LM236-LM336 Application information
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4 Application information
The LM236, LM336 voltage references are easier to use than zener diodes. Their low
impedance and wide current range facilitate biasing in any circuits. Besides, the breakdown
voltage or the temperature coefficient can be adjusted so as to optimize the performance of
the circuit.
Figure 9 represents a LM336 with a 10kΩ potentiometer to adjust the reverse breakdown
voltage which can be adjusted without altering the temperature coefficient of the circuit. The
adjustment range is generally sufficient to adjust the initial tolerance of the circuit and the
inaccuracy of the amplifier circuit.
To obtain a lower temperature coefficient two diodes can be connected in series as
indicated in Figure 10.
When the circuit is adjusted to 2.49V the temperature coefficient is minimized.
For a correct temperature coefficient, the diodes should be at the same ambient
temperature as the LM336. The value of R1 is not critical (2-20kΩ).
Figure 9. LM336 with pot for adjustment of
breakdown voltage
Figure 10. Temperature coefficient adjustment
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