MIC45116 Evaluation Board 20V/6A/DC-to-DC Power Module General Description Getting Started Micrel’s MIC45116 is a synchronous step-down regulator module, featuring a unique adaptive ON-time control architecture. The singular module package includes a DCto-DC controller, power MOSFETs, bootstrap diode, bootstrap capacitor, and an inductor; simplifying the design and layout process for the end user. 1. VIN Supply Connect a supply to the VIN (TP6) and GND (TP7) terminals, paying careful attention to the polarity and the supply range (4.75V < VIN < 20V). Monitor IIN with a current meter and monitor input voltage at VIN and GND terminals with a voltmeter. Do not apply power until Step 4. This highly integrated solution expedites system design and improves product time-to-market. The internal MOSFETs and inductor have been optimized to achieve high efficiency at a low output voltage. The fully optimized design can deliver up to a 6A current under a wide input voltage range of 4.75V to 20V, without an additional cooling requirement. The MIC45116-1 uses Micrel’s HyperLight Load® (HLL). MIC45116-2 uses Micrel’s Hyper Speed Control™ architecture which enables ultra-fast load transient response and allows for a reduction of output capacitance. The MIC45116 offers 1% output accuracy that can be adjusted from 0.8V up to 85% of the input voltage with two external resistors. Note the output capacitor Cb is only rated to 6.3V. The basic parameters of this evaluation board include a 4.75V to 20V input, a 0.8V to 5V at 6A output. Datasheets and support documentation are available on Micrel’s web site at: www.micrel.com. Requirements The MIC45116-1 and MIC45116-2 evaluation board’s minimum requirement is one power supply with at least 6A current capability. No external linear regulator is required to power the internal biasing of the IC because the MIC45116 has an internal PVDD LDO. In the applications with VIN < +5.5V, PVDD should be tied to VIN to bypass the internal linear regulator. The output load can either be a passive or an active load. Precautions The MIC45116 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 20V. Exceeding 30V on the VIN could damage the device. The voltage rating of the output capacitor is 6.3V. The output capacitor should be replaced with higher voltage rated one to set the output voltage above 5V. 2. Connect Load and Monitor Output Connect a load to the VOUT (TP8) and GND (TP9) 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 on board 100kΩ pull-up resistor (R4) to VIN, which allows the output to be turned on when PVDD exceeds its UVLO threshold. An EN connector (TP3) 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 MIC45116 evaluation board. 4. Turn Power Turn on the VIN supply and verify that the output voltage is regulated to 1.8V. 5. Loop Measurement Control loop frequency response can be measured by injecting AC sweep signal and measuring voltage across test points A and B. R3 should change to a small resistor value in the range of 10Ω to 20Ω for the loop measurement. Ordering Information Part Number Description MIC45116-1YMP EV MIC45116-1 Evaluation Board MIC45116-2YMP EV MIC45116-2 Evaluation Board Hyper LightLoad is a registered trademark of Micrel, Inc. 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 12, 2015 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board Features Leaving the RBOTTOM open by removing all jumpers on the feedback headers gives a 0.8V output voltage. All other voltages not listed above can be set by modifying RBOTTOM value according to Equation 2: Feedback Resistors The output voltage on the MIC45116 evaluation board, which is preset to 1.8V, is determined by the feedback divider, as illustrated in Equation 1: VOUT R51 = VREF × 1 + R BOTTOM R BOTTOM = Eq. 1 R51× VREF Eq. 2 VOUT − VREF Note that the output voltage should not be set to exceed 5V unless the output capacitor (C6) is replaced with a higher voltage rating. where VREF = 0.8V, and RBOTTOM is the lower feedback resistor. Table 1. Typical Values of Some Components VOUT VIN R51 (Top Feedback Resistor) R (Bottom Feedback Resistor) C12 (Cff) COUT 1.0V 5V to 20V 10kΩ 40.2kΩ 1.0nF 100µF/6.3V 1.2V 5V to 20V 10kΩ 20.0kΩ 1.0nF 100µF/6.3V 1.5V 5V to 20V 10kΩ 11.5kΩ 1.0nF 100µF/6.3V 1.8V 5V to 20V 10kΩ 8.06kΩ 1.0nF 100µF/6.3V 2.5V 5V to 20V 10kΩ 4.75kΩ 1.0nF 100µF/6.3V 3.3V 5V to 20V 10kΩ 3.24kΩ 1.0nF 100µF/6.3V 5V 7V to 20V 10kΩ 1.91kΩ 1.0nF 100µF/6.3V March 12, 2015 2 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board The short-circuit current limit can be programmed by using Equation 3: SW Node A test pad (SW) is placed close to the module for monitoring the switching waveform. It is one of the most critical waveforms for the converter. R26 = Current Limit The MIC45116 uses the RDS(ON) of the low-side MOSFET and external resistor connected from the ILIM pin to the SW node to decide the current limit. VIN Eq. 3 ICLIM = Desired current limit RDS(ON) = On-resistance of low-side power MOSFET, 16mΩ typically VCL = Current-limit threshold (typical absolute value is 14mV per Electrical Characteristics in the MIC45116 data sheet) MIC45116 ICL = Current-limit source current (typical value is 80µA, per Electrical Characteristics in the