LT1171CT Linear Technology, LT1171CT Datasheet

IC SW-REG HI-EFF 2.5A TO220-5

LT1171CT

Manufacturer Part Number
LT1171CT
Description
IC SW-REG HI-EFF 2.5A TO220-5
Manufacturer
Linear Technology
Type
Step-Down (Buck), Step-Up (Boost), Inverting, Cuk, Flyback, Forward Converterr
Datasheet

Specifications of LT1171CT

Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
1.25 ~ 40 V
Current - Output
2.5A
Frequency - Switching
100kHz
Voltage - Input
3 ~ 40 V
Operating Temperature
0°C ~ 100°C
Mounting Type
Through Hole
Package / Case
TO-220-5 (Bent and Staggered Leads)
Power - Output
100W
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

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Quantity:
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FEATURES
n
n
n
n
n
n
n
n
n
n
n
APPLICATIONS
n
n
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n
n
USER NOTE:
This data sheet is only intended to provide specifications, graphs, and a general functional
description of the LT1170/LT1171/LT1172. Application circuits are included to show the capability
of the LT1170/LT1171/LT1172. A complete design manual (AN19) should be obtained to assist in
developing new designs. This manual contains a comprehensive discussion of both the LT1070
and the external components used with it, as well as complete formulas for calculating the values
of these components. The manual can also be used for the LT1170/LT1171/LT1172 by factoring in
the higher frequency. A CAD design program called SwitcherCAD
TYPICAL APPLICATION
Wide Input Voltage Range: 3V to 60V
Low Quiescent Current: 6mA
Internal 5A Switch
(2.5A for LT1171, 1.25A for LT1172)
Shutdown Mode Draws Only 50μA Supply Current
Very Few External Parts Required
Self-Protected Against Overloads
Operates in Nearly All Switching Topologies
Flyback-Regulated Mode Has Fully Floating Outputs
Comes in Standard 5-Pin Packages
LT1172 Available in 8-Pin MiniDIP and
Surface Mount Packages
Can Be Externally Synchronized
+
Logic Supply 5V at 10A
5V Logic to ±15V Op Amp Supply
Battery Upconverter
Power Inverter (+ to –) or (– to +)
Fully Floating Multiple Outputs
*REQUIRED IF INPUT LEADS 2"
C3*
100μF
GND
Boost Converter (5V to 12V)
LT1170
V
5V
IN
V
50 μ H
C
L1**
V
R3
1k
SW
FB
C1
1μF
** COILTRONICS 50-2-52
PULSE ENGINEERING 92114
MBR330
D1
+
®
100μF
is also available.
10μH
C2
1000μF
L2
High Efficiency Switching Regulators
C3
OUTPUT
FILTER
R1
10.7k
1%
1170/1/2 TA01
R2
1.24k
1%
12V
1A
100kHz, 5A, 2.5A and 1.25A
DESCRIPTION
The LT
switching regulators. They can be operated in all standard
switching configurations including buck, boost, flyback,
forward, inverting and “Cuk.” A high current, high efficiency
switch is included on the die along with all oscillator, con-
trol and protection circuitry. Integration of all functions
allows the LT1170/LT1171/LT1172 to be built in a standard
5-pin TO-3 or TO-220 power package as well as the 8-pin
packages (LT1172). This makes them extremely easy to
use and provides “bust proof” operation similar to that
obtained with 3-pin linear regulators.
The LT1170/LT1171/LT1172 operate with supply voltages
from 3V to 60V, and draw only 6mA quiescent current.
They can deliver load power up to 100W with no exter-
nal power devices. By utilizing current-mode switching
techniques, they provide excellent AC and DC load and
line regulation.
The LT1170/LT1171/LT1172 have many unique features not
found even on the vastly more difficult to use low power
control chips presently available. They use adaptive antisat
switch drive to allow very wide ranging load currents with
no loss in efficiency. An externally activated shutdown
mode reduces total supply current to 50μA typically for
standby operation.
L, LT, LTC, LTM, Linear Technology, the Linear logo and SwitcherCAD are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
100
80
60
40
20
0
0
®
LT1170
1170/LT1171/LT1172 are monolithic high power-
Maximum Output Power*
BOOST
10
LT1170/LT1171/LT1172
INPUT VOLTAGE (V)
20
BUCK-BOOST
FLYBACK
V
O
30
= 5V
BUCK-BOOST
V
O
= 30V
40
50
** DIVIDE VERTICAL POWER SCALE
* ROUGH GUIDE ONLY. BUCK MODE
P
SPECIAL TOPOLOGIES DELIVER
MORE POWER.
BY TWO FOR LT1171, BY FOUR
FOR LT1172.
OUT
= (5A)(V
OUT
)
LT1170/1/2 TA02
117012fg
1

