FeaTures
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LT3763
60V High Current
Step-Down LED Driver Controller
DescripTion
The
LT
®
3763
is a fixed frequency, synchronous, step-down
DC/DC controller designed to accurately regulate output
currents up to 20A. The average current mode control-
ler will maintain inductor current regulation over a wide
output voltage range from 0V to 55V. Output current is
set by analog voltages on the CTRL pins and an external
sense resistor. Voltage regulation and overvoltage protec-
tion are set with a voltage divider from the output to the
FB pin. The switching frequency is programmable from
200kHz to 1MHz through an external resistor on the RT
pin or with the SYNC pin and an external clock signal.
Input and output current sensing provides input current
limiting and an accurate measurement of these currents.
The FBIN pin is provided for applications requiring a peak
power tracking function.
Additional features include an accurate external reference
voltage for use with the CTRL pins, an accurate UVLO/
EN pin that allows for programmable UVLO hysteresis,
a PWM driver for LED applications, output voltage fault
detection, and thermal shutdown.
Accurately Control Input and Output Current
3000:1 True Color PWM™ Dimming
±1.5% Voltage Regulation Accuracy
±6% Current Regulation Accuracy
6V to 60V Input Voltage Range
Wide Output Range Up to 55V
<2µA Shutdown Current
Control Pin for Thermal Control of Load Current
Input and Output Current Monitor and Limit
Open, Short, and C/10 Fault Detection
PWM Driver Output for LED Applications
Thermally Enhanced 28-Lead FE Package
applicaTions
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High Power Architectural Lighting
Automotive Lighting
Aviation and Marine Strobe Lights
Solar-Powered Chargers, Laser Diodes
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. Protected by U.S. Patents including 7199560, 7321203 and
others pending.
Typical applicaTion
20A, Pulse Width Modulated, Single LED Driver
V
IN
10V TO 30V
2.5m
84.5k
15.4k
IVINP
EN/UVLO
2.2µF
V
REF
45.3k
CTRL2
470k
50k
CTRL1
FBIN
IVINMON
ISMON
PWM
SYNC
RT
82.5k
10nF
SS
LT3763
BOOST
SW
INTV
CC
47.5k
BG
GND
50
1nF
50
1nF
SENSE
+
SENSE
–
PWMOUT
FAULT
FB
V
C
59k
4.7nF
12.1k
3763 TA01
1k
1µF
1k
100µF
4.7µF
IVINN
V
IN
TG
220nF
1.5µH
2.5m
V
OUT
6V, 20A MAXIMUM
220µF
×2
22µF
PWM Dimming
PWM
10V/DIV
V
SW
50V/DIV
I
L
5A/DIV
5µs/DIV
3763 TA01b
10
10
33nF
47.5k
3763fb
For more information
www.linear.com/LT3763
1
LT3763
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
BG
INTV
CC
V
IN
EN/UVLO
V
REF
IVINN
IVINP
IVINMON
FAULT
1
2
3
4
5
6
7
8
9
29
GND
28 GND
27 BOOST
26 SW
25 TG
24 PWM_OUT
23 GND
22 PWM
21 SYNC
20 RT
19 ISMON
18 V
C
17 SENSE
+
16 SENSE
–
15 SS
V
IN
, EN/UVLO, IVINP, and IVINN ...............................60V
SENSE
+
and SENSE
–
.................................................60V
CTRL1, CTRL2, FB, and FBIN ......................................3V
SYNC and PWM ..........................................................6V
INTV
CC
and
FAULT.......................................................6V
V
C
, RT, and SS ............................................................3V
V
REF
, IVINMON, and ISMON........................................3V
SW ............................................................................60V
BOOST ......................................................................66V
BOOST-SW..................................................................6V
Operating Junction Temperature (Notes 2, 3)
LT3763E/LT3763I .............................. –40°C to 125°C
LT3763H ............................................ –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
FBIN 10
FB 11
GND 12
CTRL2 13
CTRL1 14
FE PACKAGE
28-LEAD PLASTIC TSSOP
θ
JA
= 30°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LT3763EFE#PBF
LT3763IFE#PBF
LT3763HFE#PBF
TAPE AND REEL
LT3763EFE#TRPBF
LT3763IFE#TRPBF
LT3763HFE#TRPBF
PART MARKING*
LT3763FE
LT3763FE
LT3763FE
PACKAGE DESCRIPTION
28-Lead Plastic TSSOP
28-Lead Plastic TSSOP
28-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
elecTrical characTerisTics
PARAMETER
Input Voltage Range
Supply Undervoltage Lockout
V
IN
Pin Quiescent Current
Non-Switching Operation
Shutdown Mode
EN/UVLO Pin Threshold (Falling Edge)
EN/UVLO Hysteresis
EN/UVLO Pin Current
SYNC Pin Threshold (Falling Edge)
SYNC Pin Hysteresis
From Low to High
CONDITIONS
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 5V unless otherwise noted.
