Winbond Electronics Corporation America Single Channel CODEC Mini Evaluation Board W681xxxES User’s Guide Rev 2.0 October 23, 2003 1 1 Description The W681xxxR-ES has the bare minimum for a digital telephone handset application which will allow the designers to easily connect this small footprint daughter board to their applications. The evaluation system targets developers of such systems as VoIP, Digital Telephony, mobile devices (wireless headsets), PBX that would like to test and or develop with Winbond Family of Voice CODECs into a new system with minimal or no additional analog design at all (“Plug & Play”). 2 Features Smallest form that contain the bare minimum components to allow a handset/headset application. It allows system developers to bypass the analog in and analog out components with a simplified procedure. 3 • Prototype area for developer to hook up the side-tone resistor on board or RJ9 (hand-set jack) or headset jack. • The board has the resistors that will allow the maximum amplification for a 32 Ohm speaker and a standard microphone • All CODEC pins lead to holes that enable the developer to solder wires to connect to his system board. • The board is designed to minimize any outside noises for the cleanest signals possible. Hardware 3.1 Power supply requirements 3V or 5V depending on the selected CODEC. Winbond Codec Part Number Operating Voltage W6810ES 5V W681512ES 5V W681310 ES 3V Table 3.1: Power Supply ( The User needs to connect VCC and GND Pins ) VCC GND 2 3.2 Schematics VCC R10 R1 1.5K 1K C4 4.7uF @10v + VCC C1 0.1uF C2 R12 2K R9 27K C3 CON4 C8 1200pf 19 R4 1K R6 27K R7 20K R2 1.5K R8 3K VAG 20 VREF 1 RO- 2 PAI 3 PAO- 4 1 PAO+ 5 CON1 1 17 J22 C6 AO FST BCLKT PCMT AIAI+ MCLK VAG VREF PCMR BCLKR FSR RO- PAOPAO+ C5 0.1uF 0 Ohm R11 FST BCLKT PCMT (FRAME SYNC TRANSMIT) (BIT CLOCK TRANSMIT) (PCM OUTPUT) 11 MCLK (2.048 MHz MASTER CLOCK IN) 8 9 7 PCMR BCLKR FSR (PCM INPUT) (BIT CLOCK RECEIVE) (FRAME SYNC RECEIVE) u/A PUI 16 10 U/A PUI (PCM MODE CONTROL) (POWER CONTROL) W68XXXX 0.1uF CON1 VREF RO- W6810, W681512 or W681310 are Populated with C6 and R11 as shown below. PAI 1 1 J1 FSR 1 R11 PAO- Populated Not Populated W6810 Not Populated Not Populated W681512 Populated Not Populated W681310 1 1 VCC 1 J13 U/A 1 J16 CON1 CON1 CON1 J8 J14 J17 PCMR 1 FST 1 AO 1 CON1 CON1 CON1 CON1 J3 J9 J15 J18 BCLKR 1 J4 J5 PUI 1 1 CON1 AI- AI+ 1 VAG 1 CON1 J10 J11 CON1 BCLKT CON1 J12 1 CON1 Figure 1: EW681xxxES Board Schematics Telephone Handset Default Diagram 4 Connecting Microphone and Speaker to the W681xxxES J23 can be used to connect an RJ9 plug from a “standard” telephone handset or headset to the appropriate pins on the board (Table 4.0). The default resistor and capacitor values on the board are used for the maximum amplification with no saturation of a 32ohm speaker using a standard microphone. Unfortunately the only thing “standard” about the RJ9 handset jack is that the microphone and speaker are always on the same pins. BUT, the microphone polarity can be positive, or negative, depending upon how the manufacturer designed their telephone set. This means that one has about a 50% chance of wiring it up wrong the first time UNLESS you know ahead of time which polarity handset you have. Many years ago, with carbon microphones acting as variable resistors this was not an issue. But with today’s modern handsets using polarized electret microphones polarity is very important. The circuit in Figure 1 assumes that the positive side of the microphone is connected to pin 1 of the RJ9 plug and the negative side to pin 4. Reversing the wires from the RJ9 to the holes in J23 will solve the polarity problem if there is no audio. Pin1 Pin2 Pin3 Pin4 Mic+ Speaker- Speaker+ Mic Table 4.0 : J23 Pin assignments 3 1 J19 CON1 CON1 MCLK CON1 J6 1 CON1 CON1 PAO+ PCMT J2 1 Device Number J7 CON1 CON1 C6 14 12 13 PAI 15 J21 AO 18 0.1uF VCC U1 R5 27K VDD 1 2 3 4 VSS R3 1K 0.1uF J23 MIC+ SPKSPK+ MIC- 6 C7 1200pf 1 J20 CON1 Note: It is recommended to use short wires to hook up this board to the prototype system for minimal added noise. 