is31lt3360-sdls3-ebaic

IS31LT3360 AIC DEMO BOARD GUIDE
DESCRIPTION
RECOMMENDED EQUIPMENT
The IS31LT3360 is a continuous mode inductive
step-down converter, designed for driving a single LED
or multiple series connected LEDs efficiently from a
voltage source higher than the LED voltage. The chip
operates from an input supply between 6V and 40V
and provides an externally adjustable output current of
up to 1.2A.


The IS31LT3360 includes an integrated output switch
and a high-side output current sensing circuit, which
uses an external resistor to set the nominal average
output current.


Output current can be adjusted linearly by applying an
external control signal to the ADJ pin. The ADJ pin will
accept either a DC voltage or a PWM waveform. This
will provide either a continuous or a gated output
current.
Applying a voltage of 0.2V or lower to the ADJ pin
turns the output off and switches the chip into a low
current standby state.
The chip is assembled in SOT89-5 package.
IS31LT3360 AIC DEMO board is used in RGB lamp or
the general LED lamp.

40VDC or 12~24VAC power supply
3 pcs of LED panel (1W LED, 9 LEDs in series on
each panel)
Multi-meter
RECOMMENDED INPUT AND OUTPUT RATINGS
Input: 6~40VDC or 12~24VAC
Output: 1~9 LEDs in series/667mA
Note: The input voltage must be 5V higher than the output
voltage (total VREF).
ABSOLUTE MAXIMUM RATINGS

