® DEM-PCM3500 EVALUATION BOARD INSTRUCTION MANUAL FEATURES DESCRIPTION ● EVALUATION BOARD FOR THE PCM3500 MODEM/VOICE CODEC ● DIP SWITCH FOR SETTING HARDWARE MODE CONTROLS ● CONNECTORS FOR SERIAL INTERFACE, SYSTEM CLOCK, ANALOG INPUT/OUTPUT, AND POWER SUPPLIES ● PROTOTYPE AREA FOR BUILDING ANALOG FRONT END (AFE) CIRCUITS ● SINGLE POWER SUPPLY: +2.7V to +3.6V The DEM-PCM3500 is a simple evaluation board for the PCM3500 single-channel CODEC. It is designed for quick evaluation of the PCM3500 features and performance. A prototype area allows for external analog input and output circuitry to be mounted directly on the evaluation board. BLOCK DIAGRAM Power Supply Analog OUT Digital Interface PCM3500 (DUT) Analog IN CMOS 3.3V or TTL Logic Mode Control Switch International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 © 1999 Burr-Brown Corporation SBAU028 LI-536A Printed in U.S.A. August, 1999 CONNECTORS CN1 is the power supply connector for the DEM-PCM3500. The +VCC pin may be set between +2.7V and +3.6V. The GND pin should be connected to the negative (–) or ground terminal of the power supply or battery, and functions as the analog ground connection. CN2 is the host interface connector. It includes connections for the serial interface and system clock input /output. The connector pins correspond directly to the pin names of the PCM3500. Refer to the PCM3500 data sheet for more details regarding the operation and requirements for these connections. SW1 DESCRIPTION PWDN H = Power Down Disabled (normal operation) L = Power Down Enabled LOOP H = ADC-to-DAC Loop Back Enabled L = ADC-to-DAC Loop Back Disabled HPFD H = ADC High Pass Filter Disabled L = ADC High Pass Filter Enabled T/S H = Time Slot Mode Enabled L = Time Slot Mode Disabled M/S H = Master Mode Enabled L = Slave Mode Enabled TABLE I. DIP Switch Settings. CN3 is the analog input connector. The VIN pin is connected to the PCM3500 analog-to-digital converter input, while the GND pin is connected to analog ground. The full-scale input voltage for VIN is 0.6VCC (in Vp-p), or 1.8Vp-p for a +3V power supply. CRYSTAL OSCILLATOR OPERATION The PCM3500 contains an internal crystal oscillator circuit. The oscillator can be used to generate the 512fS system clock (512 times the desired sample frequency). The crystal value must be equal to 512fS. A fundamental mode, parallel resonant crystal is recommended. The load capacitors, CS, should be set in the range from 10pF – 33pF, with 22pF being the typical value. When using the crystal oscillator, BCK and FS should be derived from SCKIO when using Slave mode. Alternatively, the PCM3500 may be set to Master mode so that the BCK and FS are generated by the CODEC itself. CN4 is the analog output connector. The VOUT pin is connected to the PCM3500 digital-to-analog converter output, while the GND pin is connected to analog ground. The fullscale output voltage at VOUT is typically 0.6VCC (in Vp-p), or 1.8Vp-p for a +3V power supply. DIP SWITCH SETTINGS Table I shows the function of each switch setting for SW1. Each switch corresponds directly to a pin of the PCM3500. Refer to the PCM3500 data sheet for more details regarding the operation and requirements for these pin functions. GND VCC CN1 VH2 + C9 100µF C10 0.1µF CN3 VH2 M/S T/S HPFD LOOP PWDN VIN C2 2.2µF + C3 4.7µF + SW1 DSS105 C1 1µF + PWDN C4 4.7µF + U1 PCM3500 1 2 3 4 LOOP 5 HPFD 6 7 8 9 CN2 VH8 10 11 DOUT 12 FSO VCC VCOM VREF1 AGND VREF2 VOUT VIN AGND AGND PDWN M/S LOOP TSC HPFD BCK XTI FS XTO DIN SCKIO DOUT DGND FSO VDD FS 24 BCK SCKIO GND XTI XTI FIGURE 1. Schematic. ® DEM-PCM3500 2 C7 4.7µF + CN4 VH2 C11 1µF + 23 22 VOUT 21 20 19 18 17 GND PDWN LOOP HPFD XTAL XTI 16 15 14 SCKIO CS 13 C5 0.1µF DIN SCKO GND C6 0.1µF + C8 4.7µF OPTIONAL CS Bottom Layer Top Layer Silk Screen FIGURE 2. Printed Circuit Board Plots. ® 3 DEM-PCM3500 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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