LP38859-1.2EVAL

User's Guide SNVA165B – June 2006 – Revised April 2013 AN-1480 LP38859S-1.2 Evaluation Board 1 Introduction This board is designed to enable the evaluation of the LP38859 voltage regulator. Each board is assembled and tested in the factory. This evaluation board has the TO-263 5–lead package mounted. 2 General Description The LP38859 is a dual-rail LDO linear regulator capable of supplying up to 3A of output current, and incorporates a Soft-Start feature. The device has been designed to work with 10 µF input and output ceramic capacitors, and 1µF bias capacitors. Footprints areas for CIN and COUT will allow for a variety of sizes. 3 Operation The input voltage, applied between VIN and GND, should be at least 1.0 V greater than VOUT, and no higher than the applied VBIAS voltage. The bias voltage, applied between VBIAS and GND should be above the minimum bias voltage of 3.0 V, and no higher than the maximum of 5.5 V. Loads can be connected to VOUT with reference to GND. VOUT and VIN test points are provided on the board to allow accurate measurements directly on the evaluation board, eliminating any voltage drop on the PCB traces or connecting wires to the load. The Soft-Start time for VOUT is an exponential function, and is adjusted by changing the Soft-Start capacitor (CSS) on device pin one. An internal resistor (rSS) and the external capacitor (CSS) form an RC circuit. Five RC time constants is considered to be the Soft-Start time. Soft-Start Time = 5 x rSS x CSS (1) The installed soft-start capacitor (CSS) is 10 nF (0.01 μF), and the internal rSS is typically 16 kΩ. Figure 1. VOUT vs CSS All trademarks are the property of their respective owners. SNVA165B – June 2006 – Revised April 2013 Submit Documentation Feedback AN-1480 LP38859S-1.2 Evaluation Board Copyright © 2006–2013, Texas Instruments Incorporated 1 Hardware 4 www.ti.com Hardware The schematic is shown in Figure 2 and the layout of the evaluation board is shown in Figure 3. TP2 TP5 TP3 TP4 LP38859S-1.2 IN (2) VIN VOUT (4) OUT C1 10 PF BIAS (5) VBIAS C2 1 PF C3 10 PF SS (1) GND (3) C5 0.01 PF GND Figure 2. Evaluation Board Schematic PCB Layout C5, 0.010 PF R 2 C S S TP1 C4 LP38859S1.2 TP5 TP5 C2 C2 R1 R1 TP2 J5 VBIAS C2, 1 PF C3 C3 C1 C1 C1, 10 PF LP38859S-1.2EV LP3885X-T/X-Rev2 R2 / C5 5 TP2 TP4 TP4 C3, 10 PF TP3 TP3 J2 J3 J4 VIN GND VOUT Figure 3. Evaluation Board Component and Pin Layout 6 Power Dissipation The TO-263 package alone has a junction to ambient thermal resistance (θJA) rating of 60°C/W. When mounted on the LP38859S evaluation board the θJA rating is approximately 37°C/W. Although there is only approximately 0.28 square inches of copper area immediately under the tab, the top copper surface area is extended to additional copper area on the bottom of the board by five thermal vias. 2 AN-1480 LP38859S-1.2 Evaluation Board Copyright © 2006–2013, Texas Instruments Incorporated SNVA165B – June 2006 – Revised April 2013 Submit Documentation Feedback Power Dissipation www.ti.com With the 37°C/W thermal rating the LP38859S evaluation board will dissipate a maximum of 2.75W with TA = 25°C. Figure 4. Maximum Power Dissipation vs Ambient Temperature SNVA165B – June 2006 – Revised April 2013 Submit Documentation Feedback AN-1480 LP38859S-1.2 Evaluation Board Copyright © 2006–2013, Texas Instruments Incorporated 3 Bill of Materials (BOM) 7 www.ti.com Bill of Materials (BOM) Table 1. Bill of Materials (BOM) 4 ID Name Description U1 U1 LP38859 Texas Instruments LP38859 C1 CIN 10 µF, 10%, MLCC, 10V, X7R, 1210 AVX 1210ZC106KAT2A C2 CBIAS 1 µF, 10%, MLCC, 10V, X7R, 0805 AXV 0805ZC105KAT2A C3 COUT 10 µF, 10%, MLCC, 10V, X7R, 1210 AVX 1210ZC106KAT2A C4 — Not Installed C5 CSS 0.010 µF, 10%, MLCC, 16 V, X7R, 0805 J1 — Not Installed J2 VIN Banana Jack : Insulated Solder Terminal RED J3 GND Banana Jack : Insulated Solder Terminal BLACK J4 VOUT Banana Jack : Insulated Solder Terminal ORANGE 108–0906–001 J5 VBIAS Banana Jack : Insulated Solder Terminal BLUE 108–0910–001 R1 — Not Installed — — R2 — Not Installed — — TP1 — Not Installed — — TP2 TPIN TP3 TPGND TP4 TPOUT Keystone 1593-2 TP5 TPBIAS Turret Terminal : Mounting Hole Diameter = 0.062” Manufacturer Part Number — — AVX 0805YC103KAT2A — 108–0902–001 Johnson Components AN-1480 LP38859S-1.2 Evaluation Board Copyright © 2006–2013, Texas Instruments Incorporated 108–0903–001 SNVA165B – June 2006 – Revised April 2013 Submit Documentation Feedback IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily performed. TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide adequate design and operating safeguards. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use of any TI components in safety-critical applications. In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and requirements. Nonetheless, such components are subject to these terms. No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties have executed a special agreement specifically governing such use. Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of non-designated products, TI will not be responsible for any failure to meet ISO/TS16949. Products Applications Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps DSP dsp.ti.com Energy and Lighting www.ti.com/energy Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial Interface interface.ti.com Medical www.ti.com/medical Logic logic.ti.com Security www.ti.com/security Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video RFID www.ti-rfid.com OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com Wireless Connectivity www.ti.com/wirelessconnectivity Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2013, Texas Instruments Incorporated