LT3492
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FEATURES
APPLICATIONS
DESCRIPTION
Triple Output LED Driver
with 3000:1 PWM Dimming
The LT
®
3492 is a triple output DC/DC converter designed
to operate as a constant-current source and is ideal for
driving LEDs. The LT3492 works in buck, boost or buck-
boost mode. The LT3492 uses a fi xed frequency, current
mode architecture resulting in stable operation over a
wide range of supply and output voltages. A frequency
adjust pin allows the user to program switching frequency
between 330kHz and 2.1MHz to optimize effi ciency and
external component size.
The external PWM input provides 3000:1 LED dimming
on each channel. Each of the three channels has a built-in
gate driver to drive an external LED-disconnect P-channel
MOSFET, allowing high dimming range. The output current
range of each channel of the LT3492 is programmed with
an external sense resistor.
The CTRL pin is used to adjust the LED current either for
analog dimming or overtemperature protection.
n True Color PWM™ Dimming Delivers Up to 3000:1
Dimming Ratio
n Built-In Gate Driver for PMOS LED Disconnect
n Three Independent Driver Channels with 600mA,
60V Internal Switches
n Operates in Buck, Boost, Buck-Boost Modes
n CTRL Pin Accurately Sets LED Current Sense
Threshold Over a Range of 10mV to 100mV
n Adjustable Frequency: 330kHz to 2.1MHz
n Open LED Protection
n Wide Input Voltage Range:
Operation from 3V to 30V
Transient Protection to 40V
n Surface Mount Components
n 28-Lead (4mm × 5mm) QFN and TSSOP Packages
n RGB Lighting
n Billboards and Large Displays
n Automotive and Avionic Lighting
n Constant-Current Sources
High Dimming Ratio Triple Output Buck-Mode LED Power Supply
3000:1 PWM Dimming at 100Hz
TYPICAL APPLICATION
0.3A
0.47µF 0.47µF
ISN1
330m 330m
TG1
PVIN
58V
10 LEDs
33µH
ISP1
0.3A
ISN2
TG2
33µH
ISP2
0.3A
0.47µF
ISN3
1µF
s3
330m
10k
150k
49.9k 680pF
3492 TA01a
TG3
33µH
ISP3
SW1 SW2
LT3492
GND
SW3 TG1-3
VC1-3
VREF
CTRL1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
3V TO 24V 1µF
FADJ
OVP1-3
1.3MHz
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. 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.
PWM
5V/DIV
1µs/DIV 3492 TA01b
ILED
0.2A/DIV
IL
0.5A/DIV
LT3492
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ABSOLUTE MAXIMUM RATINGS
VIN (Note 4) ...............................................................40V
SW1-SW3, ISN1-ISN3, ISP1-ISP3 ............................60V
TG1-TG3 ...............................................ISP – 10V to ISP
PWM1-PWM3 ...........................................................20V
VREF
, CTRL1-CTRL3, FADJ, VC1-VC3, OVP1-OVP3 ....2.5V
SHDN (Note 4) ...........................................................VIN
(Note 1)
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
TOP VIEW
FE PACKAGE
28-LEAD PLASTIC TSSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
SHDN
PWM3
PWM2
PWM1
VREF
CTRL3
CTRL2
CTRL1
FADJ
VC3
VC2
VC1
OVP3
OVP2
VIN
TG3
ISN3
ISP3
SW3
SW2
ISP2
ISN2
TG2
SW1
ISP1
ISN1
TG1
OVP1
GND
29
TJMAX = 125°C, θJA = 30°C/W, θJC = 10°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
9 10
TOP VIEW
GND
29
UFD PACKAGE
28-LEAD (4mm s 5mm) PLASTIC QFN
11 12 13
28 27 26 25 24
14
23
6
5
4
3
2
1
PWM1
VREF
CTRL3
CTRL2
CTRL1
FADJ
VC3
VC2
ISP3
SW3
SW2
ISP2
ISN2
TG2
SW1
ISP1
PWM2
PWM3
SHDN
VIN
TG3
ISN3
VC1
OVP3
OVP2
OVP1
TG1
ISN1
7
17
18
19
20
21
22
16
815
TJMAX = 125°C, θJA = 34°C/W, θJC = 2.7°C/W
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3492EFE#PBF LT3492EFE#TRPBF LT3492FE 28-Lead Plastic TSSOP –40°C to 125°C
LT3492IFE#PBF LT3492IFE#TRPBF LT3492FE 28-Lead Plastic TSSOP –40°C to 125°C
LT3492EUFD#PBF LT3492EUFD#TRPBF 3492 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C
LT3492IUFD#PBF LT3492IUFD#TRPBF 3492 28-Lead (4mm × 5mm) Plastic QFN –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
*For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/
ORDER INFORMATION
Operating Junction Temperature Range
(Note 2) .................................................. –40°C to 125°C
Max Junction Temperature .................................... 125°C
Storage Temperature Range
TSSOP ............................................... –65°C to 150°C
UFD .................................................... –65°C to 125°C
LT3492
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ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at TA = 25°C. VIN = 5V, SHDN = 5V, PWM1-3 = 5V, FADJ = 0.5V, CTRL1-3 = 1.5V,
OVP1-3 = 0V, unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Operation Voltage (Note 4) 3 30 V
VIN Undervoltage Lockout 2.1 2.4 V
Full-Scale LED Current Sense Voltage ISP1-3 = 48V
l
98
96
100 103
104
mV
mV
One-Tenth Scale LED Current Sense Voltage CTRL1-3 = 100mV, ISP1-3 = 48V 7 10 13 mV
ISPn/ISNn Operating Voltage 2.5 60 V
VREF Output Voltage IREF = 200µA, Current Out of Pin l1.96 2 2.04 V
VREF Line Regulation 3V ≤ VIN ≤ 40V, IREF = 10µA 0.03 %/V
Quiescent Current in Shutdown SHDN = 0V 0.1 10 µA
Quiescent Current Idle PWM1-PWM3 = 0V 6 8 mA
Quiescent Current Active (Not Switching) VC1-VC3 = 0V 11 15 mA
Switching Frequency FADJ = 1.5V
FADJ = 0.5V
FADJ = 0.1V
1800
1000
280
2100
1300
340
2400
1600
400
kHz
kHz
kHz
Maximum Duty Cycle FADJ = 1.5V (2.1MHz)
FADJ = 0.5V (1.3MHz)
FADJ = 0.1V (330kHz)
73
80
78
87
97
%
%
%
CTRL1-3 Input Bias Current Current Out of Pin, CTRL1-3 = 0.1V 20 100 nA
FADJ Input Bias Current Current Out of Pin, FADJ = 0.1V 20 100 nA
OVP1-3 Input Bias Current Current Out of Pin, OVP1-3 = 0.1V 10 100 nA
OVP1-3 Threshold 0.95 1 1.05 V
VC1-3 Idle Input Bias Current PWM1-3 = 0V –20 0 20 nA
VC1-3 Output Impedance ISP1-3 = 48V 10 MΩ
EAMP gm (ΔIVC/ΔVCAP-LED)ISP1-3 = 48V 200 µS
SW1-3 Current Limit (Note 3) 600 1000 1300 mA
SW1-3 VCESAT ISW = 500mA (Note 3) 340 mV
SW1-3 Leakage Current SHDN = 0V, SW = 5V 2 µA
LT3492
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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 LT3492E is guaranteed to meet performance specifi cations
from 0°C to 125°C junction temperature. Specifi cations over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT3492I is guaranteed over the full –40°C to 125°C operating junction
temperature range.