Related parts for LT1171CT

LT1171CT Summary of contents

Page 1

... L, LT, LTC, LTM, Linear Technology, the Linear logo and SwitcherCAD are registered ® is also available. trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Maximum Output Power* 100 L2 ...

Page 2

... PACKAGE 5-LEAD PLASTIC TO-220 =100°C, θ = 2°C/W, θ LT1170CT/LT1170HVCT 75°C/W JMAX JC JA =100°C, θ = 4°C/W, θ LT1171CT/LT1171HVCT 75°C/W JMAX JC JA =100°C, θ = 8°C/W, θ LT1172CT/LT1172HVCT 75°C/W JMAX JC JA Based on continuous operation 125°C for intermittent fault conditions. JMAX ...

Page 3

... LT1172HVIQ#TRPBF LT1172CSW#PBF LT1172CSW#TRPBF LT1170CT#PBF LT1170CQ#TRPBF LT1170IT#PBF LT1170IT#TRPBF LT1170HVCT#PBF LT1170HVCT#TRPBF LT1170HVIT#PBF LT1170HVIT#TRPBF LT1171CT#PBF LT1171CT#TRPBF LT1171IT#PBF LT1171IT#TRPBF LT1171HVCT#PBF LT1171HVCT#TRPBF LT1171HVIT#PBF LT1171HVIT#TRPBF LT1172CT#PBF LT1172CT#TRPBF LT1172HVCT#PBF LT1172HVCT#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. ...

Page 4

LT1170/LT1171/LT1172 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER V Reference Voltage REF I Feedback Input Current B g Error Amplifier Transconductance m Error Amplifier Source or Sink Current Error Amplifier Clamp Voltage Reference Voltage Line Regulation ...

Page 5

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER DC Maximum Switch Duty Cycle MAX Shutdown Mode Supply Current Shutdown Mode Threshold Voltage Flyback Sense Delay Time (Note 5) Note 1: Stresses beyond those listed under Absolute Maximum ...

Page 6

LT1170/LT1171/LT1172 TYPICAL PERFORMANCE CHARACTERISTICS Switch Current Limit vs Duty Cycle 25°C –55°C 8 125° DIVIDE VERTICAL SCALE BY TWO FOR LT1171, BY FOUR FOR LT1172 ...

Page 7

TYPICAL PERFORMANCE CHARACTERISTICS Shutdown Mode Supply Current 200 180 160 140 T = 150°C J 120 100 80 60 –55°C ≤ T ≤ 125° 100 V ...

Page 8

LT1170/LT1171/LT1172 TYPICAL PERFORMANCE CHARACTERISTICS Transconductance of Error Amplifier 7000 6000 5000 4000 g 3000 2000 1000 0 –1000 1k 10k 100k FREQUENCY (Hz) BLOCK DIAGRAM V IN 2.3V REG 100kHz OSC MODE SELECT – FB ERROR AMP + 1.24V REF ...

Page 9

OPERATION The LT1170/LT1171/LT1172 are current mode switchers. This means that switch duty cycle is directly controlled by switch current rather than by output voltage. Referring to the block diagram, the switch is turned “on” at the start of each oscillator ...

Page 10

LT1170/LT1171/LT1172 OPERATION Care should be taken for miniDIP applications to ensure that the worst case input voltage and load current conditions do not cause excessive die temperatures. The following formulas can be used as a rough guide to calculate LT1172 ...

