MIC22405YML EV Evaluation Board 4A Integrated Switch High-Efficiency Synchronous Buck Regulator with Frequency Programmable upto 4MHz General Description Getting Started The Micrel MIC22405 is a high-efficiency, 4A, integrated 1. V Supplies IN switch, synchronous buck (step-down) regulator. The Connect the V supply (2.9V to 5.5V) across the VIN and IN MIC22405 achieves more than 95% efficiency and GND terminals. Monitor V at the VIN and GND terminals IN switches at 1MHz. The ultra-high speed control loop keeps with a voltmeter. the output voltage within regulation even under extreme 2. Enable/SHDN Inputs transient load swings commonly found in FPGAs and low- The enable input EN is internally pulled up with a 1A voltage ASICs. The output voltage is pre-bias safe and is current source. When external on/off control is desired adjustable down to 0.7V. install Q1 and R5, and connect a logic level control signal to the SHDN input. When SHDN is high the output is off, The MIC22405 offers a full range of sequencing and and when SHDN is low the output is on. tracking options. The Enable/Delay (EN/DLY) and Power 3. Monitor Outputs Good (PG) inputs allow versatile turn-on and turn-off Monitor the output V with a scope or DVM connected OUT sequencing across multiple devices. The Ramp Control across the VOUT and GND terminals. (RC) input allows start-up voltage tracking, either directly or ratio-metrically. 4. Output Load Connect a load across the VOUT and GND terminals. Use an active or passive load. The MIC22405 is available in a 20-pin 3mm x 4mm MLF with a junction operating range from 40 C to +125C. 5. Turn On the Power Turn on the power supply and verify that V = 1.8V. OUT Data sheets and support documentation are found on the Micrel web site: www.micrel.com. Requirements The MIC22405YML EV requires a power supply of 2.9V to Ordering Information 5.5V, and a test load. Ensure that the power supply can Part Number Description provide the wattage required for the chosen test load. The load can be active (electronic load) or passive (resistor). MIC22405YML EV Evaluation Board for the MIC22405YML Additionally, monitor the Power Good output (PG) with a multimeter or an oscilloscope if desired. Precautions There is no reverse input protection on this board. While connecting supplies and signals ensure that correct polarities are observed. 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 Micrel, Inc. MIC22405 Evaluation Board Evaluation Board Features Ramp Control (RC) Ramp control allows slowing the slew rate of the Enable/Delay (EN/DLY) MIC22405 output. Increase the value of capacitor C6 to Enable/Delay allows delayed turn on of the MIC22405. reduce the slew rate. Install a capacitor in location C4 to increase the start-up delay of the MIC22405. Power Good Output (PG) Open drain output PG pulls low when the output voltage of Shutdown Input (SHDN) the MIC22405 is out of specification. PG is pulled up to V IN SHDN allows enable/disable of the MIC22405 with an by a 47.5k resistor. external logic signal. To activate the shutdown feature install components into the locations labeled Q1 and R5 Switch Voltage (V ) SW (component recommendations are listed in the Bill of Test point V is provided to monitor the internal switching SW Materials later in this document). With the components node. V is isolated from the switch node by 49.9 SW installed, force SHDN high to disable the MIC22405, and resistor R7. low to allow the MIC22405 to operate normally. July 2011 2 M9999-071911-B