Linear Technology LT1085IT, LT1084MK, LT1084IT, LT1085CT, LT1085CM Datasheet

7.5A, 5A, 3A Low Dropout

Positive Adjustable Regulators

FEATURES

■Three-Terminal Adjustable

■Output Current of 3A, 5A or 7.5A

■Operates Down to 1V Dropout

■Guaranteed Dropout Voltage at Multiple Current Levels

■Line Regulation: 0.015%

■Load Regulation: 0.1%

■100% Thermal Limit Functional Test

■Fixed Versions Available

APPLICATIOUS

■High Efficiency Linear Regulators

■Post Regulators for Switching Supplies

■Constant Current Regulators

■Battery Chargers

DEVICE	OUTPUT CURRENT*
LT1083	7.5A
LT1084	5.0A
LT1085	3.0A

*For a 1.5A low dropout regulator see the LT1086 data sheet.

DESCRIPTIOU

The LT®1083 series of positive adjustable regulators are designed to provide 7.5A, 5A and 3A with higher efficiency than currently available devices. All internal circuitry is designed to operate down to 1V input-to-output differential and the dropout voltage is fully specified as a function of load current. Dropout is guaranteed at a maximum of 1.5V at maximum output current, decreasing at lower load currents. On-chip trimming adjusts the reference voltage to 1%. Current limit is also trimmed, minimizing the stress on both the regulator and power source circuitry under overload conditions.

The LT1083/LT1084/LT1085 devices are pin compatible with older three-terminal regulators. A 10 F output capacitor is required on these new devices. However, this is included in most regulator designs.

Unlike PNP regulators, where up to 10% of the output current is wasted as quiescent current, the LT1083 quiescent current flows into the load, increasing efficiency.

, LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIOU

5V, 7.5A Regulator

VIN ≥ 6.5V	IN	LT1083	OUT			5V AT 7.5A
	+	ADJ		121Ω
				1%	+
	10µF					10µF*
				365Ω		TANTALUM
				1%
*REQUIRED FOR STABILITY						1083/4/5 ADJ TA01

INPUT/OUTPUT VOLTAGE DIFFERENTIAL (V)

Dropout Voltage vs Output Current

2

1

0

0	IFULL LOAD
	OUTPUT CURRENT

1083/4/5 ADJ TA02

1

LT1083/LT1084/LT1085

ABSOLUTE WMAXIWMUWM RATINGSU

(Note 1)

Power Dissipation ...............................	Internally Limited
Input-to-Output Voltage Differential
“C” Grades ..........................................................	30V
“I” Grades ............................................................	30V
“M” Grades ..........................................................	35V
Operating Junction Temperature Range
“C” Grades: Control Section ..................	0°C to 125°C
Power Transistor ...............	0°C to 150°C
“I” Grades: Control Section .............	– 40°C to 125°C
Power Transistor ..........	– 40°C to 150°C

“M” Grades: Control Section .............	– 55°C to 150°C
Power Transistor ..........	– 55°C to 200°C
Storage Temperature Range .................	– 65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................	300°C
PRECOUDITIOUIUG

100% thermal shutdown functional test.

PACKAGE/ORDER IUNFORWMATIOUN
	FRONT VIEW		ORDER PART	TAB IS	FRONT VIEW		ORDER PART
				OUTPUT
			NUMBER				NUMBER
TAB	3	VIN			3	VIN
IS	2	VOUT	LT1084CT		2	VOUT	LT1083CP
OUTPUT
	1	ADJ	LT1084IT		1	ADJ	LT1084CP
	T PACKAGE		LT1085CT		P PACKAGE
			LT1085IT
	3-LEAD PLASTIC TO-220
					3-LEAD PLASTIC TO-3P
	θJA = 50°C/W				θJA = 35°C/W
	BOTTOM VIEW		LT1083CK		FRONT VIEW		LT1085CM
	CASE IS				3	VIN
VIN			LT1083MK	TAB
	OUTPUT
	2		LT1084CK	IS	2	VOUT
			LT1084MK	OUTPUT	1	ADJ
	1		LT1085CK		M PACKAGE
			LT1085MK
ADJ					3-LEAD PLASTIC DD
					θJA = 30°C/W*
	K PACKAGE
				*WITH PACKAGE SOLDERED TO 0.5IN2 COPPER AREA
	2-LEAD TO-3 METAL CAN
				OVER BACKSIDE GROUND PLANE OR INTERNAL POWER
	θJA = 35°C/W			PLANE. θJA CAN VARY FROM 20°C/W TO > 40°C/W
				DEPENDING ON MOUNTING TECHNIQUE.

ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.

PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
Reference Voltage	IOUT = 10mA, TJ = 25°C,
	(VIN – VOUT) = 3V		1.238	1.250	1.262	V
	10mA ≤ IOUT ≤ IFULL LOAD
	1.5V ≤ (VIN – VOUT) ≤ 25V (Notes 4, 6, 7)	●	1.225	1.250	1.270	V
Line Regulation	ILOAD = 10mA, 1.5V ≤ (VIN – VOUT) ≤ 15V, TJ = 25°C (Notes 2, 3)			0.015	0.2	%
		●		0.035	0.2	%
	M Grade: 15V ≤ (VIN – VOUT) ≤ 35V (Notes 2, 3)	●		0.05	0.5	%
	C, I Grades: 15V ≤ (VIN – VOUT) ≤ 30V (Notes 2, 3)	●		0.05	0.5	%

2

LT1083/LT1084/LT1085

ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.

PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
Load Regulation	(VIN – VOUT) = 3V
	10mA ≤ IOUT ≤ IFULL LOAD
	TJ = 25°C (Notes 2, 3, 4, 6)			0.1	0.3	%
		●		0.2	0.4	%
Dropout Voltage	VREF = 1%, IOUT = IFULLLOAD (Notes 5, 6, 8)	●		1.3	1.5	V
Current Limit
LT1083	(VIN – VOUT) = 5V	●	8.0	9.5		A
	(VIN – VOUT) = 25V	●	0.4	1.0		A
LT1084	(VIN – VOUT) = 5V	●	5.5	6.5		A
	(VIN – VOUT) = 25V	●	0.3	0.6		A
LT1085	(VIN – VOUT) = 5V	●	3.2	4.0		A
	(VIN – VOUT) = 25V	●	0.2	0.5		A
Minimum Load Current	(VIN – VOUT) = 25V	●		5	10	mA
Thermal Regulation	TA = 25°C, 30ms Pulse
LT1083				0.002	0.010	%/W
LT1084				0.003	0.015	%/W
LT1085				0.004	0.020	%/W
Ripple Rejection	f = 120Hz, CADJ = 25µF, COUT = 25µF Tantalum
	IOUT = IFULL LOAD, (VIN – VOUT) = 3V (Notes 6, 7, 8)	●	60	75		dB
Adjust Pin Current	TJ = 25°C			55		µA
		●			120	µA
Adjust Pin Current Change	10mA ≤ IOUT ≤ IFULL LOAD
	1.5V ≤ (VIN – VOUT) ≤ 25V (Note 6)	●		0.2	5	µA
Temperature Stability		●		0.5		%
Long Term Stability	TA = 125°C, 1000 Hrs			0.3	1	%
RMS Output Noise (% of VOUT)	TA = 25°C
	10Hz = ≤ f ≤ 10kHz			0.003		%
Thermal Resistance Junction-to-Case	Control Circuitry/Power Transistor					°C/W
LT1083	K Package				0.6/1.6
	P Package				0.5/1.6	°C/W
LT1084	K Package				0.75/2.3	°C/W
	P Package				0.65/2.3	°C/W
	T Package				0.65/2.7	°C/W
LT1085	K Package				0.9/3.0	°C/W
	M, T Packages				0.7/3.0	°C/W

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are measured at a constant junction temperature by low duty cycle pulse testing.

Note 3: Line and load regulation are guaranteed up to the maximum power dissapation (60W for the LT1083, 45W for the LT1084 (K, P), 30W for the LT1084 (T) and 30W for the LT1085). Power dissipation is determined by the input/output differential and the output current. Guaranteed maximum power dissipation will not be available over the full input/output voltage range.

