Chip information, Low-cost, fail-safe temperature monitor, Set-point resistor – Rainbow Electronics MAX6510 User Manual
Page 7
mal shutdown, power-up, recalibration, or other tem-
perature-dependent function.
Low-Cost, Fail-Safe Temperature Monitor
In high-performance/high-reliability applications, multi-
ple temperature monitoring is important. The high-level
integration and low cost of the MAX6509/MAX6510
facilitate the use of multiple temperature monitors to
increase system reliability. Figure 6 shows two
MAX6510s with different temperature thresholds. This
ensures that fault conditions that can overheat the mon-
itored device cause no permanent damage. The first
temperature monitor activates the fan when the die
temperature exceeds +45°C. The second MAX6510
triggers a system shutdown if the die temperature
reaches +75°C. The second temperature monitor’s out-
put asserts when a wide variety of destructive fault con-
ditions occur, including latchups, short circuits, and
cooling-system failures.
Set-Point Resistor
To set the trip-point temperature, connect a resistor
between SET and GND. The resistor’s value is deter-
mined either from the R
SET
vs. Temperature graphs
(see Typical Operating Characteristics) or from the
equations below.
To set the temperature trip point from -40°C to 0°C, use
the following equation:
R
SET
= [(1.3258 · 10
5
) / (T+1.3)] - 310.1693 -
[(5.7797 · 10
6
) / (T+1.3)
2
]
To set the temperature trip point from 0°C to +125°C,
use the following equation:
R
SET
= [(8.3793 · 10
4
) / T] - 211.3569 +
[(1.2989 · 10
5
) / T
2
]
where T is the trip temperature in Kelvin.
MAX6509/MAX6510
Resistor-Programmable
SOT Temperature Switches
_______________________________________________________________________________________
7
MAX6509CAUK
MAX6509HAUK
+5V
HYST
SET
HYST
GND
V
CC
GND
V
CC
R
PULL-UP
100k
OUT
OUT
OUT OF RANGE
MAX6510HAUT
HYST
V
CC
V
CC
100k
R
SET
R
SET
R
SET
100k
30k
OUTSET
GND
+5V
MAX6509CAUT
GND
SET
OUTSET
HYST
V
CC
V
CC
OUT
30k
OUT
OUT OF RANGE
OVERTEMP
UNDERTEMP
R
SET
Figure 5. Temperature-Window Detector
MAX6510HAUT
GND
HYST
+5V
30k
R
SET
MAX6510HAUT
GND
HYST
SET
V
CC
V
CC
OUT
SET
OUT
OUTSET
OUTSET
TEMPERATURE
FAULT
FAN
CONTROL
µP
HEAT
HEAT
55k
R
SET
V
CC
V
CC
Figure 6. Low-Power, High-Reliability, Fail-Safe Temperature
Monitor
Chip Information
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