PAM2861 EVB User Guide PAM2861EV Board User Guide AE Department 1. Revision Information Date 2008/8/18 Revision V1.0 Description Initial Release Comment 2. EV Board Schematic R2 VIN LED+ R1 ISENSE C3 VS ET 3 GND 2 1 L1 LX 4 IC1 LX C1 VIN 5 D1 C2 VSET LED- This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2861 EVB User Guide 3. EVB PAM2861 EB86AB Description PAM2861 EB86AB is an evaluation board for the PAM2861/2 (SOT-23-5 package), a high power LED buck driver. The board is targeted to be used in providing a simple and convenient evaluation environment for the PAM2861/2. Efficiency on the board make it easy to be evaluated. Use single power supply to drive 1-10 serials (PAM2861) or 1-6 serials (PAM2862) 1W or 3W power LED. 4. EV Board View Control signal EV board operational sequence: a. Connect power supply to Vin, (PAM2861 up to 40V, PAM2862 up to 24V). b. Connect LED- to power LED cathode and LED+ to power LED anode. c. Connect control signal to VSET if need external control, 0.4-2.5VDC voltage for analog dimming or <500Hz PWM signal for PWM dimming. This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2861 EVB User Guide 5. EV Board BOM List Item Value Type X5R/X7R, Ceramic/1206 X5R/X7R, Ceramic/0603 Rating Description C1 10µF 25V Input coupling CAP C2 10nF 50V comp CAP C3 NC L1 100µH SDR75 0.7A Inductor D1 R1 IC1 PCB SS14 0.3Ω PAM2861/2 SMA 0805 SOT-23-5 PAM2861 EB86AB 1A/40V 1% Schottky Diode Iset Resistor Power management IC Vender and Part No. Torch TMK316BJ106KL-T Murata GRM188R71H103K Wurth WE-PD2 type L 74477520 100uH SS14 PAM2861/2 6. External Components Selection Input Capacitors (C1) and Output Capacitor (C3) (1) C1 Low ESR needed, 10uF, X5R/X7R ceramic recommended (2) C3 can not used. Soft start Capacitors (C2) (1) This capacitor is to increase soft start, 10nF for 1.5mS. (2) The capacitor can not use in normal application. Iset Resistors (R1) (1) R set the power LED current , ILED=0.1V/R R=R1//R2. (2) R, 0.3Ω±1% for 1W LED (about 333mA). (3) R, 0.143Ω±1% for 3W LED (about 700mA). Inductor (L1) (1) Low DCR needed, 100uH (rating 0.7A) recommended for 1W LED. (2) Low DCR needed, 47uH (rating 1.2A) recommended for 3W LED. Schottky Diode (D1,D2,D3,D4,D5) (1) SS14 (1A, 40V) recommended. (2) B140 (1A, 40V) recommended. This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product. PAM2861 EVB User Guide 7. PCB Layout Guidelines (1) Connect L1, LX, D1 with short and wide connections. Minimize the switching circuit area to avoid unexpected radiation. (2) Place the Iset resistor R1,R2 as close to the sense pin as possible. (3) Make sure the current flow path has a wide trace. When current path need vias, use the multiple vias to decrease impedance. (4) PAM2861/2 integrate the power MOSFET. Make sure the heat dissipation area is large enough and have a low thermal resistance to atmosphere. 8. PCB Layout Example Top Layer Bottom Layer This application note contains new product information. Diodes, Inc. reserves the right to modify the product specification without notice. No liability isassumed as a result of the use of this product. No rights under any patent accompany the sale of the product.