AD790JNZ Analog Devices Inc, AD790JNZ Datasheet - Page 8

• Manufacturer Part Number: AD790JNZ
• Description: Comparator Single R-R O/P ±16.5V/7V 8-Pin PDIP
• Manufacturer: Analog Devices Inc
• Type: General Purposer

Specifications of AD790JNZ

• Package: 8PDIP
• Rail To Rail: Rail to Rail Output
• Number Of Channels Per Chip: 1
• Minimum Single Supply Voltage: 4.5 V
• Power Supply Type: Single|Dual
• Design Resources: Automated Calibration Technique That Reduces AD5360 Offset Voltage to Less Than 1 mV (CN0123)
• Number Of Elements: 1
• Output Type: CMOS, TTL
• Voltage - Supply: 4.5 V ~ 33 V, ±4.5 V ~ 16.5 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Comparator Type: Precision
• No. Of Comparators: 1
• Response Time: 45ns
• Ic Output Type: CMOS, Open-Collector / Drain, TTL
• Supply Current: 8mA
• Rohs Compliant: Yes
• Output Compatibility: CMOS, TTL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD790
Figure 11. A Bipolar to CMOS TTL Line Receiver (N, Q
Package Pinout)
STANDARD
SCHOTTKY
*
A RESISTOR UP TO 10k
REDUCE THE SOURCE AND SINK CURRENT OF
THE DRIVER. HOWEVER, THIS WILL SLIGHTLY
LOWER THE MAXIMUM USABLE CLOCK RATE.
DIODE
1k
Ω
BIPOLAR
SIGNAL
INPUT
–
5V
Ω
2
3
MAYBE USED TO
1
4
8
GND
+
6
5V
5
400 *
7
Ω
TTL
LEVEL
OUTPUT
4.7V
0.3V
–8–
Bipolar to CMOS/TTL
It is sometimes desirable to translate a bipolar signal (e.g.,
± 5 V) coming from a communications cable or another section
of the system to CMOS/TTL logic levels; such an application is
referred to as a line receiver. Previously, the interface to the
bipolar signal required either a dual (± ) power supply or a refer-
ence voltage level about which the line receiver would switch.
The AD790 may be used in a simple circuit to provide a unique
capability: the ability to receive a bipolar signal while powered
from a single 5 V supply. Other comparators cannot perform
this task. Figure 11 shows a 1 kΩ resistor in series with the input
signal which is then clamped by a Schottky diode, holding the
input of the comparator at 0.4 V below ground. Although the
comparator is specified for a common mode range down to –V
(in this case ground) it is permissible to bring one of the inputs
a few hundred mV below ground. The comparator switches
around this level and produces a CMOS/TTL compatible swing.
The circuit will operate to switching frequencies of 20 MHz.
REV. D
S
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