LT3595A
16 Channel
Buck Mode LED Driver
DESCRIPTION
FEATURES
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4.5V to 45V Input Supply Range
Up to 50mA LED Current per Channel
100mA, 45V Internal Switches
Improvements vs LT3595
Pinout Allows 1-Sided PCB Layout
Higher Maximum Switch Duty Cycle
LED Current Accuracy (7% vs 8%)
±4% LED Current Matching
16 Independent LED Channels
5000:1 True Color PWMTM Dimming Range
LEDs Disconnected in Shutdown
Internal Schottky Diodes
2MHz Switching Frequency
RSET Pin Sets Master LED Current
Typical Efficiency: 92%
Open LED Detection and Thermal Protection
56-Pin 5mm × 9mm × 0.75mm QFN Package
The LT®3595A is a high performance LED Driver designed
to drive sixteen independent channels of up to 10 LEDs
at currents up to 50mA. Series connection of the LEDs
provides identical LED currents resulting in uniform brightness. Power switches, Schottky diodes, and compensation
components are all internal, providing a small converter
footprint and lower component cost. The high 2MHz
switching frequency permits the use of tiny, low profile
inductors and capacitors. A fixed frequency, current mode
architecture results in stable operation over a wide range
of supply and output voltage.
A single external resistor sets the LED current for all sixteen
channels, and dimming is then controlled for each channel by pulse width modulating the individual PWM pins.
LED current accuracy is 7%, channel-to-channel current
matching is ±4% and the PWM dimming range is 5000:1.
The part is available in a 5mm × 9mm × 0.75mm 56-pin
QFN package.
APPLICATIONS
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L, LT, LTC and LTM 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.
LED Video Billboards
LCD Televisions
Stadium and Advertising Displays
TYPICAL APPLICATION
16-Channel LED Driver (Three LEDs per Channel), 20mA Current
0.47μF
SW4
L4
L5
SW5
SW6
SW7
L7
0.47μF
SW13
L13
L12
SW12 L11 SW11 VIN SW10 L10
0.47μF
0.47μF
0.47μF
0.47μF
SW8
ISW
20mA/DIV
L8
PWM9
PWM10
PWM11
PWM12
PWM13
PWM14
PWM15
PWM16
GND
RSET
SW9 L9
LED
BRIGHTNESS
CONTROL
ILED
10mA/DIV
400ns/DIV
VIN = 15V
3 LEDS AT 20mA
3595A TA01b
T = 10ms
tON = 2μs
100μH
L15 SW15 VIN SW14 L14
VPWM
5V/DIV
100μH
100μH
100μH
L6
0.47μF
75.0k
L3
100μH
100μH
100μH
SW3
5000:1 PWM
Dimming at 100Hz
0.47μF
LT3595A
100μH
10μF
SW2
0.47μF
100μH
VCC
3V TO
5.5V
L2
0.47μF
100μH
LED
BRIGHTNESS
CONTROL
L1 SW1
OPENLED
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
PWM8
SHDN
VCC
L16 SW16
0.47μF
100μH
100k
100μH
VCC
0.47μF
100μH
0.47μF
100μH
0.47μF
100μH
10μF
100μH
VIN
15V TO
45V
0.47μF
0.47μF
3595A TA01
3595af
1
LT3595A
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
PWM1
PWM2
PWM3
PWM4
RSET
VCC
PWM13
PWM14
PWM15
TOP VIEW
PWM16
Input Voltage (VIN) ....................................................45V
L1-16 Voltage ...........................................................45V
Supply Voltage (VCC) ..................................................6V
RSET, OPENLED, PWM1-16, SHDN Voltage.................6V
Operating Junction Temperature Range
(Note 2) .............................................–40°C to 125°C
Storage Temperature Range...................–65°C to 125°C
56 55 54 53 52 51 50 49 48 47
L16 1
46 L1