MIC45116 data sheet). ΔIL(PP) = Inductor current peak-to-peak, since the inductor is integrated, use Equation 4 to calculate the inductor ripple current. SW R26 ICL where: PVIN C5 (ICLIM − ΔIL (PP ) × 0.5) × R DS(ON) + VCL The peak-to-peak inductor current ripple is: ILIM C16 ∆IL(PP) = PGND VOUT × (VIN(MAX) − VOUT ) VIN(MAX) × fsw × L Eq. 4 The MIC45116 has 1.0µH inductor integrated into the module. In case of hard short, the short limit is folded down to allow an indefinite hard short on the output without any destructive effect. It is mandatory to make sure that the inductor current used to charge the output capacitance during soft start is under the folded short limit; otherwise the supply will go in hiccup mode and may not be finishing the soft start successfully. Figure 1. MIC45116 Current-Limiting Circuit In each switching cycle of the MIC45116, the inductor current is sensed by monitoring the low-side MOSFET in the OFF period. The sensed voltage (V(ILIM)) is compared with the power ground (PGND) after a blanking time of 150ns. In this way the drop voltage over the R26 resistor (VCL) is compared with the drop over the bottom FET generating the short current limit. The small capacitor (C16) connected from ILIM pin to PGND filters the switching node ringing during the off-time allowing a better short-limit measurement. The time constant created by R26 and C16 should be much less than the minimum off time. The MOSFET RDS(ON) varies 30% to 40% with temperature. Therefore, it is recommended to add a 50% margin to ICLIM in the above equation to avoid false current limiting due to increased MOSFET junction temperature rise. With R26 = 1.62kΩ and C16 = 15pF, the typical output current limit is about 8.2A. The VCL drop allows programming of short limit through the value of the resistor (R26) if the absolute value of the voltage drop on the bottom FET is greater than VCL. In that case the V(ILIM) is lower than PGND and a short circuit event is triggered. A hiccup cycle to treat the short event is generated. The hiccup sequence including the soft-start reduces the stress on the switching FETs and protects the load and supply for severe short conditions. March 12, 2015 3 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board MIC45116 Evaluation Board Schematic Figure 2. Schematic of MIC45116 Evaluation Board March 12, 2015 4 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board Bill of Materials Item C4 Part Number B41125A5337M Manufacturer (1) TDK Description 330µF/25V, ALE Capacitor (optional) C2, C3, C7, C8, C9, C11, C17 Qty. 1 Open C1 C3216X5R1E106M085AC TDK 10uF/25V, 1206, X5R, 20%, MLCC 1 C5, C10, C13, C14, C15 GRM188R71H104KA93D Murata 0.1µF/50V, X7R, 0603, 10%, MLCC 5 C6 C3216X5R0J107M160AB TDK 100µF/6.3V, X5R, 1206, 20%, MLCC 1 C12 C1608C0G1H102J080AA TDK 1.0nF/50V, NP0, 0603, 5%, MLCC 1 C16 GRM1885C1H150JA01D Murata 15pF/50V, NP0, 0603, 5%, MLCC 1 CON1, CON2, CON3, CON4 8191 15A, 4-Prong Through-Hole Screw Terminal 4 J1 M50-3500742 Harwin(4) Header 2x7 1 J2, J3, TP3 − TP5 90120-0122 Molex(5) Header 2 5 R4 CRCW0603100K0FKEA 100kΩ, 1%, 1/10W, 0603, Thick Film 1 (2) Keystone (3) Vishay Dale(6) R21, R1 Open R55 CRCW060340K2FKEA Vishay Dale 40.2kΩ, 1%, 1/10W, 0603, Thick Film 1 R31, R50 CRCW06020K0FKEA Vishay Dale 20kΩ, 1%, 1/10W, 0603, Thick Film 2 R32 CRCW060311K5FKEA Vishay Dale 11.5kΩ, 1%, 1/10W, 0603, Thick Film 1 R49 CRCW06038K06FKEA Vishay Dale 8.06kΩ, 1%, 1/10W, 0603, Thick Film 1 R52 CRCW06034K75FKEA Vishay Dale 4.75kΩ, 1%, 1/10W, 0603, Thick Film 1 R53 CRCW06033K24FKEA Vishay Dale 3.24kΩ, 1%, 1/10W, 0603, Thick Film 1 R54 CRCW06031K91FKEA Vishay Dale 1.91kΩ, 1%, 1/10W, 0603, Thick Film 1 R2 CRCW060349K9FKEA Vishay Dale 49.9kΩ, 1%, 1/10W, 0603, Thick Film 1 R51 CRCW060310K0FKEA Vishay Dale 10kΩ, 1%, 1/10W, 0603, Thick Film 1 R26 CRCW06031K62FKEA Vishay Dale 1.62kΩ, 1%, 1/10W, 0603, Thick Film 1 R3, R12 RCG06030000Z0EA Vishay Dale 0Ω Resistor, 1%, 1/10W, 0603, Thick Film 2 TP6 − TP9, A, B 1502-2 Keystone Single-End, Through-Hole Terminal 6 Micrel, Inc.(7) 20V/6A DC-to-DC Power Module 1 U1 MIC45116-1YMP MIC45116-2YMP Notes: 1. TDK: www.TDK.com. 2. Murata: www.murata.com. 3. Keystone: www.keyelco.com. 4. Harwin: http://www.harwin.com 5. Molex: www.molex.com. 6. Vishay-Dale: www.vishay.com. 7. Micrel: www.micrel.com. March 12, 2015 5 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board PCB Layout Recommendations MIC45116 Evaluation Board Top Layer MIC45116 Evaluation Board Copper Layer 2 March 12, 2015 6 Revision 1.0 Micrel, Inc. MIC45116 Evaluation Board PCB Layout Recommendations (Continued) MIC45116 Evaluation Board Copper Layer 3 MIC45116 Evaluation Board Bottom Layer March 12, 2015 7 Revision 1.0 Micrel, Inc. MIC45116 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, Inc. is a leading global manufacturer of IC solutions for the worldwide high-performance linear and power, LAN, and timing & communications markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products. Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network of distributors and reps worldwide. Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. 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. © 2015 Micrel, Incorporated. March 12, 2015 8 Revision 1.0