SENSE ......................................................................0.4V
Operating Junction Temperature Range
(Notes 2,3) ............................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
32 31 30 29 28 27 26 25
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
1
2
3
4
5
6
7
8
UH PACKAGE
32-LEAD (5mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/W,
θ
JC
= 3°C/W
EXPOSED PAD (PIN 33) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LT3754EUH#PBF
LT3754IUH#PBF
TAPE AND REEL
LT3754EUH#TRPBF
LT3754IUH#TRPBF
PART MARKING*
3754
3754
PACKAGE DESCRIPTION
32-Lead (5mm × 5mm) Plastic QFN
32-Lead (5mm × 5mm) Plastic QFN
TEMPERATURE RANGE
–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/
3754fc
2
LT3754
elecTrical characTerisTics
PARAMETER
INPUT BIAS, REFERENCE
Minimum Operational V
IN
(To Allow GATE Switching)
Operational V
IN
V
IN
Quiescent Current
V
IN
Shutdown Current (V
IN
≠ INTV
CC
) (Not Shorted)
V
IN
Shutdown Current (V
IN
= INTV
CC
(Shorted))
SHDN/UVLO
Threshold (Micropower) (Falling) (V
SD
)
SHDN/UVLO
Threshold (UVLO) (Falling)
(Stop Switching) (V
UV
)
SHDN/UVLO
Pin Current
V
REF
Voltage
V
REF
Line Regulation
V
REF
Load Regulation
OSCILLATOR
Frequency: f
OSC
(100kHz)
Frequency: f
OSC
(1MHz)
f
OSC
(1MHz) Line Regulation
RT Pin Voltage
Minimum Off-Time
Minimum On-Time
SYNC Input High Threshold
SYNC Input Low Threshold
SYNC Input Current
SYNC Frequency Range
LINEAR REGULATOR (INTV
CC
)
INTV
CC
Regulation Voltage
Dropout (V
IN
- INTV
CC
)
INTV
CC
UVLO (+)
INTV
CC
UVLO (–)
INTV
CC
Current Limit
OVP/LED ERROR AMPLIFIERS
Transconductance (OVP)
Voltage Gain (OVP)
Transconductance (LED)
∆I
VC
= ±2.5µA
∆I
VC
= ±2.5µA
4
5
33
µmhos
V/V
µmhos
V
IN
= 12V
I
INTVCC
= 10mA
(Start Switching)
(Stop Switching)
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT
= 6V, R
ISET
= 14.7k unless otherwise noted.
CONDITIONS
V
C
= 1.5V
V
IN
= INTV
CC
(Shorted)
V
IN
≠ INTV
CC
V
IN
= INTV
CC
(Shorted)
V
IN
≠ INTV
CC
LEDx = 1.2V
CTRL = 0.1V, PWM = 0V
CTRL = 0.1V, PWM = 1.5V, (Not Switching)
SHDN/UVLO
= 0V, V
IN
=6V
SHDN/UVLO
= 0V, V
IN
= 40V
SHDN/UVLO
= 0V, V
IN
= INTV
CC
= 4.5V
SHDN/UVLO
= 0V, V
IN
= INTV
CC
= 13V
I
VIN
< 20µA
l
l
MIN
TYP
MAX
UNITS
l
l
4.2
5.5
4.5
6
4.2
9.5
0.1
10
20
0.3
1.414
1.6
1.450
0.7
1.476
2.4
0
1.485
0.01
2
4.5
6.0
13
40
5.7
12
2
10
20
40
1.538
3.2
1.524
0.05
V
V
V
V
mA
mA
µA
µA
µA
µA
V
V
µA
µA
V
%/V
mV
SHDN/UVLO
= V
UV
- 50mV
SHDN/UVLO
= V
UV
+ 50mV
I
VREF
= 0µA
I
VREF
= 0µA, 6V < V
IN
< 40V
0 < I
VREF
< 150µA (Max)
RT = 523k
RT = 39.2k
RT = 39.2k, 6V < V
IN
< 40V
RT = 39.2k
(Note 5)
(Note 5)
l
l
l
l
92
0.90
101
1
0.1
1.6
170
190
112
1.10
0.2
250
250
2.2
kHz
MHz
%/V
V
nS
nS
V
V
µA
µA
0.6
SYNC = 0V
SYNC = 5V
RT = 523k
RT = 39.2k
0.12
1.2
6.65
7
250
3.8
3.4
44
57
0
25
1.5
1.5
7.35
MHz
MHz
V
mV
V
V
mA
3754fc
3
LT3754
elecTrical characTerisTics
PARAMETER
Voltage Gain (LED)
V
C
Source Current (Out of Pin)
V