SW16 2
45 SW1
L15 3
44 L2
SW15 4
43 SW2
VIN 5
42 GND
SW14 6
41 SW3
L14 7
40 L3
SW13 8
39 SW4
L13 9
38 L4
57
L12 10
37 L5
36 SW5
SW12 11
L11 12
35 L6
SW11 13
34 SW6
GND 14
33 VIN
SW10 15
32 SW7
31 L7
L10 16
SW9 17
30 SW8
L9 18
29 L8
PWM8
PWM7
PWM6
PWM5
SHDN
OPENLED
PWM12
PWM11
PWM10
PWM9
19 20 21 22 23 24 25 26 27 28
UHH PACKAGE
56-LEAD (5mm s 9mm) PLASTIC QFN
TJMAX = 125°C, θJA = 31°C/W, θJC = 0.5°C/W
EXPOSED PAD (PIN 57) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3595AEUHH#PBF
LT3595AEUHH#TRPBF
3595A
56-Lead (5mm × 9mm) Plastic QFN
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
3595af
2
LT3595A
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VIN = 45V, VCC = 3.3V, PWM = SHDN = OPENLED = 3.3V, RSET = 75k Ω,
GND = 0V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
VIN Operating Voltage
4.5
VCC Operating Voltage
3
TYP
MAX
UNITS
V
5.5
VCC Input Under Voltage Lockout
2.6
IVIN Quiescent Current ON, No Switching
0.25
V
2.9
V
mA
IVIN Quiescent Current in Shutdown
SHDN = 0V
15
IVCC Quiescent Current ON, No Switching
VCC = 3.3V
17
IVCC Quiescent Current in Shutdown
VCC = 3.3V, SHDN = 0V
3
10
μA
IL1-16 Output Current Accuracy
RSET = 75kΩ
20
21.4
mA
±1
±4
%
1.6
2
2.4
MHz
IL1-16 Channel-to-Channel Matching
18.6
l
RSET = 75kΩ
Switching Frequency
Maximum Duty Cycle
l
80
85
Switch Current Limit
l
90
120
Switch VCESAT
ISW1-16 = 50mA
450
Switch Leakage Current
VSW1-16 = 45V
0.1
Schottky Forward Drop
ISCHOTTKY = 50mA
0.8
Schottky Leakage Current
VSW1-16 = 0.7V, SHDN = 0V
0.1
SHDN, PWM1-16 Input Low Voltage
SHDN, PWM1-16 Input High Voltage
40
μA
mA
%
150
mA
mV
6
μA
V
4
μA
0.4
V
1.6
V
SHDN Pin Bias Current
SHDN = 3.3V
35
PWM1-16 Pin Bias Current
PWM1-16 = 3.3V
0.1
OPENLED Pin Voltage
VCC = 3.3V, I OPENLED = 200μA
0.12
OPENLED Pin Input Leakage Current
OPENLED = 3.3V
0.1
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.
μA
1
μA
V
1
μA
Note 2: The LT3595A 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.
3595af
3
LT3595A
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted.
PWM Dimming Waveforms
(1000:1)
Switching Waveforms
10 LEDS
VSW1
50V/DIV
10 LEDS
IL1
50mA/DIV
5 LEDS
VSW2
50V/DIV
PWM
5V/DIV
PWM
5V/DIV
IL
20mA/DIV
IL
20mA/DIV
ILED
20mA/DIV
ILED
20mA/DIV
3595A G01
400ns/DIV
VIN = 45V
ILED = 20mA
LED Current vs RSET Resistance
1
0.1
T = 125°C
1.6
40
30
20
0.01
0.001
0.01
VIN Quiescent Current
2.0
50
LED CURRENT (mA)
LED CURRENT (mA)
10
VIN = 40V
PWM FREQUENCY = 100Hz
10 LEDS AT 20mA tON = 1ms
60
VIN = 45V
10 LEDS AT 20mA
PWM FREQUENCY = 100Hz
0
10
1
DUTY CYCLE (%)
25
100
50
10
0
20
30
VIN (V)
40
50
3595A G06
SHDN Pin Bias Current
100
VCC = 3.3V
T = 125°C
T = 25°C
16
80
T = –40°C
14
T = 25°C
ISHDN (mA)
VCC CURRENT (mA)
0.8
3595A G05
VCC Quiescent Current
18
1.2
0
150
75
100
125
RSET RESISTANCE (kΩ)
3595A G04
20
T = 25°C
T = –40°C
0.4
10
0.1
3595A G03
2ms/DIV
VIN = 40V
PWM FREQUENCY = 100Hz
10 LEDS AT 20mA tON = 10μs
LED Current vs PWM Duty Cycle
Wide Dimming Range (5000:1)
100
3595A G02
2μs/DIV
VIN CURRENT (mA)
5 LEDS
IL2
50mA/DIV
PWM Dimming Waveforms
(10:1)
12
10
8
60
T = 125°C
T = –40°C
40
6
4
20
2
0
0
0
1
2
4
3
VCC (V)
5
6
7
3595A F07
0
1
2
3
4
SHDN (V)
5
6
3595A F08
3595af
4
LT3595A
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted.