ELECTRICAL CHARACTERISTICS
Note 3: Current fl ows into pin. Current limit and switch VCESAT is
guaranteed by design and/or correlation to static test.
Note 4: Absolute maximum voltage at the VIN and SHDN pins is 40V for
nonrepetitive 1 second transients, and 30V for continuous operation.
Note 5: Gate turn-on/turn-off delay is measured from 50% level of PWM
voltage to 90% level of gate on/off voltage.
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at TA = 25°C. VIN = 5V, SHDN = 5V, PWM1-3 = 5V, FADJ = 0.5V, CTRL1-3 = 1.5V,
OVP1-3 = 0V, unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
ISP1-3 Input Bias Current 180 250 µA
ISP1-3, ISN1-3 Idle Input Bias Current PWM1-3 = 0V 1 µA
ISP1-3, ISN1-3 Input Bias Current in Shutdown SHDN = 0V 1 µA
SHDN Input Low Voltage 0.4 V
SHDN Input High Voltage 1.5 V
SHDN Pin Current SHDN = 5V, Current Into Pin 65 120 µA
PWM1-3 Input Low Voltage 0.4 V
PWM1-3 Input High Voltage 1.2 V
PWM1-3 Pin Current Current Into Pin 160 210 µA
Gate Off Voltage (ISP1-3–TG1-3) ISP1-3 = 60V, PWM1-3 = 0V 0.1 0.3 V
Gate On Voltage (ISP1-3–TG1-3) ISP1-3 = 60V 5.5 6.5 7.5 V
Gate Turn-On Delay CLOAD = 300pF, ISP1-3 = 60V (Note 5) 110 ns
Gate Turn-Off Delay CLOAD = 300pF, ISP1-3 = 60V (Note 5) 110 ns
LT3492
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Quiescent Current Switch On Voltage
Switch Frequency vs FADJ
Switch Current Limit
vs Duty Cycle
Reference Voltage
vs Temperature
Switch Current Limit vs
Temperature
(TA = 25°C unless otherwise noted)
TYPICAL PERFORMANCE CHARACTERISTICS
VIN (V)
0
8
10
14
30
3492 G01
6
4
10 20 40
2
0
12
INPUT CURRENT (mA)
PWM1-3 = 5V
VC = GND, NOT SWITCHING
PWM1-3 = 0V
DUTY CYCLE (%)
0
SWITCH CURRENT LIMIT (mA)
600
800
1200
1000
80
3492 G03
400
200
020 40 60 100
TEMPERATURE (°C)
–50
CURRENT LIMIT (mA)
800
1000
1200
25 75
3492 G04
600
400
–25 0 50 100 125
200
0
TEMPERATURE (°C)
–50
VREF (V)
2.03
25
3492 G05
2.00
1.98
–25 0 50
1.97
1.96
2.04
2.02
2.01
1.99
75 100 125
FADJ (V)
0
0
SWITCH FREQUENCY (kHz)
250
750
1000
1250
0.8
2250
3492 G06
500
0.4
0.2 1.0
0.6 1.2
1500
1750
2000
SWITCH CURRENT (mA)
0
SWITCH VOLTAGE (mV)
300
400
600
500
800
3492 G02
200
100
0200 400 600 1000
LT3492
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(TA = 25°C unless otherwise noted)
TYPICAL PERFORMANCE CHARACTERISTICS
VISP-VISN Threshold vs
Temperature PMOS Turn On Waveforms PMOS Turn Off Waveforms
TEMPERATURE (°C)
–50
VISP-VISN THRESHOLD (mV)
101
102
103
25 75
3492 G10
100
99
–25 0 50 100 125
98
97
CTRL = 1.2V
VISP = 24V
5V
0V
PWM
60V
50V
TG
200ns/DIVVISP = 60V
QG FET = 6nC
3492 G11 200ns/DIVVISP = 60V
QG FET = 6nC
3492 G12
5V
0V
PWM
60V
50V
TG
Switch Frequency vs Temperature VISP-VISN Threshold vs CTRL VISP-VISN Threshold vs VISP
CTRL (V)
0
0
VISP-VISN THRESHOLD (mV)
20
40
60
80
120
0.2 0.4 0.6 0.8
3492 G08
1 1.2
100
VISP = 24V
TEMPERATURE (°C)
–50
SWITCH FREQUENCY (MHz)
1.2
1.3
1.4
25 75
3492 G07
1.1
–25 0 50 100 125
1.0
FADJ = 0.5V
VISP (V)
0
97
VISP-VISN TRHESHOLD (mV)
98
99
100
101
102
103
10 20 30 40
3492 G09
6050
CTRL = 1.2V
LT3492
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CTRL1, CTRL2, CTRL3: LED Current Adjustment Pins. Sets
voltage across external sense resistor between ISP and ISN
pins of the respective converter. Setting CTRL voltage to
be less than 1V will control the current sense voltage to be
one-tenth of CTRL voltage. If CTRL voltage is higher than
1V, the default current sense voltage is 100mV. The CTRL
pin must not be left fl oating.
