Demo Board Manual Quick Start Guide 1.2A, Step-Down Converter with 1.4Mhz Switching Frequency Description The AP5100WG-EVM is and evaluation board for the current mode step-down converter with a built-in power MOSFET . The AP5100 enables a constant output current of up to 1.2A over a wide input supply range from 4.75V to 24V. It provides excellent line regulation, load regulation and transient response over the operating input voltage and temperature range. The AP5100 is self protected, through a cycleby-cycle current limiting algorithm and an on chip thermal protection. The AP5100 is available in SOT26 package. Applications • • Distributed Power Systems Battery Charger Performance Spec of AP5100WG-EVM Parameter Input voltage Output Current Output Voltage Output Voltage Ripple Transient Response Switching Frequency Efficiency • • Pre-Regulator for Linear Regulators WLED Drivers Conditions Peak Deviation Load step 0.2 to 0.8 v/us Performance Value 12V 1.2A 3.3V 30mVp-p 50mV 1.4Mhz 88% Figure 1. Evaluation Board Figure 2. Efficiency vs Load Current Quick Start Guide The EV-AP5100 has a simple layout and allows access to the appropriate signals through test points. To evaluate the performance of the AP5100, follow the procedure below: 1. Connect a power supply to the input terminals Vin and GND. Set Vin to 12V. Note : Vin ranges from 4.75V to 24V. 2. Connect the positive terminal of the electronic load to Vout and negative terminal to GND. 3. EN has a positive voltage through a 100K pull-up to Vin. No supply input is required for EN. Note: To use the EN function drive EN above 1.3V to start the converter and below 0.4V to stop the converter. 4. The evaluation board should now power up with a 3.3V output voltage. 5. Check for the proper output voltage of 3.3V (+/-1%) at the output terminals Vout and GND. Measurement can also be done with a multimeter with the positive and negative leads between Vout and GND. 6. Set the load to 1.2A through the electronic load. Check for the stable operation of the SW signal on the oscilloscope. Measure the switching frequency. A test point is conveniently located at the head of the inductor. Note: A 300mA load current is required to run the converter in continuous mode. Use an electronic load to supply the load current. Measurement/Performance Guidelines: 1) The evaluation board has the inductor pad spaced for easy access to the inductor current. As shown in the picture, a current probe can be connected to the wire loop to measure the inductor current. 2) When measuring the output voltage ripple, avoid long ground leads on the oscilloscope probe. 3) For efficiency measurements, connect an ammeter in series with the input supply to measure the input current. Connect an electronic load to the output for output current. 4) A 100pF capacitor is used in parallel with the feedback resistor divider network. This component ensures best performance at low temperatures. EVALUATION BOARD SCHEMATIC BILL OF MATERIALS QTY REF VALUE DESCRIPTION PACKAGE MANUFACTURER MANUFACTURER P/N 1 C5 0.1uF Ceramic Capacitor, 50V, X7R 0603 TDK C1608X7R1H104K 1 C1 10uF Ceramic Capacitor, 25V, X5R 1206 Murata GRM31CR61E106KA12L 1 C3 22nF Ceramic Capacitor, 50V, X7R 0603 TDK c1608X7R1H223K 1 C2 22uF Ceramic Capacitor, 6.3V,X5R 1206 TDK C3216X5R0J226M 1 C6 100pF Ceramic Capacitor, 50V, X7R 0603 TDK C1608COG1H101J B 1 D1 B340A Diode Schottky, 40V, 3A SOD-123 Diodes Inc 1N5819HW-7 1 L1 3.3uH Inductor, 5.6A SMD Wurth 7440650033 1 R1 49.9k Resistor, 1% 0603 Panasonic ERJ-3EKF4992V 1 R2 16.2k Resistor, 1% 0603 Panasonic ERJ-3EKF1622V 1 R3 100k Resistor, 1% 0603 Panasonic ERJ-3EKF1003V 1 U1 DC/DC Converter TSOT-26 Diodes Inc AP5100 TOP SILK LAYER BOTTOM LAYER TOP LAYER