XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator November 2016 Rev. 1A GENERAL DESCRIPTION EVALUATION BOARD MANUAL The XR76117 and XR76121 are synchronous step-down regulators combining the controller, drivers, bootstrap diode and MOSFETs in a single package for point-of-load supplies. The XR76117 has a load current rating of 15A and the XR76121 has a load current rating of 20A. A wide 5V to 22V input voltage range allows for single supply operation from industry standard 5V, 12V and 19.6V rails. With a proprietary emulated current mode Constant OnTime (COT) control scheme, the XR76117 and XR76121 provide extremely fast line and load transient response using ceramic output capacitors. They require no loop compensation, simplifying circuit implementation and reducing overall component count. The control loop also provides 0.1% load and 0.1% line regulation and maintains constant operating frequency. A selectable power saving mode, allows the user to operate in discontinuous mode (DCM) at light current loads thereby significantly increasing the converter efficiency. A host of protection features, including over-current, overtemperature, over-voltage, short-circuit, open feedback detect and UVLO, help achieve safe operation under abnormal operating conditions. FEATURES * The XR76117/21 are available in a RoHS-compliant, green/halogen-free space-saving QFN 5x6mm package. * 15A and 20A Step Down Regulators - 4.5V to 5.5V Low VIN Operation - 5V to 22V Wide Single Input Voltage - 3V to 22V operation with external 5V bias - 0.6V Adjustable Output Voltage Proprietary Constant On-Time Control - No Loop Compensation Required - Ceramic Output Cap. Stable operation - Programmable 70ns-1s On-Time - Constant 200kHz-1MHz Freq. - Selectable CCM or CCM/DCM Operation * Power-Good Flag with low impedance when power removed * Precision Enable and Programmable Soft-start Fig. 1: XR76121 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 XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator PIN ASSIGNMENT Fig. 2: XR76117/21 Pin Assignment PIN DESCRIPTION Name Pin Number FB 1 Feedback input to feedback comparator. FCCM Forcing this pin logic level high forces CCM operation TON 2 3 4 5 ILIM 6 Over-current protection programming. Connect with a resistor to SW. PGOOD 7 Power-good output. Open drain to AGND. Low Z when IC unpowered. VSNS 8 Sense pin for output OVP and open FB. VIN 9 Supply input for the regulator's LDO. Normally connected to PVIN. VCC 10 The output of regulator's LDO. It requires a 4.7uF VCC bypass capacitor. For operation using a 5V rail, VCC should be tied to VIN. PGND 11 Ground of the power stage. Internally connected to source of the low-side MOSFET. SW 12 Switch Node. Internally it connects source of the high-side MOSFET to drain of the lowside MOSFET. PVIN 13 Input voltage for power stage. Internally connected to drain of the high-side MOSFET. BST 14 High-side driver supply pin. Connect a 0.1uF bootstrap capacitor between BST and SW. EN 15 Precision enable pin. Pulling this pin above 2V will enable the regulator. SS 16 Soft-Start pin. Connect an external capacitor between SS and AGND to program the soft-start rate based on the 10uA internal source current. AGND PAD 17 Signal ground for control circuitry. AGND