Switching Frequency
vs Temperature
Current Limit vs Temperature
150
SWITCHING FREQUENCY (MHz)
130
120
110
100
SCHOTTKY LEAKAGE CURRENT (μA)
2.3
2.2
2.1
2.0
1.9
1.8
1.7
50
25
75
0
TEMPERATURE (°C)
100
1.6
–50 –25
125
50
25
75
0
TEMPERATURE (°C)
100
3595A G09
1.2
1.0
VIN = 45V
0.8
0.6
VIN = 24V
0.4
VIN = 4.5V
0.2
0
–50 –25
125
50
25
75
0
TEMPERATURE (°C)
3595A G10
Switch Saturation Voltage
(VCESAT)
100
125
3595A G11
Schottky Forward Voltage Drop
700
100
SCHOTTKY FORWARD CURRENT (mA)
SWITCH SATURATION VOLTAGE (mV)
CURRENT LIMIT (mA)
1.4
2.4
140
90
–50 –25
Schottky Leakage Current
vs Temperature
600
500
T = –40°C
400
T = 25°C
300
T = 125°C
200
100
80
60
T = 125°C
40
T = 25°C
20
T = –40°C
0
0
20
40
60
80
100
0
SWITCH CURRENT (mA)
0
0.2
0.6
0.8
0.4
SCHOTTKY FORWARD DROP (V)
3595A G12
1
3595A G13
OPENLED Waveforms
Transient Response
VSHDN
5V/DIV
ILED
CH 1
20mA/DIV
VSW
50V/DIV
OPENLED
5V/DIV
VSW
CH 1
50V/DIV
ILED
CH 2
20mA/DIV
ISW
50mA/DIV
ILED
20mA/DIV
100μs/DIV
VIN = 45V
10 LEDS AT 20mA
3595A G14
20μs/DIV
3595A G15
VIN = 45V
10 LEDS AT 20mA
3595af
5
LT3595A
PIN FUNCTIONS
L1-16 (Pins 1, 3, 7, 9, 10, 12, 16, 18, 29, 31, 35, 37,
38, 40, 44, 46): LED Pins. Connection point for the anode
of the highest LED in each string.
SHDN (Pin 24): Shutdown. Tie to 1.6V or greater to enable
the device. Tie below 0.4V to turn off the device.
SW1-16 (Pins 2, 4, 6, 8, 11, 13, 15, 17, 30, 32, 34,
36, 39, 41, 43, 45): Switch Pins. Minimize trace area
at these pins to minimize EMI. Connect the inductors to
these pins.
RSET (Pin 51): External Resistor to Set the Master LED
Current. The LED current is equal to:
VIN (Pins 5, 33): 4.5V to 45V Input Supply Pin. Must be
locally bypassed. Both VIN pins must be tied together.
PWM1-16 (Pins 19-22, 25-28, 47-50, 53-56): Input Pin
for LED Dimming Function. The rising edge of each channel
must be synchronized.
OPENLED (Pin 23): Open Collector Output for Reporting
Faults. If any channel experiences an open LED connection, the OPENLED pin is pulled low.
GND (Pins 14, 42): Ground. Connect these pins to ground.
ILED =
1 . 21V
• 1240
R SET
where RSET is the value of the external resistor. Use a
kelvin for ground metal.
VCC (Pin 52): 3.3V Input Supply. Must be locally bypassed.
Exposed Pad (Pin 57): Ground. The Exposed Pad must
be soldered to PCB. Use wide metal from backtab to the
grounds of the input capacitors on VCC and VIN .
3595af
6
LT3595A
BLOCK DIAGRAM
CIN
10μF
PWM1-16
52
VCC
3.3V
VCC
C1
10μF
VREG
L1-16
VREG
DFC
CONTROL
1 CHANNEL
16X
24
51
SHDN
RSET
VIN
VIN
COUT1-16
0.47μF
SW1-16
REF
V/I
–
+
PWM
RSET
3
R
Q
S
L1-16
100μH
+
–
ISNS
GND
RAMP
GENERATOR
OPENLED
2MHz
OSCILLATOR
23
CONTROL
3595A BD
3595af
7
LT3595A
OPERATION
The LT3595A uses a constant-frequency, current mode
control scheme to provide excellent line and load regulation. Operation is best understood by referring to the Block
Diagram. The oscillator, V-I converter and internal regulator
are shared by the sixteen converters. The control circuitry,
power switches, PWM comparators and Dimming Feedback
Control (DFC) blocks are identical for all converters.
