High-Speed LDO N-Channel Controller MIC5190/91 Evaluation Board General Description This evaluation board can be used to evaluate both the MIC5190 and MIC5191 high speed LDO’s. The MIC5190/1 are linear controllers that require an external N-Channel MOSFET for operation. This allows the device to be tailored to the end application. This evaluation board features a very low RDS(ON) MOSFET that can handle up to 2W with no airflow. At low dropout voltages (VIN – VOUT), this evaluation board can deliver up to 10A of current. The MIC5190 is used for voltages less than 1V and the MIC5191 is for applications greater than 1Vout. Requirements The MIC5190/1 evaluation board requires two input supply voltages. A power supply for VIN, which is also connected to the drain of the N-Channel MOSFET must be able to deliver the amount of load current required. The operating range of the VIN supply is 0.9 to 5.5V, but must also be a higher voltage than the output voltage plus the dropout voltage. The second supply, VCC, has an operating range from 4.5 to 13.2V. VCC supplies the gate drive for the MOSFET, therefore the VCC voltage must also be 2V greater than the MOSFETs gate source threshold required for regulation. Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN or VCC terminal may damage the device. Exceeding 6V on VIN or 14V on VCC can also damage 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 (0.9V<VIN<5.5V). Ensure the supply voltage is monitored at the VIN terminal. An ammeter and/or power supply lead resistance can reduce the voltage supplied to the input. Since the default configuration is to tie both the VIN and ISENSE pins together, the MIC5190/1 evaluation board offers no current limit protection. Ensure the VIN supply is current limited to prevent damage in short circuit conditions. In cases where the current limit is desired refer to the current limit paragraph. 2. Connect an external supply to VCC -Apply desired input voltage to the VCC and ground terminals of the evaluation board, paying careful attention to polarity and supply voltage (4.5V<VIN<13.2V). Ensure the supply voltage is monitored at the VCC terminal. 3. 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 0.9V for the MIC5190 and 1.2V for the MIC5191. This can be adjusted by changing the feedback resistors. (see next paragraph Output Voltage) 4. Enable the MIC5190/1 – Apply a 0.8V or greater voltage source to the enable pin. Alternatively, the device can be enabled by tying either VCC or VIN to the enable. Output Voltage The output voltage on the MIC5190/1 evaluation board is adjustable. The output voltage is controlled by the feedback resistors (R1 and R2) and can be calculated as follows: R1 VOUT = VREF( + 1) R2 VREF is equal to 0.5V for the MIC5190 and 1V for the MIC5191.The evaluation board is initially adjusted to 0.9V (MIC5190) or 1.2V (MIC5191), 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 0.5V (MIC5190) or 1V (MIC5191).] R2 = 100Ω ⎛ VOUT ⎞ − 1⎟ ⎜ ⎝ VREF ⎠ Power, Connect and Protect 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 November 2004 M9999-110204 (408) 955-1690 Micrel MIC5190/91 Evaluation Board Current Limit The default configuration for the MIC5190/1 evaluation board is to bypass current limit by tying the ISENSE pin to VIN. In cases where current limiting from the MIC5190/1 is required, the board can be cut as shown in Figure 1, and a sense resistor placed across the board. The required RSENSE value can be calculated as follows: 50mV RSENSE = ILIMIT November 2004 2 M9999-110204 (408) 955-1690 Micrel MIC5190/91 Evaluation Board Evaluation Board Schematic MIC5190/91 Evaluation Board Schematic Bill of Materials Item Part Number Manufacturer Description C1a, C1b C3225X5R0J226M 1206D226MAT TDK AVX 22µF/6.3V X5R 1206 22µF/6.3V X5R 1206 GRM31CR60J226KE19L Murata 22µF/6.3V X5R 1206 open C3216X7R1C475 TDK 4.7µF/16V X5R 1206 12063D475MAT GRM31CR61C475KA01L AVX Murata 4.7µF/16V X5R 1206 4.7µF/16V X5R 1206 1 C3a GRM31MR06J106KE19L Murata 10µF/6.3V X5R 0805 1 C4 CM21X5R106M06AT VJ0805Y103KXXAT Kyocera Vitramon 10µF/6.3V X5R 0805 0.01µF/25V 1 R1 R2 (MIC5190) R2 (MIC5191) CRCW08051000FRT1 Vishay 100Ω 1% 1/10W 0805 1 CRCW08051240FRT1 Vishay 124 Ω 1% 1/10W 0805 CRCW08054990FRT1 Vishay 499 Ω 1% 1/10W 0805 R3 R4 CRCW08051000FRT1 CRCW08051000FRT1 MIC5190BML or MIC5191BML Vishay Vishay MICREL 100 Ω 1% 1/10W 0805 100 Ω 1% 1/10W 0805 High Speed N-channel LDO C1d, C1c C2 U1 Qty. 2 1 1 1 1 Notes: 1. On Semiconductor Tel: 800-344-3860 2. Micro Commercial Corp. Tel: 800-346-3371 3. Sumida Tel: 408-982-9660 4. Murata Tel: 949-916-4000 5. Vishay Tel: 402-644-4218 6. Micrel Semiconductor Tel: 408-944-0800 November 2004 3 M9999-110204 (408) 955-1690 Micrel MIC5190/91 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. © 2004 Micrel, Incorporated. November 2004 4 M9999-110204 (408) 955-1690