Description Signal ground for control circuitry. Connect to AGND Pad with a short trace. Constant on-time programming pin. Connect with a resistor to AGND. ORDERING INFORMATION Refer to XR76117/21 datasheet and/or www.exar.com for exact and up to date ordering information. (c) 2016 Exar Corporation 2/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator USING THE EVALUATION BOARD OPERATION FROM A 5V RAIL (VIN=4.5V-5.5V) For operation from a 5V rail it is recommended to tie output of the LDO to VIN by populating R5VIN with a 0 resistor. This enhances the operation of the drivers at VIN<5V. Please remember to remove R5VIN for operation at higher VIN. POWERING UP Connect the VIN+/VIN- with short/thick leads to power supply. Use test pins T3 and T4 to monitor VIN+ and VIN- respectively. Connect VOUT+/VOUT- with short/thick leads to an electronic load. Use test pins T1 and T2 to monitor VOUT+ and VOUT- respectively. Apply 12V using the power supply. The XR76117/21 EVB should power up and regulate the output at 1.8V. Input voltage range is from 5V to 22V. Maximum rated current for XR76117/21 is 15A and 20A respectively. PROGRAMMING THE OUTPUT VOLTAGE VOUT can be programmed by changing RFB1 according to: - 1 0.6 1 = 2 x JUMPER J1 Where RFB2 has a nominal value of 2k. If the jumper is set to CCM position the Regulator will operate in "forced CCM". Note that, as explained in the datasheet, after power up the regulator will operate in DCM until a sufficient load is applied to transition the Regulator to CCM. Once the Regulator transitions to CCM it will continue operating in CCM regardless of load magnitude. RON must be set correspondingly, as explained in the datasheet, in order to get the desired switching frequency. If the Jumper is set to DCM/CCM position the Regulator will operate in DCM at light load. (c) 2016 Exar Corporation 3/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator EVALUATION BOARD SCHEMATICS XR76121 EVB Schematics XR76117 EVB Schematics (c) 2016 Exar Corporation 4/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator XR76121EVB BILL OF MATERIAL Reference Designator Qty. Manufacturer Manufacturer Part Number Size Component PCB 1 Exar 146-6725-02 U1 1 Exar XR76121EL-F 5mmX6mm XR76121 Evaluation Board Step-Down COT Regulator L1 1 VISHAY/DALE IHLP5050FDERR40M01 12.9x13.2mm Power Inductor 0.4uH, 44A, 1mOhm C5,C6,C7,C8 4 MURATA GRM31CR61E226KE15L 1206 CERAMIC CAP. 22uF, 25V, X5R, 10% C26,C27,C28,C29,C30 5 MURATA GRM31CR60J107ME39K 1206 CERAMIC CAP. 100uF, 6.3V, X5R, 20% CBST,CIN,C1,C2,C31-C34 8 MURATA GRM155R71H104KE14D 0402 CERAMIC CAP. 0.1uF, 50V, X7R, 10% CVCC 1 MURATA GRM188R61A475KE15D 0603 CERAMIC CER, 4.7uF, 10V, X5R, 10% CSS 1 MURATA GRM155R71H473KE14D 0402 CERAMIC CAP , 47nF, 50V, X7R, 10% CFF 1 MURATA 0402 CERAMIC CAP., 470PF, 50V, X7R, 10% RFB1,RSENS1 2 PANASONIC GRM155R71H471KA01D ERJ-2RKF4021X 0402 Resistor 4.02K Ohm, 1/10W,1%,SMD RFB2,RSENS2 2 PANASONIC ERJ-2RKF2001X 0402 Resistor 2.0K Ohm, 1/10W,1%,SMD RVIN,RBST,RBODE 3 PANASONIC ERJ-2GE0R00X 0402 Resistor 0.00 Ohm, Jumper, 1/10W, SMD RPGOOD, REN1 2 PANASONIC Resistor 10.0K Ohm, 1/10W,1%,SMD 1 PANASONIC ERJ-2RKF1002X ERJ-2RKF3831X 0402 REN2 0402 Resistor 3.83K Ohm, 1/10W,1%,SMD RLIM 1 PANASONIC ERJ-2RKF1821X 0402 Resistor 1.82K