Storage Temperature Range ................ –65°C to 150°C
pin conFiguraTion
TOP VIEW
INTV
CC
BOOST
VEE
VEE
SW
FB
V
IN
BG
TG
28 VEE
27 PWM_OUT1
26 VEE
25 PWM_OUT2
37
VEE
24 V
FNEG
23 PWM_OUT3
22 ISP
21 ISN
20 V
C1
19 V
C2
11 12 13 14 15 16 17 18
FAULT
LED_ISN
LED_ISP
SGND
V
C3
RT
SS
36 35 34 33 32 31 30 29
EN/UVLO 1
CTRL1 2
V
REF
3
CTRL2 4
CTRL3 5
CTRLT 6
PWM1 7
PWM2 8
PWM3 9
SYNC 10
UHE PACKAGE
36-LEAD (5mm
×
6mm) PLASTIC QFN
θ
JA
= 34°C/W,
θ
JC
= 3°C/W
EXPOSED PAD (PIN 37) IS VEE, MUST BE SOLDERED TO PCB
3744fa
2
For more information
www.linear.com/LT3744
LT3744
orDer inForMaTion
LEAD FREE FINISH
LT3744EUHE#PBF
LT3744IUHE#PBF
TAPE AND REEL
LT3744EUHE#TRPBF
LT3744IUHE#TRPBF
PART MARKING*
3744
3744
PACKAGE DESCRIPTION
36-Lead (5mm
×
6mm) Plastic QFN
36-Lead (5mm
×
6mm) 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 nonstandard 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/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 2V, SGND = VEE = 0V unless otherwise noted.
PARAMETER
Input Voltage Range
V
IN
Pin Quiescent Current (Note 3)
Non-Switching Operation
Shutdown Mode
EN/UVLO Pin Threshold (Rising)
EN/UVLO Hysteresis
EN/UVLO Pin Current
PWM1, PWM2, PWM3 Input High
PWM1, PWM2, PWM3 Input Low
PWM1, PWM2, PWM3 Pin Currents
CTRL1, CTRL2, CTRL3 Control Range
CTRL1, CTRL2, CTRL3, Pin Currents
CTRLT Pin Current
Reference
Reference Voltage (V
REF
Pin)
LED and Inductor Current Sensing
Full Range LED_ISP to LED_ISN
Current Regulation Accuracy, Full Range
1/20 Range LED_ISP to LED_ISN
LED_ISP and LED_ISN Pin Current
ISN and ISP Pin Current at 0V
ISN and ISP Pin Current at 0V, Dimming
ISN and ISP Pin Current at 5V
ISN and ISP Pin Current at 5V, Dimming
OC Inductor Threshold, Rising (ISP-ISN)
OC Inductor Threshold, Falling (ISP-ISN)
Internal V
CC
Regulator (INTV
CC
Pin)
Regulation Voltage
Current Limit (INTV
CC
Short)
INTV
CC
= 0V
4.75
5
50
5.25
V
mA
CTRL1 = 0.075V, PWM1 = 2V, PWM2 and PWM3 = 0V
CTRL1 = 1.5V, PWM1 = 2V,
PWM2, PWM3, LED_ISP and LED_ISN = 0V
ISN = ISP = 0V, PWM1 = 2V, PWM2 and PWM3 = 0V
ISN = ISP = 0V, PWM1 = 0V, PWM2 and PWM3 = 0V
ISN = ISP = 5V, PWM1 = 2V, PWM2 and PWM3 = 0V
ISN = ISP = 5V, PWM1 = 0V, PWM2 and PWM3 = 0V
ISN = 3V
ISN = 3V
CTRL1 = 1.5V, PWM1 = 2V, PWM2 and PWM3 = 0V
l
l
l
elecTrical characTerisTics
(Note 2)
CONDITIONS
MIN
3.3
TYP
MAX
36
UNITS
V
mA
µA
V
mV
μA
V
V
EN/UVLO
= 2V, Not Switching
V
EN/UVLO
= 0V
2.2
l
2.6
1
1.375
1.225
EN/UVLO = 1.0V
Referenced to SGND
Referenced to SGND
PWM1, PWM2, PWM3 = 2.0V
Referenced to SGND
CTRL1, CTRL2, CTRL3, = 1.5V
CTRLT = 1.5V
Referenced to SGND
l
1.3
–65
4.8
2.0
0.8
100
0
100
100
1.96
58.2
–3.0
2
3
65
390
1
10
1
110
75
2
60.0
2.04
61.8
3.0
4
1.5
V
nA
V
nA
nA
V
mV
%
mV
μA
μA
μA
μA
μA
mV
mV
3744fa
For more information
www.linear.com/LT3744
3
LT3744
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 2V, SGND = VEE = 0V unless otherwise noted.
