Datasheet

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LT1076-5

10765fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

5V Step-Down

Switching Regulator

The LT

1076-5 is a 2A ﬁ xed 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” conﬁ guration but several design innova-

tions allow this device to be used as a positive-to-negative

converter, a negative boost converter, and as a ﬂ yback con-

verter. The switch output is speciﬁ ed 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 ﬂ uctuations and makes loop gain indepen-

dent of input voltage. As a result, dynamic behavior of the

regulator is signiﬁ cantly 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 conﬁ gurations.

The LT1076-5 is available in a low cost 5- and 7-lead TO-

220 packages with frequency pre-set at 100kHz and current

limit at 2.6A. See Application Note 44 for design details.

Basic Positive Buck Converter

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- and 7-Lead Packages

Only 9.5mA Quiescent Current

Operates Up to 60V Input

5V Output Buck Converter

Tapped Inductor Buck Converter with 4A Output at

Positive-to-Negative Converter

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

All other trademarks are the property of their respective owners.

LT1076-5

SENSE

GND

1.5k

0.033μF

200μF

100μH**

†

MBR340*

MBR330P MAY BE USED

FOR V

≤ 25V

COILTRONICS #100-1-52

HURRICANE #HL-AG210LL

VALUE MAY BE REDUCED TO 50μH

FOR OUTPUT LOADS BELOW 1.5A

8V TO 40V

500μF

25V

LT1076-5 TA01

≤1.8A

†

+ +

Summary of content (8 pages)

PAGE 1
LT1076-5 5V Step-Down Switching Regulator FEATURES DESCRIPTION n The LT®1076-5 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.
PAGE 2
LT1076-5 ABSOLUTE MAXIMUM RATINGS (Note 1) 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) LT1076-5 (Note 6) ........................................
PAGE 3
LT1076-5 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TJ = 25°C. VIN = 25V, unless otherwise noted. SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Current (Note 3) VOUT = 5.5V, VIN ≤ 40V 40V < VIN < 60V VSHDN = 0.1V (Device Shutdown) (Note 9) l l 8.5 9.0 140 11 12 300 mA mA μA Minimum Supply Voltage Normal Mode Start-Up Mode (Note 4) l l 7.3 3.5 8.0 4.
PAGE 4
LT1076-5 PACKAGE DESCRIPTION Q Package 5-Lead Plastic DD Pak (Reference LTC DWG # 05-08-1461) .256 (6.502) .060 (1.524) TYP .060 (1.524) .390 – .415 (9.906 – 10.541) .165 – .180 (4.191 – 4.572) .045 – .055 (1.143 – 1.397) 15° TYP .060 (1.524) .183 (4.648) +.008 .004 –.004 +0.203 0.102 –0.102 .059 (1.499) TYP .330 – .370 (8.382 – 9.398) ( ) .095 – .115 (2.413 – 2.921) .075 (1.905) .300 (7.620) +.012 .143 –.020 +0.305 3.632 –0.
PAGE 5
LT1076-5 R Package 7-Lead Plastic DD Pak (Reference LTC DWG # 05-08-1462) .256 (6.502) .060 (1.524) TYP .060 (1.524) .390 – .415 (9.906 – 10.541) .165 – .180 (4.191 – 4.572) .045 – .055 (1.143 – 1.397) 15° TYP .060 (1.524) .183 (4.648) +.008 .004 –.004 +0.203 0.102 –0.102 .059 (1.499) TYP .330 – .370 (8.382 – 9.398) ( ) .095 – .115 (2.413 – 2.921) .075 (1.905) .300 (7.620) +.012 .143 –.020 +0.305 3.632 –0.508 ( BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK ) .
PAGE 6
LT1076-5 PACKAGE DESCRIPTION T Package 5-Lead Plastic TO-220 (Standard) (Reference LTC DWG # 05-08-1421) .390 – .415 (9.906 – 10.541) .165 – .180 (4.191 – 4.572) .147 – .155 (3.734 – 3.937) DIA .045 – .055 (1.143 – 1.397) .230 – .270 (5.842 – 6.858) .460 – .500 (11.684 – 12.700) .570 – .620 (14.478 – 15.748) .330 – .370 (8.382 – 9.398) .620 (15.75) TYP .700 – .728 (17.78 – 18.491) SEATING PLANE .152 – .202 .260 – .320 (3.861 – 5.131) (6.60 – 8.13) .095 – .115 (2.413 – 2.921) .155 – .195* (3.
PAGE 7
LT1076-5 PACKAGE DESCRIPTION T7 Package 7-Lead Plastic TO-220 (Standard) (Reference LTC DWG # 05-08-1422) .390 – .415 (9.906 – 10.541) .165 – .180 (4.191 – 4.572) .147 – .155 (3.734 – 3.937) DIA .045 – .055 (1.143 – 1.397) .230 – .270 (5.842 – 6.858) .460 – .500 (11.684 – 12.700) .570 – .620 (14.478 – 15.748) .330 – .370 (8.382 – 9.398) .620 (15.75) TYP .700 – .728 (17.780 – 18.491) .095 – .115 (2.413 – 2.921) .155 – .195* (3.937 – 4.953) SEATING PLANE .152 – .202 .260 – .320 (3.860 – 5.130) (6.
PAGE 8
LT1076-5 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1074/HV 4.4A (IOUT), 100kHz High Efﬁciency Step-Down DC/DC Converter VIN: 7.3V to 45V/64V, VOUT(MIN): 2.21V, IQ: 8.5mA, ISHDN: 10μA, DD5/7, TO-2205/7 LT3430 60V, 2.75A (IOUT), 200kHz High Efﬁciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN): 1.20V, IQ: 2.5mA, ISHDN: 25μA, TSSOP16E LT1956 60V, 1.2A (IOUT), 500kHz High Efﬁciency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT(MIN): 1.20V, IQ: 2.