MIC26603 Evaluation Board 28V, 6A HyperLight Load Synchronous DC-DC Buck Regulator SuperSwitcher IIG General Description Getting Started The MIC26603 DC-DC regulator operates over an input 1. Connect an external supply to the V terminal. IN supply range of 4.5V to 28V and provides a regulated output Apply the desired input voltage to the V and ground IN at up to 6A of output current. The output voltage is adjustable terminals of the evaluation board, paying careful to 0.8V with a typical accuracy of 1%, and the device attention to polarity and supply voltage. An ammeter operates at a switching frequency of 600kHz. The switching may be placed between the input supply and the V IN frequency remains fairly constant with changes in input terminal to the evaluation board. Ensure that the voltage and output load. at the V terminal. The supply voltage is monitored IN Micrels Hyper Light Load architecture provides the resistance can reduce ammeter and/or power lead same high-efficiency and ultra-fast transient response as put. the voltage supplied to the in the Hyper Speed Control architecture under medium to e V and ground 2. Connect the load to th OUT heavy loads, but also maintains high efficiency under light ither passive (resistive) terminals. The load can be e load conditions by transitioning to variable frequency, load). An ammeter can or active (as in an electronic discontinuous mode operation. and the V terminal. be placed between the load OUT The MIC26603 utilizes an adaptive T ripple control ON s monitored at the Ensure that the output voltage i architecture. An undervoltage lockout feature is provided to terminal. V can be set to 0.9V, 1.0V, 1.2V, V OUT OUT er-sag conditions. An ensure proper operation under pow 1.5V, 1.8V, 2.5V, 3.3V, or 5.0V by a jumper. If a internal soft-start feature is provided to reduce the inrush different voltage is needed, it can be adjusted by current. Foldback current limit and hiccup mode short-circuit changing the feedback resistors. See Output protection and thermal shutdown ensures protection of the IC Voltage section. during fault conditions. 3. Enable e MIC266 th 03. The EN pin is provided on Note: This evaluation board is for 6A applications. e evaluation board. The output of th th e MIC26603 The datasheet and supporting documentation can be exceeds the UVLO threshold. turns on when V DD found on Micrels web site at: www.micrel.com. The output of the MIC26603 may be turned off by Requirements shorting the EN pin to ground. A connection on the board provides easy access to the enable pin. The MIC26603 provides a 5V regulated output for input voltage V ranging from 5.5V to 28V. When V < 5.5V, IN IN VDD should be tied to PVIN pins to bypass the internal Ordering Information linear regulator by a jumper. The output load can either be an active or passive load. Part Number Description 6A HLL DC-DC Regulator Evaluation Precautions MIC26603YJL EV Board The evaluation board does not have reverse polarity protection. Applying a negative voltage to the V terminal IN may damage the device. In addition, the maximum V IN operating voltage of the MIC26603 evaluation board is 28V. Exceeding 29V on VIN could damage the device capacitance and also makes (High V )/(Low V ). IN OUT Hyper Light Load and Hyper Speed Control are trademarks of Micrel, Inc. MLF and MicroLead Frame 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. MIC26603 10 A Evaluation Board Once R4 is selected, R7 can be calculated using: Output Voltage R4 V REF The output voltage on the MIC26603 evaluation board is R7 = adjustable. It is set by adjusting the feedback resistors (R4 V V OUT REF and one of R5, R6, R7, R8, R9, R10, R11, or R12) and can be calculated as follows as an example: For V = 0.8V: REF R4 V = V (1 + ) R4 0.8V OUT REF R7 R7 = V 0.8V OUT where V = 0.8V. REF The output voltage should not be set to exceed 5V due to the 6.3V rating of the output capacitor and limitation on line The output voltage above is set at the factory for a 1.2V regulation. Please refer to the MIC26603 datasheet output, but it can easily be changed by moving the jumper Setting Output Voltage section for more information. to a respective position to get an indicated voltage on the board. If a desired voltage is not shown on the board, it is easily modified by removing R4 and R7 and replacing them with the values that yield the desired output voltage. July 2011 2 M9999--071511-A