MIC27600 Evaluation Board 36V/7A Hyper Speed Control™ Synchronous DC/DC Buck Regulator General Description The MIC27600 DC/DC regulator operates over an input supply range of 4.5V to 36V and provides a regulated output at up to 7A of output current. The output voltage is adjustable down to 0.8V with a typical accuracy of ±1% and the device operates at a switching frequency of 300kHz. The switching frequency remains fairly constant with changes in input voltage and output load. Note: This evaluation board is for 7A applications. Datasheet and supporting documentation can be found on Micrel’s web site at: www.micrel.com. Requirements The MIC27600 evaluation board requires only a single power supply with at least 10A current capability. A linear regulator, which includes a Zener and an NPN transistor, has been installed on the board to provide housekeeping (VDD) for the MIC27600. The output load can either be a passive or an active load. Precautions The MIC27600 evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN and GND terminals may damage the device. The maximum VIN of the board is rated at 36V. Exceeding 36V on the VIN could damage the device. Getting Started 1. Connect a supply to the VIN and GND terminals. Apply desired input voltage to the VIN and GND terminals of the evaluation board, paying careful attention to polarity and supply voltage (4.5V < VIN < 36V). A current meter may be placed between the input supply and the VIN terminal of the evaluation board. Ensure the supply voltage is monitored at the VIN terminal. At heavy loads, the current meter, wires, and power lead could have voltage drops that reduce the voltage applied to the input. 2. Connect a load to the VOUT and GND terminals. The load can be either a passive (resistive) or an active (as in an electronic load) type. A current meter can be placed between the VOUT terminal and the load. Ensure the output voltage is monitored at the VOUT terminal. 3. Enable the MIC27600. An EN connector is provided on the MIC27600 evaluation board for the users to easily access the enable feature of the MIC27600. The EN pin is pulled to VDD through an internal 100kΩ resistor, which allows the output to be turned on when VDD exceeds its UVLO threshold. Applying an external logic signal on the EN pin to pull it low or using a jumper to short the EN pin to GND will shut off the output of the MIC27600 evaluation board. Output Voltage The output voltage on the MIC27600 evaluation board is preset to 3.3V. The final output voltage is determined by the feedback divider which is calculated as follows: ⎛ R4 VOUT = VREF × ⎜⎜1+ ⎝ R BOTTOM ⎞ ⎟ ⎟ ⎠ where VREF = 0.8V, and RBOTTOM is one of R5, R6, R7, R8, R9, R10, R11, R12, which corresponds to 0.9V, 1.0V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, or 5V output voltage. Leaving the RBOTTOM open gives a 0.8V output voltage. All other voltages not listed above can be set by modifying RBOTTOM value according to: R BOTTOM = R4 × VREF VOUT − VREF Note that the output voltage should not be set to exceed 5V due to the 6.3V voltage rating on the output capacitors. The maximum output voltage of the MIC27600 should be limited to 5.5V for up to 28V VIN and 3.6V for VIN higher than 28V. Hyper Speed Control is a trademark of Micrel, Inc MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2010 M9999-120310-A Micrel, Inc. MIC27600 7A Evaluation Board Ordering Information Part Number Description Package MIC27600YJL IC 