SW Voltage ...............................................................45V
V
OUT
, V
O_SW
Voltage .................................................44V
LED1 to LED6............................................................44V
PWM, SYNC, CTRL, RT, SS, V
C
...................................6V
TOP VIEW
SW
V
OUT
V
O_SW
LED1
LED2
LED3
LED4
LED5
LED6
1
2
3
4
5
6
7
8
9
25
24 V
IN
23
SHDN
22 GND
21 V
REF
20 SS
19 RT
18 PWM
17 SYNC
16 NC
15 T
SET
14 FB
13 V
C
V
O_SW
SW
24 23 22 21 20 19
LED1 1
LED2 2
LED3 3
LED4 4
LED5 5
LED6 6
OPENLED
10
I
SET
11
CTRL 12
FE PACKAGE
24-LEAD PLASTIC TSSOP
T
JMAX
= 125°C,
θ
JA
= 38°C/W
EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB
UF PACKAGE
24-LEAD (4mm 4mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT3598EUF#PBF
LT3598IUF#PBF
LT3598EFE#PBF
LT3598IFE#PBF
TAPE AND REEL
LT3598EUF#TRPBF
LT3598IUF#TRPBF
LT3598EFE#TRPBF
LT3598IFE#TRPBF
PART MARKING*
3598
3598
LT3598
LT3598
PACKAGE DESCRIPTION
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead (4mm
×
4mm) Plastic QFN
24-Lead Plastic TSSOP
24-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
V
IN
3598fb
2
LT3598
ELECTRICAL CHARACTERISTICS
PARAMETER
Minimum Operating Voltage
Maximum Operating Voltage
Reference Voltage
Reference Voltage Line Regulation
Maximum V
REF
Pin Current
FB Pin Bias Current
FB Error Amp Transconductance
FB Error Amp Voltage Gain
FB Pin Voltage
Current Loop Amp Transconductance
Current Loop Amp Voltage Gain
V
C
Sink Current
Quiescent Current
Quiescent Current in Shutdown
I
SET
Voltage
LED Current
LED String Current Matching
LED Open Detection Threshold
OPENLED
Sink Current
Minimum LED Regulation Voltage
LED1-6 Leakage Current
CTRL Pin Bias Current
Switching Frequency
V
LED1-6
= 1V, V
OUT
= 5V, PWM = 0V
V
LED1-6
= 42V, V
OUT
= 44V, PWM = 0V
V
CTRL
= 0.8V (Note 4)
RT = 309kΩ
RT = 51.1kΩ
RT = 14.7kΩ
RT = 309kΩ
RT = 51.1kΩ
RT = 14.7kΩ
(Note 5)
I
SW
= 0.5A
V
SW
= 40V
171
0.9
2.25
90
87
80
1.5
V
SHDN
= 5V, PWM = 0V, Not Switching
V
SHDN
= 0V
V
CTRL
= 1.5V, V
TSET
= 1.5V, R
ISET
= 14.7kΩ
R
ISET
= 14.7kΩ
20mA LED Current
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
SHDN
= V
IN
unless otherwise noted. (Note 2)
CONDITIONS
MIN
TYP
3
1.216
1.210
200
100
300
600
1.22
1.24
21
80
10
3.5
0
0.985
19.5
1.000
20
±0.5
0.2
2
0.8
0.1
0.2
50
190
1
2.5
602
l
MAX
3.2
30
1.260
1.260
0.03
250
UNITS
V
V
V
V
%/V
μA
nA
μmhos
V/V
1.230
0.01
3.2V < V
IN
< 30V, V
C
= 0.3V
Out of Pin
V
FB
= 1.230V (Note 3)
ΔI = 5μA
1.26
V
μmhos
V/V
μA
5
1
1.015
20.7
±1.5
0.25
mA
μA
V
mA
%
V
mA
V
1
2
125
209
1.1
2.75
μA
μA
nA
kHz
MHz
MHz
mV
%
%
%
T
SET
Voltage
Maximum Switch Duty Cycle
95
90
86
2
0.12
0.2
5
2.5
Switch Current Limit
Switch V
CESAT
Switch Leakage Current
A
V
μA
3598fb
3
LT3598
ELECTRICAL CHARACTERISTICS
PARAMETER
SHDN
Pin Current
SHDN
Voltage High
SHDN
Voltage Low
Soft-Start Charging Current
PWM Input High Voltage
PWM Input Low Voltage
PWM Pin Bias Current
SYNC Input High Voltage
SYNC Input Low Voltage
SYNC Pin Bias Current
V
O_SW
Switch Resistance
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 LT3598E 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,
SYNC = 0V
SYNC = 3.3V
25
0.1
PWM = 3.3V
1.5
0.4
50
1
1000
0.1
V
SS
= 0.1V
5
1
0.4
1
10
V
SHDN
= 0V
V
SHDN
= 5V
1.6
0.4
15
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
SHDN
= V
IN
unless otherwise noted. (Note 2)
CONDITIONS
MIN
TYP
0.1
30
MAX
1
60
UNITS
μA
μA
V
V
μA
V
V
μA
V
V
μA
μA
Ω
characterization and correlation with statistical process controls. The
LT3598I is guaranteed over the full –40°C to 125°C operating junction
temperature range.
Note 3:
Current flows out of FB pin.
Note 4:
Current flows out of CTRL pin.
Note 5:
Current limit guaranteed by design and/or correlation to static test.
Current limit is independent of duty cycle and is guaranteed by design.