C
Sink Current (OVP)
V
C
Sink Current (LED)
V
C
Output High (clamp) (V
COH
)
V
C
Output Low (clamp) (V
COL
)
V
C
Switching Threshold (V
CSW
)
SENSE AMP
SENSE Input Current (Out of Pin)
SENSE Current Limit Threshold
Current Mode Gain
SENSE Over Current Limit Threshold
LED CURRENT / CONTROL
I
SET
Pin Voltage
LEDx Current (20mA) (R
ISET
= 14.7k)
LEDx Current Matching (20mA) (R
ISET
= 14.7k)
LEDx Current (50mA) (R
ISET
= 5.76k)
LED Pin Regulation Voltage
T
SET
Threshold
ANALOG DIMMING
CTRL Input Current (Out of Pin)
LEDx Current (Dimming 25:1)
PWM DIMMING
PWM Input Low Threshold
PWM Input High Threshold
PWM Input Current
V
OUT
Pin Current in PWM Mode V(V
OUT
) = 60V
LEDx Leakage Current
(PWM = 0V)
FAULT DIAGNOSTICS
FAULT
Output Sink Current
LED
x
Short Threshold (V
SH
)
(V
OUT
– V
LEDx
)
LED Open Detection Threshold
LED1 = Open, V
FAULT
= 0.3V
V
OUT
= 12V
V
OUT
= 60V
V
OUT
= 12V
0.3
0.6
6
6
0.5
mA
V
V
V
PWM = 1.5V
PWM = 6V
PWM = 1.5V
PWM = 0V
V
LEDx
= 1V, V
OUT
= 12V
V
LEDx
= 50V, V
OUT
= 60V
0.7
1
1.1
6
24
370
20
0.1
0.1
1
2
1.4
V
V
µA
µA
µA
µA
µA
µA
CTRL = 1V
CTRL = 0.04V
V
LEDx
= 1V, CTRL = 0.04V
40
50
0.8
200
200
nA
nA
mA
CTRL = 1.5V
V
LEDx
= 1V, CTRL = 1.5V
V
LEDx
= 1V, CTRL = 1.5V
V
LEDx
= 1V, CTRL = 1.5V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT
= 6V, R
ISET
= 14.7k unless otherwise noted.
CONDITIONS
V
C
= 1.5V, V
LEDx
= 0.8V, OVP
SET
= 1.5V
V
C
= 1.5V, V
LEDx
= 0.8V, OVP
SET
= 0V
V
C
= 1.5V, V
LEDx
= 1.2V, OVP
SET
= 1.5V
MIN
TYP
45
10
15
9
2.3
0.8
1.1
SENSE = 0V
l
MAX
UNITS
V/V
µA
µA
µA
V
V
V
µA
65
46
90
52
6
l
60
110
mV
V/V
mV
V
∆V(V
C
)/∆V(SENSE)
100
1.00
19.29
47.85
20.2
±0.7
50.1
1.1
630
21.11
±2.8
52.35
mA
%
mA
V
mV
3754fc
4
LT3754
elecTrical characTerisTics
PARAMETER
GATE DRIVER
GATE Driver Output Rise Time
GATE Driver Output Fall Time
GATE Output Low
GATE Output High
OUTPUT VOLTAGE
V
OUT
Over Voltage Protection (OVP) Regulation Voltage
OVP
SET
Input Current (Out of Pin)
OVP
SET
= 0.22V
OVP
SET
= 1V
OVP
SET
= 0.22V, V
OUT
=12V
12.5
57
40
200
LT3754I is guaranteed to meet performance specifications from
–40°C to 125°C junction temperature.
Note 3:
For Maximum Operating Ambient Temperature, see
Thermal Calculations
in the Applications Information section.
Note 4:
GATE rise and fall times are measured between 10% and 90%
of INTV
CC
voltage.
Note 5:
See Duty Cycle Considerations in the Applications Information.
V
V
nA
V
IN
= 7V, C
L
= 3300pF (Note 4)
V
IN
= 7V, C
L
= 3300pF (Note 4)
I
GATE
= 0µA
INTV
CC
= V
IN
= 7V
I
GATE
= 0µA
6.95
30
30
0.1
nS
nS
V
V
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= V
OUT
= 6V, R
ISET
=14.7k unless otherwise noted.
CONDITIONS
MIN
TYP
MAX
UNITS
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 LT3754E 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,
characterization and correlation with statistical process controls. The
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