MIC37122 Evaluation Board High-Performance, 1A, Low-Noise, Low Dropout Regulator General Description Getting Started The MIC37122 is a high-performance low-noise, low 1. Connect an external supply to V terminal. Apply IN dropout regulator. The MIC37122 is capable of sourcing desired input voltage to the V and ground (GND) IN 1A output current and offers high-PSRR and low output terminals of the evaluation board, paying careful noise, which makes the IC an ideal general purpose attention to polarity and supply voltage. An ammeter LDO regulator for consumer applications such as set-top may be placed between the input supply and the V IN boxes and gaming consoles. terminal to the evaluation board. Ensure that the supply voltage is monitored at the V terminal. The IN The MIC37122 offers 2.5% accuracy, dropout of less ammeter and/or power lead resistance can reduce than 400mV at 1A, and low ground current (typically the voltage supplied to the input. 250A). The MIC37122 can also be put into zero-off- mode current state, drawing little current when disabled. 2. Connect the load to the V and GND terminals. OUT Additionally, an output load discharge feature allows the The load can be either passive (resistive) or active MIC37122 to discharge large capacitive loads through a (as in an electronic load). An ammeter can be low impedance path to ground upon disabling the LDO placed between the load and the V terminal. OUT regulator. Ensure that the output voltage is monitored at the V terminal. The V can be adjusted by OUT OUT The MIC37122 has an operating junction temperature changing the feedback resistors (see Output range of 40C to +125 C and is available in lead-free Voltage section in this data sheet). (RoHS-compliant) SOIC-8 and 2.0mm 2.0mm MLF 2 3. Enable the MIC37122. The enable (EN) pin is packages. The MLF package occupies only 4mm of provided on the evaluation board with a 10k pull-up PCB area, an 86% reduction in board area compared to resistor. The output of the MIC37122 may be turned SOIC-8 packaging. off by shorting the EN pin to ground. An external Datasheets and support documentation can be found on connection on the board provides easy access to Micrels web site at: www.micrel.com. the EN pin. Removing the pull-up resistor and Requirements leaving the EN pin floating will cause the regulator to operate in an indeterminate state. The MIC37122 evaluation board requires a single input power supply. The V power supply must be able to IN Output Voltage deliver 2.375V to 5.5V with more than 1A capability. The output load can either be an active or passive load. The output voltage on the MIC37122 evaluation board is adjustable. The output is set by adjusting the feedback Precautions resistors (R1 and R2) and can be calculated as follows: The evaluation board does not have reverse polarity protection. Applying a negative voltage to the V IN R1 terminal may damage the device. Additionally, the V = V 1 + REF OUT maximum V operating voltage of the MIC37122 IN R2 evaluation board is 5.5V. Exceeding 5.5V on V could IN permanently damage the device. With V = 1.0V: REF R1 R2 = VOUT 1.0V MLF and MicroLeadFrame are 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. MIC37122 Evaluation Board Ordering Information Part Number Description Package MIC37122YM EV Adjustable Output SOIC-8L MIC37122YMT EV Adjustable Output 2mm 2mm MLF -6L MIC37122YM Evaluation Board Schematic (8-Pin SOIC) MIC37122YM Evaluation Board (J1, J2, and R3 are for test purposes only) October 2011 2 M9999-101211-A