MIC2169A Evaluation Board 500kHz MSOP-10 Synchronous Step-Down Controller General Description The MIC2169A is a high-efficiency, simple to use 500kHz PWM synchronous buck control IC housed in a small MSOP-10 package. The MIC2169A allows compact DC-toDC solutions with a minimal external component count and cost. The output voltage can be precisely regulated down to 0.8V. The adaptive all N-Channel MOSFET drive scheme allows efficiencies over 95% across a wide load range. Note: This evaluation board is for 3A applications. A 7A output evaluation board is also available. The literature for the 7A evaluation can be found in the MIC2169A data sheet. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. Adjusting Output Voltage The output voltage on the MIC2169A evaluation board is adjustable. The output voltage is controlled by the feedback resistors (R1 and R2) and can be calculated as follows: Requirements The MIC2169A evaluation board requires an input power source that is able to deliver greater than 3A at 12V. Ensure the output voltage selected does not exceed 5V, since the tantalum output capacitor has a 6.3V voltage rating. Typically the working voltage for tantalum capacitors should never exceed 80% of their rated voltage value. When output voltages greater than 5V are desired, the output capacitor should be replaced with one where the output voltage is less than 80% of the output capacitor voltage rating (tantalum capacitors). Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN (J1) terminal may damage the device. The MIC2169A evaluation board is tailored for a 5V to 12V input voltage range. The input voltage range should not exceed 14.5V on the input. ⎛ R2 ⎞ VOUT = 0.8V ⎜ + 1⎟ ⎝ R3 ⎠ The evaluation board is initially adjusted to 1.5V, but can easily be modified by removing R3 and replacing it with the value that yields the desired output voltage. The R2 resistor is recommended for a 3kΩ to 10kΩ resistor range. ⎛ 0.8V R 3 = 10kΩ⎜⎜ ⎝ VOUT − 0.8V ⎞ ⎟ ⎟ ⎠ Ordering Information Getting Started 1. 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 (5V≤VIN≤12V). 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. 2. Enabling the MIC2169A. The MIC2169A is enabled as soon as a power supply with a voltage in the range of 3V to 14.5V is connected across the VIN (J1) and GND (J2) terminals. Part Number Description Package MIC2169AYMM IC 10-Pin MSOP MIC2169A Tiny3A EV Evaluation Board 10-Pin MSOP 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 2007 1 M9999-053107-A Micrel, Inc. MIC2169A Evaluation Board J1 VIN = 5V to 12V 1 +VIN C8 0.1µF D1 SD103BWS C14 0.1µF/25V 10 Q1 SI48O4BDY 7 1 R6 9 R7 1 8 4 7 FB C6 1000pF 5 R2 10K R4 RES R1 Open C1 0.1µF/25V C3 Open C4 CAP R3 11.3K J4 GND 6 R11 1K 4 CAP 3 C10 0.1µF GND C11 OPEN LSD COMP/EN R5 + C2 330µF D2 (Open 1N5819HW) 2 R8 J3 VO = 1.5V 1 2 6 5 VSW U1 MIC2169AYMM COUT = AVX TPSD337M006R0045 C5 1 HSD L1 2.0µH CDR7D28MN-2R0 2 2 BST 8 VDD CS VIN 1 2 3 C9 1µF/16V C7 10µF/6V R9 602 R10 5 1 2 C13 10µF/16V 2 + C13 100µF/20V J2 GND MIC2169A Schematic May 2007 2 M9999-053107-A Micrel, Inc. MIC2169A Evaluation Board Bill of Materials Item C1,C8, C10,C14 C2 Part Number VJ0603Y104KXXAT 594D337X06R3D2T TPSD337M006R0045 Manufacturer (1) Vishay Victramon Vishay/Sprague C7 C9 C12 C13 VJ0603A102KXXAT 08056D106MAT2A Vishay Victramon(1) AVX TDK 0805YD105MAT2A (2) TDK (3) SD103BWS Vishay(1) 1N5819HW CDR7D28MN-2R0 CRCW06031002FKEY3 1 Diodes Inc. (1) 68µF, 20V Tantalum (4) Sumida(5) R1,R4 R2 1000pF/25V 10µF/16V, X7R, Ceramic Capacitor Vishay/Sprague AVX(2) L1 4 1µF/16V, X7R, 0805, Ceramic Capacitor AVX TPSD686M020R0100 D2 OPEN 10µF/6.3V, 0805 Ceramic Capacitor (3) TDK(3) D1 4 (2) C2012X5R0J106M 594D686X0020D2T 0.1µF/25V, 0603 330µF, 6.3V, Tantalum AVX(2) C2012X7R1C105K C3225X7R1C106M Qty. (1) C3,C4 C5,C11 C6 Description (1) Vishay Dale (1) 1 1 1 1 1 1 1 Schottky Diode 1 OPEN 1 2.0µH, 7A Inductor 1 OPEN (0603 size) 2 10K, 0603, 1/10W, 1% 1 R3 CRCW06031152FKEY3 Vishay Dale 11.5K, 0603, 1/10W, 1% 1 R5 CRCW06034R02FKEY3 Vishay Dale(1) 4.02Ω, 0603, 1/10W, 1% 1 R6,R8 OPTIONAL 0Ω, TRACE ON BOARD 2 (1) R7 CRCW06032R00FKEY3 Vishay Dale R9 CRCW06036020FKEY3 Vishay Dale(1) CRCW080510R0FKEY3 R10 R11 CRCW06031001FKEY3 Si4804BDY Q1 U1 2Ω, 0603, 1/10W, 1% 1 602Ω, 0603, 1/10W, 1% 1 (1) 10Ω, 0805 ,1/8W, 1% 1 (1) 1K, 0603, 1/10W, 1% 1 Dual Power N-Channel Transistors 1 Vishay Dale Vishay Dale (1) Vishay/Siliconix IRF8910 International Rectifier(6) AM4920N Analog Power(7) MIC2169AYMM Micrel, Inc. 1 1 (8) Step-Down Controller 1 Notes: 1. Vishay: www.vishay.com 2. AVX: www.avxcorp.com 3. TDK: www.tdk.com 4. Dioses, Inc.: www.diodes.com 5. Sumida: www.sumida.com 6. Internacional Rectifier: www.irf.com 7. Analog Power: www.analogpowerinc.com 8. Micrel, Inc.: www.micrel.com May 2007 3 M9999-053107-A Micrel, Inc. MIC2169A Evaluation Board PCB Layout Top Layer with Silkscreen Bottom Layer with Silkscreen May 2007 4 M9999-053107-A Micrel, Inc. MIC2169A 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. May 2007 5 M9999-053107-A