Ohm, 1/10W,1%,SMD RFF 1 PANASONIC ERJ-2RKF4020X 0402 Resistor 402 Ohm, 1/10W,1%,SMD RON 1 PANASONIC ERJ-2RKF6191X 0402 Resistor 6.19K Ohm, 1/10W,1%,SMD LIN T1-T4,VCC,PGOOD,SS,EN,AGND 1 VISHAY/DALE CRCW12100000Z0EAHP 2010 Resistor 0.00 Ohm, Jumper, 3/4W, SMD J1 9 Wurth Elektronik 61300111121 2.54mm Header 1 pin 1 Wurth Elektronik 61300311121 2.54mm Header 3 pin 1 Wurth Elektronik 61300211121 2.54mm Header 2 pin 4 1 Wurth Elektronik Wurth Elektronik 7471287 60900213421 2.54mm Mountin Tab WA-MTAB Header Jumper Size Component J2 VIN-, VIN+, VOUT-, VOUT+ J1-Jumper XR76117EVB BILL OF MATERIAL Reference Designator Qty. Manufacturer PCB 1 Exar 146-6725-02 U1 1 Exar XR76117EL-F L1 1 VISHAY/DALE IHLP4040DZERR36M01 Manufacturer Part Number XR76117 Evaluation Board 5mmX6mm Step-Down COT Regulator 10.3x10.92mm Power Inductor 0.36uH, 31.5A, 1.3mOhm C5,C6,C7,C8 4 MURATA GRM31CR61E226KE15L 1206 CERAMIC CAP. 22uF, 25V, X5R, 10% C26,C27,C28 3 MURATA GRM31CR60J107ME39K 1206 CERAMIC CAP. 100uF, 6.3V, X5R, 20% CBST,CIN,C1,C2,C31-C34 8 MURATA GRM155R71H104KE14D 0402 CERAMIC CAP. 0.1uF, 50V, X7R, 10% CVCC 1 MURATA GRM188R61A475KE15D 0603 CERAMIC CER, 4.7uF, 10V, X5R, 10% CSS 1 MURATA GRM155R71H473KE14D 0402 CERAMIC CAP , 47nF, 50V, X7R, 10% CFF 1 MURATA 0402 CERAMIC CAP., 470PF, 50V, X7R, 10% RFB1,RSENS1 2 PANASONIC GRM155R71H471KA01D ERJ-2RKF4021X 0402 Resistor 4.02K Ohm, 1/10W,1%,SMD RFB2,RSENS2 2 PANASONIC ERJ-2RKF2001X 0402 Resistor 2.0K Ohm, 1/10W,1%,SMD RVIN,RBST,RBODE 3 PANASONIC ERJ-2GE0R00X 0402 Resistor 0.00 Ohm, Jumper, 1/10W, SMD RPGOOD, REN1 2 PANASONIC Resistor 10.0K Ohm, 1/10W,1%,SMD 1 PANASONIC ERJ-2RKF1002X ERJ-2RKF3831X 0402 REN2 0402 Resistor 3.83K Ohm, 1/10W,1%,SMD RLIM 1 PANASONIC ERJ-2RKF3161X 0402 Resistor 3.16K Ohm, 1/10W,1%,SMD RFF 1 PANASONIC ERJ-2RKF4020X 0402 Resistor 402 Ohm, 1/10W,1%,SMD RON 1 PANASONIC ERJ-2RKF6191X 0402 Resistor 6.19K Ohm, 1/10W,1%,SMD LIN T1-T4,VCC,PGOOD,SS,EN,AGND 1 VISHAY/DALE CRCW12100000Z0EAHP 2010 Resistor 0.00 Ohm, Jumper, 3/4W, SMD J1 9 Wurth Elektronik 61300111121 2.54mm Header 1 pin 1 Wurth Elektronik 61300311121 2.54mm Header 3 pin 1 Wurth Elektronik 61300211121 2.54mm Header 2 pin 4 1 Wurth Elektronik Wurth Elektronik 7471287 60900213421 2.54mm Mountin Tab WA-MTAB Header Jumper J2 VIN-, VIN+, VOUT-, VOUT+ J1-Jumper (c) 2016 Exar Corporation 5/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator EVALUATION BOARD LAYOUT Fig. 3: Assembly Top Fig. 4: Assembly Bottom Fig. 5: Top Fig. 6: Bottom (c) 2016 Exar Corporation 6/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator Fig. 7: Layer 2 Fig. 8: Layer 3 Fig. 9: Layer 4 Fig. 10: Layer 5 (c) 2016 Exar Corporation 7/8 Rev. 1A XR76117/21 PowerBlox 15A and 20A Synchronous Step Down COT Regulator DOCUMENT REVISION HISTORY Revision Date 1A 11/16 Description Initial release of document BOARD REVISION HISTORY Board Revision Date REV 2.0 2/16 Description Initial release of evaluation board FOR FURTHER ASSISTANCE Email: customersupport@exar.com powertechsupport@exar.com Exar Technical Documentation: http://www.exar.com/TechDoc/ 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 herein 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 or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. (c) 2016 Exar Corporation 8/8 Rev. 1A