MIC28510 Evaluation Board 75V/4A Hyper Speed Control™ Synchronous DC/DC Buck Regulator General Description Getting Started The MIC28510 DC/DC regulator operates over an input supply range of 4.5V to 75V and provides a regulated output at up to 4A of output current. The output voltage is adjustable down to 0.8V with a typical accuracy of ±1%. The switching frequency is adjustable and once adjusted the switching frequency remains fairly constant with changes in input voltage and output load. The basic parameters of the evaluation board are: 1. VIN Supply. Connect a power supply to the VIN and GND terminals, paying careful attention to the polarity and supply voltage range (5V < VIN < 75V). The input current IIN can be monitored with a current meter. Do not apply power until Step 4. 2. Connect Load and Monitor Output. 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 may be placed between the VOUT terminal and load to monitor the output current. Ensure the output voltage is monitored at the VOUT terminal. 3. Enable Input. The EN pin has an internal 100k pull-up resistor to VDD, which allows the output to be turned on when VDD exceeds its UVLO threshold. An EN connector is provided on the evaluation board for users to easily access the enable feature. 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 MIC28510 evaluation board. 4. Turn On the Power. Turn on the VIN supply and verify that the output voltage is regulated to 3.3V. • Input Voltage − 5V to 75V • Output Voltage − 0.8V to 5V at 4A(1) (2) 12V at up to 4A • 250kHz Switching Frequency (Adjustable from 100kHz to 500kHz) Notes: 1, 2. Refer to thermal de-rating curves shown in Typical Characteristics section. Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com Requirements The MIC28510 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 MIC28510. The output load can either be a passive or an active load. Precautions The MIC28510 evaluation board does not have reverse polarity protection. Applying a negative voltage to the PVIN and GND terminals may damage the device. The maximum PVIN of the board is rated at 75V. Exceeding 75V on the PVIN could damage the device. Ordering Information Part Number Description MIC28510 5V EV Evaluation Board up to 5V Output MIC28510 12V EV Evaluation Board 12V Output Hyper Speed Control is a trademark of Micrel, 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 March 2012 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board The switching frequency can be adjusted between 100kHz and 500kHz by changing the resistor divider connected network consisting of R18 and R19 from PVIN to PGND. Features Feedback Resistors The output voltage on the MIC28510 evaluation board, which is preset to 3.3V, is determined by the feedback divider, shown in Equation 1: ⎛ R4 VOUT = VREF × ⎜⎜1+ ⎝ R BOTTOM ⎞ ⎟ ⎟ ⎠ Eq. 1 where VREF = 0.8V, and RBOTTOM is one of R5-R12, which corresponds to 0.9V, 1.0V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, or 5V. 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 Equation 2: R BOTTOM = R4 × VREF VOUT − VREF Eq. 2 Figure 1. Switching Frequency Adjustment Equation 3 illustrates the estimated switching frequency: Note that the output voltage should not be set to exceed 5V due to the 6.3V voltage rating on the output capacitors. If higher than 5V output is desired, it is recommended to use the designs shown in the MIC28510 12V/4A output evaluation board schematic, where the output capacitors, L1, R3, and R17 are optimized for 12V output. SW Node Test point J11 (VSW) is placed for monitoring the switching waveform, one of the most critical waveforms