Datasheet
+
-
INP
INN
HYSTP
HYSTN
OUT
LMP7300
C1
2.32 k:
1%
205 k:
1%
0.1 PF
R
4
46.4 k:
1%
R
3
15.4 k:
1%
R
2
19.6 k:
1%
+
-
INP
INN
HYSTP
HYSTN
OUT
C2
2.32 k:
1%
205 k:
1%
USB POWER SOURCE
4.3V to 5.5V
V
REF
V
REF
0.1 PF
V
+
* NTC Thermistor
Such as: OMEGA #44008
30 k: @ 25°C
19.74 k: @ 35°C
46.67 k: @ 15°C
R
T
*
R
1
61.9 k:
1%
V
LOW
TEMPERATUE
FAULT
1 M:
1 M:
V
HIGH
TEMPERATURE
FAULT
LMP7300
LMP7300
SNOSAT7F –AUGUST 2007–REVISED MARCH 2013
www.ti.com
EVALUATION BOARDS
Texas Instruments provides the following PCB boards as an aid in evaluating the LMP7300 performance.
Evaluation Board
Device Package
Ordering ID
LMP7300MA 8-Pin SOIC LMP7300MA-EVAL
WINDOW COMPARATOR
Figure 25 shows two LMP7300s configured as a micropower window detector in a temperature level detection
application. The circuit shown monitors the ambient temperature change. If the temperature rises outside the
15°C to 35°C window, either comparator 1 for high temp, or comparator 2 for low temp, will set low, indicating a
fault condition has occurred. The open collector outputs are pulled up separately but can be wire-OR’d for a
single fault indication. If the temperature returns inside the window it must overcome the 22 mV asymmetric
hysteresis band established on either comparator. For the high side the temperature must drop below 34°C and
for the low side the temperature must rise above 16°C for the outputs to reset high and remove the fault
indication. The temperature is sensed by a 30 kΩ @ 25°C Omega Precision NTC Thermistor #44008 (±0.2% tol).
Figure 24. Temperature Controlled Window Detector to Monitor Ambient Temperature
PRECISION HIGH TEMPERATURE SWITCH
The LMP7300 brings accuracy and stability to simple sensor switch applications. Figure 26 shows the LMP7300
setup in a high temperature switch configuration. The input bridge establishes the trip point at 85°C and the reset
temperature at 80°C. The comparator is set up with positive hysteresis of 14.3 mV and no negative hysteresis.
When the temperature is rising it trips at 85°C. The 14.3 mV hysteresis allows the temperature to drop to 80°C
before reset.
14 Submit Documentation Feedback Copyright © 2007–2013, Texas Instruments Incorporated
Product Folder Links: LMP7300