Datasheet

LT3748
3
3748fb
For more information www.linear.com/LT3748
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: The LT3748E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design
characterization and correlation with statistical process controls. The
LT3748I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3748H is guaranteed over the full –40°C to
150°C operating junction temperature range. The LT3748MP is guaranteed
over the full –55°C to 150°C operating junction temperature range. High
junction temperatures degrade operating lifetimes. Operating lifetime is
derated at junction temperatures greater than 125°C.
Note 3: Current flows out of the pin.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum SENSE Current Limit Threshold V
C
= 2.2V
l
95
90
100
100
105
110
mV
mV
Minimum SENSE Current Limit Threshold
V
C
= 0V 15 mV
Maximum to Minimum SENSE Threshold
Ratio
l
5.2 6.6 8.2 mV/mV
SENSE Overcurrent Threshold V
C
= 2.2V 115 130 145 mV
SENSE Input Bias Current V
SENSE
= 10mV (Note 3) 10 15 20 µA
R
REF
Voltage V
C
= 1.1V
l
1.20
1.195
1.223 1.24
1.245
V
V
R
REF
Voltage Line Regulation 5V < V
IN
< 100V 0.005 0.025 %/V
R
REF
Pin Bias Current (Note 3)
l
35 500 nA
TC Current into R
REF
R
TC
= 20k 27.5 µA
Error Amplifier Voltage Gain 115 V/V
Error Amplifier Transconductance
∆I = 10µA
155 µmhos
V
C
Source Current V
C
= 1.1V, V
RREF
= 0.5V –45 µA
V
C
Sink Current V
C
= 1.1V, V
RREF
= 2V 48 µA
Flyback Comparator Trip Current Current into R
FB
Pin, R
REF
= 6.04k 10 µA
Minimum GATE Off-Time 700 ns
Minimum GATE On-Time 250 ns
Maximum Discontinuous Off-Time V
C
= 0V 24 µs
Maximum GATE Off-Time V
RREF
= 0.5V 55 µs
Maximum GATE On-Time V
SENSE
= 0V 55 µs
GATE Output Rise Time C
L
= 3300pF, 10% to 90% 16 ns
GATE Output Fall Time C
L
= 3300pF, 10% to 90% 16 ns
GATE Output Low (V
OL
) 0.05 V
GATE Output High (V
OH
) V
INTVCC
– 0.05 V
electrical characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 10V, unless otherwise noted.
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