AP65450EV1 650kHz, 18V, 4A, COT Synchronous DC/DC Buck Converter in SO-8EP Description The AP65450 is an adaptive on-time mode synchronous buck converter providing high efficiency, excellent transient response and high DC output accuracy for low-voltage regulation in digital TV and monitor. The constant-on-time control scheme handles wide input/output voltage ratios and provides low external component count. The internal proprietary circuit enables the device to adopt both low equivalent series resistance (ESR) output capacitors, such as SP-CAP or POSCAP and ultra-low ESR ceramic capacitors. • • • • • Gaming Consoles Flat Screen TV Sets and Monitors Set Top Boxes Distributed Power Systems Green Electronics The adaptive on-time control supports seamless transition between continuous conduction mode (CCM) at higher load conditions and discontinuous conduction mode (DCM) at lighter load conditions. DCM allows AP65450 maintain high efficiency at light load conditions. The AP65450 also features programmable softstart, UVLO, OTP and OCP to protect the circuit. This IC is available in SO-8EP package. • • • • Home Audio Consumer Electronics Network Systems FPGA, DSP and ASIC Supplies Performance Spec of AP65450EV1 (Rev2) Parameter Conditions Input voltage Range 4.5V to 18V Output Current Output Voltage Output Voltage Ripple Peak-to-peak Deviation Transient Response Load step from 0A to 4A Switching Frequency Efficiency AP65450EV1 Document number: Rev. 2.0 Performance Value 12V 4A 1.05V 20mVP-P 30mVP-P 650kHz 90% @VOUT=5V 1 of 5 www.diodes.com September 2014 © Diodes Incorporated AP65450EV1 650kHz, 18V, 4A, COT Synchronous DC/DC Buck Converter in SO-8EP Figure 1. Evaluation Board (Rev2) Figure 2. Load Transient 0 to 4A Figure 3. Efficiency Figure 4. Light Load Efficiency VO=2.5V VO=1.8V VO=1.5V VO=1.2V VO=3.3V VO=5V VO=1.05V PCB Layouts Top Layer AP65450EV1 Document number: Rev. 2.0 Bottom Layer 2 of 5 www.diodes.com September 2014 © Diodes Incorporated AP65450EV1 650kHz, 18V, 4A, COT Synchronous DC/DC Buck Converter in SO-8EP Quick Start Guide The AP65450EV1 has a simple layout and allows access to the appropriate signals through test points. To evaluate the performance of the AP65450, follow the procedure below: 1. Connect a power supply to the input terminals VIN and GND. Set VIN to 12V. 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 1.9V to start the converter and below 0.6V to stop the converter. 4. The evaluation board should now power up with a 1.05V output voltage. 5. Check for the proper output voltage of 1.05V (±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 4A 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. Measurement/Performance Guidelines: 1) When measuring the output voltage ripple, maintain the shortest possible ground lengths on the oscilloscope probe. Long ground leads can erroneously inject high frequency noise into the measured ripple. 2) 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. AP65450EV1 Document number: Rev. 2.0 3 of 5 www.diodes.com September 2014 © Diodes Incorporated AP65450EV1 650kHz, 18V, 4A, COT Synchronous DC/DC Buck Converter in SO-8EP EVALUATION BOARD SCHEMATIC BILL OF MATERIALS REF VALUE DESCRIPTION PACKAGE MANUFACTURER MANUFACTURER P/N C1, C2 C4 10µF Ceramic Cap, 25V, X5R 1210 Murata GRM32DR61E106KA12L 8.2nF 0805 AVX 0805YC822KAT2A C5 1µF Ceramic Capacitor, 16V, X7R Ceramic Cap, 16V, X7R 0805 Kemet C0805C105K4RACTU C6 0.1µF 0805 Samsung CL21B104KACNNNC C8, C9 L1 22µF Ceramic Capacitor, 25V, X7R Ceramic Cap, 25V, X5R 1210 AVX 12103D226KAT2A SMD Wurth 744311150 R1 8.25kΩ Inductor, SMD 6.9mmWx6.9mmLx4mmH Resistor, 1% 0805 Panasonic ERJ-6ENF8251V R2 22.1kΩ Resistor, 1% 0805 Panasonic ERJ-6ENF2212V R3 100kΩ Resistor, 1% 0805 Panasonic ERJ-6ENF1003V DC/DC Converter SO-8EP Diodes Inc AP65450SP 1.5µH U1 AP65450EV1 Document number: Rev. 2.0 4 of 5 www.diodes.com September 2014 © Diodes Incorporated AP65450EV1 650kHz, 18V, 4A, COT Synchronous DC/DC Buck Converter in SO-8EP IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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