MIC22705YML EV Evaluation Board 1MHz, 7A Integrated Switch High- Efficiency Synchronous Buck Regulator General Description The Micrel MIC22705 is a high-efficiency, 7A, integrated Getting Started switch, synchronous buck (step-down) regulator. The 1. V Supplies IN MIC22705 achieves more than 95% efficiency and Connect the V supply (2.9V to 5.5V) across the PVIN and IN switches at 1MHz. The ultra-high speed control loop keeps PGND terminals. Monitor V at the PVIN and PGND IN the output voltage within regulation even under the terminals with a voltmeter. extreme transient load swings commonly found in FPGAs 2. Enable/SHDN Inputs and low-voltage ASICs. The output voltage is pre-bias safe and is adjustable down to 0.7V. The enable input EN is internally pulled up with a 1A current source. When external on/off control is desired, The MIC22705 offers a full range of sequencing and install Q1 and R5, and connect a logic level control signal tracking options. The Enable/Delay (EN/DLY) and Power to the SHDN input. When SHDN is high, the output is off, Good (PG) inputs allow versatile turn-on and turn-off and when SHDN is low, the output is on. sequencing across multiple devices. The Ramp Control (RC) input allows start-up voltage tracking, either directly 3. Monitor Outputs or ratio-metrically. Monitor the output V with a scope or DVM connected OUT The MIC22705 is available in a 24-pin 4mm x 4mm MLF across the VOUT and PGND terminals. with a junction operating range from 40 C to +125C. 4. Output Load Data sheets and support documentation are found on the Connect a load across the VOUT and PGND terminals. Micrel web site: www.micrel.com. Use an active or passive load. 5. Turn On the Power Requirements Turn on the power supply and verify that V = 1.8V. OUT The MIC22705YML EV requires a power supply of 2.9V to 5.5V, and a test load. Ensure that the power supply can provide the wattage required for the chosen test load. The Ordering Information load can be active (electronic load) or passive (resistor). Additionally, monitor the Power Good output (PG) with a Part Number Description multimeter or an oscilloscope if desired. MIC22705YML EV Evaluation Board for the MIC22705YML Precautions There is no reverse input protection on this board. When connecting supplies and signals ensure that correct polarities are observed. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC22705 Evaluation Board EV Board Features Ramp Control (RC) Ramp control allows slowing the slew rate of the See the MIC22705YML datasheet for detailed MIC22705 output. Increase the value of capacitor C7 to explanations of these functions. reduce the slew rate. Enable/Delay (EN/DLY) Power Good Output (PG) Enable/Delay allows delayed turn on of the MIC22705. Open drain output PG pulls low when the output voltage of Install a capacitor in location C6 to increase the start-up the MIC22705 is out of specification. PG is pulled up to V IN delay of the MIC22705. by a 47.5k resistor. Shutdown Input (SHDN) Switch Voltage (V ) SW SHDN allows enable/disable of the MIC22705 with an Test point V is provided to monitor the internal switching SW external logic signal. To activate the shutdown feature, node. V is isolated from the switch node by 49.9 SW install components into the locations labeled Q1 and R5 resistor R6. (component recommendations are listed in the Bill of Materials later in this document). With the components installed, force SHDN high to disable the MIC22705, and low to allow the MIC22705 to operate normally. Delay (DELAY) DELAY allows a delayed Power Good output (PG) indication. Install a capacitor in location C8 to increase the Power Good delay timing of the MIC22705. February 2011 2 M9999-020411-A