Fairchild Semiconductor LM431SC, LM431SB, LM431SA Datasheet

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LM431SA/LM431SB/LM431SC

Programmable Shunt Regulator

Features

•Programmable Output Voltage to 36 Volts

•Low Dynamic Output Impedance 0.20 Typical

•Sink Current Capability of 1.0 to 100mA

•Equivalent Full-Range Temperature Coefficient of 50ppm/° C Typical

•Temperature Compensated for Operation Over Full Rated Operating Temperature Range

•Low Output Noise Voltage

•Fast Turn-on Response

Description

The LM431SA/LM431SB/LM431SC are three terminal output adjustable regulators with thermal stability over operating temperature range. The output voltage can be set any value between VREF (approximately 2.5 volts) and 36 volts with two external resistors. These devices have a typical dynamic output impedance of 0.2Ω Active output circuit provides a sharp turn-on characteristic, making these devices excellent replacement for Zener Diodes in many applications.

SOT-89

1

1. Ref 2. Anode 3. Cathode

SOT-23F

3

1 2

1. Cathode 2. Ref 3. Anode

Internal Block Diagram

Rev. 1.0.3

©2002 Fairchild Semiconductor Corporation

LM431SA/LM431SB/LM431SC

Absolute Maximum Ratings

(Operating temperature range applies unless otherwise specified.)

Parameter	Symbol	Value	Unit
Cathode Voltage	VKA	37	V
Cathode current Range (Continuous)	IKA	-100 ~ +150	mA
Reference Input Current Range	IREF	0.05 ~ +10	mA
Thermal Resistance Junction-Air (Note1,2)
MF Suffix Package	Rθ JA	350	° C/W
ML Suffix Package		220
Power Dissipation (Note3,4)
MF Suffix Package	PD	350	mW
ML Suffix Package		560
Junction Temperature	TJ	150	° C
Operating Temperature Range	TOPR	-25 ~ +85	° C
Storage Temperature Range	TSTG	-65 ~ +150	° C

Note:

1. Thermal resistance test board

Size: 76.2mm * 114.3mm * 1.6mm (1S0P) JEDEC Standard: JESD51-3, JESD51-7

2.Assume no ambient airflow.

3.TJMAX = 150° C, Ratings apply to ambient temperature at 25° C

4.Power dissipation calculation: PD = (TJ - TA)/Rθ JA

Recommended Operating Conditions

Parameter	Symbol	Min.	Typ.	Max.	Unit
Cathode Voltage	VKA	VREF	-	36	V
Cathode Current	IKA	1.0	-	100	mA

2

LM431SA/LM431SB/LM431SC

Electrical Characteristics

(TA = +25° C, unless otherwise specified)

	Parameter	Symbol	Conditions			LM431SA				LM431SB			LM431SC			Unit
					Min.		Typ.	Max.	Min.		Typ.	Max.	Min.	Typ.	Max.
	Reference	VREF	VKA=VREF, IKA=10mA		2.450		2.500	2.550	2.470		2.495	2.520	2.482	2.495	2.508	V
	Input Voltage
	Deviation of
	Reference	∆ VREF/	VKA=VREF, IKA=10mA		-				-				-
	Input Voltage						4.5	17			4.5	17		4.5	17	mV
	Over-	∆ T	TMIN≤ TA≤ TMAX
	Temperature
	Ratio of
	Change in			∆ VKA=10V-	-		-1.0	-2.7	-		-1.0	-2.7	-	-1.0	-2.7
	Reference			VREF
		∆ VREF/	IKA
	Input Voltage															mV/V
		∆ VKA	=10mA
	to the Change			∆ VKA=36V-
	in Cathode				-		-0.5	-2.0	-		-0.5	-2.0	-	-0.5	-2.0
				10V
	Voltage
	Reference	IREF	IKA=10mA,		-		1.5	4	-		1.5	4	-	1.5	4		A
	Input Current		R1=10KΩ ,R2=∞
	Deviation of
	Reference		IKA=10mA,
	Input Current				-				-				-
		∆ IREF/∆ T	R1=10KΩ ,R2=∞				0.4	1.2			0.4	1.2		0.4	1.2		A
	Over Full
			TA =Full Range
	Temperature
	Range
	Minimum
	Cathode	IKA(MIN)	VKA=VREF		-		0.45	1.0	-		0.45	1.0	-	0.45	1.0	mA
	Current for
	Regulation
	Off -Stage	IKA(OFF)
	Cathode		VKA=36V, VREF=0		-		0.05	1.0	-		0.05	1.0	-	0.05	1.0		A
	Current
	Dynamic	ZKA	VKA=VREF,		-		0.15	0.5	-		0.15	0.5	-	0.15	0.5	Ω
	Impedance		IKA=1 to 100mA ,f ≥ 1.0kHz

Note1

TMIN = -25° C, TMAX = +85° C

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