FADJ: Switching Frequency Adjustment Pin. Setting FADJ
voltage to be less than 1V will adjust switching frequency
up to 2.1MHz. If FADJ voltage is higher than 1V, the default
switching frequency is 2.1MHz. The FADJ pin must not
be left fl oating.
GND: Signal Ground and Power Ground. Solder exposed
pad directly to ground plane.
ISN1, ISN2, ISN3: Noninverting Input of Current Sense
Error Amplifi er. Connect directly to LED current sense
resistor terminal for current sensing of the respective
converter.
ISP1, ISP2, ISP3: Inverting Input of Current Sense Error
Amplifi er. Connect directly to other terminal of LED current
sense resistor terminal of the respective converter.
OVP1, OVP2, OVP3: Open LED Protection Pins. A voltage
higher than 1V on OVP turns off the internal main switch
of the respective converter. Tie to ground if not used.
PWM1, PWM2, PWM3: Pulse Width Modulated Input.
Signal low turns off the respective converter, reduces
quiescent supply current and causes the VC pin for that
converter to become high impedance. PWM pin must not
be left fl oating; tie to VREF if not used.
SHDN: Shutdown Pin. Used to shut down the switching
regulator and the internal bias circuits for all three convert-
ers. Tie to 1.5V or greater to enable the device. Tie below
0.4V to turn off the device.
SW1, SW2, SW3: Switch Pins. Collector of the internal
NPN power switch of the respective converter. Connect
to external inductor and anode of external Schottky recti-
fi er of the respective converter. Minimize the metal trace
area connected to this pin to minimize electromagnetic
interference.
TG1, TG2, TG3: The Gate Driver Output Pin for Discon-
nect P-Channel MOSFET. One for each converter. When
the PWM pin is low, the TG pin pulls up to ISP to turn
off the external MOSFET. When the PWM pin is high, the
external MOSFET turns on. ISPn-TGn is limited to 6.5V to
protect the MOSFET. Leave open if the external MOSFET
is not used.
VC1, VC2, VC3: Error Amplifi er Compensation Pins. Connect
a series RC from these pins to GND.
VIN: Input Supply Pin. Must be locally bypassed. Powers
the internal control circuitry.
VREF: Reference Output Pin. Can supply up to 200µA. The
nominal Output Voltage is 2V.
PIN FUNCTIONS
LT3492
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–
+
–
+
+
EAMP
A1
–+ V1
PWM1
VC
1V
PWM
COMPARATOR
SLOPE
R1 2k
–+VSENSE ILED LED ARRAY
M1
RSENSE
A8
CTRL
BUFFER
Q3
1V
CTRL1
VC1
Q1
GND
R2
20k
R6
R5
–
+
–
+
A3
SR LATCH
ISENSE
REPLICATED FOR EACH CHANNEL
SHARED COMPONENTS
S
RQ
A2
–
+
A9
A6 NPN
DRIVER
–
+
A10
A4
A7
MOSFET
DRIVER
A5
VIN
VREF
FADJ
3492 BD
SHDN
OVP1
R3
R4
RC
PWM1TG1ISN1ISP1 SW1
D1
L1
VIN
C2
C1
CC
VIN
VIN
C3
C4
INTERNAL
REGULATOR
AND UVLO
2V
REFERENCE
RAMP
GENERATOR
OSCILLATOR
Q2
VIN
200µA
Figure 1. LT3492 Block Diagram Working in Boost Confi guration
BLOCK DIAGRAM
LT3492
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APPLICATIONS INFORMATION
Operation
The LT3492 uses a fi xed frequency, current mode control
scheme to provide excellent line and load regulation. Op-
eration can be best understood by referring to the Block
Diagram in Figure 1. The oscillator, ramp generator, refer-
ence, internal regulator and UVLO are shared among the
three converters. The control circuitry, power switch etc.,
are replicated for each of the three converters. Figure 1
shows the shared circuits and only converter 1 circuits.
If the SHDN pin is logic low, the LT3492 is shut down
and draws minimal current from VIN. If the SHDN pin is
logic high, the internal bias circuits turn on. The switching
regulators start to operate when their respective PWM
signal goes high.
The main control loop can be understood by following
the operation of converter 1. The start of each oscillator
cycle sets the SR latch, A3, and turns on power switch
Q1. The signal at the noninverting input (SLOPE node)
of the PWM comparator A2 is proportional to the sum
of the switch current and oscillator ramp. When SLOPE
exceeds VC (the output of the error amplifi er A1), A2 resets
the latch and turns off the power switch Q1 through A4
and A5. In this manner, A10 and A2 set the correct peak
current level to keep the output in regulation. Amplifi er
A8 has two noninverting inputs, one from the 1V internal
voltage reference and the other one from the CTRL1 pin.
Whichever input is lower takes precedence. A8, Q3 and R2
force V1, the voltage across R1, to be one tenth of either
1V or the voltage of CTRL1 pin, whichever is lower. VSENSE
is the voltage across the sensing resistor, RSENSE, which is
connected in series with the LEDs. VSENSE is compared to
V1 by A1. If VSENSE is higher than V1, the output of A1 will
decrease, thus reducing the amount of current delivered to
LEDs. In this manner the current sensing voltage VSENSE
is regulated to V1.
