ST LM236, LM336 User Manual

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)

8

7

6

5

1- NC

V+

NC

NC

ADJ

2- NC

3- NC

4- V-

5- ADJ

6- NC

7- NC

1

2

3

4

8- V+

NC

NC

NC

V+

May 2007

Rev 3

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Schematic diagram	LM236-LM336

1 Schematic diagram

Figure 1. Schematic diagram

2	Absolute maximum ratings
	Table 1.	Absolute maximum ratings (AMR)
	Symbol	Parameter		LM236		LM336,B	Unit
	IR	Current
		Reverse			15		mA
	IF
		Forward			10
	Toper	Operating free-air temperature range		-25 to +85		0 to +70	°C
	Tstg	Storage temperature range		-65 to +150			°C

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LM236-LM336						Electrical characteristics
3	Electrical characteristics
Table 2.	Electrical characteristics
Symbol		Parameter		LM236			LM336,B				Unit
			Min.	Typ.	Max.	Min.		Typ.	Max.
	Reference breakdown voltage
VR	Tamb = +25°C, IR = 1mA
	LM236, LM336		2.44	2.49	2.54	2.39		2.49		2.59	V
	LM336B					2.44		2.49		2.54
	Reverse breakdown voltage change with current
VR	400µA ≤ IR ≤ 10mA
	Tamb	= +25°C		2.6	6			2.6		10	mV
	Tmin	≤ Tamb ≤ Tmax		3	10			3		12
ZD	Reverse dynamic impedance (IR = 1mA)										Ω
	T	= +25°C		0.2	0.6			0.2		1
	amb	≤ Tamb ≤ Tmax
	Tmin			0.4	1			0.4		1.4
KVT	Temperature stability (VR = 2.49V, IR = 1mA)			3.5	9			1.8		6	mV
KVH	Long term stability (Tamb = +25°C ±0.1°C, IR= 1mA)			20				20			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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Electrical characteristics			LM236-LM336
Figure 4.	Dynamic impedance	Figure 5.	Response time
Dynamic impedance (Ohm)		Voltage swing (V)
	Frequency (Hz)		Time (µs)
Figure 6.	Reverse characteristics	Figure 7.	Forward characteristics
Reverse current (mA)		Forward voltage (V)
	Reverse voltage (V)		Forward current (mA)
Figure 8.	Temperature drift
Reverse voltage (V)
	Temperature (°C)

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LM236-LM336	Application information

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 Figure 10. Temperature coefficient adjustment breakdown voltage

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