmitters are TTL/CMOS compatible inverters which
translate the inputs to RS-232 outputs. The input logic
T
OR
R
IN
threshold is about 26% of V , or 1.3V for V
= 5V. A logic
CC
CC
IN
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
T
OUT
OR
V
OL
V
OL
R
OUT
t
t
PLH
PHL
t
t
PHL + PLH
AVERAGE PROPAGATION DELAY =
2
FIGURE 6. PROPAGATION DELAY DEFINITION
minimum load impedance, V
= 4.5V, and maximum
CC
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
HIN241A Operation in Shutdown
The HIN213A features two receivers, R4 and R5, which
remain active in shutdown mode. During normal operation
the receivers propagation delay is typically 0.5µs. This
propagation delay may increase slightly during shutdown.
When entering shut down mode, receivers R4 and R5 are
V
= 0V.
CC
Receivers
The receiver inputs accept up to ±30V while presenting the
required 3kΩ to 7kΩ input impedance even if the power is off
not valid for 80µs after SD = V . When exiting shutdown
IL
mode, all receiver outputs will be invalid until the charge
pump circuitry reaches normal operating voltage. This is
typically less than 2ms when using 0.1µF capacitors.
(V
= 0V). The receivers have a typical input threshold of
CC
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 . The output will be low whenever the input is
Application Information
CC
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. The receiver Enable line EN, (EN on HIN213A)
when unasserted, disables the receiver outputs, placing
them in the high impedance mode. The receiver outputs are
also placed in the high impedance state when in shutdown
mode (except HIN213A R4 and R5).
The HIN2XXA 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 5kΩ resistor
connected to V+.
V+
V
CC
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.
400kΩ
300Ω
T
XIN
T
OUT
GND < T
< V
CC
XIN
V-
V- < V
TOUT
< V+
FIGURE 4. TRANSMITTER
V
CC
R
XIN
R
OUT
-30V < R
< +30V
XIN
GND < V
ROUT
< V
CC
5kΩ
GND
FIGURE 5. RECEIVER
3-14