Converters 2 and 3 are identical to converter 1.
PWM Dimming Control
The LED array can be dimmed with pulse width modulation
using the PWM1 pin and an external P-channel MOSFET,
M1. If the PWM1 pin is pulled high, M1 is turned on by
internal driver A7 and converter 1 operates nominally.
A7 limits ISP1-TG1 to 6.5V to protect the gate of M1. If
the PWM1 pin is pulled low, Q1 is turned off. Converter 1
stops operating, M1 is turned off, disconnects the LED
array and stops current draw from output capacitor C2. The
VC1 pin is also disconnected from the internal circuitry and
draws minimal current from the compensation capacitor
CC. The VC1 pin and the output capacitor store the state
of the LED current until PWM1 is pulled up again. This
leads to a highly linear relationship between pulse width
and output light, and allows for a large and accurate dim-
ming range. A P-channel MOSFET with smaller total gate
charge (QG) improves the dimming performance, since
it can be turned on and off faster. Use a MOSFET with a
QG lower than 10nC, and a minimum VTH of –1V to –2V.
Don’t use a Low VTH PMOS. To optimize the PWM control
of all the three channels, the rising edge of all the three
PWM signals should be synchronized.
In the applications where high dimming ratio is not required,
M1 can be omitted to reduce cost. In these conditions,
TG1 should be left open. The PWM dimming range can be
further increased by using CTRL1 pin to linearly adjust the
current sense threshold during the PWM1 high state.
Loop Compensation
Loop compensation determines the stability and transient
performance. The LT3492 uses current mode control to
regulate the output, which simplifi es loop compensation.
To compensate the feedback loop of the LT3492, a series
resistor-capacitor network should be connected from the
VC pin to GND. For most applications, the compensation
capacitor should be in the range of 100pF to 2.2nF. The com-
pensation resistor is usually in the range of 5k to 50k.
To obtain the best performance, tradeoffs should be made
in the compensation network design. A higher value of
compensation capacitor improves the stability and dim-
ming range (a larger capacitance helps hold the VC voltage
when the PWM signal is low). However, a large compen-
sation capacitor also increases the start-up time and the
time to recover from a fault condition. Similarly, a larger
compensation resistor improves the transient response
but may reduce the phase margin. A practical approach
is to start with one of the circuits in this data sheet that
LT3492
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is similar to your application and tune the compensation
network to optimize the performance. The stability, PWM
dimming waveforms and the start-up time should be
checked across all operating conditions.
Open-LED Protection
The LT3492 has open-LED protection for all the three
converters. As shown in Figure 1, the OVP1 pin receives
the output voltage (the voltage across the output capacitor)
feedback signal from an external resistor divider. OVP1
voltage is compared with a 1V internal voltage reference by
comparator A6. In the event the LED string is disconnected
or fails open, converter 1 output voltage will increase, caus-
ing OVP1 voltage to increase. When OVP1 voltage exceeds
1V, the power switch Q1 will turn off, and cause the output
voltage to decrease. Eventually, OVP1 will be regulated to
1V and the output voltage will be limited. In the event one
of the converters has an open-LED protection, the other
converters will continue functioning properly.
Switching Frequency and Soft-Start
The LT3492 switching frequency is controlled by FADJ
pin voltage. Setting FADJ voltage to be less than 1V will
reduce switching frequency.
If FADJ voltage is higher than 1V, the default switch-
ing frequency is 2.1MHz. In general, a lower switching
frequency should be used where either very high or very
low switch duty cycle is required or higher effi ciency is
desired. Selection of a higher switching frequency will
allow use of low value external components and yield a
smaller solution size and profi le.
As a cautionary note, operation of the LT3492 at a com-
bination of high switching frequency with high output
voltage and high switch current may cause excessive
internal power dissipation. Consideration should be given
to selecting a switching frequency less than 1MHz if these
conditions exist.
Connecting FADJ pin to a lowpass fi lter (R5 and C4 in
Figure 1) from the REF pin provides a soft-start function.
During start-up, FADJ voltage increases slowly from 0V
to the setting voltage. As a result, the switching frequency
increases slowly to the setting frequency. This function
limits the inrush current during start-up.
Input Capacitor Selection
For proper operation, it is necessary to place a bypass
capacitor to GND close to the VIN pin of the LT3492. A
1µF or greater capacitor with low ESR should be used. A
ceramic capacitor is usually the best choice.
In the buck mode confi guration, the capacitor at PVIN has
large pulsed currents due to the current returned though
the Schottky diode when the switch is off. For the best
reliability, this capacitor should have low ESR and ESL
and have an adequate ripple current rating. The RMS
input current is:
IIN(RMS) =ILED •1–D
()
•D
where D is the switch duty cycle. A 1µF ceramic type ca-
pacitor placed close to the Schottky diode and the ground
plane is usually suffi cient for each channel.
Output Capacitor Selection
The selection of output fi lter capacitor depends on the load
and converter confi guration, i.e., step-up or step-down.
For LED applications, the equivalent resistance of the LED
is typically low, and the output fi lter capacitor should be
large enough to attenuate the current ripple.
To achieve the same LED ripple current, the required fi lter
capacitor value is larger in the boost and buck-boost mode
applications than that in the buck mode applications. For
the LED buck mode applications at 1.3MHz, a 0.22µF ce-
ramic capacitor is usually suffi cient for each channel. For
the LED boost and buck-boost applications at 1.3MHz, a
1µF ceramic capacitor is usually suffi cient for each chan-
nel. Lower switching frequency requires proportionately
higher capacitor values. If higher LED current ripple can
be tolerated, a lower output capacitance can be selected
to reduce the capacitor’s cost and size.
Use only ceramic capacitors with X7R or X5R dielectric,
as they are good for temperature and DC bias stability of
the capacitor value. All ceramic capacitors exhibit loss of
capacitance value with increasing DC voltage bias, so it
may be necessary to choose a higher value capacitor to get
the required capacitance at the operation voltage. Always
check that the voltage rating of the capacitor is suffi cient.