4.5V input voltage or by its maximum duty cycle. The duty
cycle is the fraction of time that the internal switch is on
divided by the total period. It is determined by the input
voltage and the voltage across the LEDs:
The LT3595A enters shutdown mode when the SHDN
pin is lower than 400mV. If the SHDN pin is above 1.6V,
then the LT3595A turns on. At the start of each oscillator
cycle, the power switch is turned on. Current ramps up
through the output capacitor, the inductor, and the switch
to ground. When the voltage across the output capacitor
is larger than the LEDs’ forward voltage, current flows
through the LEDs.
where VLED is the voltage drop across the LEDs, VD is
the Schottky forward drop, and VCESAT is the saturation
voltage of the internal switch. This leads to a minimum
input voltage of:
When the switch is on, a voltage proportional to the switch
current is added to a stabilizing ramp and the resulting
sum is fed into the positive terminal of the PWM comparator. When this voltage exceeds the level at the negative
input of the PWM comparator, the PWM logic turns off
the power switch. The level at the negative input of the
PWM comparator is set by the error amplifier output. This
voltage is set by the LED current and the bandgap reference. In this manner, the error amplifier sets the correct
peak current level in the inductor to keep the LED output
current in regulation. The external RSET resistor is used
to program the LED current from 10mA to 50mA.
Input Voltage Range
The minimum input voltage required to generate a specific
output voltage in an LT3595A application is limited by its
DC =
VLED + VD
VVIN − VCESAT + VD
VIN(MIN) =
VLED + VD
+ VCESAT − VD
DCMAX
where DCMAX is the minimum rating of maximum duty
cycle.
The maximum input voltage is limited by the absolute
maximum rating of 45V.
Pulse-Skipping
At low duty cycles, the LT3595A may enter pulse-skipping
mode. Low duty cycle occurs at higher input voltages and
lower LED count. The LT3595A can drive currents without pulse-skipping provided the voltage across the LED
string is greater than 15% of the input supply voltage. If
the current decreases to the point that the LED voltage is
less than 15% of the input supply, the device may begin
skipping pulses. This will result in some low frequency
ripple, although the LED current remains regulated on an
average basis down to 10mA.
3595af
8
LT3595A
OPERATION
Discontinuous Current Mode
The LT3595A can drive a 10-LED string at 15mA LED
current operating in continuous conduction mode using
the recommended external components shown in the application circuit on page 1 of this data sheet. As current
is further reduced, the regulator enters discontinuous
conduction mode. The photo in Figure 1 details circuit
operation driving ten LEDs at 10mA load. The inductor
current reaches zero during the discharge phase and the
SW pin exhibits ringing. The ringing is due to the LC tank
circuit formed by the inductor in combination with the
switch and diode capacitance. This ringing is not harmful;
far less spectral energy is contained in the ringing than in
the switch transitions.
VSW
20V/DIV
IL
20mA/DIV
400ns/DIV
3595A F01
VIN = 45V
10 LEDS AT 10mA
Figure 1. Switching Waveforms
APPLICATIONS INFORMATION
Table 1. Inductor Manufacturers
Inductor Selection
A 100μH inductor is recommended for most LT3595A
applications. Although small size and high efficiency are
major concerns, the inductor should have low core losses
at 2MHz and low DCR (copper wire resistance). Some
inductors that meet these criteria are listed in Table 1. An
efficiency comparison of different inductors is shown in
Figure 2.
