Datasheet

2
LT1372/LT1377
(Note 1)
Supply Voltage ....................................................... 30V
Switch Voltage
LT1372/LT1377 .................................................. 35V
LT1372HV .......................................................... 42V
S/S Pin Voltage....................................................... 30V
Feedback Pin Voltage (Transient, 10ms) .............. ±10V
Feedback Pin Current........................................... 10mA
Negative Feedback Pin Voltage
(Transient, 10ms)............................................. ±10V
Operating Junction Temperature Range
Commercial ........................................ 0°C to 125°C*
Industrial ......................................... 40°C to 125°C
Short Circuit ......................................... 0°C to 150°C
Storage Temperature Range ................ 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART NUMBER
LT1372CN8
LT1372HVCN8
LT1372CS8
LT1372HVCS8
LT1372IN8
LT1372HVIN8
LT1372IS8
LT1372HVIS8
LT1377CS8
LT1377IS8
1
2
3
4
8
7
6
5
TOP VIEW
V
C
FB
NFB
S/S
V
SW
GND
GND S
V
IN
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C, θ
JA
= 100°C/ W (N8)
T
JMAX
= 125°C, θ
JA
= 120°C/ W (S8)
S8 PART MARKING
1372
1372I
1377
1377I
1372H
1372HI
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
REF
Reference Voltage Measured at Feedback Pin 1.230 1.245 1.260 V
V
C
= 0.8V 1.225 1.245 1.265 V
I
FB
Feedback Input Current V
FB
= V
REF
250 550 nA
900 nA
Reference Voltage Line Regulation 2.7V V
IN
25V, V
C
= 0.8V 0.01 0.03 %/V
V
NFB
Negative Feedback Reference Voltage Measured at Negative Feedback Pin 2.540 2.490 2.440 V
Feedback Pin Open, V
C
= 0.8V 2.570 2.490 2.410 V
I
NFB
Negative Feedback Input Current V
NFB
= V
NFR
–45 –30 15 µA
Negative Feedback Reference Voltage 2.7V V
IN
25V, V
C
= 0.8V 0.01 0.05 %/V
Line Regulation
g
m
Error Amplifier Transconductance I
C
= ±25µA 1100 1500 1900 µmho
700 2300 µmho
Error Amplifier Source Current V
FB
= V
REF
– 150mV, V
C
= 1.5V 120 200 350 µA
Error Amplifier Sink Current V
FB
= V
REF
+ 150mV, V
C
= 1.5V 1400 2400 µA
Error Amplifier Clamp Voltage High Clamp, V
FB
= 1V 1.70 1.95 2.30 V
Low Clamp, V
FB
= 1.5V 0.25 0.40 0.52 V
A
V
Error Amplifier Voltage Gain 500 V/V
V
C
Pin Threshold Duty Cycle = 0% 0.8 1 1.25 V
f Switching Frequency 2.7V V
IN
25V
LT1372 450 500 550 kHz
0°C T
J
125°C 430 500 580 kHz
40°C T
J
< 0°C (I Grade) 400 580 kHz
LT1377 0.90 1 1.10 MHz
0°C T
J
125°C 0.86 1 1.16 MHz
40°C T
J
< 0°C (I Grade) 0.80 1.16 MHz
The denotes specifcatons which appy over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
IN
= 5V, V
C
= 0.6V, V
FB
= V
REF
, V
SW
, S/S and NFB pins open, unless otherwise noted.
Consult factory for parts specified with wider operating temperature ranges.
*Units shipped prior to Date Code 9552 are rated at 100°C maximum
operating temperature.
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ELECTRICAL CHARACTERISTICS