MIC5281 Evaluation Board 120VIN, 25mA, Ultra-Low IQ, High-PSRR LDOs General Description Getting Started The MIC5281 is a high-performance, low-dropout linear regulator featuring a very-low noise output and a very-wide input voltage range (6V to 120V). The MIC5281 supplies an output current of up to 25mA and is offered in both fixed output voltage (3.3V/5.0V) and adjustable output voltage (1.27V to 5.5V) options. Ideal for high input voltage applications such as industrial and telecom, the MIC5281 offers ±3% initial accuracy, extremely-high power supply rejection ratio (>90db) and ultra-low quiescent current (6µA typical). The MIC5281 is optimized for line transient response, which makes it ideal for applications operating in harsh environments. 1. Connect an external supply to VIN terminal. Apply desired input voltage to the VIN and ground terminals of the evaluation board, paying careful attention to polarity and supply voltage. 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. 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 that the output voltage is monitored at the VOUT terminal. The VOUT can be adjusted by changing the feedback resistors. See “Output Voltage” section. 3. Enable the MIC5281. The EN pin is provided on the evaluation board with a 10k pull-up resistor. The output of the MIC5281 may be turned off by shorting the EN pin to ground. An external connection on the board provides easy access to the enable pin. Removing the pull-up resistor and leaving the EN pin floating will cause the regulator to operate in an indeterminate state. The MIC5281 operates over the −40ºC to +125ºC temperature range and is available in the lead-free, RoHScompliant 8-pin ePad MSOP and 8-pin MSOP packages. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. Requirements The MIC5281 evaluation board requires a single power supply to provide VIN. The VIN power supply must be able to deliver a minimum of 6V more than 25mA capability. The output load can either be an active or passive load. Precautions The evaluation board does not have reverse polarity protection, thus applying a negative voltage to the VIN terminal may damage the device. In addition, the maximum VIN operating voltage of the MIC5281 evaluation board is 120V. Exceeding 120V on VIN could permanently damage the device. Ordering Information Part Number Description MIC5281YMME EV Evaluation board featuring the 25mA MIC5281YMME with adjustable output Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com October 2012 M9999-101112-A Micrel, Inc. MIC5281YMME Evaluation Board The output voltage can easily be modified by removing R1 and RFB and replacing them with the values that yield the desired output voltage. Once R1 is selected, RFB can be calculated using: Applications Information Output Voltage The output voltage on the MIC5281YMME evaluation board is adjustable. The output is set by connecting one of the feedback resistors into the circuit via a jumper short. The output voltage can be programmed to 1.8V, 2.5V, 3.3V, or 5V. The output voltage for the MIC5281 evaluation board is set at the factory for a 5V output. In general, the output voltage can be calculated using the following equation: VOUT ⎛ R = VREF × ⎜1 + 1 ⎜ R FB ⎝ R FB = R 1 × VREF VOUT − VREF For VREF = 1.27V: ⎞ ⎟ ⎟ ⎠ R FB = R1 × 1.27V VOUT − 1.27V where VREF = 1.27V, R1 is the combination of R1 and R2 in the EVB circuit schematic, and RFB is the feedback resistor that will be connected from FB to ground amongst R3, R4, R5, and R6 in the circuit schematic. October 2012 2 M9999-101112-A Micrel, Inc. MIC5281YMME Evaluation Board Evaluation Board Schematic MIC5281YMME Evaluation Board (J1 is for test purposes only) October 2012 3 M9999-101112-A Micrel, Inc. MIC5281YMME Evaluation Board Bill of Materials Item Part Number Manufacturer GRM55DR72E105KW01L C1 C2 TDK(2) 2220PC105MAT1A AVX(3) GRM21BR71E104KA01L Murata 08053C104KAT2A GRM21BR61A106KE19L C3 TDK 0805ZD106KAT2A AVX ⎯ C5 1 0.1µF/25V Ceramic Capacitor, X7R, 0805 1 10µF/10V Ceramic Capacitor, X5R, 0805, 10% 1 AVX TDK ⎯ 1µF/250V Ceramic Capacitor, X7R, 20% Murata C2012X7R1A106K C4 Qty. Murata C5750X7R2E105M C2012X7R1E104K Description (1) ⎯ Large value electrolytic capacitor, 250V (minimum) DNP ⎯ Minimum 250V Ceramic Capacitor (any value) DNP R1 CRCW060300R0F Vishay(4) R2 CRCW06032942F R3 0Ω Film Resistor, Size 0603, 1% 1 Vishay 29.4kΩ Film Resistor, Size 0603, 1% 1 CRCW06031002F Vishay 10.0kΩ Film Resistor, Size 0603, 1% 1 R4 CRCW06031822F Vishay 18.2kΩ Film Resistor, Size 0603, 1% 1 R5 CRCW06033012F Vishay 30.1kΩ Film Resistor, Size 0603, 1% 1 R6 CRCW06036982F Vishay 69.8kΩ Film Resistor, Size 0603, 1% 1 120VIN, 25mA, Ultra-Low IQ, High-PSRR LDOs 1 U1 MIC5281YMME (5) Micrel, Inc. Notes: 1. Murata: www.murata.com. 2. TDK: www.tdk.com. 3. AVX: www.avx.com. 4. Vishay: www.vishay.com. 5. Micrel, Inc.: www.micrel.com. October 2012 4 M9999-101112-A Micrel, Inc. MIC5281YMME Evaluation Board Evaluation Board PCB Layout MIC5281YMME Evaluation Board – Top Silkscreen Layer MIC5281YMME Evaluation Board – Top Layer October 2012 5 M9999-101112-A Micrel, Inc. MIC5281YMME Evaluation Board Evaluation Board PCB Layout (Continued) MIC5281YMME Evaluation Board – Bottom Layer MIC5281YMME Evaluation Board – Bottom Silkscreen October 2012 6 M9999-101112-A Micrel, Inc. MIC5281YMME 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 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. © 2011 Micrel, Incorporated. October 2012 7 M9999-101112-A