LT1170/LT1171/LT1172
100kHz, 5A, 2.5A and 1.25A
High Efficiency Switching Regulators
Fea T Descrip T
n
Wide Input Voltage Range: 3V to 60V The LT 1170/LT1171/LT1172 are monolithic high power-
n
switching regulators. They can be operated in all standard
Low Quiescent Current: 6mA
n
switching configurations including buck, boost, flyback,
Internal 5A Switch
forward, inverting and Cuk. A high current, high efficiency
(2.5A for LT1171, 1.25A for LT1172)
n
switch is included on the die along with all oscillator, con-
Shutdown Mode Draws Only 50A Supply Current
n
trol and protection circuitry. Integration of all functions
Very Few External Parts Required
n allows the LT1170/LT1171/LT1172 to be built in a standard
Self-Protected Against Overloads
n 5-pin TO-3 or TO-220 power package as well as the 8-pin
Operates in Nearly All Switching Topologies
n packages (LT1172). This makes them extremely easy to
Flyback-Regulated Mode Has Fully Floating Outputs
n use and provides bust proof operation similar to that
Comes in Standard 5-Pin Packages
n obtained with 3-pin linear regulators.
LT1172 Available in 8-Pin MiniDIP and
Surface Mount Packages
The LT1170/LT1171/LT1172 operate with supply voltages
n
Can Be Externally Synchronized
from 3V to 60V, and draw only 6mA quiescent current.
They can deliver load power up to 100W with no exter-
a T
nal power devices. By utilizing current-mode switching
n
techniques, they provide excellent AC and DC load and
Logic Supply 5V at 10A
n line regulation.
5V Logic to 15V Op Amp Supply
n
Battery Upconverter
The LT1170/LT1171/LT1172 have many unique features not
n
Power Inverter (+ to ) or ( to +)
found even on the vastly more difficult to use low power
n
Fully Floating Multiple Outputs
control chips presently available. They use adaptive antisat
USER NOTE:
switch drive to allow very wide ranging load currents with
This data sheet is only intended to provide specifications, graphs, and a general functional
no loss in efficiency. An externally activated shutdown
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
mode reduces total supply current to 50A typically for
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
standby operation.
of these components. The manual can also be used for the LT1170/LT1171/LT1172 by factoring in
L, LT, LTC, LTM, Linear Technology, the Linear logo are registered trademarks of Linear
the higher frequency. A CAD design program called SwitcherCAD is also available.
Technology Corporation. All other trademarks are the property of their respective owners.
Typical a T
Boost Converter (5V to 12V) Maximum Output Power*
100
* ROUGH GUIDE ONLY. BUCK MODE
L1**
5V L2
OUTPUT
LT1170 P = (5A)(V )
50H
OUT OUT
10H
FILTER
SPECIAL TOPOLOGIES DELIVER
80
MORE POWER.
C3
** DIVIDE VERTICAL POWER SCALE
100F
D1 BUCK-BOOST BY TWO FOR LT1171, BY FOUR
V MBR330 V = 30V FOR LT1172.
