MIC2207 Evaluation Board 3mm × 3mm 2MHz Buck Converter General Description The Micrel MIC2207 is a high efficiency PWM buck (step-down) regulator that provides up to 3A of output current. The MIC2207 operates at 2MHz and has proprietary internal compensation that allows a closed loop bandwidth of over 200 KHz The low on-resistance internal p-channel MOSFET of the MIC2207 allows efficiencies over 94% and reduces external component count and eliminates the need for an expensive current sense resistor. The MIC2207 operates from 2.7V to 5.5V input and the output can be adjusted down to 1V. The devices can operate with a maximum duty cycle of 100% for use in low-dropout conditions. Requirements The MIC2207 evaluation board requires an input power source that is able to deliver greater than 2.7V at over 3A. The output load can either be an active or passive source. Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. In addition, the maximum operating voltage of the MIC2207 evaluation board is 5.5V. Exceeding 6V on the input could damage the device. For short circuit testing, an additional input capacitor over 22uF is required. This is preferably an electrolytic, but may be tantalum or ceramic. When using long test leads to provide power to the device, the inductance can be over 1uH. During a short circuit condition, the high peak currents through the test leads may cause the input voltage to spike and exceed the absolute maximum rating of 6V, possibly damaging the device. Getting Started 1. Connect an external supply to VIN. Apply desired input voltage to the VIN and ground terminals of the evaluation board, paying careful attention to polarity and supply voltage (2.7V<VIN<5.5V). An ammeter may be placed between the input supply and the VIN terminal to the evaluation board. Ensure the supply voltage is monitored at the VIN terminal. The ammeter and/or power lead resistance can reduce the voltage supplied to the input. 2. Connect the load to the VOUT and ground terminals. The load can be either passive (resistive) or active (as in an electronic load). An ammeter can be placed between the load and the VOUT terminal. Ensure the output voltage is monitored at the VOUT terminal. The default output voltage is set to 1.8V. This can be adjusted by changing the feedback resistors. See “Output Voltage.” 3. Enable the MIC2207. Apply a 1.3V or greater voltage source to the enable pin. Typical Application MIC2207 Evaluation Board Schematic Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com May 2006 M9999-051706 (408) 955-1690 Micrel, Inc. MIC2207 Evaluation Board The evaluation board is initially adjusted to 1.8V, but can easily be modified by removing R2 and replacing it with the value that yields the desired output voltage. (Removing R2 sets the output to 1V.) Output Voltage The output voltage on the MIC2207 evaluation board is adjustable. The output voltage is controlled by the feedback resistors (R1 and R2) and can be calculated as follows: R2 = ⎛ R1 ⎞ VOUT = 1V × ⎜ + 1⎟ ⎝ R2 ⎠ May 2006 2 10k Ω V ⎛ OUT ⎞ − 1⎟ ⎜ 1V ⎝ ⎠ M9999-051706 (408) 955-1690 Micrel, Inc. MIC2207 Evaluation Board Evaluation Board Schematic MIC2207 Evaluation Board Schematic Bill of Materials Item Part Number Manufacturer C2012JB0J106K C5,C6 TDK (1) Description Qty. 10µF Ceramic Capacitor X5R 0805 6.3V (2) 10µF Ceramic Capacitor X5R 0805 6.3V GRM219R60J106KE19 Murata 08056D106MAT AVX(3) 10µF Ceramic Capacitor X5R 0805 6.3V 2 C7 0402ZD104MAT (3) AVX 0.1µF Ceramic Capacitor X5R 0402 10V 1 C1-4, C10-12* 0402ZD104MAT AVX(3) 0.1µF Ceramic Capacitor X5R 0402 10V C2012JB0J475K (1) C9 C8 D1 L1 R4 Murata 06036D475MAT AVX(3) VJ0402A820KXAA U1 (2) Vishay VT 4.7µF Ceramic Capacitor X5R 0603 6.3V (4) (4) SSA33L Vishay Semi (1) 4.7µF Ceramic Capacitor X5R 0603 6.3V 1 82pF Ceramic Capacitor 0402 1 3A Schottky 30V SMA 1 1µH Inductor 8.8mΩ 7.1mm (L) x 6.8mm (W) x 3.2mm (H) RLF7030-1R0N6R4 TDK 744 778 9001 Wurth Electronik 1µH Inductor 12mΩ 7.3mm (L) x 7.3mm (W) x 3.2mm (H) (4) 1µH Inductor 17.5mΩ (L) 6.47mm x (W) 6.86mm x (H) 1.8mm 1 (4) 10KΩ1% 0402 resistor 1 Vishay Dale CRCW04021002F Vishay Dale CRCW04026652F Vishay Dale(4) 66.5 kΩ 1% 0402 For 2.5VOUT CRCW04021243F Vishay Dale(4) 124 kΩ 1% 0402 For 1.8 VOUT CRCW04022003F (4) 200 kΩ 1% 0402 For 1.5 VOUT (4) Vishay Dale 402 kΩ 1% 0402 For 1.2 VOUT Vishay Dale(4) Open CRCW04024023F R3 4.7µF Ceramic Capacitor X5R 0603 6.3V GRM188R60J475KE19 IHLP2525AH-01 1 R1,R3 TDK CRCW040210R0F MIC2207YML † Vishay Dale (4) Vishay Dale Micrel * (5) For 1.0 VOUT 1 10Ω 1% 0402 resistor 1 2MHz 3A Buck Regulator 1 Notes: 4. Vishay: www.Vishay.com 1. TDK: www.TDK.com 2. Murata Tel: www.Murata.com 5. Micrel Semiconductor :www.Micrel.com 3. AVX: www.AVX.com † May 2006 3 Micrel IC = Pb-Free M9999-051706 (408) 955-1690 Micrel, Inc. MIC2207 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. © 2005 Micrel, Incorporated. May 2006 4 M9999-051706 (408) 955-1690