for the converter. Current Limit The MIC28510 has internal FETs, and the current limit is implemented by sensing the RDS-ON of bottom FET. The MIC28510 has a fixed current limit of 6.5A (typical). Loop Gain Measurement The resistor, R13, is placed in series with the regulator feedback path. The control loop gain can be measured by connecting an impedance analyzer across the resistor and selecting the resistor value in between 20Ω to 50Ω. Setting the Switching Frequency The MIC28510 is an adjustable-frequency, synchronous buck regulator featuring a unique digitally modified adaptive on-time control architecture. March 2012 f SW_ADJ = f O × R19 R18 + R19 Eq. 3 where fO = Switching Frequency when R18 is 100k and R19 being open, fO should be typically 450kHz. For more precise setting, it is recommended to use Figure 2: Figure 2. Switching Frequency vs. R19 The evaluation board design is optimized for a switching frequency of 250kHz. If the switching frequency is programmed to either lower end or higher end, the design needs optimization. 2 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board MIC28510 0.8V to 5V/4A Evaluation Board Typical Characteristics Thermal Derating Efficiency (VIN = 48V) vs. Output Current 4 100 VOUT = 3.3V fsw = 250kHz L = 10µH Tj_MAX =125°C 5.0V 3.3V 2.5V 1.8V 1.5V 1.2V 1.0V 0.9V 0.8V 70 60 50 40 fSW = 250kHz 30 3 VIN = 8V LOAD CURRENT (A) EFFICIENCY (%) LOAD CURRENT (A) 90 80 Thermal Derating 4 2 VIN = 75V VIN = 48V 1 0 1 2 3 4 5 25 6 VIN = 75V VOUT = 5V 1 fSW = 250kHz L = 10µH Tj_MAX = 125°C 40 55 70 85 25 100 MAXIMUM AMBIENT TEMPERATURE (°C) OUTPUT CURRENT (A) VIN = 24V VIN = 12V 40 55 70 3 VIN = 12V VIN =18V 2 VIN = 24V 1 0 0 85 MAXIMUM AMBIENT TEMPERATURE (°C) 100 85 100 V OUT = 2.5V LOAD CURRENT (A) fSW = 250kHz L = 10µH Tj_MAX = 125°C LOAD CURRENT (A) VOUT = 3.3V fSW = 250kHz L = 10µH Tj_MAX = 125°C 2 70 4 VOUT = 5V VIN =18V 55 Thermal Derating 4 1 40 MAXIMUM AMBIENT TEMPERATURE (°C) Thermal Derating Thermal Derating 4 LOAD CURRENT (A) 2 0 0 10 25 VIN = 48V V IN = 5V 20 3 3 fSW = 250kHz L = 10µH Tj_MAX = 125°C 3 VIN = 12V 2 VIN =18V 1 VIN = 24V 0 25 40 55 70 85 MAXIMUM AMBIENT TEMPERATURE (°C) 100 25 40 55 70 85 100 MAXIMUM AMBIENT TEMPERATURE (°C) Die Temperature* : The temperature measurement was taken at the hottest point on the MIC28510 case mounted on a 5 square inch 4 layer, 0.62”, FR-4 PCB with 2oz. finish copper weight per layer, see Thermal Measurement section. Actual results will depend upon the size of the PCB, ambient temperature and proximity to other heat emitting components. March 2012 3 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board MIC28510 0.8V to 5V/4A Output Evaluation Board Schematic MIC28510 Evaluation Board for 0.8V to 5V/4A Output March 2012 4 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Bill of Materials 0.8V to 5V/4A Output Item C1 C2, C3 C13 C6 C10 C8, C9 C11 C12 C16 C4, C5, C7, C14, C15 D1 D2 L1 Q1 R1 R2, R16 R3 R4 R5 R6 March 2012 Part Number EEU-FC2A101B GRM32ER72A225KA35L C3225X7R2A225KT5 GRM32ER60J107ME20L 12106D107MAT2A 06035C104KAT2A GRM188R71H104KA93D C1608X7R1H104K GRM188R72A104KA35D C1608X7S2A104K 0805ZC225MAT2A GRM21BR71A225KA01L C2012X7R1A225K GRM188R72A102KA01D C1608X7R2A102K 06031C102KAT2A GRM188R71H472KA01D C1608X7R2A472K 06035C472KAT2A GRM21BR71A105KA01L C2012X7R1A105K Manufacturer Panasonic (1) Murata(2) (3) TDK Murata(2) (4) AVX AVX(4) Murata(2) (3) TDK Murata(2) (3) TDK (4) AVX Murata(2) TDK(3) Murata(2) TDK(3) (4) AVX Murata(2) TDK(3) (4) AVX Murata(2) (3) TDK Description 100µF Aluminum Capacitor, SMD, 100V Qty. 1 2.2µF Ceramic Capacitor, X7R, Size 1210, 100V 2 100µF Ceramic Capacitor, X5R, Size 1210, 6.3V 1 0.1µF Ceramic Capacitor, X7R, Size 0603, 50V 1 0.1µF Ceramic Capacitor, X7R, Size 0603, 100V 1 2.2µF Ceramic Capacitor, X7R, Size 0805, 10V 2 1nF Ceramic Capacitor, X7R, Size 0603, 100V 1 4.7nF Ceramic Capacitor, X7R, Size 0603, 50V 1 1µF Ceramic Capacitor, X7R, Size 0805, 10V 1 Small Signal Schottky Diode 1 Open BAT46W-TP BAT46W-7-F MMXZ5232B-TP CMDZ5L6 DR125-100-R FCX493 CRCW06034R75FKEA CRCW08051R21FKEA CRCW060316K5FKEA CRCW060310K0FKEA CRCW060380K6FKEA CRCW060340K2FKEA MCC(5) Diodes Inc.