LM236-LM336
2.5V voltage references
Features
●Low temperature coefficient
●Wide operating current of 400µA to 10mA
●0.2Ω dynamic impedance
●Guaranteed temperature stability
●Fast turn-on
Description
The LM236 and LM336 are precision 2.5V regulator diodes. These voltage reference monolithic ICs operate like 2.5V Zener diodes with a low temperature coefficient and a dynamic impedance of 0.2Ω. A third pin enables adjusting the reference voltage and the temperature coefficient.
TO92
(Plastic package)
SO8
(Plastic micropackage)
Pin connections
TO92
(Bottom view)
ADJ v+ v-
SO8
(Top view)
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6 |
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1- NC |
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V+ |
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NC |
NC |
ADJ |
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2- NC |
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3- NC |
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4- V- |
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5- ADJ |
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6- NC |
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7- NC |
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8- V+ |
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NC |
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NC |
NC |
V+ |
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May 2007 |
Rev 3 |
1/15 |
www.st.com
Schematic diagram |
LM236-LM336 |
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2 |
Absolute maximum ratings |
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Table 1. |
Absolute maximum ratings (AMR) |
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Symbol |
Parameter |
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LM236 |
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LM336,B |
Unit |
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IR |
Current |
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Reverse |
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15 |
mA |
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IF |
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Forward |
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10 |
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Toper |
Operating free-air temperature range |
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-25 to +85 |
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0 to +70 |
°C |
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Tstg |
Storage temperature range |
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-65 to +150 |
°C |
2/15
LM236-LM336 |
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Electrical characteristics |
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3 |
Electrical characteristics |
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Table 2. |
Electrical characteristics |
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Symbol |
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Parameter |
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LM236 |
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LM336,B |
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Unit |
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Min. |
Typ. |
Max. |
Min. |
Typ. |
Max. |
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Reference breakdown voltage |
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VR |
Tamb = +25°C, IR = 1mA |
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LM236, LM336 |
2.44 |
2.49 |
2.54 |
2.39 |
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2.49 |
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2.59 |
V |
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LM336B |
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2.44 |
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2.49 |
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2.54 |
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Reverse breakdown voltage change with current |
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VR |
400µA ≤ IR ≤ 10mA |
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Tamb |
= +25°C |
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2.6 |
6 |
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2.6 |
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10 |
mV |
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Tmin |
≤ Tamb ≤ Tmax |
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3 |
10 |
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3 |
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12 |
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ZD |
Reverse dynamic impedance (IR = 1mA) |
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Ω |
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T |
= +25°C |
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0.2 |
0.6 |
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0.2 |
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1 |
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amb |
≤ Tamb ≤ Tmax |
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Tmin |
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0.4 |
1 |
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0.4 |
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1.4 |
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KVT |
Temperature stability (VR = 2.49V, IR = 1mA) |
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3.5 |
9 |
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1.8 |
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6 |
mV |
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KVH |
Long term stability (Tamb = +25°C ±0.1°C, IR= 1mA) |
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20 |
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20 |
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ppm |
Figure 2. Reverse voltage change |
Figure 3. Zener noise voltage |
Reverse voltage change (mV) |
Noise (nV/√Hz) |
Reverse current (mA) |
Frequency (Hz) |
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3/15
Electrical characteristics |
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LM236-LM336 |
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Figure 4. |
Dynamic impedance |
Figure 5. |
Response time |
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Dynamic impedance (Ohm) |
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Voltage swing (V) |
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Frequency (Hz) |
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Time (µs) |
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Figure 6. |
Reverse characteristics |
Figure 7. |
Forward characteristics |
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Reverse current (mA) |
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Forward voltage (V) |
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Reverse voltage (V) |
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Forward current (mA) |
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Figure 8. |
Temperature drift |
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Reverse voltage (V) |
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Temperature (°C) |
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4/15
LM236-LM336 |
Application information |
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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 Figure 10. Temperature coefficient adjustment breakdown voltage
5/15