Feedback Pin Voltage (Transient, 1ms) ................... ±15V
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec .................... 300°C
(Note 1)
Operating Junction Temperature Range
LT1170M/LT1171M
(OBSOLETE)
....... –55°C to 150°C
LT1172M ............................................ –55°C to 125°C
LT1170/LT1171/LT1172HVC,
LT1170/LT1171/LT1172C (Oper.)............. 0°C to 100°C
LT1170/LT1171/LT1172HVC
LT1170/LT1171/LT1172C (Sh. Ckt.) ........ 0°C to 125°C
LT1170/LT1171/LT1172HVI,
LT1170/LT1171/LT1172I (Oper.) .......... –40°C to 100°C
LT1170/LT1171/LT1172HVI,
LT1170/LT1171/LT1172I (Sh. Ckt.)...... –40°C to 125°C
pin conFiguraTion
BOTTOM VIEW
TOP VIEW
GND 1
V
C
2
FB 3
NC* 4
J8 PACKAGE
8-LEAD CERDIP
T
JMAX
= 125°C,
θ
JA
= 100°C/W
* Do not connect Pin 4 of the LT1172 DIP or SO to external
circuitry. This pin may be active in future revisions.
8
7
6
5
E2
V
SW
E1
V
IN
V
IN
K PACKAGE
4-LEAD TO-3 METAL CAN
LT1170MK: T
JMAX
= 150°C,
θ
JC
= 2°C/W,
θ
JA
= 35°C/W
LT1170CK: T
JMAX
= 100°C,
θ
JC
= 2°C/W,
θ
JA
= 35°C/W
LT1171MK: T
JMAX
= 150°C,
θ
JC
= 4°C/W,
θ
JA
= 35°C/W
LT1171CK: T
JMAX
= 100°C,
θ
JC
= 4°C/W,
θ
JA
= 35°C/W
LT1172MK: T
JMAX
= 150°C,
θ
JC
= 8°C/W,
θ
JA
= 35°C/W
LT1172CK: T
JMAX
= 100°C,
θ
JC
= 8°C/W,
θ
JA
= 35°C/W
Based on continuous operation.
T
JMAX
= 125°C for intermittent fault conditions.
V
SW
1
4
2
3
V
C
CASE
IS GND
FB
GND 1
V
C
2
FB 3
NC* 4
N8 PACKAGE
8-LEAD PDIP
TOP VIEW
8
7
6
5
E2
V
SW
E1
V
IN
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 100°C,
θ
JA
= 100°C/W (N)
T
JMAX
= 100°C,
θ
JA
= 120°C/W to 150°C/W
depending on board layout (S)
* Do not connect Pin 4 of the LT1172 DIP or SO to external
circuitry. This pin may be active in future revisions.
OBSOLETE
TOP VIEW
FRONT VIEW
5
4
3
2
1
Q PACKAGE
5-LEAD DD
T
JMAX
= 100°C,
θ
JA
= *°C/W
*
θ
will vary from approximately 25°C/W with 2.8 sq.
in. of 1oz. copper to 45°C/W with 0.20 sq. in. of 1oz.
copper. Somewhat lower values can be obtained with
additional copper layers in multilayer boards.
V
IN
V
SW
GND
FB
V
C
NC 1
NC 2
GND 3
V
C
4
FB 5
NC 6
NC 7
NC 8
16 NC
15 NC
14 E2
13 V
SW
12 E1
11 V
IN
10 NC
9
NC
FRONT VIEW
5
4
3
2
1
T PACKAGE
5-LEAD PLASTIC TO-220
LT1170CT/LT1170HVCT: T
JMAX
=100°C,
θ
JC
= 2°C/W,
θ
JA
= 75°C/W
LT1171CT/LT1171HVCT: T
JMAX
=100°C,
θ
JC
= 4°C/W,
θ
JA
= 75°C/W
LT1172CT/LT1172HVCT: T
JMAX
=100°C,
θ
JC
= 8°C/W,
θ
JA
= 75°C/W
Based on continuous operation.
T
JMAX
= 125°C for intermittent fault conditions.
V
IN
V
SW
GND
FB
V
C
SW PACKAGE
16-LEAD PLASTIC SO WIDE
T
JMAX
= 100°C,
θ
JA
= 150°C/W
Based on continuous operation.
T
JMAX
= 125°C for intermittent fault conditions.