PARAMETER
NMOS FET Drivers
Non-Overlap Time TG to BG
Non-Overlap Time BG to TG
Minimum On-Time BG
Minimum On-Time TG
Top Gate Driver Switch R
ON
Gate Pull Up
Gate Pull Down
Bottom Gate Driver Switch R
ON
Gate Pull Up
Gate Pull Down
PWM Out Drivers
PWM_OUT Switch R
ON
Gate Pull Up
Gate Pull Down
PWMX High To PWM_OUTX High Delay
PWMX Low To PWM_OUTX Low Delay
Oscillator
Switching Frequency Range
RT Pin Current Limit
SYNC Input High
SYNC Input Low
SYNC Pin Current
SYNC Range
Switching Frequency
f
SW
Soft-Start
Charge Current
Fault
Lower Fault Falling V
FB
Threshold
Lower Fault Rising V
FB
Hysteresis
Upper Fault Rising V
FB
Threshold
Upper Fault Falling V
FB
Hysteresis
Fault Voltage Low
Fault Leakage Current
I
FAULT
= 2mA
l
l
elecTrical characTerisTics
CONDITIONS
MIN
TYP
50
50
MAX
UNITS
ns
ns
ns
ns
Ω
Ω
Ω
Ω
(Note 3)
(Note 3)
V
BOOST
– V
SW
= 5V
V
INTVCC
= 5V
50
160
3
1.5
2.5
1.5
V
INTVCC
= 5V, V
FNEG
= –15V
5
1.65
175
80
100
66
1000
Ω
Ω
ns
ns
kHz
μA
V
0.8
V
nA
900
kHz
kHz
kHz
μA
mV
mV
1.14
V
mV
V
nA
Referenced to SGND
Referenced to SGND
SYNC = 2.0V
Tested at 190kHz and 1.1MHz with R
T
= 422kΩ
R
T
= 40.2kΩ
R
T
= 422kΩ
PWM1 = 2V, SS, PWM2 and PWM3 = 0V
l
2.0
25
90
950
95
4.8
240
1.06
1000
104
5
250
30
1.100
–30
0.1
50
1050
120
5.2
260
l
3744fa
4
For more information
www.linear.com/LT3744
LT3744
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
EN/UVLO
= 2V, SGND = VEE = 0V unless otherwise noted.
PARAMETER
Voltage Regulation Amplifier
FB Pin Current
g
m
Feedback Regulation Voltage
LED Current Control Loop g
m
Amplifier
Input Bias Current (LED_ISP and LED_ISN)
Output Impedance
g
m
Differential Gain
C/10 Comparator
Falling Threshold
Rising Hysteresis
LED_ISN = 0V, Threshold = LED_ISP-LED_ISN,
CTRL1 = CTRL2 = CTRL3 = 2V
LED_ISN = 0V, Threshold = LED_ISP-LED_ISN,
CTRL1 = CTRL2 = CTRL3 = 2V
4.0
6
3.0
8.0
mV
mV
CTRL1 = 1.5V, PWM1 = 2V, PWM2, PWM3, LED_ISP
and LED_ISN = 0V
65
25
200
5
μA
MΩ
μA/V
kV/V
l
elecTrical characTerisTics
CONDITIONS
V
FB
= 1.2V
MIN
TYP
1.2
600
MAX
UNITS
µA
μA/V
1.169
1.205
1.241
V
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 an extended periods may affect device
reliability and lifetime.
Note 2:
The LT3744E 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
LT3744I is guaranteed to meet performance specifications over the –40°C
to 125°C operating junction temperature range.
Note 3:
The minimum on and off times are guaranteed by design and are
not tested.
Note 4:
Do not apply a positive or negative voltage to INTV
CC
, RT, V
REF
,
SS, TG, BG, PWM_OUT1, PWM_OUT2, or PWM_OUT3 pins, otherwise
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