MIC4930 Evaluation Board HyperSpeed 5A Buck Regulator in 3mm x 4mm DFN Package Getting Started General Description 1. Connect an external supply to the VIN (J1) terminal This board enables the evaluation of the MIC4930, a fully and GND (J2). integrated 5A switching regulator featuring HyperSpeed With the output of the power supply disabled, set its control and Power Good output indication. The MIC4930 is voltage to the desired input test voltage (2.7V VIN highly efficient throughout the entire output current range, 5.5V). An ammeter may be placed between the input exceeding 95% over 5V input to 3.3V output range. The supply and the VIN (TP4) terminal. Be sure to monitor tiny 3mm x 4mm DFN package, in combination with the the supply voltage at the VIN (TP4) terminal, as the high switching frequency, allows for a compact, small ammeter and/or power lead resistance can reduce the footprint solution. The MIC4930 provides accurate output voltage supplied to the device. voltage regulation under the most demanding conditions and responds extremely fast to a load transient with 2. Connect a load to the V (J3) and ground (J4) OUT exceptionally small output voltage ripple. terminals. Data sheets and other support documents can be found on The load can be either active passive (resistive) or Micrels web site at: www.micrel.com. active (electronic load). In case of electronic load, keep the load disabled until the MIC4930 has been Requirements powered up. An ammeter may be placed between the load and the The MIC4930 evaluation board requires a single power output terminal. Ensure the output voltage is monitored source adjustable up to at least 5.5V, with 5A of current at the V (TP6) terminal. capability. The load can either be active (electronic load) OUT or passive (resistor) with the capability to dissipate 20W. It 3. Enable the MIC4930. is ideal to have an oscilloscope available to view the circuit The MIC4930 evaluation board has a pull-up resistor waveforms, but not essential. For the simplest tests, two R6 to V . With a jumper installed in positions 1-2 of IN voltage meters are required to measure input and output TP5, the output voltage will be enabled when the input voltage. For efficiency measurements, two voltage meters supply of >2.7V is applied. To disable the device, and two ammeters are required to prevent errors due to apply a voltage below 0.5V to the EN (TP2) terminal, measurement inaccuracies. or install a jumper across positions 2-3 of TP5. Precautions 4. Power Good. There is no reverse input protection on this board. Be A Power good test point (TP3) is provided to monitor certain that the correct polarity is observed when the Power Good function. The Power Good output will connecting the input source. go high (approximately 80s) after the output voltage The maximum VIN of the board is rated at 5.5V, and the reaches 88% of its nominal voltage. maximum load current is rated at 5A. Input power leads should ensure negligible voltage drop Ordering Information up to the maximum load, and should be kept as short as possible to minimize inductance. Part Number Description MIC4930YFL EV 1.8V Fixed Output Evaluation Board For load transient and/or pre-biased output start-up testing up to 5.5V VIN, the use of a bulk electrolytic capacitor in position C7 (at least 100F, 10V rating) is recommended. HyperSpeed 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. MIC4930 Evaluation Board Evaluation Board Other Features Feedback Resistors (R1, R2) for Adjustable Output The output voltage is set nominally to 1.8V. This output can be changed by adjusting the upper resistor, R1, in the feedback potential divider. Therefore: R2 = R1 x V /(V -V ) REF OUT REF Where V = 0.625V REF Some example values are: V R1 R2 OUT 1.0V 120k 180k 1.2V 274k 294k 1.5V 316k 226k 1.8V 301k 160k 2.5V 316k 105k 3.3V 309k 71.5k The feed-forward capacitor, C3, is typically in the range 22pF-39pF. The MIC4930 features an internal ripple injection network, whose current is injected into the FB node and integrated by C3, thus the waveform at FB is approximately a triangular ripple. The size of C3 dictates the amount of ripple amplitude at the FB node. Smaller values of C3 yield higher FB ripple amplitude and better stability, but also degrade somewhat line regulation and transient response. 041514-1.0 April 15, 2014 2