MIC22602YML Evaluation Board Integrated 6A Synchronous Buck Regulator General Description The Micrel MIC22602 is a high efficiency 6A Integrated synchronous buck (step-down) regulator. The MIC22602 is optimized for highest power density and achieves over 90% efficiency while switching at 1MHz. The MIC22602 features integrated 6A MOSFETs, flexible sequencing and tracking abilities. This board enables the evaluation of the MIC22602. The board is optimized for ease of testing, with all the components on a single side. The voltage-mode feedback loop is designed to allow high bandwidth with just 2 external compensation components. The high-side MOSFET is a P-Channel device, allowing duty cycle control up to 100%. The ultra-high-speed control loop keeps the output voltage within regulation even under extreme transient load swings commonly found in FPGAs and low voltage ASICs. The output voltage can be adjusted down to 0.7V to address all low voltage power needs. The MIC22602 offers a full range of sequencing and tracking options. The EN/DLY pin combined with the POR/PG pin allows multiple outputs to be sequenced in any way on turn-on and turn-off using EN/DLY pin. The RC (Ramp Control™) pin allows the device to be connected to another MIC22602 to keep the output voltages within a certain voltage margin on start up. Requirements This board needs a single bench power source adjustable over the input voltage of 2.6V< VIN < 5.5V that can provide at least 6A of current. The loads can either be active (electronic load) or passive (resistor) with the ability to dissipate the maximum load power while keeping accessible surfaces ideally < 70°C. Precautions There is no reverse input protection on this board. When connecting the input sources, ensure that the correct polarity is observed. Under extreme load conditions, such as short circuit testing, input transients can be quite large if long test leads are used. In such cases a 470µF, 10V electrolytic capacitor is installed at the VIN terminals to prevent over voltage damage to the IC. Getting Started 1. Connect VIN supply to the input terminals PVIN and PGND. With the output of this supply disabled, set its voltage to the desired input test voltage (2.6V< VIN < 5.5V). This supply voltage should be monitored at the test boards input terminals to allow voltage drops in the test cables (and ammeter if used) to be accounted for. An ammeter can be added inline with the +VIN input terminal to accurately measure input current. 2. Connect the loads to the output terminals between VOUT and PGND. Again, this output voltage should be monitored by connecting the voltmeter at the VOUT and PGND terminals. An ammeter can be added inline with the +VO terminal of the evaluation board to accurately measure the output current. The Output voltage has been set to 1.8V. Output voltage can be changed by selecting the resistor R2. Initially, set the output load to 0A to check that the output is regulating properly prior to loaded tests. 