LMC6762AIM National Semiconductor, LMC6762AIM Datasheet - Page 9

• Manufacturer Part Number: LMC6762AIM
• Description: COMPARATOR DUAL CMOS R/R, SMD, 6762
• Manufacturer: National Semiconductor

Specifications of LMC6762AIM

• Comparator Type: General Purpose
• No. Of Comparators: 2
• Response Time: 4µs
• Ic Output Type: Push Pull
• Supply Current: 12µA
• Supply Voltage Range: 2.7V To 15V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application Hints
1.0 INPUT COMMON-MODE VOLTAGE RANGE
At supply voltages of 2.7V, 5V and 15V, the LMC6762 has an
input common-mode voltage range which exceeds both sup-
plies. As in the case of operational amplifiers, CMVR is
defined by the V
mode range of the device. A CMRR (∆V
(typical) implies a shift of
mode range of the device. The absolute maximum input
voltage at V
room temperature.
A wide input voltage range means that the comparator can
be used to sense signals close to ground and also to the
power supplies. This is an extremely useful feature in power
supply monitoring circuits.
An input common-mode voltage range that exceeds the
supplies, 20 fA input currents (typical), and a high input
impedance makes the LMC6762 ideal for sensor applica-
tions. The LMC6762 can directly interface to sensors without
the use of amplifiers or bias circuits. In circuits with sensors
which produce outputs in the tens to hundreds of millivolts,
the LMC6762 can compare the sensor signal with an appro-
priately small reference voltage. This reference voltage can
be close to ground or the positive supply rail.
2.0 LOW VOLTAGE OPERATION
Comparators are the common devices by which analog sig-
nals interface with digital circuits. The LMC6762 has been
designed to operate at supply voltages of 2.7V without sac-
rificing performance to meet the demands of 3V digital sys-
tems.
At supply voltages of 2.7V, the common-mode voltage range
extends 200 mV (guaranteed) below the negative supply.
This feature, in addition to the comparator being able to
sense signals near the positive rail, is extremely useful in low
voltage applications.
FIGURE 1. An Input Signal Exceeds the LMC6762
Power Supply Voltages with No Output Phase
+
= 5V is 200 mV beyond either supply rail at
OS
shift of the comparator over the common-
Inversion
<
1 mV over the entire common-
OS
/∆V
CM
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) of 75 dB
9
At V
4 µs with overdrives of 100 mV. Please refer to the perfor-
mance curves for more extensive characterization.
3.0 SHOOT-THROUGH CURRENT
The shoot-through current is defined as the current surge,
above the quiescent supply current, between the positive
and negative supplies of a device. The current surge occurs
when the output of the device switches states. This transient
switching current results in glitches in the supply voltage.
Usually, glitches in the supply lines are compensated by
bypass capacitors. When the switching currents are minimal,
the values of the bypass capacitors can be reduced consid-
erably.
FIGURE 2. Even at Low-Supply Voltage of 2.7V, an
Input Signal which Exceeds the Supply Voltages
+
FIGURE 3. LMC6762 Circuit for Measurement
= 2.7V, propagation delays are t
Produces No Phase Inversion at the Output
of the Shoot-Through Current
PLH
= 4 µs and t
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www.national.com
01232007
PHL
=