Datasheet
LT3477
3
3477fc
ELECTRICAL CHARACTERISTICS
The ● indicates specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 2.5V, V
SHDN
= 2.5V.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Maximum V
REF
Pin Current Out of Pin 100 μA
Soft-Start Pin Current SS = 0.5V, Out of Pin 9 μA
FBP Pin Bias Current 25 100 nA
FBN Pin Bias Current 25 100 nA
Feedback Amplifi er Offset Voltage FBP – FBN, V
C
= 1V –2 2 6 mV
Feedback Amplifi er Voltage Gain 500 V/V
Voltage Feedback Amplifi er Transconductance 500 μS
Feedback Amplifi er Sink Current V
FBP
= 1.25V, V
FBN
= 1.5V, V
C
= 1V 10 μA
Feedback Amplifi er Source Current V
FBP
= 1.25V, V
FBN
= 1V, V
C
= 0.5V 10 μA
Current Sense Amplifi er Sense Voltage Positive Rail, V
CM
= 25V, E Grade
Positive Rail, V
CM
= 25V, I Grade
Ground
●
●
97.5
97.5
88
100
100
100
102.5
103
112
mV
mV
mV
Switching Frequency R
T
= 17.2k
R
T
= 107.4k
R
T
= 2.44k
0.9
160
2.7
1
200
3.5
1.15
240
4.3
MHz
kHz
MHz
Maximum Switch Duty Cycle R
T
= 17.2k
●
87 93 %
Switch Current Limit (Note 3) 3 4 5 A
Switch V
CESAT
I
SW
= 1A (Note 3) 150 200 mV
Switch Leakage Current SW = 40V 0.2 5 μA
SHDN Pin Current V
SHDN
= 5V
V
SHDN
= 0V
30
0.1
60
1
μA
μA
SHDN Pin Threshold 0.3 1.5 2 V
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 LT3477E is guaranteed to meet performance specifi cations
from 0°C to 70°C. Specifi cations over the – 40°C to 85°C operating
junction temperature range are assured by design, characterization and
correlation with statistical process controls. The LT3477I is guaranteed
over the full –40°C to 125°C operating junction temperature range.
Note 3: Switch current limit and switch V
CESAT
for UF package guaranteed
by design and/or correlation to static test.
TYPICAL PERFORMANCE CHARACTERISTICS
Switch V
CE(SAT)
Switch Current Limit
V
REF
SWITCH CURRENT (A)
0
0
V
CE(SAT)
(V)
0.10
0.20
0.30
0.25
0.5
1
1.5 2
3477 G01
2.5
0.40
0.50
0.05
0.15
125°C
–50°C
0.35
0.45
3
25°C
TEMPERATURE (°C)
–50 –25
0
CURRENT (A)
2
5
0
50
75
3477 G02
1
4
3
25
100
125
TEMPERATURE (°C)
–50
1.21
V
REF
(V)
1.22
1.23
1.24
1.25
050
100
150
3477 G03
1.26
1.27
–25 25
75
125
V
IN
= 25V
V
IN
= 2.5V