3. Enable the input supply. By default, the output voltage is enabled when an input supply of > 2.6V is applied. When this threshold is crossed, the EN pin capacitor (1nF) begins to charge at 1V/µs until it reaches 1.25V, where switching begins. To test the Enable functions of the MIC22602, a test point is provided. Ordering Information Part Number Description MIC22602YML EV Evaluation board with the Integrated 6A MIC22602 device Ramp 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 January 2010 M9999-012610-A Micrel, Inc. MIC22602 Evaluation Board Other Features DELAY Time Input Adding an external capacitor to this DELAY pin allows the Power Good delay to be adjusted to perform as a PowerOn Reset (POR). As with the RC pin, this pin has an internal 1µA current source and sink. After EN pin voltage is driven high, the VOUT will start to rise (rate determined by RC pin capacitor). As the FB pin voltage goes above 90% of its nominal set voltage, DELAY pin voltage begins to rise as the 1µA source charges the external capacitor. When the threshold of 1.24V is crossed, the POR/PG pin is asserted high and DELAY pin continues to charge to a voltage SVIN. When FB pin voltage falls below 90% of nominal, POR/PG is asserted low immediately. However, if EN pin is driven low, the POR/PG pin voltage will fall immediately to the low state and DELAY pin voltage will begin to fall as the external capacitor is discharged by the 1µA current sink. When the threshold of ((VTP+1.24V)1.24V) is crossed (VTP is the internal voltage clamp, VTP=0.9V), the VOUT will begin to fall at a rate determined by the RC pin capacitor. As the voltage change in both cases is 1.24V, both rising and falling delays are matched. EN/DLY Input C6 creates a delay set by an internal 1µA source charging to a 1.25V threshold. A switch (Q1) is used from EN pin-toground as shutdown ‘SHDN’ control. There is approximately 1.3µs enable delay from ‘SHDN’ going low to the start of switching. Using a pulse generator, with a low impedance output connected to the EN terminal, will remove this delay as it defeats the internal 1µA source. RC (Ramp Control™) Capacitor The MIC22602 has a nominal 1µA current source/sink to the RC pin. The startup output voltage waveform tracks the voltage on RC pin. The 100% output voltage is represented by 0.7V on RC pin. The default value of C7 connected to the RC pin is 470pF. This sets the output ramp up time to approximately 190µs. Feedback resistors The output voltage can be changed by adjusting the upper or lower resistor in the FB potential dividers. It is recommended that R1 or R2 value should be kept <10k to reduce noise susceptibility and offset currents from creating voltage errors. Therefore select R1<10k. The resistor divider network for a desired VOUT is given by: R2 = POR (Power-On Reset) Output This is an open drain connection with an on board pull-up resistor (R3) to SVIN. This is only asserted high when the FB pin reaches >90% of its nominal set voltage. This can be used as part of the tracking and sequencing function described in the data sheet. R1 ⎛ VOUT ⎞ ⎜⎜ − 1⎟⎟ ⎝ VREF ⎠ where VREF is 0.7V and VOUT is the desired output voltage. January 2010 2 M9999-012610-A Micrel, Inc. MIC22602YML Evaluation Board Evaluation Board Performances Efficiency @ 3.3V OUT Efficiency @ 1.8V OUT 100 95 90 85 80 75 70 100 95 3.3VIN 90 85 5.5VIN 2.6VIN 80 75 70 65 60 55 50 0 January 2010 65 60 55 1 2 3 4 5 OUTPUT CURRENT (A) 50 0 6 3 VIN = 5.5V 1 2 3 4 5 OUTPUT CURRENT (A) 6 M9999-012610-A Micrel, Inc. MIC22602YML Evaluation Board Evaluation Board Schematic J2 GND U1 MIC22602-YML 3 1 C1 22µF TP2 4 J1 VIN = 3.3V 2 C2 22µF C3 22µF SVIN C4 22µF C5 22µF 6.3V 1 PVIN SW 8 6 PVIN SW 9 13 PVIN SW 10 18 PVIN SW 11 17 SVIN SW 20 SW 21 SW 22 SW 23 FB 14 COMP 15 SGND C8 N.U. EP DELAY D1 DFLS220 