MIC2039 Evaluation Board High-Accuracy, High-Side, Adjustable Current Limit Power Switch General Description Getting Started The MIC2039 is a high-side MOSFET power distribution 1. Connect an external supply to V terminal. IN switch providing increased system reliability by using 5% Apply the desired input voltage to the V and ground IN current limit accuracy. terminals of the evaluation board, paying careful The MIC2039 has an operating input voltage range from attention to polarity and supply voltage. The user can 2.5V to 5.5V, is internally current limited, and has thermal place an ammeter between the input supply and the shutdown to protect the device and system. The MIC2039 V terminal to the evaluation board. Make sure that IN is offered with either active-high or active-low logic level the supply voltage is monitored at the V terminal. The IN enable input controls. It has an open drain fault status ammeter and/or power lead resistance can reduce the output flag with a built-in 32ms delay that asserts low voltage supplied to the input. during overcurrent or thermal shutdown conditions. 2. Connect the load to the V and ground terminals. OUT The MIC2039 switch features an adjustable output current The load can be either passive (resistive) or active (as limit that is resistor programmable from 0.2A to 2.5A. The in an electronic load). The user can place an ammeter MIC2039 switch also offers a unique Kickstart feature, between the load and the V terminal. Make sure OUT which allows momentary high-current surges up to the that the output voltage is monitored at the V OUT secondary current limit (I ) during startup or while LIMIT 2nd terminal. operating in steady state. This is useful for charging loads 3. Enable the switch. with high inrush currents, such as capacitors. After an The MIC2039 evaluation boards are configured for overcurrent condition is established, these switches enter default enable using a 10k pull-up resistor from the into a constant current limit mode unless the die ENABLE pin to VIN. To disable the switch, place a temperature exceeds the thermal shutdown specification. jumper short across the jumper pins at TP2. The MIC2039 is offered in both 6-pin SOT-23 and 6-pin 4. Fault detection 2mm x 2mm thin DFN packages. It has an operating The MIC2039 is equipped with an error flag pin, junction temperature range of 40C to +125C. FAULT/. TP3 is provided to monitor the FAULT/ pin. Requirements The MIC2039 evaluation board requires a single power supply to provide V . The V power supply must be able IN IN Ordering Information to deliver a minimum of 2.5V and more than 1.5A Part Number Description capability. The output load can either be active or passive. Evaluation board featuring the Precautions MIC2039AYM6 Power Switch MIC2039-05AYM6 EV The evaluation board does not have reverse polarity Current limit is set for 500mA protection. Applying a negative voltage to the V terminal IN Evaluation board featuring the can damage the device. In addition, the maximum V IN MIC2039-1AYM6 EV MIC2039AYM6 Power Switch operating voltage of the MIC2039 evaluation board is 5.5V. Current limit is set for 1A Exceeding 5.5V on V can permanently damage the IN Evaluation board featuring the device. MIC2039-05AYMT EV MIC2039AYMT Power Switch Current limit is set for 500mA Evaluation board featuring the MIC2039-1AYMT EV MIC2039AYMT Power Switch Current limit is set for 1A Ramp Control 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. MIC2039 Evaluation Board Application Information Adjustable Current Limit where I is the typical current limit from the electrical LIMIT table. If the output current exceeds the set current limit, The factory sets the MIC2039-xYMx evaluation boards the MIC2039 switch enters constant current limit mode. for either a 500mA or 1A current limit. However, The maximum allowable current limit may be less than connecting a resistor (R3) from the ILIMIT pin to GND the full specified and/or expected current if the MIC2039 allows the current limit to be adjusted from 0.2A to 2.5A. is not mounted on a circuit board with sufficiently low For the MIC2039-xYMT evaluation board, jumper TP4 thermal resistance. Resistor values (1%) for select must be shorted for R3 to connect to the ILIMIT pin of current limit settings are shown in Table 1. the IC. The following equation determines the value of R3: I 0.2A 0.5A 1.0A 2A 2.5A LIMIT R3 289/I Eq. 1 R3 1.43k 576 287 143 115 LIMIT Table 1. Resistor Selection for Adjustable Current Limit October 2012 2 M9999-100112-A