IN O
60
12V
V BOOST
SW
LT1170/1/2 TA02
1A
FLYBACK
+
R1
C2
LT1170 10.7k 40
+ 1000F
1%
C3*
100F
FB
20
V
GND C
BUCK-BOOST
R2
R3 V = 5V
1.24k O
1k
1%
0
C1 0 10 20 30 40 50
1F
INPUT VOLTAGE (V)
*REQUIRED IF INPUT LEADS 2" ** COILTRONICS 50-2-52
1170/1/2 TA01
PULSE ENGINEERING 92114
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For more information www.linear.com/LT1170
POWER (W) **
ion pplica
ions pplica
ion uresLT1170/LT1171/LT1172
(Note 1)
a Te Maxi Mu M r a T
Supply Voltage Operating Junction Temperature Range
LT1170/LT1171/LT1172HV (Note 2) .......................60V LT1170M/LT1171M (OBSOLETE) ....... 55C to 150C
LT1170/LT1171/LT1172 (Note 2) ............................40V LT1172M (OBSOLETE) ....................... 55C to 125C
Switch Output Voltage LT1170/LT1171/LT1172HVC,
LT1170/LT1171/LT1172HV .....................................75V LT1170/LT1171/LT1172C (Oper.) ............. 0C to 100C
LT1170/LT1171/LT1172 .........................................65V LT1170/LT1171/LT1172HVC
LT1172S8 ..............................................................60V LT1170/LT1171/LT1172C (Sh. Ckt.) ........ 0C to 125C
Feedback Pin Voltage (Transient, 1ms) ................... 15V LT1170/LT1171/LT1172HVI,
Storage Temperature Range .................. 65C to 150C LT1170/LT1171/LT1172I (Oper.) .......... 40C to 100C
Lead Temperature (Soldering, 10 sec ....................300C LT1170/LT1171/LT1172HVI,
LT1170/LT1171/LT1172I (Sh. Ckt.) ...... 40C to 125C
p in c F T
BOTTOM VIEW
V V TOP VIEW
TOP VIEW SW C
1
GND 1 8 E2
GND 1 8 E2 2
CASE
3 IS GND
4
V 2 7 V
V 2 7 V C SW
C SW
FB 3 E1
FB 3 E1 V 6
6 IN FB
K PACKAGE NC* 4 5 V
NC* 4 5 V IN
IN
4-LEAD TO-3 METAL CAN
LT1170MK: T = 150C, = 2C/W, = 35C/W N8 PACKAGE S8 PACKAGE
J8 PACKAGE
JMAX JC JA
LT1170CK: T = 100C, = 2C/W, = 35C/W 8-LEAD PDIP 8-LEAD PLASTIC SO
8-LEAD CERDIP
JMAX JC JA
LT1171MK: T = 150C, = 4C/W, = 35C/W
JMAX JC JA
T = 100C, = 100C/W (N)
T = 125C, = 100C/W JMAX JA
JMAX JA
LT1171CK: T = 100C, = 4C/W, = 35C/W
JMAX JC JA
T = 100C, = 120C/W to 150C/W
JMAX JA
LT1172MK: T = 150C, = 8C/W, = 35C/W
JMAX JC JA
depending on board layout (S)
* Do not connect Pin 4 of the LT1172 DIP or SO to external
LT1172CK: T = 100C, = 8C/W, = 35C/W
JMAX JC JA
circuitry. This pin may be active in future revisions.
Based on continuous operation.
* Do not connect Pin 4 of the LT1172 DIP or SO to external
T = 125C for intermittent fault conditions.
JMAX
OBSOLETE
circuitry. This pin may be active in future revisions.
OBSOLETE
TOP VIEW
TAB IS
NC 1 16 NC
FRONT VIEW
FRONT VIEW
GND
NC 2 15 NC
5 V
IN
5 V
IN
4 V
SW GND 3 14 E2
TAB IS 4 V
SW
3 GND
GND
V 4 13 V
C SW
3 GND
2 FB
1 V FB 5 12 E1
C 2 FB
NC 6 11 V 1
V
Q PACKAGE IN C
5-LEAD DD
NC 7 10 NC
T PACKAGE
T = 100C, = *C/W
JMAX JA 5-LEAD PLASTIC TO-220
NC 8 9 NC
LT1170CT/LT1170HVCT: T =100C, = 2C/W, = 75C/W
JMAX JC JA
* will vary from approximately 25C/W with 2.8 sq.
LT1171CT/LT1171HVCT: T =100C, = 4C/W, = 75C/W
SW PACKAGE JMAX JC JA
in. of 1oz. copper to 45C/W with 0.20 sq. in. of 1oz.
LT1172CT/LT1172HVCT: T =100C, = 8C/W, = 75C/W
16-LEAD PLASTIC SO WIDE JMAX JC JA
copper. Somewhat lower values can be obtained with
Based on continuous operation.
additional copper layers in multilayer boards.
T = 100C, = 150C/W
JMAX JA
T = 125C for intermittent fault conditions.
JMAX
Based on continuous operation.
T = 125C for intermittent fault conditions.
JMAX
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For more information www.linear.com/LT1170
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