EFFICIENCY (%)
100
COILCRAFT 1812FS-104KLB
COILCRAFT LPS4012-104MLB
TOKO A915AY-101M
TDK VLCF4020T-101MR26
COILTRONICS SD3812-101
COILTRONICS SD52-101
95
90
PART
SERIES
INDUCTANCE
RANGE (μH)
RELEVANT TO
LT3595A
DIMENSIONS
(mm)
Coilcraft
www.coilcraft.com
DO1605
LPS4012
1812FS
MSS5131
100 to 680
100 to 680
100 to 680
100 to 390
5.4 × 4.2 × 1.8
4 × 4 × 1.2
5.8 × 4.9 × 3.8
5.1 × 5.1 × 3.1
Sumida
www.sumida.com
CDC4D20
100 to 680
4.8 × 4.8 × 2
Toko
www.tokoam.com
D53LC
100 to 680
5.2 × 5.4 × 3
TDK
www.component.
tdk.com
VLCF4020T
100 to 330
4×4×2
Coiltronics
www.cooperet.com
SD3812
SD52
100 to 330
100 to 330
4 × 4 × 1.2
5.6 × 5.2 × 2
Murata
www.murata.com
LQH32M
LQH43M
100 to 560
100 to 680
3.2 × 2.5 × 2
4.5 × 3.2 × 2
VENDOR
Capacitor Selection
85
10
20
30
ILED (mA)*
VIN = 45V L = 100μH
10 LEDS
*ILED ADJUSTED WITH RSET
40
50
3595A F02
Figure 2. Efficiency Comparison of Different Inductors
The small size of ceramic capacitors make them ideal for
LT3595A applications. Only X5R and X7R types should
be used because they retain their capacitance over wider
voltage and temperature ranges than other types such as
Y5V or Z5U. Typically, 10μF capacitors on VIN and VCC
are sufficient. The output capacitor used across the LED
3595af
9
LT3595A
APPLICATIONS INFORMATION
string depends on the number of LEDs and can vary from
0.47μF to 1μF. Refer to Table 2 for proper output capacitor
selection.
Table 2. Recommended Output Capacitor Values (VLED = 3.5V)
# LEDs
COUT (μF)
3-10
0.47
1-2
1
Table 3. Recommended Ceramic Capacitor Manufacturers
Taiyo Yuden
TDK
408-573-4150
www.t-yuden.com
847-803-6100
www.component.tdk.com
Murata
770-436-1300
www.murata.com
Kemet
800-533-1992
www.kemet.com
Table 3 shows a list of several ceramic capacitor manufacturers. Consult the manufacturers for detailed information
on their entire selection of ceramic parts.
Open LED Detection
The LT3595A detects an open LED on any channel and
reports it to the OPENLED pin. The fault also reports during startup until the output voltage and LED current are
in regulation. Therefore, it can also be used as a “power
ok” signal.
Programming LED Current
The set resistor (RSET in the Block Diagram) controls
the LED current in all sixteen channels. LED current as
a function of the RSET resistance is shown in the Typical
Performance Characteristics. Common values for LED current and their required resistor values are listed in Table 4.
Since resistor error directly translates to LED current error,
precision resistors are preferred (1% is recommended).
The maximum allowed resistor value is 150k.
Table 4. LED Current vs RSET Resistance
RSET (kΩ)
ILED (mA)
150
10
75.0
20
49.9
30
37.4
40
30.1
50
3595af
10
LT3595A
APPLICATIONS INFORMATION
Dimming Control
The sixteen PWM1-16 inputs control the dimming function. Each channel is modulated by its corresponding
PWM1-16 input. On a rising edge of any PWM1-16, the
IC’s internal support circuitry is enabled and the specific
channel turns on. LED current flows in the channel until
the falling edge of the PWM1-16 input. In this way, the
average LED current is modulated. The minimum on time
of a channel is 2μs and the maximum period is 10ms (at
100Hz). Therefore, the maximum dimming ratio is 5000:1.
Since the maximum RSET produces 10mA, the minimum
modulated LED current is 2μA.
When multiple channels are modulated, the rising edges
of PWM1-16 must be synchronized. The falling edges may
be asynchronous. A sample timing diagram is shown in
Figure 3.
SYNCHRONIZED RISING EDGES
PWM1-4
tON(MIN) = 2μs
PWM5-8
tMAX = 10ms
PWM9-16
ILED1-4
ILED5-8
ILED9-16
3595A F03
Figure 3. Timing Diagram for Multi-Channel Modulation
3595af
11
LT3595A
APPLICATIONS INFORMATION
Board Layout Considerations
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
To prevent electromagnetic interference (EMI) problems,
proper layout of high frequency switching paths is essential.
Minimize the length and area of all traces connected to
the SW1-16 and PWM1-16 pins. Keep the sense voltage
pins (VIN and L1-16) away from the switching nodes.
