MAX6635MSA+ Maxim Integrated Products, MAX6635MSA+ Datasheet - Page 11

• Manufacturer Part Number: MAX6635MSA+
• Description: IC TEMP SENSOR SMBUS 8-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of MAX6635MSA+

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 150°C
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -55°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Full Temp Accuracy: +/- 2.5 C
• Digital Output - Bus Interface: Serial (3-Wire, I2C)
• Digital Output - Number Of Bits: 12 bit + Sign
• Maximum Operating Temperature: + 150 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 10. Simple Thermostat
ALERT has programmable polarity and two modes:
comparator and interrupt. Polarity and mode are select-
ed through the Configuration register (Table 4). The
ALERT output is open drain.
With ALERT in interrupt mode, the MAX6634/MAX6635
look for a T
an alarm for an undertemperature fault, as well as for
an overtemperature fault. Once either fault has
occurred, it remains active until deasserted by a read
of any register. The device then begins to look for a
temperature change crossing the hysteresis level. The
activation of ALERT is subject to the depth of the fault
queue.
For example: If T
20°C, and the fault queue depth is set to 4, ALERT
does not assert until four consecutive conversions
exceed 100°C. If the temperature is then read through
the I
asserts again when four consecutive conversions are
less than 80°C.
In comparator mode, ALERT is asserted when the num-
ber of consecutive conversions exceeding the value in
the T
register, is equal to the depth of the fault queue. ALERT
deasserts when the number of consecutive conversions
2
HIGH
C-compatible interface, ALERT deasserts. ALERT
+3V TO +5.5V
MAX6634
register, or lower than the value in the T
HIGH
V CC
4
12-Bit Plus Sign Temperature Sensors with
8
ALERT
or a T
HIGH
______________________________________________________________________________________
4kΩ
3
SMBus/I
LOW
is set to 100°C, T
fault. The ALERT pin asserts
(MAX6634/MAX6635)
2N3904
Temperature Alert
RELAY
5VDC, 20mA
125VAC, 1A
Comparator Mode
HEATER
Interrupt Mode
2
HYST
C-Compatible Serial Interface
HEATER
SUPPLY
is set to
LOW
less than T
is equal to the depth of the fault queue.
For example: If T
80°C, and the fault queue depth is set to four, ALERT
does not assert until four consecutive conversions
exceed 100°C, or are below 80°C. ALERT only
deasserts if four consecutive conversions are less than
T
Comparator mode allows autonomous clearing of an
ALERT fault without the intervention of a master and is
ideal to use for driving a thermostat (Figure 10).
The MAX6635 also includes an overtemperature output
that is always in comparator mode. Whenever the tem-
perature exceeds a value in the programmable T
register, OVERT is asserted. OVERT only deasserts
after the temperature drops below T
the fault queue is activated, OVERT is subject to that
queue, which sets the number of faults that must occur
before OVERT asserts or deasserts. This helps prevent
spurious alarms in noisy environments.
Comparator mode also allows autonomous clearing of
an OVERT fault without the intervention of a master and
thus is ideal to use for driving a cooling fan (Figure 11).
In this application, the polarity of OVERT is active high.
The MAX6633/MAX6634/MAX6635 feature a shutdown
mode, accessible through the serial interface that
saves power by turning off everything except the POR
Figure 11. Fan Controller
HIGH
- T
HYST
Overtemperature Alarm (MAX6635)
HIGH
or greater than T
+3V TO +5.5V
MAX6635
- T
HIGH
4
V
HYST
CC
8
OVERT
is set to 100°C, T
or greater than T
10kΩ
3
LOW
+12V
FAN
MAX
+ T
12V 300mA
MOTOR
LOGIC-LEVEL
MOSFET
HYST
- T
LOW
LOW
Shutdown
HYST
.
+ T
is set to
. When
HYST
MAX
11