LM134, LM234, LM334

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SNVS746C – MAY 2004 – REVISED MARCH 2005

If the estimate for the tempco of the diode's forward voltage drop was off, the tempco cancellation is still

reasonably effective. Assume the tempco of the diode is 2.6mV/°C instead of 2.5mV/°C (an error of 4%). The

tempco of the circuit is now:

(11)

A 1mA LM134 current source with no temperature compensation would have a set resistor of 68

Ω and a

resulting tempco of

(12)

So even if the diode's tempco varies as much as ±4% from its estimated value, the circuit still eliminates 98% of

the LM134's inherent tempco.

Typical Applications

Trim R3 to calibrate

Figure 16. Ground Referred Fahrenheit Thermometer

Figure 17. Terminating Remote Sensor for Voltage Output

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Product Folder Links: LM134 LM234 LM334