MIC24053 Evaluation Board 9A, High-Efficiency, Synchronous DC/DC Buck Regulator with Hyper Speed Control SuperSwitcher II Power-Up Precautions General Description The evaluation board does not have reverse polarity The MIC24053 DC/DC synchronous buck regulator protection. Applying a negative voltage to the VIN terminal operates over an input supply range of 4.5V to 19V and may damage the device. The maximum VIN operating provides a regulated output at up to 9A of load current. voltage of the MIC24053 evaluation board is 19V. It has The output voltage is adjustable down to 0.8V with a two different layout designs, one (Figure 1) optimized for typical accuracy of 1%. The device operates at a evaluation and a second (Figure 2) optimized for a smaller switching frequency of 600kHz, which remains relatively footprint. The evaluation board is only populated with constant with changes in input voltage and output load. components shown in Figure 1. Micrels Hyper Speed Control architecture allows for ultra- Getting Started fast transient response, while reducing the output capacitance. It also makes (High V )/(Low V ) operation IN OUT 1. VIN Supply. possible. The 19V operating rating of the device provides Connect a supply to the VIN and GND terminals, adequate design safety margin for 12V input applications. paying careful attention to the polarity and the supply The MIC24053 utilizes an adaptive T ripple control ON range (5V < VIN < 19V). An ammeter may be placed architecture. An undervoltage lockout feature is provided to between the input supply and the VIN terminal to the ensure proper operation under power-sag conditions. An evaluation board. Ensure that the supply voltage is internal soft-start feature is provided to reduce the inrush monitored at the VIN terminal. The ammeter and/or current. Foldback current limit and hiccup mode short-circuit power lead resistance can reduce the voltage supplied protection and thermal shutdown ensures protection of the IC to the input. Do not apply power until Step 4. during fault conditions. 2. Connect the load to the VOUT and ground terminals. The basic parameters of the MIC24053 evaluation board are a VIN supply of 5V to 19V, output voltage of 0.8V to 5V at The load can be either passive (resistive) or active (as (1) 9A , and 600kHz switching frequency. in an electronic load). An ammeter can be placed between the load and the VOUT terminal. Ensure that Note: the output voltage is monitored at the VOUT terminal. 1. Refer to the temperature curves presented in the Evaluation Board Performance section. Also, note that the typical minimum input 3. Enable Input. voltage to maximum output voltage conversion is limited by the maximum duty cycle. An EN connector is provided on the evaluation board for users to easily access the enable feature. The output of the MIC24053 turns on when VDD exceeds Datasheets and support documentation are available on the UVLO threshold. The output of the MIC24053 may Micrels web site at: www.micrel.com. be turned off by shorting the EN pin to ground. Requirements 4. Turn on the power. The MIC24053 evaluation board requires only a single Turn on VIN power supply and verify that the output power supply with at least 10A current capability. The voltage is regulated to 1.8V. MIC24053 has internal VDD LDO so no external linear regulator is required to power the internal biasing of the IC. Ordering Information When VIN < 5.5V, VDD should be tied to PVIN pins to bypass the internal linear regulator by a jumper. The Part Number Description output load can either be an active or passive load. 9A HSC DC/DC Buck Regulator MIC24053YJL EV Evaluation Board Hyper Speed Control, SuperSwitcher II, and Any Capacitor are trademarks 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. MIC24053 Evaluation Board Output Voltage The output voltage on the MIC24053 evaluation board is adjustable. It is set by adjusting the feedback resistors, referring Equation 1: R4 V = V 1 + Eq. 1 OUT FB R BOTTOM where V = 0.8V and R is one of the R5, R6, R7, FB BOTTOM R8, R9, R10, R11, R12 which corresponds to 0.9V, 1.0V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, or 5V. Leaving the R BOTTOM open gives a 0.8V output voltage. The output voltage above is set at the factory for a 1.8V output, but it can easily be changed by moving the jumper 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 R and replacing it with the BOTTOM values that yield the desired output voltage. Once R4 is selected, R can be calculated using Equation 2: BOTTOM R4 V FB R = Eq. 2 BOTTOM V V OUT FB For V = 0.8V, as in Equation 3: FB R4 0.8V R = Eq. 3 BOTTOM V 0.8V OUT The output voltage should not be set to exceed 5V due to the 6.3V rating of the output capacitor and limitation on line regulation. Please refer to the Setting the Output Voltage and Ripple Injection subsections in the Application Information section of the MIC24053 data sheet for more detailed information. Revision 1.0 February 11, 2013 2