C10 47µF 6.3V C11 47µF 6.3V 3 1 4 2 J7 VOUT 1.8V TP1 R1 R2 698 1.1k C12 100pF C9 39pF 16 J5 RC 3 PGND C7 470pF RC PGND R5 N.U. 4 24 TP3 EN PGND 2 2 19 4 C6 N.U. PGND 1 12 3 POR/PG J4 SHDN Q1 N.U. 7 J3 EN 5 SVIN L1 1.0µH C13 10nF R4 20k J6 DELAY SVIN R3 47.5k J8 SGND J11 POR Notes: 1. If buck capacitor on input rail is away (4 inches or more) from the MIC22602, install the 470µF buck capacitor near VIN. 2. Source impedance should be as low as 10mΩ. Bill of Materials Item C1, C2, C3, C4, C5 C6 Part Number TDK 08056D226MAT AVX(2) GRM21BR60J226ME39L Murata(3) Open(VJ0603Y102KXQCW1BC) Vishay(4) Open(GRM188R71H102KA01D) (3) VJ0603Y471KXACW1BC C1608X7R1H471M C8 C9 C10, C11 C12 C13 January 2010 GRM31CR60J476ME19 1 1000pF/50V, COG, 0603, Ceramic Capacitor Vishay 470pF, 0603, Ceramic Capacitor TDK(1) Open(GRM188R71H102KA01D) C3216X5R0J476M 5 (4) (3) VJ0402A390KXQCW1BC 22µF/6.3V, X5R, 0805, Ceramic Capacitor 1000pF/50V, X7R, 0603, Ceramic Capacitor TDK(1) Vishay(4) GRM1555C1H390JZ01D Qty 1nF, 0603, Ceramic Capacitor Murata Open(VJ0603Y102KXQCW1BC) Open(C1608C0G1H102J) Description (1) C2012X5R0J226M Open(C1608C0G1H102J) C7 Manufacturer 1nF, 0603, Ceramic Capacitor, Murata 1000pF/50V, X7R, 0603, Ceramic Capacitor TDK(1) Murata TDK(1) 39pF/50V, COG, 0402, Ceramic Capacitor (5) 47µF/6.3V, X5R, 1206, Ceramic Capacitor 47µF/6.3V, X5R, 1206, Ceramic Capacitor (3) GRM31CC80G476ME19L Murata 47µF/4V, X6S, 1206, Ceramic Capacitor VJ0402A101KXQCW1BC Vishay(4) 100pF, 0603, Ceramic Capacitor (3) 2 1 GRM1555C1H101JZ01D Murata 100pF/50V, COG, 0402, Ceramic Capacitor GRM188R71H103KA01D Murata(3) 10nF, 0603, Ceramic Capacitor 4 1 39pF/10V, 0402, Ceramic Capacitor (3) Murata 1 1000pF/50V, COG, 0603, Ceramic Capacitor (3) BC components 1 1 M9999-012610-A Micrel, Inc. Cin MIC22602YML Evaluation Board B41125A3477M000 SS2P2L D1 DFLS220 SPM6530T-1R0M120 L1 HCP0704-1R0-R R1 CRCW06031101FKEYE3 R2 CRCW04026980FKEYE3 R3 CRCW06034752FKEYE3 R4 R5 1 Vishay Diodes, Inc.(6) Schottky Diode, 2A, 20V 1 TDK(1) Coiltronics(7) Vishay(4) (4) Vishay (4) Vishay (4) 1µH, 12A, size 7x6.5x3mm 1 1µH, 12A, size 6.8x6.8x4.2mm Resistor, 1.1k, 0603, 1% 1 Resistor, 698Ω, 0603, 1% 1 Resistor, 47.5k, 0603, 1% 1 Vishay Resistor, 20k, 0402, 1% 1 Open(CRCW06031003FRT1) Vishay(4) Resistor, 100k, 0603, 1% 1 Signal MOSFET, SOT-23-6 1 Integrated 6A Synchronous Buck Regulator 1 Open(CMDPM7002A) U1 470µF/10V, Electrolytic, SMD, 8x10-Case (4) CRCW04022002FKEYE3 Open(2N7002E) Q1 EPCOS(10) MIC22602YML (4) Vishay Central Semiconductor(8) Micrel(9) Notes: 1. TDK: www.tdk.com 2. AVX: www.avx.com 3. Murata: www.murata.com 4. Vishay: www.vishay.com 5. BC Components: www.bccomponents.com 6. Diodes, Inc.: www.diodes.com 7. Coiltronics:coiltronics.com 8. Central Semiconductor: www.centralsemi.com 9. Micrel, Inc.: www.micrel.com 10. EPCOS Inc. : www.epcos.com January 2010 5 M9999-012610-A Micrel, Inc. MIC22602YML Evaluation Board PCB Layout Recommendations Top Silk Top Layer January 2010 6 M9999-012610-A Micrel, Inc. MIC22602YML Evaluation Board Mid Layer 1 Mid Layer 2 January 2010 7 M9999-012610-A Micrel, Inc. MIC22602YML Evaluation Board Bottom Silk Bottom Layer January 2010 8 M9999-012610-A Micrel, Inc. MIC22602YML 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 The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. 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. January 2010 © 2010 Micrel,9Incorporated. M9999-012610-A