IS31LT3360-SDLS3-EB3CH

IS31LT3360 3CH 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.  40VDC power supply 3 pcs of LED panel (3 WLEDs, 10 LEDs in series on each panel) Multi-meter RECOMMENDED INPUT AND OUTPUT RATINGS Input: 6~40VDC Output: 1~10 LEDs in series/667mA Note: The input voltage must be 2V higher than the output voltage (total VF). ABSOLUTE MAXIMUM RATINGS  Input voltage ≤ 40VDC 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. Caution: Do not exceed the conditions listed above, otherwise the board will be damaged. The chip is assembled in SOT89-5 package. PROCEDURE IS31LT3360 3CH DEMO board is used in RGB lamp or the general LED lamp. The IS31LT3360 DEMO Board is fully assembled and tested. Follow the steps listed below to verify board operation. FEATURES Caution: Do not turn on the power supply until all connections are completed.            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 VCC of the board and the negative terminal of power supply to the GND 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 panels (LED arrays) will be light. QUICK START Figure 1: Photo of IS31LT3360-3CH Evaluation Board Lumissil Microsystems – www.lumissil.com Rev. B, 04/27/2016 1 IS31LT3360 3CH DEMO BOARD GUIDE ORDER INFORMATION Part No. Temperature Range IS31LT3360-SDLS3-EB3CH IS31LT3360-SDLS4-EB3CH -40°C to +105°C (Industrial) -40°C to +125°C (Industrial) Package SOT89-5, Lead-free For pricing, delivery, and ordering information, please contacts Lumissil’s analog marketing team at analog@Lumissil.com 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/Rs [for Rs>0.082Ω] 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 RS (Ω) Nominal Average Output Current (mA) 0.082 1200 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. 0.1 1000 LX Pin 0.15 667 0.3 333 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. 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: VSENSE is divided into two ranges to improve current accuracy, please refer to bin information on Page 3. 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 values of inductance also result in a smaller change in Lumissil Microsystems – www.lumissil.com Rev. B, 04/27/2016 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. 2 IS31LT3360 3CH DEMO BOARD GUIDE VCC R4 0.33R R5 0.33R LED1+ D5 C11 SS26 5 C2 C5 22uF/50V R1 1uF 4 U1 VIN Isense 0.1uF 3 PWM1 ADJ GND LX 1 L1 C8 IS31LT3360 390pF D1 D3 SS26 SS26 AC1 R6 0.33R R7 0.33R LED2+ D6 C1 220uF/50V C12 SS26 AC2 5 C3 D2 C6 22uF/50V R2 D4 1uF 4 U2 VIN Isense 0.1uF 3 PWM2 ADJ GND LX L2 1 C9 SS26 LED1- 47uH 2 SS26 LED2- 47uH 2 IS31LT3360 390pF VCC R8 0.33R R9 0.33R LED3+ GND D7 C13 SS26 5 C4 C7 22uF/50V R3 PWM3 U3 VIN 4 1uF Isense 0.1uF 3 ADJ GND LX L3 1 LED3- C10 2 390pF 47uH IS31LT3360 Figure 2: IS31LT3360 3CH Demo Board Schematic BILL OF MATERIALS Name Symbol IC U1~U3 Resistor Description Qty Supplier Part No. LED driver 3 Lumissil IS31LT3360 R1~R3 RES,1k,1/10W,±1%,SMD 3 Yageo RL0805FR-071K0L Resistor R4~R9 RES,0.3R,1/8W,±1%,SMD 6 Yageo RL1206FR-070R3L Capacitor C1 CAP,220µF,50V,±20%,IND 1 Rubycon 220µF/50V Capacitor C2~C4 CAP,22µF,50V,±20%,SMD 3 Rubycon 22µF/50V Capacitor C5~C7 CAP,0.1µF,50V,±10%,SMD 3 Yageo CC0805KRX7R9BB104 Capacitor C8~C10 CAP,390pF,50V,±10%,SMD 3 Yageo CC0603KRX7R9BB391 Capacitor C11~C13 CAP,1µF,50V,±10%,SMD 3 Yageo CC0805KRX7R9BB105 Diode D1~D7 Schottky,SS26,2A,60V SMA 7 TOSHIBA SR260 Inductor L1~L3 47µH,ISAT≥1A 3 Würth Elektronik 744777147 Bill of materials refers to Figure 2 above. Note: C8, C9 and C10 are the optional components. They can filter the noise coupling to the ADJ pin. Lumissil Microsystems – www.lumissil.com Rev. B, 04/27/2016 3 IS31LT3360 3CH DEMO BOARD GUIDE Figure 3: Board Component Placement Guide - Top Layer Figure 4: Board PCB Layout - Top Layer Lumissil Microsystems – www.lumissil.com Rev. B, 04/27/2016 4 IS31LT3360 3CH DEMO BOARD GUIDE Figure 5: Board Component Placement Guide - Bottom Layer Figure 6: Board PCB Layout - Bottom Layer Copyright  ©  2016  Lumissil  Microsystems.  All  rights  reserved.  Lumissil  Microsystems  reserves  the  right  to  make  changes  to  this  specification  and  its  products  at  any  time  without  notice.  Lumissil  Microsystems  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.  Lumissil Microsystems 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 Lumissil Microsystems 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 Lumissil Microsystems is adequately protected under the circumstances Lumissil Microsystems – www.lumissil.com Rev. B, 04/27/2016 5 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: ISSI: IS31LT3360-SDLS3-EB3CH