MIC5018 Evaluation Board Micrel MIC5018 Evaluation Board IttyBitty™ High-Side MOSFET Driver Description Bill of Materials Item Qty. — 1 The MIC5018 evaluation board is an assembled, high-side switch for 2.7V to 9V power-switching applications. Requirements The MIC5018 evaluation board requires a power supply, load, and logic output. C1 1 Operation Q1 1 Connect the evaluation board as shown. A function generator with a TTL output, or a logic-level, square wave output, can be used as a control signal. On/off power switch operation can be simulated by setting the output frequency to about 1Hz or 2Hz. Applying logic high to the control input will energize the load; logic low will de-energize the load. The MIC5018 makes it possible to switch a supply as low as 2.7V using a logic-level MOSFET such as the IRL3103. Because the IRL3103 also has a ±20V maximum gate voltage rating, the MIC5018 evaluation board can switch a 5V logic supply or higher voltage circuit without an additional gate-to-source clamping zener. (Logic-level MOSFET gates are usually rated at ±10V maximum. See “MOSFET Selection” in the MIC5018 data sheet for more information.) Supply Precautions Description Micrel, MIC5018BM4 IttyBitty™ high-side MOSFET driver AVX, TAJB475M020 Note 1 4.7µF 20V tantalum International Rectifier, IRL3103 Note 2 14mΩ N-channel power MOSFET Note 1: See “Operation: Supply Precautions” for information on safely using tantalum capacitors. Note 2: Manufacturer’s preliminary data sheet ratings: 14mΩ at VGS = 10V, ID = 34A, TJ = 25°C; 19mΩ at VGS = 4.5V, ID = 28A, TJ = 25°C. The gate features logic-level performance with ±20V maximum rating. Heat sinking is required at higher currents. Load Precautions A 100Ω, 1/4W resistor can be used as a low-current demonstration load. When switching other loads, always stay within the current rating of the MOSFET and power supply. See Note 2, above. The evaluation board MOSFET is located near the edge of the board so that it can be fastened to a flat heat sink. The MIC5018 evaluation board includes a tantalum bypass capacitor on the supply input. Always apply power using the power supply’s on/off switch. Avoid applying power by connecting the supply input to an operating power supply. Applying power instantaneously to any tantalum capacitor may cause capacitor failure. Inductive loads require a Schottky diode to control the inductive kick that occurs upon turnoff. Refer to the MIC5018 data sheet for a connection example. At high current, leads to a resistive load may also exhibit enough inductance to cause significant inductive kick. Wiring 2.7V to 9V Supply TTL + – Load Control Logic Your load here or try a 100Ω 1/4W resistor MIC5018 Evaluation Board Wiring MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA January 1996 1 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 MIC5018 Evaluation Board MIC5018 Evaluation Board Micrel Schematic Diagram VS Q1 MIC5018 > 2.4V = On < 0.8V = Off 2 CTL 4 CTL G LOAD 1 GND 2.7V to 9V C1 4.7µF Load 74HC04 or other logic VS 3 * International Rectifier 100mΩ, 17A max. TO-220 package GND Power Supply GND MIC5018 Evaluation Board Schematic Diagram Printed Circuit Layout Top Actual Size Silk Screen (Top) Actual Size Bottom Actual Size MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX USA + 1 (408) 944-0970 This information is believed to be accurate and reliable; however, no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 1995 Micrel Incorporated MIC5018 Evaluation Board 2 January 1996