Table 1 shows some recommended capacitor vendors.
APPLICATIONS INFORMATION
LT3492
11
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Table 1. Ceramic Capacitor Manufacturers
VENDOR TYPE SERIES
Taiyo Yuden Ceramic X5R, X7R
AVX Ceramic X5R, X7R
Murata Ceramic X5R, X7R
Kemet Ceramic X5R, X7R
TDK Ceramic X5R, X7R
Inductor Selection
Inductor value is selected based on switching frequency
and desired transient response. The data sheet applica-
tions show appropriate selections for a 1.3MHz switching
frequency. Proportionately higher values may be used if a
lower switching frequency is selected.
Several inductors that work well with the LT3492 are listed
in Table 2. However, there are many other manufacturers
and devices that can be used. Consult each manufacturer
for more detailed information and their entire range of
parts. Ferrite core inductors should be used to obtain the
best effi ciency. Choose an inductor that can handle the
necessary peak current without saturating, and ensure that
the inductor has a low DCR (copper-wire resistance) to
minimize I2R power losses. An inductor with a magnetic
shield should be used to prevent noise radiation and cross
coupling among the three channels.
Diode Selection
The Schottky diode conducts current during the interval
when the switch is turned off. Select a diode VR rated
for the maximum SW voltage. It is not necessary that
the forward current rating of the diode equal the switch
current limit. The average current, IF
, through the diode
is a function of the switch duty cycle. Select a diode with
forward current rating of:
I
F = IL • (1 – D)
where IL is the inductor current.
If using the PWM feature for dimming, it is important to
consider diode leakage, which increases with the tem-
perature from the output during the PWM low interval.
Therefore, choose the Schottky diode with suffi cient low
leakage current at hot temperature. Table 3 shows several
Schottky diodes that work well with the LT3492.
APPLICATIONS INFORMATION
Table 2. Surface Mount Inductors
PART NUMBER
VALUE
(μH)
DCR
(Ω MAX) IRMS (A)
SIZE
W × L × H (mm3)
Sumida
CDRH4D28 15 0.149 0.76 5.0 × 5.0 × 3.0
CDRH5D28 22 0.122 0.9 6.0 × 6.0 × 3.0
33 0.189 0.75
CooperET
SD20 15 0.1655 1.25 5.0 × 5.0 × 2.0
22 0.2053 1.12
SD25 33 0.2149 1.11 5.0 × 5.0 × 2.5
Taiyo Yuden
NP04SZB 15 0.180 0.95 4.0 × 4.0 × 1.8
22 0.210 0.77
TDK
VLF5014A 15 0.32 0.97 4.5 × 4.7 × 1.4
22 0.46 0.51
Würth Electronics
7447789133 33 0.24 1.22 7.3 × 7.3 × 3.2
Coilcraft
M556132 22 0.19 1.45 6.1 × 6.1 × 3.2
Table 3. Schottky Diodes
PART NUMBER VR (V) IF (A) PACKAGE
ZETEX
ZLLS350 40 0.38 SOD523
ZLLS400 40 0.52 SOD323
DIODES
B1100 100 1.0 SMA
ROHM
RB160M-60 60 1.0 PMDU/SOD-123
Undervoltage Lockout
The LT3492 has an undervoltage lockout circuit that
shuts down all the three converters when the input volt-
age drops below 2.1V. This prevents the converter from
switching in an erratic mode when powered from a low
supply voltage.
Programming the LED Current
An important consideration when using a switch with a
fi xed current limit is whether the regulator will be able to
supply the load at the extremes of input and output voltage
range. Several equations are provided to help determine
LT3492
12
3492fa
APPLICATIONS INFORMATION
this capability. Some margin to data sheet limits is included,
along with provision for 200mA inductor ripple current.
For boost mode converters:
IOUT(MAX) ≅0.4A VIN(MIN)
VOUT(MAX)
For buck mode converters:
I
LED(MAX) ≅ 0.4A
For SEPIC and buck-boost mode converters:
IOUT(MAX) ≅0.4A VIN(MIN)
(V
OUT(MAX) +VIN(MIN))
If some level of analog dimming is acceptable at minimum
supply levels, then the CTRL pin can be used with a resistor
divider to VIN (as shown in the Block Diagram) to provide
a higher output current at nominal VIN levels.
The LED current of each channel is programmed by con-
necting an external sense resistor RSENSE in series with
the LED load, and setting the voltage regulation threshold
across that sense resistor using CTRL input. If the CTRL
voltage, VCTRL, is less than 1V, the LED current is:
ILED =VCTRL
10 •RSENSE
If VCTRL is higher than 1V, the LED current is:
ILED =100mV
RSENSE
The CTRL pins should not be left open. The CTRL pin
can also be used in conjunction with a PTC thermistor to
provide overtemperature protection for the LED load as
shown in Figure 2.
Thermal Considerations
The LT3492 is rated to a maximum input voltage of 30V
for continuous operation, and 40V for nonrepetitive one
second transients. Careful attention must be paid to the
internal power dissipation of the LT3492 at higher input
voltages and higher switching frequencies/output voltage
to ensure that a junction temperature of 125°C is not
exceeded. This is especially important when operating
at high ambient temperatures. Consider driving VIN from
5V or higher to ensure the fastest switching edges, and
minimize one source of switching loss. The exposed
pad on the bottom of the package must be soldered to
a ground plane. This ground should then be connected
to an internal copper ground plane with thermal vias
placed directly under the package to spread out the heat
dissipated by the LT3492.