Note 4: IFULL LOAD is defined in the current limit curves. The IFULLLOAD curve is defined as the minimum value of current limit as a function of

input-to-output voltage. Note that the 60W power dissipation for the LT1083 (45W for the LT1084 (K, P), 30W for the LT1084 (T), 30W for the LT1085) is only achievable over a limited range of input-to-output voltage.

Note 5: Dropout voltage is specified over the full output current range of the device. Test points and limits are shown on the Dropout Voltage curve.

Note 6: For LT1083 IFULL LOAD is 5A for – 55°C ≤ TJ < – 40°C and 7.5A for TJ ≥ –40°C.

Note 7: 1.7V ≤ (VIN – VOUT) ≤ 25V for LT1084 at – 55°C ≤ TJ ≤ – 40°C. Note 8: Dropout is 1.7V maximum for LT1084 at – 55°C ≤ TJ ≤ – 40°C.

3

LT1083/LT1084/LT1085

TYPICAL PERFORWMANUCE CHARACTERISTICS

	LT1083													LT1083									LT1083
	Dropout Voltage													Short-Circut Current									Load Regulation
(V)	2	INDICATES GUARANTEED TEST POINT											12										0.10
												(A)CURRENTCIRCUIT-SHORT										(%)DEVIATIONVOLTAGEOUTPUT		I = 7.5A
DIFFERENTIALINPUT/OUTPUTMINIMUM				–40°C ≤ TJ ≤ 150°C									10				25°C						0.05
		0°C ≤ TJ ≤ 125°C											8					150°C					0
	1				TJ = 150°C								6										–0.05
															–55°C
													4										–0.10
					TJ = 25°C
			TJ = –55°C										2										–0.15
															IFULL LOAD
													0		GUARANTEED								–0.20
	0													0			15	20	25	30	35							75	100
	0	1	2	3	4	5	6	7	8	9	10				5	10							–50	–25	0	25	50			125	150
				OUTPUT CURRENT (A)											INPUT/OUTPUT DIFFERENTIAL (V)											TEMPERATURE (°C)
									LT1083/4/5 ADJ G01										LT1083/4/5 ADJ G02										LT1083/4/5 ADJ G03
	LT1084													LT1084									LT1084
	Dropout Voltage												10	Short-Circut Current									Load Regulation
	2																						0.10
(V)		INDICATES GUARANTEED TEST POINT											9
																								I = 5A
DIFFERENTIALINPUT/OUTPUTMINIMUN												(A)CURRENTCIRCUIT-SHORT										(%)DEVIATIONVOLTAGEOUTPUT
				–55°C ≤ TJ ≤ 150°C									8										0.05
		0°C ≤ TJ ≤ 125°C											7			150°C		25°C					0
													6
													5					–55°C					–0.05
	1
							TJ = –55°C						4
		TJ = 150°C			TJ = 25°C								3										–0.10
													2
																							–0.15
													1		IFULL LOAD
															GUARANTEED
	0												0	0	5	10	15	20	25	30	35		–0.20
																												75	100
	0		1	2		3	4		5		6												–50	–25	0	25	50			125	150
															INPUT/OUTPUT DIFFERENTIAL (V)
			OUTPUT CURRENT (A)																							TEMPERATURE (°C)
									LT1083/4/5 ADJ G04											LT1083/4/5 ADJ G05									LT1083/4/5 ADJ G06
	LT1085													LT1085									LT1085
	Dropout Voltage													Short-Circut Current									Load Regulation
(V)	2	INDICATES GUARANTEED TEST POINT											6										0.10
																								I = 3A
DIFFERENTIALINPUT/OUTPUTMINIMUM												(A)CURRENTCIRCUIT-SHORT										(%)DEVIATIONVOLTAGEOUTPUT
				–55°C ≤ TJ ≤ 150°C									5										0.05
		0°C ≤ TJ ≤ 125°C											4				25°C						0
	1							TJ = –55°C					3				150°C						–0.05
					TJ = 25°C										–55°C
		TJ = 150°C											2										–0.10
													1		IFULL LOAD								–0.15
															GUARANTEED
	0												0				15	20	25	30	35		–0.20
	0		1			2		3			4		0		5	10							–50	–25	0	25	50	75	100	125	150
			OUTPUT CURRENT (A)												INPUT/OUTPUT DIFFERENTIAL (V)											TEMPERATURE (°C)

