XRP6668EVB

XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter February 2012 Rev. 1.1.0 GENERAL DESCRIPTION EVALUATION BOARD MANUAL The XRP6668 is a dual channel synchronous current mode PWM step down (buck) converter capable of delivering up to 1 Amp of current per channel and optimized for portable battery-operated applications. Based on a current mode 1.5MHz constant frequency PWM control scheme, the XRP6668 reduces the overall component count and solution footprint as well as provides a low output voltage ripple and excellent line and load regulation. It also implements a PFM mode to improve light load efficiency as well as a 100% duty cycle LDO mode. Output voltage is adjustable to as low as 0.6V with a better than 3% accuracy while a low quiescent current supports the most stringent battery operating conditions. Built-in over temperature and under voltage lock-out protections insure safe operations under abnormal operating conditions. The XRP6668 is offered in a RoHS compliant, “green”/halogen free 8-pin exposed pad SOIC package. FEATURES  Dual Channel Step Down Converter  Guaranteed Dual 1A/1A Output Current  Input Voltage: 2.5V to 5.5V  1.5MHz PWM Current Mode Control  PFM Mode Operations at Light Load  100% Duty Cycle LDO Mode Operations  Adjustable Output Voltage Range  Internal Compensation Network  30µA Quiescent Current  Over Temperature & UVLO Protections EVALUATION BOARD SCHEMATICS Fig. 1: XRP6658EVB 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 XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter PIN ASSIGNMENT Fig. 2: XRP6658 Pin Assignment PIN DESCRIPTION Name Pin Number Description VIN1 1 Channel 1 Power Input Pin. Must be closely decoupled to GND pin with a 4.7μF or greater ceramic capacitor. SW1 2 Channel 1 Switch Pin. Must be connected to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. VIN2 3 Channel 2 Power Input Pin. Must be closely decoupled to GND pin with a 4.7μF or greater ceramic capacitor. SW2 4 Channel 2 Switch Pin. Must be connected to Inductor. This pin connects to the drains of the internal main and synchronous power MOSFET switches. VFB2 5 Channel 2 Feedback Pin. Receives the feedback voltage from an external resistive divider across the output. EN2 6 Channel 2 Enable Pin. Minimum 1.2V to enable the device. Maximum 0.4V to shutdown the device. VFB1 7 Channel 1 Feedback Pin. Receives the feedback voltage from an external resistive divider across the output. EN1 8 Channel 1 Enable Pin. Minimum 1.2V to enable the device. Maximum 0.4V to shutdown the device. GND Exposed Pad Connect to GND. ORDERING INFORMATION Refer to XRP6668’s datasheet and/or www.exar.com for exact and up to date ordering information. © 2012 Exar Corporation 2/7 Rev. 1.1.0 XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter USING THE EVALUATION BOARD set by the feedback resistors. The board will operate with a load current IOUT of up to 1A and provide efficiency equal to figures 4 and 5 of XRP6658 datasheet. INITIAL SETUP Set the input supply to a voltage between 2.5V to 5.5V 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 hand side of the board. Check to make sure that jumper J1 is set to VIN. The board will power-up and regulate to the desired output voltage VOUT © 2012 Exar Corporation JUMPER J1 FUNCTION Jumper J1 can be used to either short EN pin to VIN or to GND. The Board is supplied from EXAR with the jumper set to connect EN to VIN. 3/7 Rev. 1.1.0 VIN = 2.5V - 5.5V VIN = 3.3V - 5.5V VIN2 EN2 GND SW2 VIN2 SW1 VIN1 GND EN1 C5 4.7uF NP 4.7uF NP C8 C1 C4 4 3 2 1 NP R7 EN2 NP R9 SW2 VFB2 VIN2 SW1 VFB1 2.2uH L2 5 6 7 XRP6668 8 VIN1 EN1 U1 2.2uH L1 GND 4/7 9 © 2012 Exar Corporation 1 J2 C3 3 3 22pF C7 22pF J1 2 2 VIN1 1 NP R10 200k R5 453k R2 NP R8 C2 C6 10uF 20 100k R6 100k R3 10uF R4 20 R1 NP C9 NP C10 GND T2 VOUT = 1.8V VOUT2 GND FB2 FB1 GND VOUT = 3.3V VOUT1 T1 GND XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter EVALUATION BOARD SCHEMATICS Rev. 1.1.0 XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter BILL OF MATERIAL Ref. Qty Manufacturer Part Number EVAL BD 1 Exar Corp XRP6668EVB Size Component XRP6668 Evaluation Board U1 1 Exar Corp XRP6668 C1, C5 2 Murata GRM21BR71C475KA73L C4, C8 2 C2, C6 2 C9, C10 2 C3, C7 2 ESOP-8L 0805 Synchronous Step-Down Regulator Ceramic 4.7µF, 16V, X7R Not populated Murata GRM21BR71A106KE51L 0805 Ceramic 10uF, 10V, X7R Not populated Murata GRM1885C1H220JA01D 0603 4.8mm x 4.8mm x 2.8mm Ceramic 22pF, 50V, C0G L1, L2 2 Wurth Electronik 7440430022 R1, R4 2 Vishay CRCW060320R0FKTA 0603 20Ω Resistor, 0.1W, 1% R2 1 Vishay CRCW0603453KFKTA 0603 453KΩ Resistor, 0.1W, 1% R5 1 Vishay CRCW0603200KFKTA 0603 200KΩ Resistor, 0.1W, 1% R3, R6 2 Vishay CRCW0603100KFKTA 0603 100KΩ Resistor, 0.1W, 1% J1, J2 2 Wurth Electronik 61303611121 J1, J2 (Jumpers) Test Point VIN, VOUT, EN, SW, GND, FB, TP 2 Wurth Electronik 609002115121 Mill-Max 0300-115-01-4727100 16 © 2012 Exar Corporation 5/7 Inductor 2.2uH, 2.5A, 23mΩ 0.64mm SQ x 3 Pin Header, 2.54mm pitch 6mm 0.1” 0.042” diameter Jumper short Test Point Post Rev. 1.1.0 XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter EVALUATION BOARD LAYOUT Fig. 3: Component Placement – Top Side Fig. 4: Component Placement 2 – Top Side Fig. 5: Layout – Top Side Fig. 6: Layout - Bottom © 2012 Exar Corporation 6/7 Rev. 1.1.0 XRP6668EVB 1A/1A Dual Channel 1.5MHz Sync. Step Down Converter REVISION HISTORY Revision Date 1.0.0 09/16/2010 Initial release of document Description 1.1.0 02/07/2012 Updated bill of material and schematics 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 7/7 Rev. 1.1.0