el5281 Intersil Corporation, el5281 Datasheet - Page 7

• Manufacturer Part Number: el5281
• Description: Dual 8ns High-speed Comparator
• Manufacturer: Intersil Corporation

Applications Information
Power Supplies and Circuit Layout
The EL5281 comparator operates with single and dual
supply with 5V to 12V between V
side of the comparator is supplied by a single supply from
2.7V to 5V. The rail-to-rail output swing enables direct
connection of the comparator to both CMOS and TTL logic
circuits. As with many high speed devices, the supplies must
be well bypassed. Elantec recommends a 4.7µF tantalum in
parallel with a 0.1µF ceramic. These should be placed as
close as possible to the supply pins. Keep all leads short to
reduce stray capacitance and lead inductance. This will also
Pin Descriptions
PIN NUMBER
4, 11
10
12
13
14
1
2
3
5
6
7
8
9
PIN NAME
LATCHB
LATCHA
OUTB
OUTA
INA+
INB+
GND
INA-
INB-
VSD
VS+
VS-
NC
7
Positive supply current
Positive input, channel A
Negative input, channel A
Negative input, channel B
Positive input, channel B
Negative supply voltage
Ground
Output, channel B
Latch input, channel A
Digital supply voltage
Not connected
Latch input, channel B
Output, channel A
S
+ and V
S
-. The output
FUNCTION
EL5281
minimize unwanted parasitic feedback around the
comparator. The device should be soldered directly to the
PC board instead of using a socket. Use a PC board with a
good, unbroken low inductance ground plane. Good ground
plane construction techniques enhance stability of the
comparator.
Input Voltage Considerations
The EL5281 input range is specified from 0.1V below V
2.25V below V
output still responds correctly to a small differential input
signal. The differential input stage is a pair of PNP
transistors, therefore, the input bias current flows out of the
(Reference Circuit 1)
(Reference Circuit 1)
(Reference Circuit 1)
(Reference Circuit 3)
(Reference Circuit 2)
S
+. The criterion for the input limit is that the
IN-
LATC
EQUIVALENT CIRCUIT
V
SD
V
S
V
+
S
-
V
Circuit 1
Circuit 2
Circuit 3
S
+
V
S
-
V
SD
OUT
V
V
S
IN+
S
+
-
S
- to