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LT3476IUHF#TRPBF

P1-P3P4-P6P7-P9P10-P12P13-P14
LT3476
1
3476fb
n
RGGB Lighting
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Automotive and Avionic Lighting
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TFT LCD Backlighting
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Constant-Current Sources
ApplicAtions
typicAl ApplicAtion
High Current
Quad Output LED Driver
The LT
®
3476 is a quad output DC/DC converter designed
to operate as a constant-current source for driving high
current LEDs. A fixed frequency, current mode architecture
results in stable operation over a wide range of supply and
output voltages. A frequency adjust pin allows the user to
program switching frequency between 200kHz and 2MHz
to optimize efficiency and external component size.
The LT3476 senses output current at the high side of
the LED. High side current sensing is the most flexible
scheme for driving LEDs, allowing buck, boost or buck-
boost configurations. Each current monitor threshold is
trimmed to within 2.5% at the full scale of 105mV. With
an external sense resistor, the user programs the output
current range of each channel. Each of the four regulators
is independently operated by that channel’s PWM signal.
This PWM feature allows precise adjustment of the color
mixing or dimming ratio of the LED source. Dimming
ratios up to 1000:1 can be achieved.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and True
Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
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True Color PWM
TM
Dimming Delivers Up to 5000:1
Dimming Ratio (In Boost Configuration)
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LED Current Regulation with High-Side Sense
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VADJ Pin Accurately Sets LED Current Sense
Threshold Over Range 10mV to 120mV
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Four Independent Driver Channels with 1.5A, 36V
Internal NPN Switches
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Frequency Adjust Pin: 200kHz to 2MHz
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High Efficiency Conversion = Up to 96%
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Open LED Protection
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Low Shutdown Current < 10µA
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Wide V
IN
Range: 2.8V to 16V
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Thermally Enhanced, 38-Lead, 5mm × 7mm
QFN Package
100W Quad 1A × 8 LED Driver
1000:1 PWM Dimming at 100Hz
10µH
2.2µF
1nF
21k
REF
CAP1-4
SW4
1.05V
SW1
CAP1
100mΩ
LED1
1A
SW2 SW3
VC1-4
VADJ1-4
LED1-4
V
IN
PWM1-4
PWM1-4
RT
0.22µF 0.22µF
UP TO
8 LEDS
V
IN
2.8V TO 16V
PV
IN
33V
CAP2
100mΩ
LED2
GNDSHDN
LT3476
3476 TA01
SHDN
10µH
100k
2.2µF
× 4
4.99k
0.22µF 0.22µF
1A 1A 1A
10µH
CAP3
100mΩ
LED3
CAP4
100mΩ
LED4
10µH
PWM
5V/DIV
I
LED
500mA/DIV
5µs/DIV
3476 TA02
FeAtures Description
LT3476
2
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V
IN
............................................................................16V
PWM1-4, SHDN ........................................................16V
SW1-4, LED1-4, CAP1-4 ...........................................36V
REF, RT, V
ADJ1-4
, VC1-4 ..............................................2V
Operating Junction Temperature Range
(Notes 2 and 3) ...................................... –40°C to 125°C
Maximum Junction Temperature .......................... 125°C
Storage Temperature Range .................. –65°C to 125°C
Lead Temperature (Soldering, 10 sec) ................... 300°C
(Note 1)
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Range
2.8 16 V
