LM2736Y EVAL

User's Guide SNVA135A – October 2005 – Revised April 2013 AN-1418 LM2736 Evaluation Board 1 Introduction The LM2736 demo board is configured to convert 5V input to 1.5V output at 750 mA load current using the LM2736X 1.6 MHz or the LM2736Y 550 kHz step down DC-DC regulator. The tiny low profile thin SOT23 package allows the demo board to be manufactured using less than 1 square inch of a 4-layer printed circuit board. The circuit is configured with the boost diode connected to VIN, and according to the datasheet, VIN must not exceed the maximum operating limit of 5.5V + VfD2 using this configuration. This will ensure that the voltage between the Boost and SW pins, VBOOST - VSW, does not exceed 5.5V for proper operation. For more information regarding this requirement, see the LM2736 Thin SOT 750mA Load Step-Down DC-DC Regulator Data Sheet (SNVS316). A bill of materials below describes the parts used on this demo board. A schematic and layout have also been included below along with measured performance characteristics. The schematics at the end of this document show how to re-configure this demo board for various input and output conditions as discussed in the LM2736 datasheet. Short or leave open the indicated connection as indicated in the schematics. The above restrictions for the input voltage are valid only for the demo board as shipped with the demo board schematic below. 2 Operating Conditions VIN = 5V VO = 1.5V IO = 750 mA D3 C4 R3 D2 R4 VIN VIN BOOST C3 C1 R5 L1 VOUT SW D1 VEN C2 R1 EN FB GND GND R2 GND Figure 1. LM2736 Demo Board Schematic All trademarks are the property of their respective owners. SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated AN-1418 LM2736 Evaluation Board 1 Operating Conditions www.ti.com Figure 2. Efficiency vs Load Current Table 1. Bill of Materials (BOM) X-Version Part ID Part Value Manufacturer Part Number Package Type C1, Input Cap 4.7 µF, 10V, X5R Murata GRM42-6X5R475K10 1206 C2, Output Cap 10 µF, 6.3V, X5R Murata GRM42-6X5R106K6.3 1206 C3, Boost Cap 0.01 µF Vishay VJ1206Y103KXXA 1206 D2, Boost Diode 1Vf @ 50 mA Diode Diodes, Inc. 1N4148W SOD-123 R2 10 kΩ, 1% Vishay CRCW12061002F 1206 U1 750 mA Buck Regulator Texas Instruments LM2736 Thin SOT23-6 D1, Catch Diode 0.34Vf Schottky 1A, 20VR International Rectifier MBRA120 SMA L1 4.7 µH, 1.6A, 28 mΩ TDK SLF6028T-4R7M1R6 6028 R1 2 kΩ, 1% Vishay CRCW12062001F 1206 R3 0Ω Vishay CRCW12060000F 1206 R5 50 kΩ, 1% Vishay CRCW08055002F 0805 D3, C4, R4 Open Table 2. Bill of Materials (BOM) Y-Version 2 Part ID Part Value Manufacturer Part Number Package Type C1, Input Cap 10 µF, 10V, X5R Murata GRM42-6X5R106K10 1206 C2, Output Cap 10 µF, 6.3V, X5R Murata GRM42-6X5R106K6.3 1206 C3, Boost Cap 0.01 µF Vishay VJ1206Y103KXXA 1206 D2, Boost Diode 1Vf @ 50 mA Diode Diodes, Inc. 1N4148W SOD-123 R2 10 kΩ, 1% Vishay CRCW12061002F 1206 U1 750 mA Buck Regulator Texas Instruments LM2736 Thin SOT23-6 D1, Catch Diode 0.34Vf Schottky 1A, 20VR International Rectifier MBRA120 SMA L1 10 µH, 1.3A, 53 mΩ TDK SLF6028T-100M1R3 6028 R1 2 kΩ, 1% Vishay CRCW12062001F 1206 R3 0Ω Vishay CRCW12060000F 1206 R5 50 kΩ, 1% Vishay CRCW08055002F 0805 D3, C4, R4 Open AN-1418 LM2736 Evaluation Board SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated PCB Layout www.ti.com 3 PCB Layout Figure 3. Top Layer SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated AN-1418 LM2736 Evaluation Board 3 PCB Layout www.ti.com Figure 4. Internal Plane 1 (GND) 4 AN-1418 LM2736 Evaluation Board SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated PCB Layout www.ti.com Figure 5. Internal Plane 2 (VIN) SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated AN-1418 LM2736 Evaluation Board 5 PCB Layout www.ti.com Figure 6. Bottom Layer 6 AN-1418 LM2736 Evaluation Board SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated Additional Circuit Configuration Schematics www.ti.com 4 Additional Circuit Configuration Schematics C4 D3 R3 D2 R4 VIN BOOST VIN C1 C3 R5 L1 SW VOUT D1 VEN C2 EN R1 FB GND R2 GND GND Figure 7. VBOOST Derived From VOUT D3 C4 R3 D2 R4 VIN BOOST VIN C1 C3 R5 L1 VOUT SW D1 VEN C2 EN R1 FB GND R2 GND GND Figure 8. VBOOST Derived From VSHUNT SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated AN-1418 LM2736 Evaluation Board 7 Additional Circuit Configuration Schematics www.ti.com D3 C4 R3 D2 R4 VIN VIN C1 BOOST C3 R5 L1 SW VOUT D1 VEN C2 EN R1 FB GND R2 GND GND Figure 9. VBOOST Derived From Series Zener Diode (VIN) D3 C4 R3 D2 R4 BOOST VIN VIN C3 C1 R5 L1 VOUT SW D1 VEN C2 EN R1 FB GND R2 GND GND Figure 10. VBOOST Derived From Series Zener Diode (VOUT) 8 AN-1418 LM2736 Evaluation Board SNVA135A – October 2005 – Revised April 2013 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated 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. 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