XRP7659EVB

XRP7659 1.5A 18V 1.4MHz non-Synchronous Step-Down Converter August 2012 Rev. 1.0.0 GENERAL DESCRIPTION EVALUATION BOARD MANUAL The EXAR XRP7659 Evaluation kit is a fully assembled and tested surface-mount PCB that demonstrates the XRP7659 non-synchronous step-down regulator. The current-mode switching regulator generates a preset 3.3V output with a load of up to 1.5A. The EVB kit requires a single input voltage VIN source, if EN is tied to VIN via jumper J1 (default setting as supplied from EXAR). If J1 is set to EN=EXT position, then a logic-level active-high signal is required at EN pin in order to turn the regulator on and off. FEATURES STANDARD CONFIGURATION  1.5A Continuous Output Current The XRP7659EVB evaluation board is configured to operate under the following conditions and parameters:  4.5V to 18V Wide Input Voltage  Input voltage range:  Output voltage range:  Output current/load range:  PWM Current-Mode Control  1.4MHz Constant frequency 4.5V - 18V 3.3V 0 – 1.5A  Adjustable Output Voltage  0.81V to 15V Range / ±3% Accuracy  Enable Function and integrated Softstart  Built-in Thermal, Over-Current, UVLO and Output Over-Voltage Protection  RoHS Compliant, “Green”/Halogen Free SOT-23-6 Package EVALUATION BOARD SCHEMATICS R1 R2 EN=EXT 1 BS CB 10nF SW U1 XRP7659 6 5 4 R3 IN EN 1 2 3 GND FB J1 2 3 3PIN_JUMPER 1 2 3 43k, 1% 14k, 1% L1, 744777004 100k, 5% VIN VOUT 4.7uH, 4A CIN 10uF/25V D1, MBR230LSFT1 2A/30V GND COUT 22uF/6.3V GND Fig. 1: XRP7659 Evaluation Board Schematics Exar Corporation 48720 Kato Road, Fremont CA 94538, USA www.exar.com Tel. +1 510 668-7000 – Fax. +1 510 668-7001 XRP7659 1.5A 18V 1.4MHz non-Synchronous Step-Down Converter PIN ASSIGNMENT Fig. 2: XRP7659 Pin Assignment PIN DESCRIPTION Name Pin Number Description BS 1 Bootstrap pin. Connect a 10nF bootstrap capacitor between BS and SW pins. The voltage across the bootstrap capacitor drives the internal high-side MOSFET. GND 2 Ground pin. FB 3 Feedback pin. Connect to a resistor divider to program the output voltage. If V FB exceeds 0.972V the OVP is triggered. If VFB drops below 0.25V the short circuit protection is activated. EN 4 Enable Input Pin. Forcing this pin above 1.5V enables the IC. Forcing the pin below 0.4V shuts down the IC. For automatic enable connect a 100kΩ resistor between EN and IN. IN 5 Power Input Pin. Must be closely decoupled to GND pin with a 10µF/25V or greater ceramic capacitor. SW 6 Power switch output pin. Connect to inductor and bootstrap capacitor. ORDERING INFORMATION Refer to XRP7659’s datasheet and/or www.exar.com for exact and up to date ordering information. USING THE EVALUATION BOARD is set to the left side (position marked EN=VIN). The board will power up and regulate the output at 3.3V upon turning on the input supply. The XRP7659 will operate with a load current of up to 1.5A and should provide nominal efficiency equal to figure 4 of the datasheet. STANDARD CONFIGURATION The evaluation board is configured to operate under the following conditions and parameters:  Input voltage range:  Output voltage range:  Output current/load range: 4.5V - 18V 3.3V 0 – 1.5A JUMPER J1 FUNCTION Jumper J1 can be used to either connect EN to VIN or allow an independent logic-level control signal to be applied to EN. The board is supplied