MIC5234YME Evaluation Board Low-Quiescent Current 150mA LDO Regulator General Description Getting Started The MIC5234 is a low-quiescent current, μCap lowdropout regulator. A maximum operating input voltage of 30V and quiescent current of 20μA make it ideal for supplying keep-alive power in systems with high-voltage batteries. Capable of 150mA output, the MIC5234 has a dropout voltage of only 320mV. It can also survive an input transient of –20V to +32V. The MIC5234 needs only a 2.2μF output capacitor for stable operation. The MIC5234 is available in an 8-pin ePad SOIC package with a junction operating range from –40°C to +125°C. Data sheets and support documentation are available on the Micrel web site: www.micrel.com. Requirements The MIC5234YME Evaluation Board requires a 2.3V to 30V power supply, and a test load. Make sure that the power supply can provide the wattage needed for the chosen test load. The load can be active (electronic load) or passive (resistor). Additionally, monitor the Power Good output (PG) with a multimeter or an oscilloscope. Precautions There is no reverse input protection on this board. While connecting supplies and signals, make sure that correct polarities are observed. 1. VIN Supplies Connect the VIN supply (2.3V to 30V) across the VIN and GND terminals. Monitor VIN at the VIN and GND terminals with a voltmeter. JP1 is a 2-pin header test point provided for monitoring VIN. 2. Enable Inputs The enable input EN is logic high active and needs pull up to input or a voltage source. When EN is pulled low the output is off; when EN is high the output is on. 3. Monitor Outputs Monitor the output VOUT with a scope or DVM connected across the VOUT and GND terminals. 4. Output Load Connect a load across the VOUT and GND terminals. Use an active or passive load. 5. Turn On the Power Turn on the power supply and verify that VOUT = 1.8V. Ordering Information Part Number Description MIC5234YME EV Evaluation Board for the MIC5234YME 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 September 2012 M9999-092412-A Micrel, Inc. MIC5234 Evaluation Board Reverse Current Protection The MIC5234 is designed to limit the reverse current flow from output to input if the MIC5234 output has been tied to the output of another power supply. Output Capacitor The MIC5234 has been designed to minimize the effect of the output capacitor ESR on the closed loop stability. As a result, ceramic or film capacitors can be used at the output. Stability can also be maintained throughout the specified load and line conditions with 2.2μF film or ceramic capacitors. Input Capacitor An input capacitor may be needed when the device is not near the source power supply or when it is supplied by a battery. Small, surface mount, ceramic capacitors can be used for bypassing. Larger values may be needed if the source supply has high ripple. Evaluation Board Features See the MIC5234 Data Sheet for detailed explanations of these functions. Enable (EN) EN allows the MIC5234 to turn on/off. A logic low on EN pin keeps MIC5234 in shutdown mode with a typical 0.1µA input current. Output Adjust (ADJ) The MIC5234 can be adjusted from 1.24V to 20V by using two external resistors. The resistors set the output voltage based on Equation 1: ⎛ R1 ⎞ VOUT = VREF × ⎜1 + ⎟ ⎝ R2 ⎠ Eq. 1 Where VREF = 1.23V. The evaluation board is provided with R2=120Ω and jumper (JP3-JP6) to easily set the output voltage to 5V, 3.3V, 2.5V, and 1.8V. September 2012 2 M9999-092412-A Micrel, Inc. MIC5234 Evaluation Board Evaluation Board Schematic Bill of Materials Item Part Number C1, C5 EKY-500ELL101MHB5D 12065C475KAT2A C2, C3 GRM31CR71H475KA12L C3216X5R1H475K 0805YD225KAT2A Manufacturer United Chemi-con(1) Description Qty. Capacitor, Aluminum, 100µF, 50V, 20%, Radial 2 Capacitor, 4.7µF, 50V, X5R, size 1206 2 Capacitor, 2.2µF, 16V, X7R, size 0805 1 (2) AVX Murata(3) TDK (4) AVX C4 GRM219R61C225KA88D R1 CRCW060310K0FKEA Vishay(5) Resistor, 10KΩ, 1%, size 0603 1 R2 CRCW06031200FKEA Vishay Resistor, 120Ω, 1%, size 0603 1 R3 CRCW06033830FKEA Vishay Resistor, 383Ω, 1%, size 0603 1 R4 CRCW06032000FKEA Vishay Resistor, 200Ω, 1%, size 0603 1 Resistor, 127Ω, 1%, size 0603 1 Resistor, 56Ω, 1%, size 0603 1 Low-Quiescent Current µCap LDO Regulator 1 C2012X7R1C225K R5 CRCW06031270FKEA R6 CRCW060356R0FKEA U1 MIC5234YME Murata TDK (5) Vishay Vishay Micrel (6) Notes: 1. United Chemi-Con: www.chemi-con.com. 2. AVX: www.avx.com. 3. Murata: www.murata.com. 4. TDK: www.tdk.com. 5. Vishay: www.vishay.com. 6. Micrel, Inc.: www.micrel.com. September 2012 3 M9999-092412-A Micrel, Inc. MIC5234 Evaluation Board Evaluation Board PCB Layout MIC5234 Evaluation Board Top Layer MIC5234 Evaluation Board Top Silk September 2012 4 M9999-092412-A Micrel, Inc. MIC5234 Evaluation Board Evaluation Board PCB Layout (Continued) MIC5234 Evaluation Board Bottom Layer MIC5234 Evaluation Board Bottom Silk September 2012 5 M9999-092412-A Micrel, Inc. MIC5234 Evaluation Board MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB www.micrel.com Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. 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. © 2012 Micrel, Incorporated. September 2012 6 M9999-092412-A