MIN
6
3.75
4.0
1.7
0.2
1.47
EN/UVLO = 1.4V, V
IN
= 6V
1.4
1.52
185
5
1.5
675
1.6
TYP
MAX
60
4.25
3.5
2
1.57
UNITS
V
V
mA
µA
V
mV
µA
V
mV
3763fb
V
EN/UVLO
= 1.4V, Not Switching
V
EN/UVLO
= 0V
2
For more information
www.linear.com/LT3763
LT3763
elecTrical characTerisTics
PARAMETER
PWM Pin Threshold (Falling Edge)
PWM Pin Hysteresis
CTRL1 Pin Current
CTRL2 Pin Current
Reference
Reference Voltage (V
REF
pin)
Inductor Current Sensing
Full Range SENSE
+
to SENSE
–
SENSE
+
Pin Current
SENSE
–
Pin Current
Internal V
CC
Regulator (INTV
CC
Pin)
Regulation Voltage
Current Limit
NMOS FET Driver
Non-Overlap Time TG to BG
Non-Overlap Time BG to TG
Minimum On-Time BG
Minimum On-Time TG
Minimum Off-Time BG
High Side Driver Switch On-Resistance
Gate Pull-Up
Gate Pull-Down
Low Side Driver Switch On-Resistance
Gate Pull-Up
Gate Pull-Down
Switching Frequency
Soft-Start
Charging Current
Voltage Regulation Amplifier
Input Bias Current
g
m
Feedback Regulation Voltage
FAULT Comparator
Upper FAULT Threshold (FB Rising)
Upper FAULT Threshold Hysteresis
Lower FAULT Threshold (FB Falling)
Lower FAULT Threshold Hysteresis
FAULT
Pull-Down Current
Input Voltage Regulation
FBIN Pin Current
Sense Voltage
(V
SENSE+
– V
SENSE–
)
V
FBIN
= 1.5V
V
FBIN
= 1.22V, V
SENSE–
= 4V
V
FBIN
= 1.26V, V
SENSE–
= 4V
150
10
45
nA
mV
mV
3763fb
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 5V unless otherwise noted.
CONDITIONS
MIN
1.4
V
CTRL1
= 1.5V
V
CTRL1
= 1.5V, V
CTRL2
= 1.5V, V
FBIN
= 2V
l
TYP
1.5
675
20
100
MAX
1.6
UNITS
V
mV
nA
nA
1.94
48
2
51
–20
–40
2.06
54
V
mV
µA
µA
V
CTRL1
= 2V, V
CTRL2
> 2V, V
SS
= V
FBIN
= 2V, V
C
= 1.2V
V
SENSE+
= V
SENSE–
= 4V
V
SENSE+
= V
SENSE–
= 4V, V
CTRL1
= 1.5V
I
LOAD
= 10mA
V
INTVCC
= 0V
l
l
4.8
5
60
42
44
5.2
V
mA
ns
ns
ns
ns
ns
Ω
Ω
Ω
Ω
(Note 4)
(Note 4)
(Note 4)
V
CBOOST
– V
SW
= 5V
V
INTVCC
= 5V
R
T
= 40kΩ
R
T
= 221kΩ
930
180
50
55
140
2.2
1.3
2.2
1
l
1000
200
11
1070
220
kHz
kHz
µA
nA
µA/V
V
FB
= 1.3V
V
SENSE+
= V
SENSE–
= V
CTRL1
= 2V
l
750
850
1.188
1.137
0.24
1.206
1.16
40
l
1.224
1.183
0.26
V
V
mV
V
mV
mA
l
0.25
40
8
V
FAULT
= 2V, V
FB
= 0V
For more information
www.linear.com/LT3763
3
LT3763
elecTrical characTerisTics
PARAMETER
Output Current Monitor
Sense Voltage
(V
SENSE+
– V
SENSE–
)
Input Current Monitor
Sense Voltage
(V
IVIN+
– V
IVIN–
)
Input Current Limit Sense Voltage
(V
IVIN+
– V
IVIN–
)
PWM Driver
PWM_OUT Driver On-Resistance
Gate Pull-Up
Gate Pull-Down
PWM to PWM_OUT Propagation Delay
Rising
Falling
Current Control Loop g
m
Amp
Offset Voltage
Input Common Mode Range
V
CM(LOW)
V
CM(HIGH)
Output Impedance
g
m
Differential Gain
Overvoltage
FB Overvoltage Protection (V
FB
Maximum)
Overcurrent
Overcurrent Protection
(V
SENSE+
– V
SENSE–
Maximum)
V
SENSE–
= 0V, R
T
= 221kΩ
85
mV
1.515
V
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 5V unless otherwise noted.