117012fh
2
For more information
www.linear.com/LT1170
LT1170/LT1171/LT1172
orDer inForMaTion
LEAD FREE FINISH
LT1172MJ8
LT1172CJ8#PBF
(OBSOLETE)
LT1170MK#PBF
(OBSOLETE)
LT1170CK#PBF
(OBSOLETE)
LT1171MK#PBF
(OBSOLETE)
LT1171CK#PBF
(OBSOLETE)
LT1172MK#PBF
(OBSOLETE)
LT1172CK#PBF
(OBSOLETE)
LT1172CN8#PBF
LT1172IN8#PBF
LT1172CS8#PBF
LT1172IS8#PBF
LT1170CQ#PBF
LT1170IQ#PBF
LT1170HVCQ#PBF
LT1171CQ#PBF
LT1171IQ#PBF
LT1171HVCQ#PBF
LT1171HVIQ#PBF
LT1172CQ#PBF
LT1172HVCQ#PBF
LT1172HVIQ#PBF
LT1172CSW#PBF
LT1170CT#PBF
LT1170IT#PBF
LT1170HVCT#PBF
LT1170HVIT#PBF
LT1171CT#PBF
LT1171IT#PBF
LT1171HVCT#PBF
LT1171HVIT#PBF
LT1172CT#PBF
LT1172HVCT#PBF
http://www.linear.com/product/LT1170#orderinfo
PART MARKING*
LT1172
PACKAGE DESCRIPTION
8-Lead CERDIP
8-Lead CERDIP
4-Lead TO-3 Metal Can
4-Lead TO-3 Metal Can
4-Lead TO-3 Metal Can
4-Lead TO-3 Metal Can
4-Lead TO-3 Metal Can
4-Lead TO-3 Metal Can
LT1172
LT1172
1172
1172I
LT1170
LT1170
LT1170HV
LT1171
LT1171
LT1171HV
LT1171HV
LT1172
LT1172HV
LT1172HV
LT1172CSW
LT1170
LT1170
LT1170HV
LT1170
LT1171
LT1171
LT1171HV
LT1171HV
LT1172
LT1172HV
8-Lead PDIP or 8-Lead Plastic SO
8-Lead PDIP or 8-Lead Plastic SO
8-Lead PDIP or 8-Lead Plastic SO
8-Lead PDIP or 8-Lead Plastic SO
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
5-Lead DD
16-Lead Plastic SO Wide
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
5-Lead Plastic TO-220
TEMPERATURE RANGE
–55°C to 125°C
0°C to 100°C
–55°C to 125°C
0°C to 100°C
–55°C to 125°C
0°C to 100°C
–55°C to 125°C
0°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
–40°C to 100°C
0°C to 100°C
0°C to 100°C
TAPE AND REEL
LT1172MJ8#TR
LT1172CJ8#TRPBF
LT1170MK#TRPBF
LT1170CK#TRPBF
LT1171MK#TRPBF
LT1171CK#TRPBF
LT1172MK#TRPBF
LT1172CK#TRPBF
LT1172CN8#TRPBF
LT1172IN8#TRPBF
LT1172CS8#TRPBF
LT1172IS8#TRPBF
LT1170CQ#TRPBF
LT1170IQ#TRPBF
LT1170HVCQ#TRPBF
LT1171CQ#TRPBF
LT1171IQ#TRPBF
LT1171HVCQ#TRPBF
LT1171HVIQ#TRPBF
LT1172CQ#TRPBF
LT1172HVCQ#TRPBF
LT1172HVIQ#TRPBF
LT1172CSW#TRPBF
LT1170CQ#TRPBF
LT1170IT#TRPBF
LT1170HVCT#TRPBF
LT1170HVIT#TRPBF
LT1171CT#TRPBF
LT1171IT#TRPBF
LT1171HVCT#TRPBF
LT1171HVIT#TRPBF
LT1172CT#TRPBF
LT1172HVCT#TRPBF
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
117012fh
For more information
www.linear.com/LT1170
3
LT1170/LT1171/LT1172
elecTrical characTerisTics
SYMBOL PARAMETER
V
REF
I
B
g
m
Reference Voltage
Feedback Input Current
Error Amplifier Transconductance
Error Amplifier Source or Sink Current
Error Amplifier Clamp Voltage
Reference Voltage Line Regulation
A
V
I
Q
Error Amplifier Voltage Gain
Minimum Input Voltage (Note 5)
Supply Current
Control Pin Threshold
Normal/Flyback Threshold on Feedback Pin
V
FB
Flyback Reference Voltage (Note 5)
Change in Flyback Reference Voltage
Flyback Reference Voltage Line Regulation
(Note 5)
Flyback Amplifier Transconductance (g
m
)
Flyback Amplifier Source and Sink Current
BV
Output Switch Breakdown Voltage
I
FB
= 50µA
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
C
= 0.5V, V
FB
= V
REF
, output pin open, unless otherwise noted.