4.1 Adjusting the Amplifier levels for optimal performance In the handset, application the gain from the handset microphone is set to 27 for the input amplifier. This is because the acoustical chamber in the telephone type handset lets the electret microphone provide an output of ~28 mVRMS. The chamber typically has a gain of three over a bare microphone (or one placed with only a small opening to the outside world.) Because of the high sensitivity of the earphone (150 Ώ impedance) in a typical handset, the output gain from the Power Amp is set to ~0.16 for a satisfactory listening level. SCHEMATIC COMPONENT # R3,4 R5,6 C7,8 R9 R7 R8 TELEPHONE HANDSET (Values Populated on the board) 1K 27K 1200 pF SELECT 20K 3K VoIP PHONE SET (No acoustic Chamber) 600Ώ LINE IN/OUT (Tip/Ring) 1K 91K 330 pF SELECT 20K 3K 10K 10K N/U N/U 27k 27k Table 4.1: Suggested Components Values By Application In the VoIP telephone, or small wireless phones, the plastic case is typically too small to provide a reasonable acoustic chamber. Thus the output from the microphone is less than in the previous example. This results in having to set the input gain of the CODEC to ~75 to 90. This results in a comparable signal level to the receive telephone handset but, because of the increased gain, the Signal-to-Noise Ratio (SNR) has decreased and the signal sounds noisier. On the receive side, the gain is set as in the previous example. When the Power Amp gain is as low as 0.16 a 32 ohm load can be driven. If the CODEC is used in a telephone Line Card or a VoIP gateway to the external telephone network then it will usually be set for 0TLP in and out. This means that the input gain and output gain will be 1:1 and the values of resistors will be different again. Note that the output of RO- is at 0TLP and going differential will double this level out of the Power Amp. However, R13 and R14 are 300 ohm resistors to match to the 600 ohm line and the voltage presented to the line will be 0TLP. Resistor R9 sets the side-tone level (the signal fed back to the ear piece from the microphone so the telephone sounds “live”) to the level desired by the designer. In most 600 ohm audio line applications, this feature is not needed. R11 is a just a 0 ohm jumper to allow the board to be used with more than one model of CODEC. See the chart. R12 is a pull-up resistor for the PCM Transmit line if there is not one elsewhere in the application. 4 VDD C7 330 pF R10 1K C4 4.7uF R5 91K R1 1.5K C2 0.1uF R3 1K AI- AO TO FILTERS AND ENCODER + M1 R2 1.5K C3 0.1uF R4 1K AI+ R6 91K VAG C8 330 pF R9 SELECT SIDETONE LEVEL CONTROL R8 3K LS1 FROM FILTER AND DECODER R7 20K RO- PAO- PAI PAO+ 32 Ohm SPEAKER Figure 2: VoIP Phone Set Diagram R5 10K C2 0.1uF R3 10K AI- LINE IN AO + C3 0.1uF R4 10K TO FILTERS AND ENCODER AI+ R6 10K VAG R13 R8 27K FROM FILTER AND DECODER RO- R7 27K to 600 Ohm Line/Load PAO- PAI Note: R13 and R14 are not on board PAO+ R14 Figure 3: 600 Ohm Line IN/OUT Diagram 5 300 OHM 300 OHM LINE OUT 5 Ordering information Table 5.0 describes the various CODEC Evaluation Systems. Evaluation Board part Number W6810ES W681512ES W681310 ES Winbond Codec Part number W6810IR W681512R W681310R Table 5.0: W681xxxES Part Number The information contained in this datasheet may be subject to change without notice. It is the responsibility of the customer to check the Winbond USA website (www.winbond-usa.com) periodically for the latest version of this document, and any Errata Sheets that may be generated Headquarters Winbond Electronics Corporation America No. 4, Creation Rd. III 2727 North First Street, San Jose, Science-Based Industrial Park, CA 95134, U.S.A. Hsinchu, Taiwan TEL: 1-408-9436666 TEL: 886-3-5770066 FAX: 1-408-5441798 FAX: 886-3-5665577 http://www.winbond-usa.com/ http://www.winbond.com.tw/ Taipei Office Winbond Electronics (Shanghai) Ltd. 27F, 299 Yan An W. Rd. Shanghai, 200336 China TEL: 86-21-62365999 FAX: 86-21-62356998 Winbond Electronics Corporation Japan 9F, No. 480, Pueiguang Rd. Neihu District, Taipei, 114, Taiwan TEL: 886-2-81777168 FAX: 886-2-87153579 Winbond Electronics (H.K.) Ltd. 7F Daini-ueno BLDG, 3-7-18 Shinyokohama Kohoku-ku, Yokohama, 222-0033 TEL: 81-45-4781881 FAX: 81-45-4781800 Unit 9-15, 22F, Millennium City, No. 378 Kwun Tong Rd., Kowloon, Hong Kong TEL: 852-27513100 FAX: 852-27552064 Please note that all data and specifications are subject to change without notice. All the trademarks of products and companies mentioned in this datasheet belong to their respective owners. 6