(6) MCC(5) Central Semi(7) Cooper Bussmann(8) Diodes Inc/ZETEX(6) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) 1 5.6V Zener Diode 10µH Inductor, 5.35A RMS, 7A Saturation Current 100V NPN Transistor 4.75Ω Resistor, Size 0603, 1% 1.21Ω Resistor, Size 0805, 1% 16.5kΩ Resistor, Size 0603, 1% 10kΩ Resistor, Size 0603, 1% 80.6kΩ Resistor, Size 0603, 1% 40.2kΩ Resistor, Size 0603, 1% 5 1 1 1 2 1 1 1 1 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Bill of Materials 0.8V to 5V/4A Output (Continued) Item R7 R8 R9 R10 R11 R12 R13 R14 R15 R17 (OPEN) R18, R19 R20 R21 (OPEN) U1 Part Number CRCW060320K0FKEA CRCW060311K5FKEA CRCW06038K06FKEA CRCW06034K75FKEA CRCW06033K24FKEA CRCW06031K91FKEA CRCW06030000Z0EAHP CRCW080510K0JNEA CRCW060349R9FKEA CRCW0603715RFKEA CRCW0603100KFKEAHP CRCW06032R00FKEA CRCW0603348RFKEA MIC28510YJL Manufacturer Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) Vishay Dale(9) (10) Micrel. Inc. Description 20kΩ Resistor, Size 0603, 1% 11.5kΩ Resistor, Size 0603, 1% 8.06kΩ Resistor, Size 0603, 1% 4.75kΩ Resistor, Size 0603, 1% 3.24kΩ Resistor, Size 0603, 1% 1.91kΩ Resistor, Size 0603, 1% 0Ω Resistor, Size 0603 10kΩ Resistor, Size 0805, 1% 49.9Ω Resistor, Size 0603, 1% 715Ω Resistor, Size 0603, 1% 100kΩ Resistor, Size 0603, 1% 2Ω Resistor, Size 0603, 1% 348Ω Resistor, Size 0603, 1% 75V/4A Synchronous Buck DC/DC Regulator Qty. 1 1 1 1 1 1 1 1 1 2 1 1 Notes: 1. Panasonic: www.panasonic.com. 2. Murata: www.murata.com. 3. TDK: www.tdk.com. 4. AVX: www.avx.com. 5. MCC: www.mccsemi.com. 6. Diode Inc.: www.diodes.com. 7. Central Semi: www.centralsemi.com. 8. Cooper: www.cooperbussman.com. 9. Vishay: www.vishay.com. 10. Micrel, Inc.: www.micrel.com. March 2012 6 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board MIC28510 12V/4A Output Evaluation Board Typical Characteristics Efficiency vs. Output Current Thermal Derating 100 4 95 85 80 3 Load Current (A) 90 EFFICIENCY (%) VOUT = 12V 18V 24V 30V 48V 75V 75 70 VOUT = 12V 65 fSW = 250kHz L = 27μH 60 fSW =250kHz L=27μH Tj_MAX =125°C 24VIN 2 18VIN 48VIN 1 75VIN 55 0 50 0 1 2 3 4 OUTPUT CURRENT (A) 5 6 25 40 55 70 85 100 115 Maximum Ambient Temperature (°C) Die Temperature* : The temperature measurement was taken at the hottest point on the MIC28510 case mounted on a 5 square inch 4 layer, 0.62”, FR-4 PCB with 2oz. finish copper weight per layer, see Thermal Measurement section. Actual results will depend upon the size of the PCB, ambient temperature and proximity to other heat emitting components. March 2012 7 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board MIC28510 12V/4A Output Evaluation Board Schematic MIC28510 Evaluation Board for 12V/4A Output March 2012 8 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Bill of Materials (12V Up to 4A) Output Item C1 C2, C3 C13, C4 Part Number EEU-FC2A101B GRM32ER61C476ME15 EMK325BJ476MM-T GRM32ER61C476ME15 EMK325BJ476MM-T 06035C104KAT2A C6 GRM188R71H104KA93D C1608X7R1H104K C10 C8, C9 GRM188R72A104KA35D (3) Taiyo Yuden Murata(2) (3) Taiyo Yuden Murata(2) TDK Murata(2) (5) Murata(2) 1 2.2µF Ceramic Capacitor, X7R, Size 1210, 100V 