CONDITIONS
V
ISMON
Regulated to 1V, V
SENSE–
= 10V
V
ISMON
Regulated to 200mV, V
SENSE–
= 10V
V
IVINMON
Regulated to 1V, V
IVIN+
= 12V
V
IVINMON
Regulated to 200mV, V
IVIN+
= 12V
l
MIN
45
5
46
6
45
TYP
50
10
50
10
50
MAX
55
15
54
14
55
UNITS
mV
mV
mV
mV
mV
V
INTVCC
= 5V
V
INTVCC
= 5V
2.2
0.9
11
38
l
Ω
Ω
ns
ns
3
mV
V
V
MΩ
625
µA/V
V/mV
V
SENSE–
= 4V, V
CTRL1
= 0V
(Note 5)
V
CM(HIGH)
Measured from V
IN
to V
CM
, V
SENSE+
= V
SENSE–
–3
0
0
1.4
3.5
375
475
1.7
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 LT3763E 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
LT3763I is guaranteed to meet performance specifications over the
–40°C to 125°C operating junction temperature range. The LT3763H is
guaranteed over the –40°C to 150°C operating junction temperature range.
High junction temperatures degrade operating lifetimes; operating lifetime
is derated for junction temperatures greater than 125°C.
Note 3:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
Note 4:
The minimum on- and off-times are guaranteed by design and are
not tested.
Note 5:
The minimum common mode voltage is guaranteed by design and
is not tested.
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3763fb
For more information
www.linear.com/LT3763
LT3763
Typical perForMance characTerisTics
EN/UVLO Threshold (Falling)
1.70
6.0
EN/UVLO Current
10000
1000
EN/UVLO CURRENT (µA)
5.5
QUIESCENT CURRENT (nA)
100
10
1
0.1
0.01
Quiescent Current (Shutdown)
6V
IN
12V
IN
60V
IN
EN/UVLO THRESHOLD (V)
1.64
1.58
5.0
1.52
1.46
4.5
1.40
6
24
V
IN
(V)
42
60
3763 G01
4.0
6
24
V
IN
(V)
42
60
3763 G02
0.001
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3763 G03
Quiescent Current (Non-Switching)
3.0
2.03
V
REF
Voltage
6V
IN
12V
IN
60V
IN
1.5
1.4
V
REF
CURRENT LIMIT (mA)
1.3
1.2
1.1
1.0
V
REF
Current Limit
QUIESCENT CURRENT (mA)
2.02
2.5
V
REF
(V)
2.0
2.00
T
A
= 150°C
T
A
= 25°C
T
A
= –50°C
6
24
V
IN
(V)
42
60
3763 G04
2.01
1.5
1.99
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3763 G05
0.9
T
A
= 150°C
T
A
= 25°C
T
A
= –50°C
6
24
V
IN
(V)
42
60
3763 G06
RT Current Limit
70
16
SS Current
6
5
14
SS CURRENT (µA)
4
12
V
INTVCC
(V)
0
25 50 75 100 125 150
TEMPERATURE (°C)
3763 G08
INTV
CC
Current Limit
64
RT CURRENT LIMIT (µA)
58
3
2
52
46
10
1
8
–50 –25
0
40
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3763 G07
0
10
20
30
I
INTVCC
(mA)
40
50
60
3763 G09
3763fb
For more information
www.linear.com/LT3763
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