LT3474/LT3474-1
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VBOOST = 16V, VOUT = 4V unless otherwise noted (Note 3).
PARAMETER
CONDITIONS
5V < V < 36V
MIN
TYP
0.01
0.0002
20
MAX
UNITS
%/V
Reference Voltage Line Regulation
Reference Voltage Load Regulation
IN
0 < I
< 250μA
%/μA
nA
REF
l
V
ADJ
Pin Bias Current (Note 4)
400
Switching Frequency
R = 80.6k
470
450
500
530
540
kHz
kHz
T
l
l
Maximum Duty Cycle
R = 80.6k
90
95
76
98
%
%
%
T
R = 10k
T
R = 232k
T
Foldback Frequency
R = 80.6k, V
= 0V
OUT
70
2.65
10.3
0.9
0.8
100
100
1.5
1
kHz
V
T
SHDN Threshold (to Switch)
SHDN Pin Current (Note 5)
PWM Threshold
2.6
8.3
0.4
2.7
12.3
1.2
V
= SHDN Threshold
μA
SHDN
V
V Switching Threshold
C
V
V Source Current
C
V = 1V
C
μA
V Sink Current
C
V = 1V
C
μA
LED to V Current Gain
μA/mA
V/mA
A/V
V
C
LED to V Transresistance
C
V to Switch Current Gain
C
2
V Clamp Voltage
C
1.9
0.01
13.8
0.1
l
V Pin Current in PWM Mode
C
V = 1V, V = 0.3V
C PWM
1
μA
OUT Pin Clamp Voltage (LT3474)
OUT Pin Current in PWM Mode
Switch Current Limit (Note 6)
13.2
14.5
10
V
l
l
V
= 4V, V
= 0.3V
PWM
μA
OUT
–40°C to 85°C
LT3474I, LT3474I-1 at 125°C
1.6
1.5
2.1
3.2
3.2
A
A
Switch V
I
I
= 1A
= 1A
380
30
500
50
1
mV
mA
μA
V
CESAT
SW
SW
Boost Pin Current
Switch Leakage Current
Minimum Boost Voltage (Note 7)
Boost Diode Forward Voltage
0.01
1.9
2.5
I
= 100mA
600
mV
DIO
operating temperature range are assured by design, characterization and
correlation with statistical process controls. The LT3474I and LT3474I-1
are guaranteed to meet performance specifications over the –40°C to
125°C operating temperature range.
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 4: Current flows out of pin.
Note 5: Current flows into pin.
Note 6: Current limit is guaranteed by design and/or correlation to static
test. Slope compensation reduces current limit at higher duty cycles.
Note 7: This is the minimum voltage across the boost capacitor needed to
Note 2: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 3: The LT3474E and LT3474E-1 are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
guarantee full saturation of the internal power switch.
3474fd
3
Linear [ Linear ]