28-Pin 5mm × 6mm MLF® MIC27600YJL EV Evaluation Board Evaluation Board Schematic MIC27600 Evaluation Board (J13, R13, R15, are for testing purposes) December 2010 2 M9999-120310-A Micrel, Inc. MIC27600 Evaluation Board Bill of Materials Item C1 Part Number Manufacturer (1) B41125A6107M EPCOS C13 C6, C7, C10 C8, C9 C11 C12 100µF/50V, Aluminum Capacitor, SMD 1 4.7µF/50V, Ceramic Capacitor, X7R, Size 1210 2 100µF/6.3V Ceramic Capacitor, X5R, Size 1210 1 0.1µF/50V, Ceramic Capacitor, X7R, Size 0603 3 2.2µF/10V, Ceramic Capacitor, X7R, Size 0805 2 1nF/50V, Ceramic Capacitor, X7R, Size 0603 1 22nF/50V, Ceramic Capacitor, X7R, Size 0603 1 470µF, 6.3V, 7mΩ OSCON 1 Small Signal Schottky Diode, 50V, SOD-323 1 5.6V Zener Diode 1 AVX Murata(3) GRM32ER71H475KA88L (4) C3225X7S1H475M TDK 12106D107MAT2A AVX(2) Murata(3) GRM32ER60J107ME20L (4) C3225X5R0J107M TDK 06035C104KAT2A AVX(2) Murata(3) GRM188R71H104KA93D (4) C1608X7R1H104K TDK 0805ZC225MAT2A AVX(2) Murata(3) GRM21BR71A225KA01L (4) C2012X7R1A225K TDK 06035C102KAT2A AVX(2) Murata(3) GRM188R71H102KA01D (4) C1608X7R1H102K TDK 06035C223KAZ2A AVX(2) GRM188R71H223K Murata(3) (4) TDK C1608X7R1H223K C15 Qty (2) 12105C475KAZ2A C2, C3 Description SANYO(5) 6SEPC470M (Open) C4, C5, C14 Open MCC(6) SD101BWS-TP D1 Diodes Inc(7) SD101BWS-7 (8) SD101BWS D2 CMDZ5L6 L1 HCF1305-4R0-R Vishay MCC(6) Central Semi(9) Cooper Bussmann(10) 4.0µH Inductor, 12A Saturation Current 1 Notes: 1. EPCOS: www.epcos.com. 2. AVX: www.avx.com. 3. Murata: www.murata.com. 4. TDK: www.tdk.com. 5. SANYO: www.sanyo.com. 6. MCC.: www.mccsemi.com. 7. Diode Inc.: www.diodes.com. 8. Vishay: www.vishay.com. 9. Central Semi: www.centralsemi.com. 10. Cooper Bussmann: www.cooperbussmann.com. December 2010 3 M9999-120310-A Micrel, Inc. MIC27600 Evaluation Board Bill of Materials (Continued) Item Q1 R1 R2, R16 R3, R4 R5 R6 R7 Part Number FCX619 CRCW06034R75FKEA CRCW08051R21FKEA CRCW060310K0FKEA CRCW060380K6FKEA CRCW060340K2FKEA CRCW060320K0FKEA Manufacturer Diodes Inc (7) Description Qty 50V NPN Transistor, SOT-89 1 (8) 4.75Ω Resistor, Size 0603, 1% 1 (8) 1.21Ω Resistor, Size 0805, 1% 2 (8) 10kΩ Resistor, Size 0603, 1% 2 (8) 80.6kΩ Resistor, Size 0603, 1% 1 (8) 40.2kΩ Resistor, Size 0603, 1% 1 (8) 20kΩ Resistor, Size 0603, 1% 1 (8) Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale R8 CRCW060311K5FKEA Vishay Dale 11.5kΩ Resistor, Size 0603, 1% 1 R9 CRCW06038K06FKEA Vishay Dale(8) 8.06kΩ Resistor, Size 0603, 1% 1 CRCW06034K75FKEA (8) 4.75kΩ Resistor, Size 0603, 1% 1 (8) 3.24kΩ Resistor, Size 0603, 1% 1 (8) 1.91kΩ Resistor, Size 0603, 1% 1 (8) 0Ω Resistor, Size 0603 1 (8) 5.23kΩ Resistor, Size 0603, 1% 1 (8) 49.9Ω Resistor, Size 0603, 1% 1 (8) 1.21Ω Resistor, Size 0603, 1% 1 36V/7A Synchronous Buck DC-DC Regulator 1 R10 R11 R12 R13 R14 R15 R16 U1 CRCW06033K24FKEA CRCW06031K91FKEA CRCW06030000FKEA CRCW06035K23FKEA CRCW060349R9FKEA CRCW06031R21FKEA MIC27600YJL Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale Micrel. Inc. (11) Note: 11. Micrel, Inc.: www.micrel.com. December 2010 4 M9999-120310-A Micrel, Inc. MIC27600 Evaluation Board PCB Layout Recommendations Top Layer Mid-Layer 1 (Ground Plane) December 2010 5 M9999-120310-A Micrel, Inc. MIC27600 Evaluation Board PCB Layout Recommendations (Continued) Mid-Layer 2 Bottom Layer 1 December 2010 6 M9999-120310-A Micrel, Inc. MIC27600 Evaluation Board MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2010 Micrel, Incorporated. December 2010 7 M9999-120310-A