Linear Technology LT1076CT-5, LT1076CR-5, LT1076-5, LT1076IT-5, LT1076HVIT-5 Datasheet

FEATURES

■Fixed 5V Output

■2A On-Board Switch

■100kHz Switching Frequency

■2% Output Voltage Tolerance Over Temperature

■Greatly Improved Dynamic Behavior

■Available in Low Cost 5-Lead Package

■Only 9.5mA Quiescent Current

■Operates Up to 60V Input

APPLICATIOUS

■5V Output Buck Converter

■Tapped Inductor Buck Converter with 4A Output at 5V

■Positive-to-Negative Converter

LT1076-5

5V Step-Down

Switching Regulator

DESCRIPTIOU

The LT1076-5 is a 2A fixed 5V output monolithic bipolar switching regulator which requires only a few external parts for normal operation. The power switch, all oscillator and control circuitry, all current limit components, and an output monitor are included on the chip. The topology is a classic positive “buck” configuration but several design innovations allow this device to be used as a positive-to- negative converter, a negative boost converter, and as a flyback converter. The switch output is specified to swing 40V below ground, allowing the LT1076-5 to drive a tapped inductor in the buck mode with output currents up to 4A.

The LT1076-5 uses a true analog multiplier in the feedback loop. This makes the device respond nearly instantaneously to input voltage fluctuations and makes loop gain independent of input voltage. As a result, dynamic behavior of the regulator is significantly improved over previous designs.

On-chip pulse by pulse current limiting makes the LT1076- 5 nearly bust-proof for output overloads or shorts. The input voltage range as a buck converter is 8V to 60V, but a self-boot feature allows input voltages as low as 5V in the inverting and boost configurations.

The LT1076-5 is available in a low cost 5-lead TO-220 package with frequency pre-set at 100kHz and current limit at 2.6A. See Application Note 44 for design details.

TYPICAL APPLICATIOU

Basic Positive Buck Converter

100μH**†

5V

8V TO 40V

VIN

VSW

≤1.8A

LT1076-5

MBR340*

* MBR330P MAY BE USED

SENSE

FOR VIN ≤ 25V

GND

VC

** COILTRONICS #100-1-52

HURRICANE #HL-AG210LL

R3

† VALUE MAY BE REDUCED TO 50μH

1.5k

+

+

FOR OUTPUT LOADS BELOW 1.5A

C3

C2

C1

200μF

0.033μF

500μF

LT1076-5 TA01

25V

1

LT1076-5

ABSOLUTE

WAXIWUW

RATIUGS

PACKAGE/ORDER IUFORWATIOU

Input Voltage
LT1076-5............................................................	45V
LT1076HV-5 .......................................................	64V
Switch Voltage with Respect to Input Voltage
LT1076-5............................................................	64V
LT1076HV-5 .......................................................	75V
Switch Voltage with Respect to Ground Pin
(VSW Negative)	35V
LT1076-5 (Note 5)..............................................
LT1076HV-5 (Note 5) .........................................	45V
Sense Pin Voltage ...........................................	– 2V, 10V
Maximum Operating Ambient Temperature Range
LT1076C-5, LT1076HVC-5 .....................	0°C to 70°C
LT1076I-5, LT1076HVI-5 ..................	– 40°C to 85°C
Maximum Operating Junction Temperature Range
LT1076C-5, LT1076HVC-5 ...................	0°C to 125°C
LT1076I-5, LT1076HVI-5 ................	– 40°C to 125°C
Maximum Storage Temperature ..........	–65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................	300°C

FRONT VIEW			ORDER PART
7		SHDN	NUMBER
6		VC
5		SENSE
4		GND
3		ILIM	LT1076CR-5
2		VSW
1		VIN
R PACKAGE
7-LEAD PLASTIC DD

TJMAX = 110°C

θ WILL VARY FROM APPROXIMATELY 30°C/W WITH 2.8IN2 OF 1 OZ COPPER TO 70°C/W WITH 0.20IN2 OF 1 OZ COPPER.

	FRONT VIEW							LT1076CT-5
	5				VIN
	4						VSW	LT1076HVCT-5
	3				GND			LT1076IT-5
	2						VC
	1				SENSE			LT1076HVIT-5
	T PACKAGE
	5-LEAD TO-220

FOR STRAIGHT LEADS, ORDER FLOW 06

TJMAX = 110°C, θJA = 130°C/W

FRONT VIEW

7 SHDN

6 VC

5 SENSE LT1076CY-5

4 GND

3 ILIM

2 VSW

1 VIN

Y PACKAGE 7-LEAD TO-220

TJMAX = 110°C, θJA = 130°C/W

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS TJ = 25°C, VIN = 25V, unless otherwise noted.

PARAMETER	CONDITIONS		MIN	TYP	MAX	UNITS
Switch “On” Voltage (Note 1)	ISW = 0.5A	●			1.2	V
	ISW = 2A	●			1.7	V
Switch “Off” Leakage	VIN = 25V, VSW = 0				150	μA
	VIN = VMAX, VSW = 0 (Note 6)				250	μA
Supply Current (Note 2)	VOUT = 5.5V, VIN ≤ 40V	●		8.5	11	mA
	40V < VIN < 60V	●		9.0	12	mA
	VSHDN = 0.1V (Device Shutdown) (Note 8)			140	300	μA
Minimum Supply Voltage	Normal Mode	●		7.3	8.0	V
	Start-Up Mode (Note 3)	●		3.5	4.8	V
Switch Current Limit (Note 4)	ILIM = Open	●	2	2.6	3.2	A
	RLIM = 10k (Note 9)			1.8		A
	RLIM = 7k (Note 9)			1.2		A
Maximum Duty Cycle		●	85	90		%

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