LT1083/4/5 ADJ G07

LT1083/4/5 ADJ G08

LT1083/4/5 ADJ G09

4

																			LT1083/LT1084/LT1085
TYPICAL PERFORWMANUCE CHARACTERISTICS
	Minimum Operating Current									Temperature Stability										Adjust Pin Current
	10									1.27										100
(mA)	9																			90
	8																		ADJUST PIN CURRENT ( A)	80
MINIMUM OPERATING CURRENT									REFERENCE VOLTAGE (V)	1.26
	7																			70
	6																			60
	5				TJ = 150°C					1.25										50
	4																			40
		TJ = 25°C
	3																			30
										1.24
	2																			20
	1		TJ = –55°C																	10
	0	5	10	15	20	25	30	35		1.23	–25	0	25	50	75	100	125	150		0	–25	0	25	50	75	100	125	150
	0									–50										–50
		INPUT/OUTPUT DIFFERENTIAL (V)											TEMPERATURE (°C)										TEMPERATURE (°C)
							LT1083/4/5 ADJ G10									LT1083/4/5 ADJ G11										LT1083/4/5 ADJ G12

RIPPLE REJECTION (dB)

LT1083

Ripple Rejection

100

90

VRIPPLE ≤ 3VP-P

V

RIPPLE

≤ 0.5VP-P

80 (VIN – VOUT) ≥ 3V

70

60
50			(VIN – VOUT) ≥ VDROPOUT
40
30
20		CADJ = 200 F AT FREQUENCIES < 60Hz
10		CADJ = 25 F AT FREQUENCIES > 60Hz
		IOUT = 7A
0
		100														1k								10k				100k
10

FREQUENCY (Hz)

1083/4/5 ADJ G13

RIPPLE REJECTION (dB)

LT1083	LT1083
Ripple Rejection vs Current	Maximum Power Dissipation*

100
90										fR =	120Hz
										VRIPPLE ≤ 3VP-P
80
70			fR =	20kHz
60			VRIPPLE ≤ 0.5VP-P
50
40
30
20			VOUT = 5V
10			CADJ = 25 F
			COUT = 25 F
0
														7
0		1		2		3		4		5		6				8

OUTPUT CURRENT (A)

1083/4/5 ADJ G14

	100
	90
	80
	70			LT1083MK
(W)	60
POWER	50
	40
	30					LT1083CP
	20
	10				LT1083CK
	0	60	70	80	90	100 110 120 130 140 150
	50

CASE TEMPERATURE (°C)

* AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE

LT1083/4/5 ADJ G15

LT1084	LT1084	LT1084
Ripple Rejection	Ripple Rejection vs Current	Maximum Power Dissipation*

	100						100						60
	90	VRIPPLE ≤ 3VP-P		VRIPPLE ≤ 0.5VP-P			90			fR = 120Hz
	80						80			VRIPPLE ≤ 3VP-P			50
(dB)				(VIN – VOUT) ≥ 3V														LT1084MK
	70					(dB)	70	fR = 20kHz
													40
RIPPLE REJECTION	60					RIPPLE REJECTION	60	VRIPPLE ≤ 0.5VP-P
		(VIN – VOUT) ≥ VDROPOUT
	50						50						30
	40						40						20	LT1084CT				LT1084CP
	30						30
													POWER(W)
	20	CADJ = 200 F AT FREQUENCIES < 60Hz					20	VOUT = 5V
													10				LT1084CK
	10	CADJ = 25 F AT FREQUENCIES > 60Hz						CADJ = 25 F
							10
		IOUT = 5A						COUT = 25 F
	0						0						0
	10	100	1k	10k	100k		0	1	2	3	4	5	50	60	70	80	90	100 110 120 130 140 150
			FREQUENCY (Hz)					OUTPUT CURRENT (A)							CASE TEMPERATURE (°C)
				1083/4/5 ADJ G16							1083/4/5 ADJ G17		* AS LIMITED BY MAXIMUM JUNCTION TEMPERATURE
																		LT1083/4/5 ADJ G18

5