CONDITIONS
Measured at Feedback Pin
V
C
= 0.8V
V
FB
= V
REF
l
l
MIN
1.224
1.214
TYP
1.244
1.244
350
MAX
1.264
1.274
750
1100
6000
7000
350
400
2.30
0.52
0.03
UNITS
V
V
nA
nA
µmho
µmho
µA
µA
V
V
%/V
V/V
∆I
C
= ±25µA
l
3000
2400
150
120
1.80
0.25
4400
200
V
C
= 1.5V
l
Hi Clamp, V
FB
= 1V
Lo Clamp, V
FB
= 1.5V
3V ≤ V
IN
≤ V
MAX
V
C
= 0.8V
0.9V ≤ V
C
≤ 1.4V
l
l
0.38
500
800
2.6
6
3.0
9
1.08
1.25
0.54
17.6
18.0
9
0.03
650
70
70
V
mA
V
V
V
V
V
V
%/V
µmho
mA
mA
V
V
V
3V ≤ V
IN
≤ V
MAX
, V
C
= 0.6V
Duty Cycle = 0
l
0.8
0.6
0.4
15.0
14.0
4.5
0.9
0.45
16.3
6.8
0.01
0.05 ≤ I
FB
≤ 1mA
I
FB
= 50µA
7V ≤ V
IN
≤ V
MAX
∆I
C
= ±10µA
V
C
= 0.6V
I
FB
= 50µA
3V ≤ V
IN
≤ V
MAX
,
I
SW
= 1.5mA
LT1170
LT1171
LT1172
LT1170
LT1171
LT1172
Duty Cycle = 50%
Duty Cycle = 50%
Duty Cycle = 80% (Note 4)
Duty Cycle = 50%
Duty Cycle = 50%
Duty Cycle = 80% (Note 4)
Duty Cycle = 50%
Duty Cycle = 50%
Duty Cycle = 80% (Note 4)
T
J
≥ 25°C
T
J
< 25°C
T
J
≥ 25°C
T
J
< 25°C
T
J
≥ 25°C
T
J
< 25°C
l
l
l
l
l
l
l
l
l
150
Source
Sink
LT1170/LT1171/LT1172
LT1170HV/LT1171HV/LT1172HV
LT1172S8
l
l
l
l
l
l
l
l
300
32
40
90
90
80
0.15
0.30
0.60
8
4
2
15
25
65
75
60
V
SAT
Output Switch “On” Resistance (Note 3)
0.24
0.50
1.00
Ω
Ω
Ω
A/V
A/V
A/V
Control Voltage to Switch Current
Transconductance
I
LIM
Switch Current Limit (LT1170)
5
5
4
2.5
2.5
2.0
1.25
1.25
1.00
25
88
85
100
10
11
10
5.0
5.5
5.0
3.0
3.5
2.5
35
112
115
A
A
A
A
A
A
A
A
A
mA/A
kHz
kHz
117012fh
(LT1171)
(LT1172)
∆I
IN
∆I
SW
f
Supply Current Increase During Switch
On-Time
Switching Frequency
l
4
For more information
www.linear.com/LT1170
LT1170/LT1171/LT1172
elecTrical characTerisTics
SYMBOL PARAMETER
DC
MAX
Maximum Switch Duty Cycle
Shutdown Mode
Supply Current
Shutdown Mode
Threshold Voltage
Flyback Sense Delay Time (Note 5)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Minimum effective switch “on” time for the LT1170/LT1171/
LT1172 (in current limit only) is ≈ 0.6µs. This limits the maximum safe
input voltage during an output shorted condition. Buck mode and inverting
mode input voltage during an output shorted condition is limited to:
3V ≤ V
IN
≤ V
MAX
V
C
= 0.05V
3V ≤ V
IN
≤ V
MAX
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
C
= 0.5V, V
FB
= V
REF
, output pin open, unless otherwise noted.
CONDITIONS
l
MIN
85
TYP
92
100
MAX
97
250
250
300
UNITS
%
µA
mV
mV
µs
100
50
150
1.5
(
R
)
I
L
+
Vf
V
IN
(max, output shorted) =
15V
+
(
t
)
(
f
)
buck and inverting mode
R = Inductor DC resistance
I
L
= 10A for LT1170, 5A for LT1171, and 2.5A for LT1172
Vf = Output catch diode forward voltage at I
L
t = 0.6µs, f = 100kHz switching frequency
Maximum input voltage can be increased by increasing R or Vf.
External current limiting such as that shown in AN19, Figure 39, will
provide protection up to the full supply voltage rating. C1 in Figure 39
should be reduced to 200pF
.
(
)
Transformer designs will tolerate much higher input voltages because
leakage inductance limits rate of rise of current in the switch. These
designs must be evaluated individually to assure that current limit is well
controlled up to maximum input voltage.
Boost mode designs are never protected against output shorts because
the external catch diode and inductor connect input to output.
Note 3:
Measured with V
C
in hi clamp, V
FB
= 0.8V. I
SW
= 4A for LT1170,
2A for LT1171, and 1A for LT1172.
Note 4:
For duty cycles (DC) between 50% and 80%, minimum guaranteed
switch current is given by I
LIM
= 3.33 (2 – DC) for the LT1170, I
LIM
= 1.67
(2 – DC) for the LT1171, and I
LIM
= 0.833 (2 – DC) for the LT1172.
Note 5:
Minimum input voltage for isolated flyback mode is 7V. V
MAX
= 55V
for HV grade in fully isolated mode to avoid switch breakdown.
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