PAM2421 EVB User Guide PAM2421 EV Board User Guide AE Department 1. Revision Information Date 2011/09 Revision V1.0 Description Initial Release Comment 2. PAM2804 General Description The PAM2421 devices are high-performance, fixed frequency, current-mode PWM step-up DC/DC converter that incorporate internal power MOSFET. The PAM2421 includes an integrated power MOSFET that supports peak currents of up to 3A. The PAM2421 utilizes simple external loop compensation allowing optimization between component size, cost, and AC performance across a wide range of applications. Additional functions include an externally programmable soft-start function for easy inrush current control, internal over-voltage protection (OVP), cycle-by-cycle current limit protection, under voltage lock-out and thermal shutdown. The PAM2421 is available in the small SOP-8(EP) package. 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. PAM2421 EVB User Guide 3. Key Features Greater than 90% Efficiency Programmable Soft Start Function Adjustable Output Voltage Up to 24V Thermal Shutdown Internal 24V Power MOSFET Under Voltage Lockout 520kHz Frequency Over Current Protection Built-in Over Voltage Protection (OVP) SOP-8 (EP) Package Open Protection 4. EV Board Schematic Vin C2 C1 C3 C4 EN 1 Vcc 2 EN 3 D1 L1 R1 C9 C10 D2 C11 SW VIN SS EN FB C7 Vcc EN R4 R2 C5 R3 C8 IC1 PGND Vo Comp R5 AGND C6 5. EVB PAM2421 TB15AA Description PAM2421 TB15AA is an evaluation board for the PAM2421, a DC/DC boost converter. The board is targeted to be used in providing a simple and convenient evaluation environment for the PAM2421. Requires parts, power supply connectors etc. on the board, which makes it easy to be evaluated. 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. PAM2421 EVB User Guide 6. EV Board View EV Board Operational Sequence: a. Connect EN to high (H side). b. Connect load to output terminal. c. Connect Vin and GND to power supply. Vin=5V or Li-ion battery. 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. PAM2421 EVB User Guide 7. External Components Selection Input & output Capacitors (C1, C2, C3, C9, C10, C11) (1) For lower output ripple, low ESR is required (C2, C3, C9, C10), Low leakage current needed, X5R/X7R ceramic recommend. (2) Provide large power, large capacitance electrolytic capacitor recommend parallel connection to the ceramic capacitor (C1, C11). Vin filter (R1, C4) (1) RC filter to filtering the switching noise on IC supply, 10Ω and 1uF ceramic capacitor recommend. Compensation net (R2, C5, C6) (1) R2 56kΩ, C5 2.2nF, C6 47pF recommended. Soft start (C7) (1) C7 0.1uF recommended. Schottky Diode (D1, D2) (1) SS34 3A/40V schottky diode recommended. (2) B340 3A/40V schottky diode recommended. Feed forward capacitor (C8) (1) Lower the output ripple, low leakage current needed, using according to application. Output Voltage programmer resistors (R3, R4, R5) (1) For programmer output voltage (2) For accurate output voltage, 1% tolerance is required. Vo=1.262*(1+R3/R4//R5). Inductor (L1) (1) Low DCR for good efficiency (2) Inductance saturate current must higher than the output current 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. PAM2421 EVB User Guide 8. Evaluation Board BOM List Item C1, C11 Value 470µF Type Ecap D10*20mm X5R/X7R, Ceramic/0805 X5R/X7R, Ceramic/1206 X5R/X7R, Ceramic/0603 X5R/X7R, Ceramic/0603 Rating 25V Description C2, C3 10µF 16V Input coupling CAP C9, C10 10µF 25V Output coupling CAP, C4 1.0µF 25V Vin coupling CAP C5 2.2nF C6 47pF C0H, Ceramic/0603 50V C7 0.1µF X5R/X7R, Ceramic/0805 50V L1 6.8µH D2 D1 R1 R2 R3 R4 R5 C8 IC1 PCB 3A/40V NC 10 56K 100K 10K NC 620K SS34 0805 0805 0805 0805 0805 0805 PAM2421 PAM2421 TB15AA 50V >3A Inductor SMC SMC 5% 1% 1% 1% 1% 1% PSOP-8 Schottky diode Vender and Part No. TAIYO YUDEN EMK212ABJ106KD-T TAIYO YUDEN TMK316BJ106KL-T TAIYO YUDEN TMK107B7105KA-T TAIYO YUDEN UMK107SD222KA-T TAIYO YUDEN UMK105CH470JV-F TAIYO YUDEN UMK212B7104KG-T WURTH 7447709006 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. PAM2421 EVB User Guide 9. 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.