Demo Board Manual Quick Start Guide 1.5A, Step-Down Converter with 1.4Mhz Switching Frequency Description The AP5101WG-EVM is and evaluation board for the current mode step-down converter with a built-in power MOSFET . The AP5101 enables a constant output current of up to 1.5A 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 AP5101 is self protected, through a cycleby-cycle current limiting algorithm and an on chip thermal protection. The AP5101 is available in SOP-8L package. Applications • • Distributed Power Systems Battery Charger Performance Spec of AP5101WG-EVM Parameter Input voltage Output Current Output Voltage Output Voltage Ripple Transient Response Switching Frequency Efficiency • • Pre-Regulator for Linear Regulators WLED Drivers Conditions Range – 4.75V to 24V Peak Deviation Load step 0.2 to 0.8 v/us Performance Value 12V 1.5A 3.3V 30mVp-p 50mV 1.4Mhz 88% Figure 1. Evaluation Board Figure 2. Efficiency vs Load Current Quick Start Guide The EV-AP5101 has a simple layout and allows access to the appropriate signals through test points. To evaluate the performance of the AP5101, 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 1.5A 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 measure 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. EVALUATION BOARD SCHEMATIC BILL OF MATERIALS QTY REF VALUE DESCRIPTION PACKAGE MANUFACTURER MANUFACTURER P/N 1 C1 10nF Ceramic Capacitor, 50V, X7R 0603 TDK C20123D106KAJ2A 2 C2 10uF Ceramic Capacitor, 25V, X5R 1210 AVX 12103D106KAJ2A 3 C3 3000pF Ceramic Capacitor, 50V,X5R 0805 Murata GRM216R71H302JA01 4 C5 22uF Ceramic Capacitor, 6.3V,X5R 1210 AVX 12103D226KAT2A 5 C8 1uF Ceramic Capacitor, 50V, X7R 0805 TDK C20112Y5V1H105Z 6 D1 B340A Diode Schottky, 40V, 3A SOD-123 Diodes Inc B340A-F 7 L1 4.7uH Inductor, 4.6A SMD Wurth Electronics 7440650047 8 R1 49.9k Resistor, 1% 0805 Panasonic ERJ-6ENF4992V 9 R2 5.6k Resistor, 1% 0805 Panasonic ERJ-6ENF5601V 10 R3 16.2k Resistor, 1% 0805 Panasonic ERJ-6ENF1622V 11 R4 100k Resistor, 1% 0603 Panasonic ERJ-3EKF1003V 12 U1 DC/DC Converter SOP-8L Diodes Inc AP5101 TOP SILK LAYER BOTTOM LAYER TOP LAYER