MIC4742YML-EV

MIC4742YML Evaluation Board Dual 2A Buck Regulator General Description The Micrel MIC4742 is a high efficiency dual PWM buck (step-down) regulator that provides up to 2A of output current for each channel. The MIC4742 operates at 2MHz and has proprietary internal compensation that allows a closed loop bandwidth of over 200kHz. The low on resistance internal P-Channel MOSFET of the MIC4742 allows efficiencies up to 92%, reduces external component count and eliminates the need for an expensive external current sense resistor. The MIC4742 operates from a 2.9V to 5.5V input and its output is adjustable down to 0.6V. The devices can operate with a maximum duty cycle of 100% for use in low-dropout applications. 3. Enable the MIC4742. The enable pins are connected to pull up resistors. Both outputs of the MIC4742 turn on when VIN exceeds the UVLO threshold at the VIN pin. Each output of the MIC4742 may be turned off by shorting the enable pin to ground or bringing the enable pin below the enable threshold. An external connection on the board provides easy access to the enable pin. Output Voltage The output voltages on the MIC4742 evaluation board are adjustable. The output voltage is controlled by the feedback resistors (R11 and R12 for VOUT1, R21 and R22 for VOUT2) and can be calculated as follows: Requirements VOUT 1 = VREF × (1 + R11 ) R12 The MIC4742 evaluation board requires an input power source that is able to deliver greater than 2.9V at over 4A. The output load can either be an active or passive load. VOUT 2 = VREF × (1 + R 21 ) R 22 Precautions The evaluation board does not have reverse polarity protection. Applying a negative voltage to the VIN terminal may damage the device. In addition, the maximum operating voltage of the MIC4742 evaluation board is 5.5V. Exceeding 6V on the input could damage the device. Where VREF = 0.6V. The evaluation board is preset at 1.8V for VOUT1 and 1.2V for VOUT2, but can easily be modified by removing R12 or R22 and replacing them with the value that yields the desired output voltage. R12 = R11 × VREF VOUT − VREF R 22 = R 21 × VREF VOUT − VREF Getting Started 1. Connect an external supply to VIN terminal. Apply desired input voltage to the VIN and ground terminals of the evaluation board, paying careful attention to polarity and supply voltage (2.9V