Datasheet

LT3598
3
3598fb
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 5V, V
SHDN
= V
IN
unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage 3 3.2 V
Maximum Operating Voltage 30 V
Reference Voltage
l
1.216
1.210
1.230 1.260
1.260
V
V
Reference Voltage Line Regulation 3.2V < V
IN
< 30V, V
C
= 0.3V 0.01 0.03 %/V
Maximum V
REF
Pin Current Out of Pin 200 μA
FB Pin Bias Current V
FB
= 1.230V (Note 3) 100 250 nA
FB Error Amp Transconductance ΔI = 5μA 300 μmhos
FB Error Amp Voltage Gain 600 V/V
FB Pin Voltage 1.22 1.24 1.26 V
Current Loop Amp Transconductance 21 μmhos
Current Loop Amp Voltage Gain 80 V/V
V
C
Sink Current 10 μA
Quiescent Current V
SHDN
= 5V, PWM = 0V, Not Switching 3.5 5 mA
Quiescent Current in Shutdown V
SHDN
= 0V 0 1 μA
I
SET
Voltage V
CTRL
= 1.5V, V
TSET
= 1.5V, R
ISET
= 14.7kΩ 0.985 1.000 1.015 V
LED Current R
ISET
= 14.7kΩ 19.5 20 20.7 mA
LED String Current Matching 20mA LED Current
l
±0.5 ±1.5 %
LED Open Detection Threshold 0.2 0.25 V
OPENLED Sink Current 2mA
Minimum LED Regulation Voltage 0.8 V
LED1-6 Leakage Current V
LED1-6
= 1V, V
OUT
= 5V, PWM = 0V
V
LED1-6
= 42V, V
OUT
= 44V, PWM = 0V
0.1
0.2
1
2
μA
μA
CTRL Pin Bias Current V
CTRL
= 0.8V (Note 4) 50 125 nA
Switching Frequency RT = 309kΩ
RT = 51.1kΩ
RT = 14.7kΩ
171
0.9
2.25
190
1
2.5
209
1.1
2.75
kHz
MHz
MHz
T
SET
Voltage 602 mV
Maximum Switch Duty Cycle RT = 309kΩ
RT = 51.1kΩ
RT = 14.7kΩ
l
90
87
80
95
90
86
%
%
%
Switch Current Limit (Note 5) 1.5 2 2.5 A
Switch V
CESAT
I
SW
= 0.5A 0.12 V
Switch Leakage Current V
SW
= 40V 0.2 5 μA