Place COUT1-16 and CIN close to the VIN pins. Always use
a ground plane under the switching regulator to minimize
interplane coupling. Recommended component placement
is shown in Figures 4-7.
Figure 4. PCB Layer 1
Figure 5. PCB Layer 2
3595af
12
LT3595A
APPLICATIONS INFORMATION
Figure 6. PCB Layer 3
Figure 7. PCB Layer 4
3595af
13
LT3595A
TYPICAL APPLICATION
30W LED Driver for 160 LEDs (16 Strings, 10 LEDs per String) at 50mA
VIN
45V
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
100μH
100μH
100μH
100μH
100μH
100μH
100μH
100μH
10μF
VCC
LED
BRIGHTNESS
CONTROL
3V TO
5.5V
L1 SW1
OPENLED
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
PWM8
SHDN
VCC
L16 SW16
L2
SW2
SW3
L3
SW4
L4
L5
SW5
L6
SW6
SW7
L7
LT3595A
SW15 VIN SW14
L15
L14
SW13
L13
L12
SW12 L11 SW11 VIN SW10 L10
SW8
L8
PWM9
PWM10
PWM11
PWM12
PWM13
PWM14
PWM15
PWM16
GND
RSET
SW9 L9
LED
BRIGHTNESS
CONTROL
30.1k
100k
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
100μH
100μH
100μH
100μH
100μH
100μH
100μH
100μH
10μF
0.47μF
0.47μF
3595A TA02
Conversion Efficiency
5000:1 PWM Dimming at 100Hz
100
EFFICIENCY (%)
VPWM
5V/DIV
95
ISW
50mA/DIV
ILED
20mA/DIV
90
400ns/DIV
3595A TA02c
10 LEDS AT 40mA*
85
10
20
30
ILED (mA)*
40
50
*ILED ADJUSTED WITH RSET
3595A TA02b
*ILED ADJUSTED WITH RSET
3595af
14
LT3595A
PACKAGE DESCRIPTION
UHH Package
56-Lead Plastic QFN (5mm × 9mm)
(Reference LTC DWG # 05-08-1727 Rev A)
0.70 p 0.05
5.50 p 0.05
(2 SIDES)
4.10 p 0.05
(2 SIDES)
3.60 REF
(2 SIDES)
3.45 p 0.05
7.13 p 0.05
PACKAGE
OUTLINE
0.20 p 0.05
0.40 BSC
6.80 REF (2 SIDES)
8.10 p 0.05 (2 SIDES)
9.50 p 0.05 (2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
5.00 p 0.10
(2 SIDES)
0.75 p 0.05
PIN 1 NOTCH
R = 0.30 TYP OR
0.35 s 45o CHAMFER
3.60 REF
55 56
0.00 – 0.05
0.40 p 0.10
PIN 1
TOP MARK
(SEE NOTE 6)
1
2
9.00 p 0.10
(2 SIDES)
6.80 REF
7.13 p 0.10
3.45 p 0.10
(UH) QFN 0406 REV A
0.200 REF
0.200 REF
0.00 – 0.05
0.75 p 0.05
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
0.20 p 0.05
R = 0.115
TYP
0.40 BSC
BOTTOM VIEW—EXPOSED PAD
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm 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
3595af
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT3595A
TYPICAL APPLICATION
16-Channel LED Driver (Three LEDs per Channel), 20mA Current
VIN
15V TO
45V
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
5000:1 PWM Dimming at 100Hz
0.47μF
VPWM
5V/DIV
0.47μF
L1 SW1
OPENLED
PWM1
PWM2
PWM3
PWM4
PWM5
PWM6
PWM7
PWM8
SHDN
VCC
L16 SW16
LED
BRIGHTNESS
CONTROL
3V TO
5.5V
L2
SW2
SW3
SW4
L4
L5
SW5
L6
SW6
SW7
100μH
100μH
100μH
100μH
100μH
L3
L7
SW8
LT3595A
L15
SW15 VIN SW14
L14
SW13
L13
L12
SW12 L11 SW11 VIN SW10 L10
ISW
20mA/DIV
L8
ILED
10mA/DIV
PWM9
PWM10
PWM11
PWM12
PWM13
PWM14
PWM15
PWM16
GND
RSET
SW9 L9
LED
BRIGHTNESS
CONTROL
0.47μF
0.47μF
0.47μF
0.47μF
0.47μF
3595A TA03b