2 47µF Ceramic Capacitor, X5R, Size 1210, 16V 2 0.1µF Ceramic Capacitor, X7R, Size 0603, 50V 1 0.1µF Ceramic Capacitor, X7R, Size 0603, 100V 1 2.2µF Ceramic Capacitor, X7R, Size 0805, 10V 2 TDK 1nF Ceramic Capacitor, X7R, Size 0603, 100V 1 4.7nF Ceramic Capacitor, X7R, Size 0603, 50V 1 1µF Ceramic Capacitor, X7R, Size 0805, 10V 1 Small Signal Schottky Diode 1 (5) Murata(2) TDK(5) 06031C102KAT2A (4) AVX Murata(2) C1608X7R2A472K TDK(5) 06035C472KAT2A (4) C2012X7R1A105K 100µF Aluminum Capacitor, SMD, 100V (5) C1608X7R2A102K GRM21BR71A105KA01L Qty. AVX(4) AVX(4) GRM188R71H472KA01D C16 Murata 0805ZC225MAT2A GRM21BR71A225KA01L Description (1) (2) TDK GRM188R72A102KA01D C12 Panasonic C1608X7S2A104K C2012X7R1A225K C11 Manufacturer AVX Murata(2) TDK(5) C5, C7, C14, Open C15 D1 D2 L1 Q1 R1 R2, R16 R3 R4 R5 (OPEN) R6 (OPEN) March 2012 BAT46W-TP MCC(6) BAT46W-7-F Diodes Inc.(7) MMXZ5232B-TP CMDZ5L6 7447709270 FCX493 CRCW06034R75FKEA CRCW08051R21FKEA CRCW060345K3FKEA CRCW060310K0FKEA CRCW060380K6FKEA CRCW060340K2FKEA MCC(6) Central Semi 1 5.6V Zener Diode (8) Wurth (9) (7) Diodes Inc./ZETEX 27µH Inductor, 5.8A Saturation Current 1 100V NPN Transistor 1 (10) 4.75Ω Resistor, Size 0603, 1% 1 (10) 1.21Ω Resistor, Size 0805, 1% 2 (10) 45.3kΩ Resistor, Size 0603, 1% 1 (10) 10kΩ Resistor, Size 0603, 1% 1 (10) 80.6kΩ Resistor, Size 0603, 1% (10) 40.2kΩ Resistor, Size 0603, 1% Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale Vishay Dale 9 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Bill of Materials 12V up-to 4A Output (Continued) Item R7 (OPEN) R8 (OPEN) R9 (OPEN) R10 (OPEN) R11 (OPEN) R12 (OPEN) R13 R14 R15 R17 R18, R19 R20 R21 (OPEN) U1 Part Number CRCW060320K0FKEA CRCW060311K5FKEA CRCW06038K06FKEA CRCW06034K75FKEA CRCW06033K24FKEA CRCW06031K91FKEA CRCW06030000Z0EAHP CRCW080510K0JNEA CRCW060349R9FKEA CRCW0603715RFKEA CRCW0603100KFKEAHP CRCW06032R00FKEA CRCW0603348RFKEA MIC28510YJL Manufacturer Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) Vishay Dale(10) (10) Micrel. Inc. Description 20kΩ Resistor, Size 0603, 1% 11.5kΩ Resistor, Size 0603, 1% 8.06kΩ Resistor, Size 0603, 1% 4.75kΩ Resistor, Size 0603, 1% 3.24kΩ Resistor, Size 0603, 1% 1.91kΩ Resistor, Size 0603, 1% 0Ω Resistor, Size 0603 10kΩ Resistor, Size 0805, 1% 49.9Ω Resistor, Size 0603, 1% 715Ω Resistor, Size 0603, 1% 100kΩ Resistor, Size 0603, 1% 2Ω Resistor, Size 0603, 1% 348Ω Resistor, Size 0603, 1% 75V/4A Synchronous Buck DC/DC Regulator Qty. 1 1 1 1 1 1 1 1 1 1 2 1 1 Notes: 1. Panasonic: www.panasonic.com. 2. Murata: www.murata.com. 3. Taiyo Yuden: www.taiyo-yuden.com. 4. AVX: www.avx.com. 5. TDK: www.tdk.com. 6. MCC: www.mccsemi.com. 7. Diode Inc.: www.diodes.com. 8. Central Semi: www.centralsemi.com. 9. Wurth: www.wurth.com. 10. Vishay Dale: www.vishay.com. 11. Micrel, Inc.: www.micrel.com. March 2012 10 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Evaluation Board PCB Layout MIC28510 Evaluation Board − Silkscreen Top MIC28510 Evaluation Board − Copper Layer 1 (Top) March 2012 11 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Evaluation Board PCB Layout (Continued) MIC28510 Evaluation Board − Copper Layer 2 MIC28510 Evaluation Board − Copper Layer 3 March 2012 12 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A Evaluation Board Evaluation Board PCB Layout (Continued) MIC28510 Evaluation Board − Copper Layer 4 MIC28510 Evaluation Board − Silkscreen Bottom March 2012 13 M9999-030712 [email protected] or (408) 955-1690 Micrel, Inc. MIC28510 4A 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. © 2012 Micrel, Incorporated. March 2012 14 M9999-030712 [email protected] or (408) 955-1690