MIC5190 POL Evaluation Board High Speed LDO Controller By Martin Galinski General Description This evaluation board can be used to evaluate the MIC5190 high speed LDO in a single-inline-package for point-of-load applications. The MIC5190 is a linear controller that requires an external N-Channel MOSFET for operation. This evaluation board features a very low RDSON MOSFET that can handle up to 1W with no airflow. At low dropout voltages (VIN – VOUT), this evaluation board can deliver over 5A of output current. Requirements The MIC5190 point-of-load 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. September 2004 Getting Started 1. Connect an external supply to VIN (J1-1) -Apply desired input voltage to the VIN (J11) and ground terminals (J1-2) 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 (J1-5) -Apply desired input voltage to the Vcc (J15) and ground terminals (J1-3) 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 (J1-8,9) and ground terminals (J1-10)- 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 MIC5190 point-of-load evaluation board is adjusted to 1V. This can be adjusted by changing the feedback resistors (see the next section “Output Voltage”). There is also a sense pin for remote sensing the voltage directly at the load. Connect sense (J1-7) to the load. R Trim (J1-4) is a trim that allows a +/-5% Trim of the output voltage. By tying this pin to ground, the output voltage is increased by 5%. By tying this pin to the output voltage, the output is reduced by 5%. M9999-090104 (408) 955-1690 Micrel MIC5190 POL Evaluation Board INPUT VOLTAGE-OUTPUT VOLTAGE (V) 4. Enable the MIC5190/1 - Apply a 0.8V or greater voltage source to the enable pin (J1-6). Alternatively, the device can be enabled by tying either VCC or VIN to the enable. Output Voltage The output voltage on the MIC5190 point-of-load 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. The evaluation board is initially adjusted to, 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)] 100 R2 = V OUT 1 VREF Max Output Current vs. (Supply Voltage-Output Voltage) 10 1 400 LFM 200 LFM 0 LFM 100 LFM 0.1 0 1 2 3 4 5 6 7 8 9 10 MAXIMUM OUTPUT CURRENT (A) Output Power The amount of power the MIC5190 point-of-load board can deliver depends on the supply voltage, the desired output voltage, load current and maximum ambient temperature. The following table illustrates the point-of-load evaluation board thermal resistance. JA Airflow (Linear Feet per Minute) 55 °C/W 0 LFM 37 °C/W 100 LFM 34 °C/W 200LFM 27 °C/W 400LFM The MIC5190 point-of-load board achieves linear voltage regulation by controlling an International Rectifier IRLR3717 N-Channel D-pack MOSFET. Since almost all the power will be dissipated in the MOSFET, the temperature should be monitored at the MOSFET. The above JA figures apply to the MOSFETs junction (Die) to ambient thermal resistance. Maximum output current can be calculated as follows; IOUT (max) = TJ (max) − TA (max) ( θ JA × VIN − VOUT ) The following graph illustrates the maximum output current versus the input-to-output voltage differential, assuming a 60°C maximum ambient temperature and a maximum junction (Die) temperature of 110°C. September 2004 2 M9999-090104 (408) 955-1690 Micrel MIC5190 POL Evaluation Board Evaluation Board Schematic VCC J1-5 VOUT SENSE J1-7 C2 1µF 16V VIN 1.0V to 5.5Vmax R4 1Ω Q1 IRLR3717 J1-1 J1-8,9 R2 100Ω C1 47µF/6.3V VIN ISENSE R5 FB 1k VCC2 U1 MIC5190 C3 0.01µF 12k COMP SGND TRIM J1-4 EN R1 C4 10µF/6.3V OUT VCC1 ENABLE J1-6 VOUT 1.0V PGND R3 100Ω GND GND J1-2 J1-10 Bill of Materials MIC5190 POL Evaluation Board Item C1 Part Number GRM31CR60J476ME19L Manufacturer C1b, C1c C2 GRM188R61C105KA93D Murata(1) C3 C4 VJ0603Y103KXXAT GRM219R60J106KE19D Vishay-Vitramon Murata R1 R2, R3 R4 R5 Q1 U1 CRCW060331212FRT1 CRCW06031000FRT1 CRCW06031R00FRT1 CRCW06031002FRT1 IRLR3717 MIC5190BML Vishay-Dale Vishay-Dale Vishay-Dale Vishay-Dale IR September 2004 Murata(1) Micrel, Inc. (4) 3 Description 47µF/6.3V Size 1206 X5R Ceramic Capacitor Open 1µF/16V Size 0603 X5R Ceramic Capacitor 0.01µF/25V Size 0603 Ceramic Capacitor 10µF/6.3V Size 0805 X5R Ceramic Capacitor 12.1k, 1%, 0603 100, 1%, 0603 1, 1%, 0603 1k, 1%, 0603 N-Channel MOSFET High Speed LDO Controller Qty. 1 1 1 1 1 2 1 1 1 1 M9999-090104 (408) 955-1690 Micrel MIC5190 POL Evaluation Board Printed Circuit Board Layouts Top Silkscreen Overlay Bottom Silkscreen Overlay Top Layer Bottom Layer MICREL, INC. 1849 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. September 2004 4 M9999-090104 (408) 955-1690