LMV393MMX/NOPB National Semiconductor, LMV393MMX/NOPB Datasheet - Page 7

• Manufacturer Part Number: LMV393MMX/NOPB
• Description: IC COMP TINY DUAL LOW V 8-MSOP
• Manufacturer: National Semiconductor
• Type: General Purposer

Specifications of LMV393MMX/NOPB

• Number Of Elements: 2
• Output Type: CMOS, Open-Collector, TTL
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Leaded Process Compatible: Yes
• Rohs Compliant: Yes
• Peak Reflow Compatible (260 C): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LMV393MMX; LMV393MMXTR

Application Circuits
BASIC COMPARATOR
A basic comparator circuit is used for converting analog sig-
nals to a digital output. The LMV331/393/339 have an open-
collector output stage, which requires a pull-up resistor to a
positive supply voltage for the output to switch properly. When
the internal output transistor is off, the output voltage will be
pulled up to the external positive voltage.
The output pull-up resistor should be chosen high enough so
as to avoid excessive power dissipation yet low enough to
supply enough drive to switch whatever load circuitry is used
on the comparator output. On the LMV331/393/339 the pull-
up resistor should range between 1k to 10kΩ.
The comparator compares the input voltage (V
inverting pin to the reference voltage (V
pin. If V
saturation voltage. On the other hand, if V
V
REF
, the output voltage (V
IN
is less than V
FIGURE 1. Basic Comparator
REF
O
, the output voltage (V
) is at V
CC
.
REF
10008004
IN
) at the inverting
is greater than
IN
) at the non-
O
10008026
) is at the
7
COMPARATOR WITH HYSTERESIS
The basic comparator configuration may oscillate or produce
a noisy output if the applied differential input voltage is near
the comparator's offset voltage. This usually happens when
the input signal is moving very slowly across the comparator's
switching threshold. This problem can be prevented by the
addition of hysteresis or positive feedback.
INVERTING COMPARATOR WITH HYSTERESIS
The inverting comparator with hysteresis requires a three re-
sistor network that are referenced to the supply voltage V
of the comparator. When V
V
(V
V
be represented as R
trip voltage V
When V
low very close to ground. In this case the three network re-
sistors can be presented as R
upper trip voltage V
The total hysteresis provided by the network is defined as
To assure that the comparator will always switch fully to V
and not be pulled down by the load the resistors values should
be chosen as follow:
a
O
in
, the voltage at the non-inverting node of the comparator
switches as high as V
< V
a
in
), the output voltage is high (for simplicity assume
is greater than V
a1
is defined as
a2
R
and R
1
//R
is defined as
ΔV
PULL-UP
CC
3
a
in series with R
in
1
). The three network resistors can
a
= V
> R
at the inverting input is less than
(V
<< R
a1
in
2
PULL-UP
//R
> V
- V
LOAD
3
a2
a
in series with R
), the output voltage is
.
2
. The lower input
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1
. The
CC
CC