ADP2323-EVALZ

Evaluation Board User Guide UG-310 One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com Evaluation Board for the ADP2323, Dual 3 A, 20 V, Synchronous Step-Down Regulator with Integrated High-Side MOSFET FEATURES GENERAL DESCRIPTION Input voltage: 4.5 V to 20 V ±1% output voltage accuracy Integrated 90 mΩ typical on-resistance high-side MOSFET Flexible output configuration Dual output: 3 A/3 A Parallel single output: 6 A Programmable switching frequency: 250 kHz to 1.2 MHz External synchronization input with programmable phase shift, or internal clock output Selectable PWM or PFM mode operation Adjustable current limit for small inductor External compensation and soft start Startup into precharged output The ADP2323 evaluation board is a complete, dual, 3 A step-down regulator solution that allows users to evaluate the performance of the ADP2323 with a near ideal printed circuit board (PCB) layout. The two pulse-width modulation (PWM) channels can be configured to deliver dual, 3 A outputs or a parallel-to-single, 6 A output. The switching frequency can be programmed between 250 kHz and 1.2 MHz, or it can be synchronized to an external clock with a programmed 60°, 90°, or 120° phase shift, which provides the possibility for a stackable multiphase power solution. The outputs of the ADP2323 evaluation board are preset to 1.2 V and 3.3 V for Channel 1 and Channel 2, respectively. With the PWM mode selected, the switching frequency is set to 500 kHz. Different output voltage settings and configurations can be achieved by changing appropriate passive components or jumper settings. The ambient temperature operating range is −40°C to +85°C. Full details on the ADP2323 dual regulator are provided in the ADP2323 data sheet, available from Analog Devices, Inc., which should be consulted in conjunction with this user guide. 10113-001 ADP2323 DEMO BOARD Figure 1. PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | Page 1 of 12 UG-310 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1  Modifying the Board.....................................................................4  General Description ......................................................................... 1  Evaluation Board Schematic and Artwork.....................................6  ADP2323 Demo Board .................................................................... 1  ADP2323 Schematic .....................................................................6  Revision History ............................................................................... 2  PCB Layout ....................................................................................7  Using the Evaluation Board............................................................. 3  Ordering Information.................................................................... 11  Powering Up.................................................................................. 3  Bill of Materials........................................................................... 11  Measuring Evaluation Board Performance .................................. 4  REVISION HISTORY 8/11—Revision 0: Initial Version Rev. 0 | Page 2 of 12 Evaluation Board User Guide UG-310 USING THE EVALUATION BOARD POWERING UP The ADP2323 evaluation board is supplied fully assembled and tested. Before applying power to the evaluation board, follow the procedures in this section. Jumper J31/Jumper J32 (Enable) Jumper J31 is used to control Channel 1. Use one of the following methods to enable or to disable Channel 1: • • To enable Channel 1, short the middle pin of J31, EN1, to high or leave it open. To disable Channel 1, short the middle pin of J31, EN1, to low and remove R2. Jumper J32 is used to control Channel 2. Use one of the following methods to enable or disable Channel 2: • • To enable Channel 2, short the middle pin of J32, EN2, to high or leave it open. To disable Channel 2, short the middle pin of J32, EN2, to low and remove R16. When the SYNC pin is configured as an input, the ADP2323 synchronizes to an external clock applied to the SYNC pin, and the internal clock must be programmed lower than the external clock. When operating in synchronization mode, PFM mode is disabled, and the ADP2323 only operates in continuous conduction mode (CCM) mode. Input Power Source If the input power source includes a current meter, use that meter to monitor the input current. Connect the positive terminal of the power source to J1 and J23 (PVIN1 and PVIN2, respectively) of the evaluation board, and the negative terminal of the power source to J3 and J27 (GND) of the evaluation board. If the power source does not include a current meter, connect a current meter in series with the input source voltage. Connect the positive lead (+) of the power source to the positive (+) ammeter terminal, the negative lead (−) of the power source to J3 and J27 (GND), and the negative lead (−) of the ammeter to J1 and J23 (PVIN1 and PVIN2, respectively). Jumper J4/Jumper J22 (TRACK) Output Load When the tracking function is not used, short the middle pin of J4, TRK1, and J22, TRK2, to high. Before connecting the load, ensure that the board is turned off. Connect an electronic load or resistor to set the load current. Jumper J19 (MODE) To connect a load to the output of Channel 1, connect the positive terminal of the load to J8 (VOUT1) of the evaluation board and connect the negative terminal of the load to J10 (GND). Jumper J19 is used to select the working mode of the ADP2323. Use one of the following methods to set the regulator to operate in PWM or PFM mode. • • To operate in PWM mode, short the middle pin of J19 to high. To operate in PFM mode, short the middle pin of J19 to low. Jumper J7 (SCFG) Jumper J7 is used to configure the SYNC pin as an input or an output. Short the middle pin of J7 to high to set the SYNC pin as an output. To sync the regulator to an external clock, set the SYNC pin as an input. External Synchronization To synchronize the regulator to an external clock, refer to Table 1 for proper configuration of the SCFG pin and the SYNC pin. Table 1. SCFG Configuration J7 (SCFG) R3 SYNC Phase Shift High Low No connect Output 0° No connect Input 90° Open 180 kΩ Input 120° Open 100 kΩ Input 60° To connect a load to the output of Channel 2, connect the positive terminal of the load to J20 (VOUT2) of the evaluation board and connect the negative terminal of the load to J17 (GND). Input and Output Voltmeter Measure the input and output voltages using voltmeters. Make sure that the voltmeters are connected to the appropriate terminals of evaluation board and not to the load or power source. If the voltmeters are not connected directly to the evaluation board, the measured voltages are incorrect due to the voltage drop across the leads and/or connections between the evaluation board, the power source, and/or the load. To measure the input voltage, connect the positive terminal of the voltmeter to J2 (PVIN1_SNS) or J24 (PVIN2_SNS) and the negative terminal to J5 or J30 (GND_SNS). Likewise, to measure the output voltage, connect the positive terminal of the voltmeter to J9 (VOUT1_SNS) or J18 or (VOUT2_SNS) and the negative terminal to J12 or J14 (GND_SNS). When the SYNC pin is configured as an output, it generates a clock with a frequency that is equal to the internal switching frequency. Rev. 0 | Page 3 of 12 UG-310 Evaluation Board User Guide Turning On the Evaluation Board Measuring Output Voltage Ripple When the power source and load are connected to the evaluation board, it can be powered for operation. To observe the output voltage ripple, place the oscilloscope probe across the output capacitor with the probe ground lead connected to the negative (−) capacitor terminal and the probe tip placed at the positive (+) capacitor terminal. Set the oscilloscope to ac, 10 mV/division, 2 μs/division time base, and 20 MHz bandwidth. Perform the following steps to turn on the board: 1. 2. 3. Ensure that the power source voltage is >4.5 V and