HIN200 thru HIN213
Detailed Description
The HIN200 thru HIN213 family of RS-232 transmitters/receiv-
ers are powered by a single +5V power supply (except HIN201
and HIN209), feature low power consumption, and meet 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 1. 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 gener-
ate +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 (V+) is approxi-
mately 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.
During shutdown mode (HIN200, HIN206 and HIN211,
SD = V
CC
, HIN213, SD = 0V) the charge pump is turned off,
V+ is pulled down to V
CC
, V- is pulled up to GND, and the
supply current is reduced to less than 10µA. The transmitter
outputs are disabled and the receiver outputs (except for
HIN213, R4 and R5) are placed in the high impedance state.
Transmitters
The transmitters are TTL/CMOS compatible inverters which
translate the inputs to RS-232 outputs. The input logic thresh-
old 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
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 cir-
cuit 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.
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
T
IN
OR
R
IN
T
OUT
OR
R
OUT
V
OL
V
OL
t
PHL
t
PLH
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 rejec-
tion. The receiver Enable line (EN, on HIN206, HIN209, and
HIN211, EN on HIN213) 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 HIN213 R4 and R5).
V+
V
CC
400kΩ
T
XIN
GND < T
XIN
< V
CC
V-
300Ω
T
OUT
V- < V
TOUT
< V+
FIGURE 2. TRANSMITTER
V
CC
R
XIN
-30V < R
XIN
< +30V
GND
5kΩ
R
OUT
GND < V
ROUT
< V
CC
FIGURE 3. RECEIVER
AVERAGE PROPAGATION DELAY =
t
PHL +
t
PLH
2
FIGURE 4. PROPAGATION DELAY DEFINITION
HIN213 Operation in Shutdown
The HIN213 features two receivers, R4 and R5, which
remain active in shutdown mode. During normal operation
the receivers propagation delay is typically 0.5µs. This prop-
agation delay may increase slightly during shutdown. When
entering shut down mode, receivers R4 and R5 are not valid
for 80µs after SD = V
IL
. When exiting shutdown 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.
8-13
HARRIS [ HARRIS CORPORATION ]
