HS-245RH, HS-246RH, HS-248RH
TABLE A. GENERAL TRANSMITTER/RECEIVER CHARACTERISTICS
TRIPLE LINE TRANSMITTER
PARAMETER
Operating Temperature Range
“ON” Output Current
Power Supply Current
Standby Current
Propagation Delay
HS-245RH
-55 to 125
1.0 Min
7.0 Max
33 Max
14 Max
UNITS
o
C
COMMENTS
mA
mA
µA
ns
Over Full Temperature Range
Per Transmitter Section
Per Transmitter Section
Over Full Temperature Range
TRIPLE LINE RECEIVER
PARAMETER
Operating Temperature Range
Power Supply
ICC (VCC = +5.0V)
Propagation Delay
RECEIVER TYPE
HS-246RH/248RH
HS-246RH/248RH
LIMITS
-55 to 125
2.6
UNITS
o
C
COMMENTS
mA
Per Receiver Section
All Receivers
30
INPUT
ns
Over Full Temperature Range
OUTPUT
Input Impedance and
Output Circuit
HS-246RH
HS-248RH
100
Hi-Z
Ω
Open Collector
6K Pull-Up Resistor
Transmitter
The HS-245RH transmitters have two inputs per transmitter,
either of which is low while the other is open during normal
operation and both inputs are open during standby. For
optimum transmitter performance, the “off” input should be
open circuit rather than being pulled towards +5V, because
this will reduce the “on” output data current. On the other
hand, the “on” and “off” output data current will increase if
the “off” input is held below its open circuit voltage. Open
collector gates such as the 7401 and 7403 or 7405 Hex-
Inverter are suitable for driving the HS-245RH transmitter
inputs. By using 2-input gates as shown in Figure 4, an
enable line can be provided so that more than one
transmitter may be connected to a line for time sharing.
When the enable line is low the transmitter will be disabled
and will present a high impedance to the transmission line as
well as requiring very little power supply current.
Complementary input signals may be derived from high
speed inverter gates as shown, or by using the
complementary outputs of a flip-flop. When the transmitter is
connected near the midpoint of a long transmission line or to
a line with terminations at both ends, two transmitter
sections should be paralleled with respective inputs and
outputs connected together in order to drive the reduced
impedance. This parallel transmitter technique can also be
used to increase the data rate on long transmission lines.
IN
G1
G2
G3
ENABLE
1/3
HS-245RH
1/3
HS-246RH
OUT
+5
GND
GND +5V -5V
2K-6K FOR TTL DRIVE
REQUIRED FOR HS-246RH
1/3
HS-248RH
OUT
GND +5V -5V
FIGURE 4. TYPICAL DATA TRANSMISSION SYSTEM
4
INTERSIL [ INTERSIL CORPORATION ]
