APPLICATION HINTS

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 per-

formance of the circuit.

Figure 1 represents a LM336 with a 10k

Ω potenti-

ometer to adjust the reverse breakdown voltage can

be adjusted without altering the temperature coeffi-

cient of the circuit. The adjustment range is gener-

ally sufficient to adjust the initial tolerance of the cir-

cuit and the inaccuracy of the amplifier circuit.

To obtain a lower temperature coefficient two diodes

can be connected in series as indicated in Figure 2.

When the circuit is adjusted to 2.49V the tempera-

ture 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 (2-20k

Ω).

R1

10k

Ω

LM336

V

R

S

Figure 1 : The LM336 with Pot for Adjustment of

Breakdown Voltage

R1

10k

Ω

LM336

V

R

S

1N4148

1N4148

Figure 2 : Temperature Coefficient Adjustment

LM236 - LM336,B

4/9