Input voltage ≤ 40VDC or 28VAC
Caution: Do not exceed the conditions listed above, otherwise
the board will be damaged.
PROCEDURE
The IS31LT3360 DEMO Board is fully assembled and
tested. Follow the steps listed below to verify board
operation.
Caution: Do not turn on the power supply until all connections
are completed.
FEATURES
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Simple low parts count
Internal 40V power switch
Wide input voltage range: 6V to 40V
Up to 1.2A output current
High efficiency (up to 98% )
Typical 1200:1 dimming rate
Typical 3% output current accuracy
Single pin on/off and brightness control using DC
voltage or PWM
Up to 1MHz switching frequency
Inherent open-circuit LED protection
Thermal shutdown protection circuitry
1)
2)
3)
4)
Connect the terminals of the power supply to the
AC1 and AC2 pin(If the board don’t have the
rectifier(D1-D4), Connect the positive terminal of
the power supply to the DC+ of the board and the
negative terminal of power supply to the DC- of
the board) .
Connect the negative of the one of LED panel
(LED arrays) to the LED1- terminal. And connect
the positive of the same LED panel (LED arrays)
to the LED1+ terminal.
Connect the other two LED panels to LED2 and
LED3 as above.
Turn on the power supply and the LED panel
(LED arrays) will be light.
QUICK START
Figure 1: Photo of IS31LT3360 Evaluation Board
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 08/31/2015
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IS31LT3360 AIC DEMO BOARD GUIDE
ORDER INFORMATION
Part No.
Temperature Range
Package
IS31LT3360-SDLS3-EBAIC
IS31LT3360-SDLS4-EBAIC
-40°C to +105°C (Industrial)
-40°C to +125°C (Industrial)
SOT89-5, Lead-free
For pricing, delivery, and ordering information, please contacts ISSI’s analog marketing team at
[email protected] or (408) 969-6600.
DETAILED DESCRIPTION
LED Current Control
The nominal average output current in the LED(s) is
determined by the value of the external current sense
resistor (RS) connected between VIN and ISENSE and in
is given by:
IOUT nom = 0.1/R S [for R S>0.082Ω]
The table below gives values of nominal average
output current for several preferred values of current
setting resistor (RS) in the typical application circuit
shown on Page 1:
RS (Ω)
Nominal Average Output
Current (mA)
0.082
1200
0.1
1000
0.15
0.3
667
333
VSENSE is divided into two range to improve current
accuracy, please refer to bin information on Page 2.
The above values assume that the ADJ pin is floating
and at a nominal voltage of VREF =1.2V.
Note that RS=0.082Ω is the minimum allowed value of
sense resistor under these conditions to maintain
switch current below the specified maximum value.
It is possible to use different values of RS if the ADJ pin
is driven from an external voltage.
Inductor Selection
Recommended inductor values are in the range 47μH
to 220μH.
Higher values of inductance are recommended at
higher supply voltages and low output current in order
to minimize errors due to switching delays, which
result in increased ripple and lower efficiency. Higher
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 08/31/2015
values of inductance also result in a smaller change in
output current over the supply voltage range. The
inductor should be mounted as close to LX pin as
possible with low resistance connections to LX and VIN
pins.
PCB Layout Consideration
Decoupling Capacitors and Coil
It is particularly important to mount the coil and the
input decoupling capacitor close to the chip to
minimize parasitic resistance and inductance, which
will degrade efficiency. The input decoupling capacitor
(0.1μF fixed) must be placed as close to the VIN and
GND pins as possible. It is also important to take
account of any trace resistance in series with current
sense resistor RS.
LX Pin
The LX pin of the chip is a fast switching node, so PCB
traces should be kept as short as possible. To
minimize ground 'bounce', the ground pin of the chip
should be soldered directly to the ground plane.
ADJ Pin
The ADJ pin is a high impedance input, so when left
floating, PCB traces to this pin should be as short as
possible to reduce noise pickup. ADJ pin can also be
connected to a voltage between 1.2V~5V. In this case,
the internal circuit will clamp the output current at the
value which is set by VADJ=1.2V.
High Voltage Traces
Avoid running any high voltage traces close to the ADJ
pin, to reduce the risk of leakage due to board
contamination. Any such leakage may raise the ADJ
pin voltage and cause excessive output current. A
ground ring placed around the ADJ pin will minimize
changes in output current under these conditions.
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IS31LT3360 AIC DEMO BOARD GUIDE
V+
R4
D5
LEDs
R5
LED2-
C4
NC
ADJ
Isense
3
R8
0R
IS31LT3360
LX
R12
0.3R
SS26
L2
47uH
C3
100nF
1
U3
3
R9
0R
IS31LT3360
C5
NC
R3
0.3R
ADJ
LX
D3
SS26
4
4
5
1
U2
GND
LX
C2
100nF
2
Isense
4
SS26
L1
47uH
LED3D2
R2
0.3R
PWM3
SS36
ADJ
R11
0.3R
PWM2
R7
0R
PWM1
SS36
3
D10
2
D9
U1
GND
C1
100nF
Vin
5
VIN
D1
R1
0.3R
Vin
220uF/50V
LEDs
6.8K
Isense
LED1C0
R10
0.3R
R6
39V
6.8K
6.8K
SS36
D6
LEDs
39V
GND
39V
2
SS36
D8
V+
5
D4
D7
V+
Vin
VCC
L3
47uH
1
IS31LT3360
C6
NC
GND
Figure 2: IS31LT3360 AIC DEMO Board Schematic
BILL OF MATERIALS
Name
Symbol
IC
U1~U3
Resistor
Description
Qty
Supplier
Part No.
LED driver
3
ISSI
IS31LT3360
R1~R3
R10~R12
RES,0.3R,1/8W,±1%,SMD
6
Yageo
RL1206FR-070R3L
Resistor
R4~R6
RES,6.8K,1/8W,±5%,SMD
3
Yageo
RC1206JR-076K8L
Resistor
R7~R9
RES,0R,1/10W,±5%,SMD
3
Yageo
RL0805FR-070RL
Capacitor
C0
CAP, 220µF,50V,±20%,IND
1
Rubycon
Capacitor
C1~C3
CAP,0.1µF,50V,±10%,SMD
3
Yageo
CC0603KRX7R9BB104
Capacitor
C4~C6
Not Installed
3
Diode
D1~D3
Schottky,SS26,2A,60V SMA
3
TOSHIBA
SR260
Diode
D4~D6
Zener,39V,0.5W,SMD
3
ST
ZMM39B
Diode
D7~D10
Schottky,SS36,3A,60V SMA
4
TOSHIBA
SR360
Inductor
L1~L3
47µH,ISAT≥1A
3
Würth
Elektronik
744777147
Bill of materials refers to Figure 2 above.
Note 1: C8, C9, C10 are the optional components. They can filter the noise coupling to the ADJ pin.
Note 2: D4, D5, D6 are the optional components. They can protect the IC as removing the loading with the power on.
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 08/31/2015
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IS31LT3360 AIC DEMO BOARD GUIDE
3
0
0
2
1
0
0
3
8
7
2
1
0
Figure 3: Board Component Placement Guide - Top Layer
Figure 4: Board PCB Layout - Top Layer
Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 08/31/2015
4
IS31LT3360 AIC DEMO BOARD GUIDE
Figure 5: Board Component Placement Guide - Bottom Layer
Figure 6: Board PCB Layout - Bottom Layer
Note: Physical dimensions are (L × W × H): 55mm × 21mm × 22mm.
Copyright © 2015 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com
Rev. A, 08/31/2015
5