PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH General Description The PAM2863 is a continuous mode inductive step-down converter, designed for driving single or multiple series connected °Cs efficiently from a voltage source higher than the °C voltage. The device operates from an input supply between 4.5V and 40V and provides an externally adjustable output current output current of up to 2A. A bill of material, schematics, and layout are included that describes the parts used on this demonstration board along with measured performance characteristics. These materials can be used as a reference design. PAM2863EV1 Specifications Parameter Value Input Voltage LED Current Number of LEDs XYZ Dimension 5 to 40VDC 1.5A (Adjustable) 1, 2 1.6” x 1.2” x 0.4” Evaluation Board GND LED- Vin LED+ Key Features Low Components Count Internal 40V NDMOS Switch 2A Output Current Analog and PWM Dimming Efficiency up to 97% Soft Start Up to 1MHz Switching Frequency Open/Short Protection Thermal Shutdown Applications High End LED Flashlight LED Light Bar Figure 1: Top View Vin LED+ GND LEDFigure 2: Bottom View Connection Instructions Input Voltage: 8 to 40VDC (VIN, GND) LED Outputs: LED+ (White), LED- (Black) PAM2863EV1 Rev1 March 2015 www.diodes.com Page 1 of 6 PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH Evaluation Board Schematic Figure 3: Evaluation Board Schematic Evaluation Board Layout Figure 4: PCB Layout Top View PAM2863EV1 Rev1 March 2015 www.diodes.com Figure 5: PCB Layout Bottom View Page 2 of 6 PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH Quick Start Guide 1. 2. 3. 4. 5. 6. By default, the evaluation board is preset at 2A LED Current by R1, R2, R3 (0.15 Ohm). Ensure that the DC source is switched OFF or disconnected. Connect the 5 to 40VDC DC line wires of power supply to Vin and GND on the board. Connect the anode wire of external LED string to LED+ output test point. Connect the cathode wire of external LED string to LED- output test point. Turn on the main switch. LED string should light up. Bill of Material # 1 2 3 4 5 6 7 8 Name IC1 C1,C2, CO C3 R1,R2, R3 L1 D1 Vset PCB Quantity 1 Part number PAM2863 Manufacturer Diodes Inc Description LED Driver MSOP-8 3 0 UMK325BJ106KM-T Not Fitted Taiyo 10µF Cer Cap 50V 10% X5R 1210 3 1 1 0 1 RL0805FR-070R15L 744770133 SS34-E3/57T Not Fitted PAM2863 EB07AA Yageo Wurth Vishay 0.15Ω Resistor 1/8W 5% 0805 SMD 33µH, 3.2A Inductor SDR127 3A/40V Schottky diode SMC Functional Performance (1 LED, 2 LEDs @1.5A) Vin (DC) 5 6 8 10 12 Vin (DC) 8 12 24 30 36 40 Pin (W) 4.663 6.175 6.505 6.228 6.337 Pin (W) 8.412 10.934 11.589 12.132 12.615 12.310 PAM2863EV1 Rev1 March 2015 www.diodes.com V_out (V) 3.55 3.61 3.63 3.63 3.63 V_out (V) 6.83 6.94 6.96 6.97 6.97 6.97 I_out (mA) 1061 1267 1315 1325 1337 I_out (mA) 1095 1303 1370 1400 1420 1420 P_out (W) 3.76 4.57 4.77 4.81 4.85 P_out (W) 7.48 9.05 9.54 9.75 9.89 9.76 Efficiency (%) 80.73 74.07 73.38 77.21 76.59 Efficiency (%) 88.87 82.74 82.31 80.40 78.42 79.25 # of LEDs 1 # of LEDs 2 Page 3 of 6 PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH I_out(mA) vs Input Voltage Vin=5-40VDC; OUT=1/2 LEDs Efficiency(%) vs Input Voltage 1 LED Vin=5-40VDC; OUT=1/2 LEDs 2 LEDs 1 LED 1500 90 1400 87 Efficiency (%) I_out(mA) 2 LEDs 1300 1200 1100 84 81 78 75 1000 72 4 10 16 22 28 34 40 Input Voltage (VDC) Figure 6 Vin (DC) vs. Iout (mA) 4 10 16 22 28 34 Input Voltage (VDC) Figure 7 Vin (DC) vs. Efficiency (%) Application Information Setting the Output Current: The internal feedback (FB) voltage is 0.1V (Typical). The output current is calculated as below: ILED = 0.1/RS where RS = R1//R2//R3 The output Current is given by the following table. RS (Ω) ILED (mA) 0.05 0.067 0.1 0.13 0.15 0.3 2000 1500 1000 760 667 333 . PAM2863EV1 Rev1 March 2015 www.diodes.com Page 4 of 6 40 PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH PCB Layout Guidelines (1) Connect L1, LX, D1 with short and wide connections. Minimize the switching circuit area to avoid unexpected radiation. (2) Make sure the LX trace not across other sensitive traces. (3) Place the Iset resistor R1, R2, R3 as close to the sense pin as possible. This resistor will flow through large current, pay attention to the thermal dissipation. (4) Make sure the current flow path has a wide trace. When current path need vias, use the multiple vias to decrease impedance. (5) PAM2863 integrates the power MOSFET and has a thermal pad. Make sure the thermal pad is soldering to PCB and heat dissipation area is large enough. (6) Pay attention to the D1 and L1 thermal dissipation. PAM2863EV1 Rev1 March 2015 www.diodes.com Page 5 of 6 PAM2863EV1 User Guide 2A LED DRIVER with INTERNAL SWITCH IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. 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