Page 11

OPERATION With t = 0.2μ 150kHz 1.5V, and R3 = 2k, offset voltage shift is ≈ 3.8mV. This is not particularly bother- some, but note that high offsets could result if R3 were ...

Page 12

LT1170/LT1171/LT1172 TYPICAL APPLICATIONS E2 E1 OPTIONAL VN2222 SHUTDOWN D2 ER82.004 600mA SCHOTTKY. OTHER FAST SWITCHING TYPES MAY BE USED AND BATTERY MAY BE TIED TOGETHER. MAXIMUM VALUE FOR V IN BATTERY VOLTAGES, HIGHEST EFFICIENCY IS OBTAINED ...

Page 13

TYPICAL APPLICATIONS Negative-to-Positive Buck-Boost Converter C4* LT1170 100μF OPTIONAL INPUT FILTER V GND –20V * REQUIRED IF INPUT LEADS ≥ 2" PULSE ENGINEERING 92114, COILTRONICS 50-2-52 ** † THIS CIRCUIT IS OFTEN USED TO ...

Page 14

LT1170/LT1171/LT1172 TYPICAL APPLICATIONS † D3 1N4001 470Ω LT1170 1μF V GND INPUT VOLTAGE > < 35V BAT D1 1N5819 2.2 μ F 200 μ F 35V 35V TANTALUM ...

Page 15

TYPICAL APPLICATIONS 2.2μF + C5* 100μF + C4* 470μF L1 50μ –15V * REQUIRED IF INPUT LEADS ≥ 2" Positive Buck Converter * REQUIRED IF INPUT LEADS ≥ 2" ** PULSE ENGINEERING 92114 ...

Page 16

LT1170/LT1171/LT1172 TYPICAL APPLICATIONS V IN 20V TO 30V GND 330μF 35V C6 0.02μF MBR330p MODE LOGIC <0.3V = NORMAL MODE >2.5V = SHUTDOWN OPEN = BURST MODE 16 Forward Converter ...

Page 17

PACKAGE DESCRIPTION CORNER LEADS OPTION .045 – .068 (1.143 – 1.650) FULL LEAD OPTION .300 BSC (7.62 BSC) .008 – .018 (0.203 – 0.457) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS .760 – .775 .320 – ...

Page 18

LT1170/LT1171/LT1172 PACKAGE DESCRIPTION .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) +.035 .325 –.015 ( ) +0.889 8.255 –0.381 NOTE: 1. DIMENSIONS ARE MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR ...

Page 19

PACKAGE DESCRIPTION .060 .256 (1.524) (6.502) .060 .183 (1.524) (4.648) .075 (1.905) .300 (7.620) BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK .067 RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN INCH/(MILLIMETER) 2. DRAWING NOT ...

Page 20

LT1170/LT1171/LT1172 PACKAGE DESCRIPTION .050 BSC .245 MIN .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 (0.254 – 0.508) .008 – .010 (0.203 – 0.254) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT ...

Page 21

PACKAGE DESCRIPTION .030 ±.005 TYP N .420 MIN RECOMMENDED SOLDER PAD LAYOUT .291 – .299 (7.391 – 7.595) NOTE 4 .010 – .029 (0.254 – 0.737) .005 (0.127) RAD MIN .009 – .013 NOTE 3 (0.229 – ...

Page 22

LT1170/LT1171/LT1172 PACKAGE DESCRIPTION .390 – .415 (9.906 – 10.541) .230 – .270 (5.842 – 6.858) .460 – .500 (11.684 – 12.700) .330 – .370 (8.382 – 9.398) .067 BSC .028 – .038 (1.70) (0.711 – 0.965 Package 5-Lead ...

Page 23

... Updated to Reactivate LT1172M from Obsoleted Parts List Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...

Page 24

... Directly Regulates ±V OUT Low 1mA Quiescent Current Synchronizable 25V 1.25A Out from an SO-8 6W Output, ±5% Regulation, No Optocoupler Needed 1.5A Switch, Good for 5V to 3.3V Push-Pull, <100μV Output Noise P-P LT 0410 REV G • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1991 117012fg ...

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