Board Layout
The high speed operation of the LT3492 demands careful
attention to board layout and component placement. The
exposed pad of the package is the only GND terminal of
the IC and is important for thermal management of the
IC. Therefore, it is crucial to achieve a good electrical and
thermal contact between the exposed pad and the ground
plane of the board. Also, in boost confi guration, the
Schottky rectifi er and the capacitor between GND and the
cathode of the Schottky are in the high frequency switching
path where current fl ow is discontinuous. These elements
should be placed so as to minimize the path between SW
and the GND of the IC. To reduce electromagnetic interfer-
ence (EMI), it is important to minimize the area of the SW
node. Use the GND plane under SW to minimize interplane
coupling to sensitive signals. To obtain good current
regulation accuracy and eliminate sources of channel to
channel coupling, the ISP and ISN inputs of each channel
of the LT3492 should be run as separate lines back to the
terminals of the sense resistor. Any resistance in series
with ISP and ISN inputs should be minimized. Avoid ex-
tensive routing of high impedance traces such as OVP and
VC. Make sure these sensitive signals are star coupled to
the GND under the IC rather than a GND where switching
currents are fl owing. Finally, the bypass capacitor on the
VIN supply to the LT3492 should be placed as close as
possible to the VIN terminal of the device.
Figure 2
50k
3492 F02
45k
2V
VREF
470
PTC
CTRL1-3
LT3492
13
3492fa
TYPICAL APPLICATIONS
Minimum BOM Buck Mode LED Driver
300:1 PWM Dimming at 100Hz Effi ciency
0.3A
C4
0.22µF
C5
0.22µF
C6
0.22µF
ISN1
330m 330m
PVIN
58V
10 LEDs
L1
33µH
L2
33µH
L3
33µH
ISP1
0.3A
ISN2
ISP2
0.3A
ISN3
C1-C3
1µF
s3
330m
ISP3
D1 D2 D3
C1-C3, C7: MURATA GRM31CR72A105KA01L
C4-C6: MURATA GRM21BR71H224KA01
D1-D3: DIODES B1100
L1-L3: TDK VLF5014AT-330MR50
10k
150k
49.9k 470pF
3492 TA07a
SW1 SW2
LT3492
GND
SW3 TG1-3
VC1-3
VREF
CTRL1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
5V
C7
1µF FADJ
OVP1-3
1.3MHz
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.5A/DIV
5µs/DIV 3492 TA07b
PWM DUTY CYCLE (%)
0
50
EFFICIENCY (%)
55
65
70
75
40 80 100
95
3492 TA07c
60
20 60
80
85
90
LT3492
14
3492fa
1000:1 PWM Dimming at 100Hz
TYPICAL APPLICATIONS
Triple Boost 100mA × 12 LED Driver
Effi ciency vs PWM Duty Cycle
12 LEDs
C2
1µF
C3
1µF
C4
1µF
PVIN
12V
100mA
1M
20k
OVP1
ISN1
TG1
1
2.2nF
3492 TA03a
L1
22µH
L2
22µH
L3
22µH
ISP1
D1 D2 D3
M1 M2 M3
SW1 SW2
LT3492
GND
SW3 TG1-3
OVP1-3
VC1-3
VREF
CTRL1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
5V
C1: MURATA GRM31MR71C225KA35
C2-C4: MURATA GRM31CR72A105KA01L
C5: MURATA GRM31MR71H105KA88
D1-D3: DIODES B1100
L1-L3: TDK VLF5014AT-220MR62
M1-M3: ZETEX ZXMP6A13F
C5
1µF
12 LEDs 100mA
1M
20k
OVP2
ISN2
TG2
1
ISP2
12 LEDs 100mA
1M
20k
OVP3
150k
18.2k
49.9k
1.3MHz
ISN3
TG3
1
ISP3
C1
2.2µF
s3
FADJ
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.1A/DIV
2µs/DIV 3492 TA03b
PWM DUTY CYCLE (%)
0
75
80
85
80
3492 TA03c
70
65
20 40 60 100
60
55
50
EFFICIENCY (%)
LT3492
15
3492fa
TYPICAL APPLICATIONS
Dual Boost LED Driver
C2
1µF
C3
1µF
C4
1µF
PVIN
12V
ISN1
M1
1
2.2nF
OPEN
3492 TA04
L1
22µH
L2
22µH
L3
22µH
ISP1
D1 D2 D3
SW1 TG1 SW2
LT3492
GND
SW3 TG2
FADJ
OVP1-3
TG3
VC1-3
VREF
CTRL1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
3V TO 12V C5
1µF
C1
2.2µF
s3
ISN2
1
ISP2
12 LEDs 200mA 20k
OVP2-3
150k
18.2k
49.9k
1.3MHz
ISN3
M2
1
ISP3
12 LEDs 100mA
1M 1M
20k
OVP1
C1: MURATA GRM31MR71C225KA35
C2-C4: MURATA GRM31CR72A105KA01L
C5: MURATA GRM31MR71H105KA88
D1-D3: DIODES B1100
L1-L3: TDK VLF5014AT-220MR62
M1, M2: ZETEX ZXMP6A13F
1000:1 PWM Dimming at 100Hz for 200mA LEDs
PWM
5V/DIV
IL2
IL3
0.5A/DIV
ILED
0.2A/DIV
2µs/DIV 3492 TA04b
Effi ciency vs PWM Duty Cycle for 200mA LEDs
PWM DUTY CYCLE (%)
0
75
80
85
80
3492 TA04c
70
65
20 40 60 100
60
55
50
EFFICIENCY (%)
LT3492
16
3492fa