from EXAR with jumper J1 set at leftside (position marked EN=VIN). This allows for automatic startup of the XRP7659 regulator when VIN is applied. INITIAL SETUP Set the input supply to 12V and connect it to VIN and GND connectors on the left side of the evaluation board. Connect the load to the VOUT and GND connectors on the right side of the board. Check to make sure that jumper J1 © 2012 Exar Corporation 2/5 Rev. 1.0.0 XRP7659 1.5A 18V 1.4MHz non-Synchronous Step-Down Converter TYPICAL PERFORMANCE CHARACTERISTICS All data taken at V IN = 12V, TJ = TA = 25°C, unless otherwise specified - Schematic and BOM from Application Information section of this manual. Fig. 3: Gain and Phase Margin Responses of XRP7659EVB Bode plots of the XRP7659EVB, as illustrated in Fig. 3, show a stable system with a ~60kHz crossover frequency and ~50dB phase margin. Furthermore, the XRP7659EVB is stable and exhibits similar performances with both the recommended resistors R1 and R2 at respectively 43kΩ and 14kΩ and the Monolithic Power System’s MP2359 recommended resistors R1 and R2 at respectively 49.9kΩ and 16.2kΩ. EVALUATION BOARD SCHEMATICS R1 R2 EN=EXT 1 BS U1 XRP7659 CB SW 10nF 6 5 4 R3 IN EN 1 2 3 GND FB J1 2 3 3PIN_JUMPER 1 2 3 43k, 1% 14k, 1% L1, 744777004 100k, 5% VIN VOUT 4.7uH, 4A CIN 10uF/25V COUT D1, MBR230LSFT1 2A/30V 22uF/6.3V GND GND Title XRP7659EVB Size A Date: © 2012 Exar Corporation Document Number 146-6691-01 Tuesday , August 07, 2012 3/5 Rev Sheet 1 of 1 Rev. 1.0.0 XRP7659 1.5A 18V 1.4MHz non-Synchronous Step-Down Converter BILL OF MATERIAL Ref. Qty Manufacturer Part Number Size Component PCB 1 Exar XRP7659EVB 2"x2" XRP7659 Evaluation kit U1 1 Exar XRP7659 SOT23-6 Buck regulator D1 1 ON Semi MBR230LSFT1 SOD123 Schottky, 2A/30V L1 1 Wurth Elektronik 744777004 7.3x7.3mm 4.7uH shielded inductor CIN 1 Murata Corp. GRM32DR61E106KA12L 1210 CER CAP 10uF, 25V, X5R COUT 1 Murata Corp. GRM31CR60J226KE19L 1206 CER CAP 22uF, 6.3V, X5R CB 1 Murata Corp. GRM188R71H103KA01D 0603 CER CAP 10000pF, X7R, 50V R1 1 Panasonic Corp. ERJ-3EKF4302V 0603 Resistor 43.0kΩ, 1% R2 1 Panasonic Corp. ERJ-3EKF1402V 0603 Resistor 14.0kΩ, 1% R3 1 Panasonic Corp. ERJ-3EKF1003V 0603 Resistor 100kΩ, 1% J1 1 Wurth Elektronik 61304011121 Conn. Header 0.1" 3POS J1(JUMPER) 1 Wurth Elektronik 609002115121 CONN JUMPER SHORT. VIN, VOUT, GND, EN 5 Vector Electronic K24C/M .042 Dia Test Point Post EVALUATION BOARD LAYOUT Fig. 5: Layout – Top Side Fig. 4: Component Placement – Top Side Fig. 6: Layout - Bottom © 2012 Exar Corporation 4/5 Rev. 1.0.0 XRP7659 1.5A 18V 1.4MHz non-Synchronous Step-Down Converter DOCUMENT REVISION HISTORY Revision Date 1.0.0 08/09/2012 Description Initial release of document BOARD REVISION HISTORY Board Revision Date 146-6691-01 08/09/2012 Description Initial release of evaluation board FOR FURTHER ASSISTANCE Email: customersupport@exar.com Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx? EXAR CORPORATION HEADQUARTERS AND SALES OFFICES 48720 Kato Road Fremont, CA 94538 – USA Tel.: +1 (510) 668-7000 Fax: +1 (510) 668-7030 www.exar.com NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user’s specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. or its in all Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. © 2012 Exar Corporation 5/5 Rev. 1.0.0