TMP01FS Analog Devices Inc, TMP01FS Datasheet - Page 16

• Manufacturer Part Number: TMP01FS
• Description: Temperature Sensor IC IC Function:Digital Temperature Sensor
• Manufacturer: Analog Devices Inc

Specifications of TMP01FS

• Package/case: 8-SOIC
• Leaded Process Compatible: No
• Ic Generic Number: 01
• Mounting Type: Surface Mount
• Operating Temp. Max: 125 C
• Operating Temp. Min: -55 C
• Rohs Status: RoHS non-compliant
• 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)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

TMP01
TRANSLATING 5 mV/K TO 10 mV/°C
A useful circuit shown in Figure 31 translates the VPTAT
output voltage, which is calibrated in Kelvins, into an output
that can be read directly in degrees Celsius on a voltmeter
display.
To accomplish this, an external amplifier is configured as a
differential amplifier. The resistors are scaled so the VREF
voltage exactly cancels the VPTAT voltage at 0.0°C.
TMP01
VPTAT
VREF
5
1
4.12kΩ
Figure 31. Translating 5 mV/K to 10 mV/°C
100kΩ
100kΩ
487Ω
TMP01
VPTAT
VREF
105kΩ
2
3
OP177
10pF
+15V
–15V
1
5
7
4
4.22kΩ
6.49kΩ
6
100kΩ
100kΩ
121Ω
V
(V
OUT
OUT
= (10mV/°C)
= 0.0V @ T = 0.0°C)
90.9kΩ
2
3
Figure 32. Translating 5 mV/K to 10 mV/°F
10pF
+15V
–15V
7
4
1.0kΩ
OP297
1/2
6
Rev. E | Page 16 of 20
100kΩ
However, the gain from VPTAT to the output is two, so that
5 mV/K becomes 10 mV/°C. Thus, for a temperature of 80°C,
the output voltage is 800 mV. Circuit errors will be due prima-
rily to the inaccuracies of the resistor values. Using 1% resistors,
the observed error was less than 10 mV, or 1°C. The 10 pF
feedback capacitor helps to ensure against oscillations. For
better accuracy, an adjustment potentiometer can be added in
series with either 100 kΩ resistor.
TRANSLATING VPTAT TO THE FAHRENHEIT SCALE
A similar circuit to the one shown in Figure 31 can be used
to translate VPTAT into an output that can be read directly in
degrees Fahrenheit, with a scaling of 10 mV/°F. Only unity gain
or less is available from the first stage differentiating circuit, so
the second amplifier provides a gain of two to complete the
conversion to the Fahrenheit scale. Using the circuit in Figure 32,
a temperature of 0.0°F gives an output of 0.00 V. At room temp-
erature (70°F), the output voltage is 700 mV. A −40°C to +85°C
operating range translates into −40°F to +185°F. The errors are
essentially the same as for the circuit in Figure 31.
6
5
100kΩ
OP297
1/2
7
V
(10mV/°F)
OUT
= 0.0V @ T = 0.0°F