MIC2225 2MHz PWM Synchronous Buck Regulator with 300mA LDO General Description The Micrel MIC2225 is a dual output regulator featuring a high efficiency 2MHz PWM synchronous buck (step-down) regulator and a 300mA LDO. The MIC2225 allows an ultra-low noise, small size, and high efficiency solution. Note: This evaluation board is for fixed output applications. Refer data sheet for available outputs and corresponding part number. In PWM mode, the MIC2225 operates with a constant frequency 2MHz PWM control. The MIC2225 operates from 2.7V to 5.5V input and features internal power MOSFETs that can supply up to 600mA output current in PWM mode. Requirements The MIC2225 evaluation board requires an input power source that is able to deliver greater than 1A at 2.7V. Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN (J1) terminal may damage the device. The MIC2225 evaluation board is tailored for a 2.7V to 5.5V input voltage range. The input voltage range should not exceed 5.5V on the input. Getting Started Connect an external supply to the VIN. Apply desired input voltage to the VIN (J1) and ground (J2) 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 that the supply voltage is monitored at the VIN terminal. The ammeter and/or power lead resistance can reduce the voltage supplied to the input. 1. Enabling the MIC2225. The MIC2225 has two enable pins. EN for buck (step-down) regulator and ENLDO for LDO. EN: A logic high will turn on the switching regulator and a logic low will shut down the switching regulator reducing the quiescent current to less than 5µA. ENLDO: A logic high will turn on the switching regulator and a logic low will shut down the switching regulator reducing the quiescent current to less than 5µA. Ordering Information Part Number Description MIC2225-XXYMT EV Evaluation board with the MIC2225-XXYMT device 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 2008 M9999-012408-A Micrel, Inc. MIC2225 Evaluation Board 8 R1 10k 1 2 JP1 1X2 L1 0.47µH / 2.2µH MIC2225-XXYMT J1 VIN 5.5V Max J7 ENLDO J6 EN C1 2.2µF/ 6.3V R2 10k C2 0.1µF/ 6.3V J2 GND VIN SW 9 4 AVIN FB 5 6 EN 7 ENLDO LDO 2 3 BIAS PGND AGND 10 R3 0 C3 2.2µF/ 6.3V J3 VO C4 2.2µF/ 6.3V J4 LDO J5 GND 1 Schematic Diagram Bill of Materials Item C1 C2 Part Number C1608X5R0J225K VJ0402Y104KXQCW1BC Manufacturer TDK (1) Vishay Vitramon 2.2µF/6.3V, X5R 1 2.2µF/6.3V, X5R 1 (2) 10k, 0603, 1/16W, 1% 1 (2) 10k, 0603, 1/16W, 1% 1 0, 0805, 1/8W, 1% 1 2.2µH, 1.1A (Isat) 1 2Mhz PWM Synchronous Buck Regulator with 300mA LDO 1 TDK C1608X5R0J225K TDK(1) Vishay Dale R2 CRCW06031002FKEYE3 Vishay Dale R3 CRCW08050000FKEYE3 Vishay Dale(2) CDRH2D11/HPNP-2R2NC U1 MIC2225-XXYMT 1 1 C1608X5R0J225K L1 2.2µF/6.3V, X5R 0.1µF/6.3V, X7R C4 CRCW06031002FKEYE3 Qty. (1) C3 R1 (2) Description Sumida (3) Micrel, Inc. (4) Notes: 1. TDK: www.tdk.com 2. Vishay: www.vishay.com 3. Sumida: www.sumida.com 4. Micrel, Inc.: www.micrel.com January 2008 2 M9999-012408-A Micrel, Inc. MIC2225 Evaluation Board PCB Layout Recommendations Top Layer Bottom Layer Note: The above figures demonstrate the recommended layout for the MIC2225 fixed output option. January 2008 3 M9999-012408-A Micrel, Inc. MIC2225 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. © 2007 Micrel, Incorporated. January 2008 4 M9999-012408-A