T = 10ms
tON = 2μs
100μH
100μH
100μH
100μH
100μH
100μH
100μH
100μH
10μF
0.47μF
400ns/DIV
VIN = 15V
3 LEDS AT 20mA
75.0k
100k
100μH
VCC
100μH
100μH
10μF
0.47μF
0.47μF
3595A TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT3463/
LT3463A
VIN: 2.3V to 15V, VOUT(MAX) = ±40V, IQ = 40μA, ISD < 1μA,
Dual Output, Boost/Inverter, 250mA ISW, Constant Off-Time, High
Efficiency Step-Up DC/DC Converter with Integrated Schottky Diodes 3mm × 3mm DFN-10 Package
LT3465/
LT3465A
Constant-Current, 1.2MHz/2.7MHz, High Efficiency White LED Boost VIN: 2.7V to 16V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1μA,
Regulator with Integrated Schottky Diode
ThinSOTTM Package
LT3466/
LT3466-1
Dual Constant-Current, 2MHz, High Efficiency White LED Boost
Regulator with Integrated Schottky Diode
VIN: 2.7V to 24V, VOUT(MAX) = 40V, IQ = 5mA, ISD < 16μA,
3mm × 3mm DFN-10 Package
LT3474
36V, 1A (ILED), 2MHz, Step-Down LED Driver
VIN: 4V to 36V, VOUT(MAX) = 13.5V, 400:1 True Color PWMTM,
ISD < 1μA, TSSOP-16E Package
LT3475
Dual 1.5A (ILED), 36V, 2MHz, Step-Down LED Driver
VIN: 4V to 36V, VOUT(MAX) = 13.5V, 3000:1 True Color PWM,
ISD < 1μA, TSSOP-20E Package
LT3476
Quad Output 1.5A, 2MHz High Current LED Driver with 1000:1
Dimming
VIN: 2.8V to 16V, VOUT(MAX) = 36V, 1000:1 True Color PWM,
ISD < 10μA, 5mm × 7mm QFN-10 Package
LT3486
Dual 1.3A , 2MHz High Current LED Driver
VIN: 2.5V to 24V, VOUT(MAX) = 36V, 1000:1 True Color PWM,
ISD < 1μA, 5mm × 3mm DFN and TSSOP-16E Packages
LT3491
Constant-Current, 2.3MHz, High Efficiency White LED Boost
Regulator with Integrated Schottky Diode
VIN: 2.5V to 12V, VOUT(MAX) = 27V, IQ = 2.6mA, ISD < 8μA,
2mm × 2mm DFN-6 and SC70 Packages
LT3497
Dual 2.3MHz, Full Function LED Driver with Integrated Schottky
Diodes and 250:1 True Color PWM Dimming
VIN: 2.5V to 10V, VOUT(MAX) = 32V, IQ = 6μA, ISD < 12μA,
3mm × 2mm DFN-10 Package
LT3498
2.3MHz, 20mA LED Driver and OLED Driver with Integrated Schottky VIN: 2.5V to 12V, VOUT(MAX) = 32V, IQ = 1.65mA, ISD < 9μA,
Diodes
3mm × 2mm DFN-12 Package
LT3517/LT3518
2.3A/1.3A 45V, 2.5MHz Full Featured LED Driver with True Color
PWM Dimming
VIN: 3V to 30V/40V, VOUT(MAX) = 42V, 3000:1 True Color PWM,
ISD < 5μA, 4mm × 4mm QFN-16 Package
LT3590
48V Buck Mode LED Driver
VIN: 4.5V to 55V, VOUT(MAX) = 5V, IQ = 700μA, ISD < 15μA,
2mm × 2mm DFN-16 and SC70 Packages
LT3591
Constant-Current, 1MHz, High Efficiency White LED Boost Regulator VIN: 2.5V to 12V, VOUT(MAX) = 40V, IQ = 4mA, ISD < 9μA,
with Integrated Schottky Diode and 80:1 True Color PWM Dimming 3mm × 2mm DFN-8 Package
True Color PWM and ThinSOT are trademarks of Linear Technology Corporation.
3595af
16 Linear Technology Corporation
LT 0209 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
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© LINEAR TECHNOLOGY CORPORATION 2007