Triple Boost 100mA × 9 LED Driver with VIN Controlled Dimming
9 LEDs
C2
1µF
C3
1µF
C4
1µF
100mA
750k
20k
OVP1
ISN1
TG1
1
2.2nF
3492 TA08
L1
15µH
L2
15µH
L3
15µH
ISP1
D1 D2 D3
M1 M2 M3
SW1 SW2
LT3492
GND
SW3 TG1-3
OVP1-3
VC1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
5V TO 16V
C1: MURATA GRM31MR71C225KA35
C2-C5: MURATA GRM31MR71H105KA88
D1-D3: ZETEX ZLLS400TA
L1-L3: TAIYO YUDEN NP04SZB 150M
M1-M3: ZETEX ZXMP6A13F
C5
1µF
9 LEDs 100mA
750k
20k
OVP2
ISN2
TG2
1
ISP2
9 LEDs 100mA
750k
430k
18.2k
OVP3
20k
100k
1MHz
ISN3
TG3
1
CTRL1-3
357k
40.2k
ISP3
C1
2.2µF
s3
VREF
FADJ
CTRL1-3
TYPICAL APPLICATIONS
LED Current Decreasing with VIN Effi ciency vs VIN
VIN (V)
2
ILED (mA)
70
80
90
18
3492 TA08b
60
50
20 610 14
40
30
110
100
VIN (V)
4
0
EFFICIENCY (%)
10
30
40
50
12
90
3492 TA08c
20
816
60
70
80
LT3492
17
3492fa
TYPICAL APPLICATIONS
Triple LED Driver Driving LED Strings in Buck, Boost and Buck-Boost Modes
2 LEDs
C3
1µF
VIN
10V TO 16V
0.3A
ISN1
TG1
330m
2.2nF
3492 TA05
L1
6.8µH
L2
22µH
L3
33µH
ISP1
D2
M1
M2
M3
1
SW1 SW2
LT 3 4 9 2
GND
SW3 TG1-3
OVP2-3
VC1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
C1: MURATA GRM55DR71H335KA0193
C2: MURATA GRM21BR71H474KA88
C3, C5: MURATA GRM31MR71H105KA88
C4: MURATA GRM21BR71H104KA01B
D1: DIODES DFLS130
D2, D3: ROHM RB160M-60
L1: TDK VLF5014AT-6R8MR99
L2: TDK VLF5014AT-229MR62
L3: TDK VLF5014AT-330MR50
M1: ZETEX ZXMP3A13F
M2, M3 ZETEX ZXMP6A13F
10 LEDs 0.1A
825k
20k
OVP2
ISN2
TG2
C2
0.47µF
D1
1
ISP2
D3
4 LEDs
100k
0.1A
18.2k
150k
49.9k
1.3MHz
ISN3
TG3
3.9M
VIN
ISP3
C4
0.1µF
C5
1µF
OVP3
C1
3.3µF
s3
VREF
CTRL1-3
FADJ
OVP1
3000:1 PWM Dimming at 100Hz for CH1 (Buck Mode) 3000:1 PWM Dimming at 100Hz for CH2 (Boost Mode)
3000:1 PWM Dimming at 100Hz for CH3 (Buck-Boost Mode)
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.5A/DIV
1µs/DIV 3492 TA05b
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.1A/DIV
1µs/DIV 3492 TA05c
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.1A/DIV
1µs/DIV 3492 TA05d
LT3492
18
3492fa
Triple Buck Mode LED Driver with Open LED Protection
0.3A
C4
0.47µF
C5
0.47µF
C6
0.47µF
D1 D2 D3
5.6k 5.6k
80.6k 80.6k
2k 2k
ISN1
M1 M2 M3
330m 330m
TG1
PVIN
48V
L1
22µH
L2
22µH
L3
22µH
M4
OVP1 OVP2
M5 M6
ISP1
0.3A
ISN2
TG2
ISP2
0.3A
ISN3
C1-C3
1µF
s3
330m
3492 TA02
TG3
ISP3
5.6k
80.6k
2k
OVP1
C1-C3, C7: MURATA GRM31CR72A105KA01L
C4-C6: MURATA GRM21BR72A474KA73
D1-D3: ROHM RB160M-60
L1-L3: TDK VLF5014AT-220MR62
M1-M3: ZETEX ZXMP6A13F
M4-M6: PHILIPS BC858B
470pF
SW1 SW2
LT3492
GND
SW3
FADJ
TG1-3
OVP1-3
VC1-3
VREF
CTRL1-3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
5V C7
1µF 430k
10k
100k
1MHz
10 LEDs 10 LEDs 10 LEDs
TYPICAL APPLICATIONS
2000:1 PWM Dimming at 100Hz Effi ciency vs PWM Duty Cycle for 200mA LEDs
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.5A/DIV
1µs/DIV 3492 TA02b
PWM DUTY CYCLE (%)
0
50
EFFICIENCY (%)
55
65
70
75
40 80 100
95
3492 TA02c
60
20 60
80
85
90
LT3492
19
3492fa
PACKAGE DESCRIPTION
FE28 (EB) TSSOP 0204
0.09 – 0.20
(.0035 – .0079)
0o – 8o
0.25
REF
0.50 – 0.75
(.020 – .030)
4.30 – 4.50*
(.169 – .177)
134
5678910
11 12 13 14
192022 21 151618 17
9.60 – 9.80*
(.378 – .386)
4.75
(.187)
2.74
(.108)
28 2726 25 24 23
1.20
(.047)
MAX
0.05 – 0.15
(.002 – .006)
0.65
(.0256)
BSC 0.195 – 0.30
(.0077 – .0118)
TYP
2
RECOMMENDED SOLDER PAD LAYOUT
EXPOSED
PAD HEAT SINK
ON BOTTOM OF
PACKAGE
0.45 p0.05
0.65 BSC
4.50 p0.10
6.60 p0.10
1.05 p0.10
4.75
(.187)
2.74
(.108)
MILLIMETERS
(INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.150mm (.006") PER SIDE
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
2. DIMENSIONS ARE IN
3. DRAWING NOT TO SCALE
SEE NOTE 4
4. RECOMMENDED MINIMUM PCB METAL SIZE
FOR EXPOSED PAD ATTACHMENT
6.4
0
(.25
2
BSC
FE Package
28-Lead Plastic TSSOP (4.4mm)
(Reference LTC DWG # 05-08-1663)
Exposed Pad Variation EB
LT3492
20
3492fa
4.00 p 0.10
(2 SIDES)
2.50 REF
5.00 p 0.10
(2 SIDES)
NOTE:
1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WXXX-X).
