TMP01FSZ Analog Devices Inc, TMP01FSZ Datasheet - Page 8

• Manufacturer Part Number: TMP01FSZ
• Description: IC SENSOR TEMP/CONTROLLER 8SOIC
• Manufacturer: Analog Devices Inc

Specifications of TMP01FSZ

• Sensing Temperature: -55°C ~ 125°C
• Output Type: Open Collector
• Voltage - Supply: 4.5 V ~ 13.2 V
• Accuracy: ±1°C
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Ic Output Type: Voltage
• Sensing Accuracy Range: ± 3°C
• Supply Current: 500µA
• Supply Voltage Range: 4.5V To 13.2V
• Sensor Case Style: SOIC
• No. Of Pins: 8
• Termination Type: SMD
• Temperature Sensor Function: Temp Sensor
• Package Type: SOIC N
• Operating Temperature (min): -55
• Operating Temperature (max): 150C
• Operating Temperature Classification: Military
• Filter Terminals: SMD
• Rohs Compliant: Yes
• Temperature Sensing Range: -40°C To +85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

TMP01
THEORY OF OPERATION
The TMP01 is a linear voltage-output temperature sensor, with
a window comparator that can be programmed by the user to
activate one of two open-collector outputs when a predeter-
mined temperature setpoint voltage has been exceeded. A low
drift voltage reference is available for setpoint programming.
The temperature sensor is basically a very accurate, temperature
compensated, band gap-type voltage reference with a buffered
output voltage proportional to absolute temperature (VPTAT),
accurately trimmed to a scale factor of 5 mV/K.
The low drift 2.5 V reference output VREF is easily divided
externally with fixed resistors or potentiometers to accurately
establish the programmed heat/cool setpoints, independent of
temperature. Alternatively, the setpoint voltages can be supplied
by other ground referenced voltage sources such as user-
programmed DACs or controllers. The high and low setpoint
voltages are compared to the temperature sensor voltage, thus
creating a two-temperature thermostat function. In addition,
the total output current of the reference (I
magnitude of the temperature hysteresis band. The open
collector outputs of the comparators can be used to control a
wide variety of devices.
TEMPERATURE HYSTERESIS
The temperature hysteresis is the number of degrees beyond
the original setpoint temperature that must be sensed by the
TMP01 before the setpoint comparator is reset and the output
disabled. Figure 14 shows the hysteresis profile. The hysteresis
is programmed by the user by setting a specific load on the
reference voltage output VREF. This output current I
called the hysteresis current, which is mirrored internally and
fed to a buffer with an analog switch.
VREF
HIGH
LOW
GND
SET
SET
1
2
3
4
HYSTERESIS
CURRENT
Figure 13. Detailed Block Diagram
REFERENCE
VOLTAGE
SENSOR
AND
CURRENT
MIRROR
COMPARATOR
WINDOW
ENABLE
1kΩ
I
HYS
TEMPERATURE
HYSTERESIS
VOLTAGE
OUTPUT
VREF
TMP01
) determines the
8
7
6
5
VREF
V+
OVER
UNDER
VPTAT
is also
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After a temperature setpoint is exceeded and a comparator
tripped, the buffer output is enabled. The output is a current
of the appropriate polarity that generates a hysteresis offset volt-
age across an internal 1000 Ω resistor at the comparator input.
The comparator output remains on until the voltage at the
comparator input, now equal to the temperature sensor voltage
VPTAT summed with the hysteresis offset, returns to the
programmed setpoint voltage. The comparator then returns
low, deactivating the open-collector output and disabling the
hysteresis current buffer output. The scale factor for the
programmed hysteresis current is:
Thus, since VREF = 2.5 V, with a reference load resistance
of 357 kΩ or greater (output current 7 μA or less), the temper-
ature setpoint hysteresis is zero degrees. Larger values of load
resistance only decrease the output current below 7 μA and
have no effect on the operation of the device. The amount of
hysteresis is determined by selecting a value of load resistance
for VREF.
PROGRAMMING THE TMP01
In the basic fixed setpoint application utilizing a simple resistor
ladder voltage divider, the desired temperature setpoints are
programmed in the following sequence:
1.
2.
3.
4.
OVER, UNDER
VOLTAGE
OUTPUT
I
Select the desired hysteresis temperature.
Calculate the hysteresis current I
Select the desired setpoint temperatures.
Calculate the individual resistor divider ladder values
needed to develop the desired comparator setpoint voltages
at SET HIGH and SET LOW.
HYS
= I
LO
HI
VREF
= 5 μA/°C + 7 μA
T
Figure 14. TMP01 Hysteresis Profile
HYSTERESIS
SETLOW
LOW
HYSTERESIS HIGH =
TEMPERATURE
HYSTERESIS LOW
VREF
.
HYSTERESIS
HIGH
T
SETHIGH