AP393 Diodes, Inc., AP393 Datasheet - Page 6

• Manufacturer Part Number: AP393
• Description: Low Power Low Offset Voltage Dual Comparators
• Manufacturer: Diodes, Inc.

Application Information
allowed to capacitively couple to the inputs via stray capacitance. This shows up only during the output voltage transition intervals as the
comparator change states. Power supply bypassing is not required to solve this problem. Standard PC board layout is helpful as it
reduces stray input-output coupling. Reducing the input resistors to < 10kΩ reduces the feedback signal levels and finally, adding even a
small amount (1.0 to 10 mV) of positive feedback (hysteresis) causes such a rapid transition that oscillations due to stray feedback are
not possible. Simply socketing the IC and attaching resistors to the pins will cause input-output oscillations during the small transition
intervals unless hysteresis is used. If the input signal is a pulse waveform, with relatively fast rise and fall times, hysteresis is not required.
All input pins of any unused comparators should be tied to the negative supply.
range of from 2.0 V
prevent the input voltages from going negative more than -0.3 V
applications section.
together to provide an output OR’ing function. An output pull-up resistor can be connected to any available power supply voltage within
the permitted supply voltage range and there is no restriction on this voltage due to the magnitude of the voltage applied to the
V
The amount of current the output device can sink is limited by the drive available (which is independent of V
When the maximum current limit is reached (approximately 16mA), the output transistor will come out of saturation and the output voltage
will rise very rapidly. The output saturation voltage is limited by the approximately 60Ω r
of the output transistor (1.0 mV) allows the output to clamp essentially to ground level for small load currents.
Typical Circuit
AP393 Rev. 5
+
terminal of the AP393 package. The output can also be used as a simple SPST switch to ground (when a pull-up resistor is not used).
The AP393 is high gain, wide bandwidth devices, like most comparators, can easily oscillate if the output lead is inadvertently
The bias network of the AP393 establishes a drain current independent of the magnitude of the power supply voltage over the
The differential input voltage may be larger than V+ without damaging the device (Note 8). Protection should be provided to
The output of the AP393 is the uncommitted collector of a grounded-emitter NPN output transistor. Many collectors can be tied
+V
+V
REF
IN
+
-
AP393
DC
Basic Comparator
to 30 V
+
Driving TTL
-
AP393
DC
. It is usually unnecessary to use a bypass capacitor across the power supply line.
(V
+5V
CC
= 5.0V
DC
10K
1/4 DM54XX
V
DC
+
3.0K
)
V
O
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6 of 15
LOW POWER LOW OFFSET VOLTAGE DUAL
DC
(at 25°C). An input clamp diode can be used as shown in the
V
+
100K
75 pF
+
-
AP393
Squarewave Oscillator
SAT
of the output transistor. The low offset voltage
Driving CMOS
100K
1/2 AP393
+
-
100K
100K
100K
+5.0V
DC
COMPARATORS
1/4 MM54CXX
+
) and the β of this device.
V
©
4.3K
+
Diodes Incorporated
AP393
1:100kHz
V
APRIL 2008
O
V
0
+