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
PIN 1
TOP MARK
(NOTE 6)
0.40 p 0.1
0
27 28
1
2
BOTTOM VIEW—EXPOSED PAD
3.50 REF
0.75 p 0.05 R = 0.115
TYP
R = 0.05
TYP
PIN 1 NOTCH
R = 0.20 OR 0.3
5
s 45o CHAMFER
0.25 p 0.05
0.50 BSC
0.200 REF
0.00 – 0.05
(UFD28) QFN 0506 REV
B
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
0.70 p0.05
0.25 p0.05
0.50 BSC
2.50 REF
3.50 REF
4.10 p 0.05
5.50 p 0.05
2.65 p 0.05
3.10 p 0.05
4.50 p 0.05
PACKAGE OUTLINE
2.65 p 0.10
3.65 p 0.10
3.65 p 0.05
PACKAGE DESCRIPTION
UFD Package
28-Lead Plastic QFN (4mm × 5mm)
(Reference LTC DWG # 05-08-1712 Rev B)
LT3492
21
3492fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
A 04/10 Corrected Pin Names for FE Package in Pin Confi guration Section 2
LT3492
22
3492fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2009
LT 0410 REV A • PRINTED IN USA
TYPICAL APPLICATION
Triple Buck-Boost Mode 100mA × 4 LED Driver
3000:1 PWM Dimming at 100Hz
PVIN
10V TO 16V
2.2nF
3492 TA06
SW1 SW2
PVIN
LT3492
GND
SW3
ISP1-3
ISN1-3
VIN
PWM1-3
SHDN
VIN
5V TO 16V C8
1µF
4 LEDs
100mA
3.9M
100k
OVP3
18.2k
ISN3
TG3
1
L1
22µH
L2
22µH
L3
22µH
ISP3
ISN2
1
ISP2
C2
0.1µF
C4
0.1µF
C6
0.1µF
C5
1µF
PVIN
C3
1µF
PVIN
C7
1µF
ISN1
D1 D2 D3
1
ISP1
3.9M
100k
OVP2
3.9M
100k
OVP1
C1
2.2µF
4 LEDs
100mA
TG2TG1
4 LEDs
100mA
M1 M2 M3
C1: MURATA GRM31MR71E225KA93
C2, C4, C6: MURATA GRM21BR71H104KA01B
C3, C5, C7: MURATA GRM31MR71H105KA88
C8: MURATA GRM31MR71E105KA93
D1-D3: ROHM RB160M-60
L1-L3: TDK VLF5014AT-220MR62
M1-M3: ZETEX ZXMP6A13F
FADJ
TG1-3
OVP1-3
VC1-3
VREF
CTRL1-3
150k
49.9k
1.3MHz
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT3496 Triple 0.75A, 2.1MHz, 45V LED Driver VIN: 3V to 30V, VOUT(MAX) = 45V, Dimming = 3000:1, ISD < 1µA,
4mm × 5mm QFN and TSSOP16E Packages
LT3474 36V, 1A (ILED), 2MHz, Step-Down LED Driver VIN: 4V to 36V, VOUT(MAX) = 13.5V, True Color PWM Dimming = 400:1,
ISD < 1µA, TSSOP16E Package
LT3475 Dual 1.5A (ILED), 36V, 2MHz Step-Down LED Driver VIN: 4V to 36V, VOUT(MAX) = 13.5V, True Color PWM Dimming = 3000:1,
ISD < 1µA, TSSOP20E Package
LT3476 Quad Output 1.5A, 36V, 2MHz High Current LED Driver
with 1000:1 Dimming
VIN: 2.8V to 16V, VOUT(MAX) = 36V, True Color PWM Dimming = 1000:1,
ISD < 10µA, 5mm × 7mm QFN Package
LT3477 3A, 42V, 3MHz Boost, Buck-Boost, Buck LED Driver VIN: 2.5V to 25V, VOUT(MAX) = 40V, Dimming = Analog/PWM, ISD < 1µA,
QFN and TSSOP20E Packages
LT3478/LT3478-1 4.5A, 42V, 2.5MHz High Current LED Driver with
3000:1 Dimming
VIN: 2.8V to 36V, VOUT(MAX) = 42V, True Color PWM Dimming = 3000:1,
ISD < 3µA, TSSOP16E Package
LT3486 Dual 1.3A, 2MHz High Current LED Driver VIN: 2.5V to 24V, VOUT(MAX) = 36V, True Color PWM Dimming = 1000:1,
ISD < 1µA, 5mm × 3mm DFN and TSSOP16E Packages
LT3517 1.5A, 2.5MHz, 45V LED Driver VIN: 3V to 30V, VOUT(MAX) = 45V, Dimming = 3000:1, ISD < 1µA,
4mm × 4mm QFN and TSSOP16E Packages
LT3518 2.3A, 2.5MHz, 45V LED Driver VIN: 3V to 30V, VOUT(MAX) = 45V, Dimming = 3000:1, ISD < 1µA,
4mm × 4mm QFN and TSSOP16E Packages
LT3755/LT3755-1 40VIN, 75VOUT, Full Featured LED Controller VIN: 4.5V to 40V, VOUT(MAX) = 75V, True Color PWM Dimming = 3000:1,
ISD < 1µA, 3mm × 3mm QFN-16 and MS16E Packages
LT3756-1 100V High Current LED Controller VIN: 6V to 100V, VOUT(MAX) = 100V, True Color PWM Dimming = 3000:1,
ISD < 1µA, 3mm × 3mm QFN-16 and MS16E Packages
LT C
®
3783 High Current LED Controller VIN: 3V to 36V, VOUT(MAX) = Ext FET, True Color PWM Dimming = 3000:1,
ISD < 20µA, 5mm × 4mm QFN10 and TSSOP16E Packages
PWM
5V/DIV
IL
0.5A/DIV
ILED
0.1A/DIV
1µs/DIV 3492 TA06b