Full-Scale LED Current Monitor Threshold Over CAP1-4/LED1-4 Operating Range
l
102
100
105 107
108
mV
mV
One-Tenth Scale LED Current Monitor Threshold V
ADJ1-4
= 100mV 8 12 16 mV
CAP1-4/LED1-4 Operating Range
2.2 33.5 V
REF Output Voltage 10µA ≥ I
REF
≥ –200µA
l
1.032 1.050 1.063 V
pin conFigurAtionAbsolute MAxiMuM rAtings
orDer inForMAtion
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3476EUHF#PBF LT3476EUHF#TRPBF 3476
38-Lead (5mm × 7mm) Plastic QFN
–40°C to 85°C
LT3476IUHF#PBF LT3476IUHF#TRPBF 3476
38-Lead (5mm × 7mm) Plastic QFN
–40°C to 125°C
LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3476EUHF LT3476EUHF#TR 3476
38-Lead (5mm × 7mm) Plastic QFN
–40°C to 85°C
LT3476IUHF LT3476IUHF#TR 3476
38-Lead (5mm × 7mm) Plastic QFN
–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.
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/
13 14 15 16
TOP VIEW
39
GND
UHF PACKAGE
38-LEAD (5mm × 7mm) PLASTIC QFN
17 18 19
38 37 36 35 34 33 32
24
25
26
27
28
29
30
31
8
7
6
5
4
3
2
1VC1
LED1
CAP1
CAP2
LED2
RT
REF
LED3
CAP3
CAP4
LED4
VC4
NC
NC
SW1
SW1
SW2
SW2
SW3
SW3
SW4
SW4
NC
NC
VC2
V
ADJ1
V
ADJ2
PWM1
PWM2
V
IN
NC
VC3
V
ADJ4
V
ADJ3
PWM4
PWM3
SHDN
NC
23
22
21
20
9
10
11
12
T
JMAX
= 125°C, θ
JA
= 34°C/W, θ
JC
= 2°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
electricAl chArActeristics
The l denotes the specifications which apply over the full operating
temperature range, (Note 3) otherwise specifications are at T
A
= 25°C. SW1-4 = 5V, V
IN
= 3.3V, SHDN = 3.3V, R
T
= 21k to GND,
PWM1-4 = 3.3V, V
ADJ1-4
= REF, CAP1-4 = 5V, unless otherwise noted.
LT3476
3
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PARAMETER CONDITIONS MIN TYP MAX UNITS
REF Line Regulation 2.8V ≤ V
IN
≤ 16V
0.003 %/V
Quiescent Current in Shutdown SHDN = 0V
0.1 10 µA
Quiescent Current Idle PWM1-4 = 0V 5.5 mA
Quiescent Current Active (Not Switching) VC1-4 = 0V 22 30 mA
Switching Frequency R
T
= 8.25k
R
T
= 21k
R
T
= 140k
1700
850
160
2000
1000
200
2300
1150
240
kHz
kHz
kHz
Nominal RT Pin Voltage 1.26 V
Maximum Duty Cycle R
T
= 8.25k (2MHz)
R
T
= 21k (1MHz)
R
T
= 140k (200kHz)
84
76
90
98
%
%
%
V
ADJ1-4
Input Bias Current Current Out of Pin –10 20 100 nA
VC1-4 Idle Input Bias Current PWM1-4 = 0V –20 0 20 nA
EAMP GM (∆I
VC
/∆V
CAP-LED
) 210 µS
VC Output Impedance 3 MΩ
SW1-4 Current Limit Static Test 1.5 2 2.5 A
SW1-4 V
CESAT
I
SW
= 1.3A to GND 350 mV
SW1-4 Leakage Current SHDN = 0V 0.1 5 µA
CAP1-4 Overvoltage Protect Threshold 33.5 35 V
CAP1-4/LED1-4 Idle Input Bias Current PWM1-4 < 0.4V, CAP = LED = 5V 100 nA
CAP1-4/LED1-4 Input Bias Current CAP = LED = 5V 70 µA
SHDN Input Low Voltage
l
0.4 V
SHDN Input High Voltage
l
1.5 V
SHDN Pin Current 16 30 µA
PWM1-4 Input Low Voltage
l
0.4 V
PWM1-4 Input High Voltage
l
1.5 V
PWM1-4 Pin Current 50 100 µA
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: 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 LT3476E is guaranteed to meet specifications from 0°Cto
85°C junction temperature. Specifications over the –40°Cto85°C
operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3476I is guaranteed to meet performance specifications over the –40°C
to 125°C operating junction temperature range.
electricAl chArActeristics
The l denotes the specifications which apply over the full operating
temperature range, (Note 3) otherwise specifications are at T
A
= 25°C. SW1-4 = 5V, V
IN
= 3.3V, SHDN = 3.3V, R
T
= 21k to GND,
PWM1-4 = 3.3V, V
ADJ1-4
= REF, CAP1-4 = 5V, unless otherwise noted.
P1-P3P4-P6P7-P9P10-P12P13-P14

LT3476IUHF#TRPBF

Mfr. #:
Buy LT3476IUHF#TRPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
LED Lighting Drivers High Current Quad Output LED Driver in QFN (5x7)
Lifecycle:
New from this manufacturer.
Delivery:
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