Datasheet

LT3599
3
3599fe
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
= 5V, unless otherwise noted. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Operating Voltage
l
2.7 3.1 V
Maximum Operating Voltage
l
30 V
Reference Voltage V
REF
I(V
REF
) = 0μA
l
1.21
1.20
1.227 1.24
1.25
V
V
Reference Voltage Line Regulation I(V
REF
) = 0μA, 3.1V < V
IN
< 30V 0.01 0.03 %/V
Maximum V
REF
Pin Current (Note 3) 100 μA
V
REF
Load Regulation 0 < I(V
REF
) ≤ 100μA (Max) 1 mV
Feedback Voltage
l
1.196 1.223 1.250 V
FB Pin Bias Current (Note 3) 100 250 nA
FB Error Amp Transconductance
ΔI = 5μA
200 μmhos
FB Error Amp Voltage Gain 210 V/V
Current Loop Amp Transconductance 50 μmhos
Current Loop Amp Voltage Gain 50 V/V
V
C
Source Current (Out of Pin) LED1-4 = 0.4V, FB = 1V, V
C
= 1.5V 8 μA
V
C
Sink Current (OVP Mode) LED1-4 = 0.4V, FB = 1.5V, V
C
= 1.5V 15 μA
Quiescent Current V
SHDN
= 5V, PWM = 0V, Not Switching, V
C
= 0.7V 3 4.8 mA
Quiescent Current in Shutdown V
SHDN
= 0V 0 1 μA
LED Current R
ISET
= 13.3k 96 99 102 mA
LED String Current Matching 100mA LED Current
l
±0.25 ±1.5 %
LED Open Detection Threshold (V
LED
–GND) FB > 1.25V 0.3 0.4 V
LED Short Detection Threshold (V
OUT
–V
LED
) 0.8 1.5 2.2 V
LED Regulation Voltage 0.77 V
LED1-4 Leakage Current V
LED1-4
= 45V 0.1 1 μA
CTRL Pin Bias Current V
CTRL
= 0.8V (Note 3) 100 200 nA
Switching Frequency R
T
= 324k
R
T
= 53.6k
R
T
= 20k
176
0.9
1.82
198
1
2.06
220
1.1
2.3
kHz
MHz
MHz
T
SET
Voltage 595 mV
Maximum Switch Duty Cycle R
T
= 324k
R
T
= 53.6k
R
T
= 20k
l
l
l
97.7
88.5
77
98.6
93
86
%
%
%
Switch Current Limit (Note 4) 2 2.5 3 A
Switch V
CESAT
I
SW
= 0.5A 0.10 V
Switch Leakage Current V
SW
= 45V, FB = 1.3V 0.2 5 μA
SHDN/UVLO Pin Threshold (V
SD_SHDN
) Shutdown 0.3 0.7 0.95 V
SHDN/UVLO Pin Threshold (V
SD_ UVLO
) Rising 1.28 1.36 1.44 V
SHDN/UVLO Pin Hysteresis Current SHDN = V
SD_UVLO
– 50mV
SHDN = V
SD_UVLO
+ 50mV
2.5 4
0
5.5 μA
μA
Soft-Start Current SS = 1V (Note 3) 11 μA
PWM Input High Threshold 1V
PWM Input Low Threshold 0.4 V