CRD44800-ST-FB 60 W Full-Bridge Reference Design for the CS44800 Features Eight full-bridge channels, 60 W each Programmable load compensation Power Supply Rejection (PSR) feedback allowing amplifier to operate from low cost linear unregulated power supplies Peak signal limiting Thermal and over-current protection > 85% amplifier efficiency Works with GUI to configure the board or in a standalone mode for easy operation. Demonstrates recommended layout and grounding arrangements Description The CRD44800-ST-FB PWM Amplifier demonstrates the CS44800, Cirrus' eight-channel pure digital PMW controller. This reference design implements an eightchannel amplifier which delivers 60 W per full-bridge channel into 8 loads using a single +30 V supply (at 10% THD+N). A 155 W Switched Mode Power Supply (SMPS) is used to power the CRD44800-ST-FB. As shown below, the CS44800 IC takes four stereo digital audio inputs in IS format and converts them to PWM outputs. This 64-pin LQFP IC provides an integrated sample rate converter for 32 kHz-192 kHz input sample rate support, volume up/down, speaker load compensation, peak limiting to prevent amplifier clipping, power supply ripple compensation, and AM frequency interference elimination. This reference design uses the the ST Micro STA500, an integrated power stage back end for digital amplifiers (four STA500 parts configured as full-bridges are used for this eight-channel design). Current limiting and thermal protection are provided by the STA500. The inductor/capacitor 2nd order low pass filter (LPF) removes high frequency components from the output signal effectively converting it from digital to analog. ORDERING INFORMATION CRD44800-ST-FB Reference Design I +30V 155W Switched Mode Power Supply +30V/+5V PSR Circuitry CS4461 ADC +30V PWM Outputs I2S Clocks & Data CS44800 (PWM Controller) Audio Driver Board To channels 3/4 To channels 5/6 I2C Host Control LPF 8 LPF 8 ST Micro STA500A To channels 7/8 Channels 1 and 2 (of 8) Cirrus Logic, Inc. www.cirrus.com Copyright (c) Cirrus Logic, Inc. 2004 (All Rights Reserved) DEC `04 DS632ARD1 1 CRD44800-ST-FB TABLE OF CONTENTS 1. SCHEMATIC DESCRIPTIONS ................................................................................................. 3 1.1 CRD44800-ST-FB PWM Amplifier ..................................................................................... 3 1.2 CRD44800-ST-FB Driver Board ........................................................................................ 3 1.3 Switched Mode Power Supply ........................................................................................... 3 2. OPERATION INFORMATION ................................................................................................... 4 2.1 Power Supply Ratings ........................................................................................................ 9 2.2 Power Supply Decoupling .................................................................................................. 9 2.3 Electromagnetic Interference (EMI) ................................................................................. 10 2.3.1 Suppression of EMI at the Source ...................................................................... 10 3. SCHEMATICS.......................................................................................................................... 12 4. LAYOUT................................................................................................................................... 19 5. BILL OF MATERIALS ............................................................................................................. 22 6. TYPICAL PERFORMANCE PLOTS ........................................................................................ 24 7. REVISION HISTORY .............................................................................................................. 28 LIST OF FIGURES Figure 1. Speaker Terminal Configuration ...................................................................................... 5 Figure 2. CS44800 Dialog Tab ........................................................................................................ 7 Figure 3. Advanced Register Debug Tab - CS44800...................................................................... 8 Figure 4. Power and Connectors................................................................................................... 12 Figure 5. CS44800 ........................................................................................................................ 13 Figure 6. Left/Right Back Surround Channels............................................................................... 14 Figure 7. Left/Right Surround Channels ........................................................................................ 15 Figure 8. LFE/Center Channels..................................................................................................... 16 Figure 9. Left/Right Channels........................................................................................................ 17 Figure 10. PSR Feedback ............................................................................................................. 18 Figure 11. Silk Screen Top............................................................................................................ 19 Figure 12. Topside Layer .............................................................................................................. 20 Figure 13. Bottomside Layer ......................................................................................................... 21 Figure 14. Bill of Materials ............................................................................................................. 22 Figure 15. Bill of Materials ............................................................................................................. 23 Figure 16. Frequency Response ................................................................................................... 24 Figure 17. THD+N vs. Frequency at 1 W, 10 W, and 20 W .......................................................... 25 Figure 18. THD+N vs. Power at 1 kHz .......................................................................................... 26 Figure 19. FFT at -60 dBFS and 1 kHz ......................................................................................... 27 LIST OF TABLES Table 1. Revision History .............................................................................................................. 28 2 CRD44800-ST-FB 1. SCHEMATIC DESCRIPTIONS 1.1 CRD44800-ST-FB PWM Amplifier The CS44800 shown in Figure 2 employs a built-in Sample Rate Converter (SRC) to support all popular sampling frequencies between 32 kHz and 192 kHz. The CS44800 produces a PWM frequency of either 384 kHz or 768 kHz (refer to CS44800 data sheet). In this design, analog or digital audio signals are always output at a 384 kHz PWM rate. The CS4461 ADC is used to monitor the signal and line frequency related ripple that is inevitable on the power supply rail when the amplifiers operate. The ripple voltage is digitized and fed back to the CS44800. The CS44800 uses this information to substantially reduce ripple related distortion and noise in the audio output signal. Four ST Micro STA500s provide the power back end to drive the speaker loads. Each STA500 consists of a pair of fully current and temperature protected full-bridge PWM output stages. The STA500 is optimized for use in open loop Class-D amplifier systems. 1.2 CRD44800-ST-FB Driver Board The CRD44800-ST-FB Driver board provides a convenient source of PCM IS signals to drive the CRD44800-ST-FB PWM Amplifier board. Eight analog inputs allow multi-channel analog audio signals to be used for evaluation of the amplifier. In addition, either optical or coaxial stereo S/PDIF signals can be used to evaluate the amplifier. In this case, the left and right digital input signals are distributed to each STA500. The CRD44800-ST-FB Driver board provides two modes of operation: stand-alone and remote. In the stand-alone mode, basic evaluation of the CS44800 is possible. The user can select between analog and digital S/PDIF input signals (jumpers J17 and J18), control the system volume, mute and unmute the system (switch S2), and enable or disable switching on the PWM output (switch S3). In the Remote mode, the DB-9 connector (J14, labelled RS-232) is connected to a host PC. All aspects of the CS44800 may then be evaluated using the supplied software. 1.3 Switched Mode Power Supply The SMPS used for the CRD44800-ST-FB is a 155 W OEM supply. The supply provides +30 V for the STA500 PWM back ends, and +5 V to power all the signal level circuitry. The SMPS is fully over-current and over-temperature protected. 3 CRD44800-ST-FB 2. OPERATION INFORMATION Switches and Indicators (Located on the Driver Board): RESET Pushbutton (S1) - forces a complete system reset. MUTE Pushbutton (S2) - mutes the audio output of the CRD44800-ST-FB, but the PWM output stage will continue switching. RAMP UP/DN Pushbutton (S3) - enables/disables the PWM output stage from switching. MUTE LED (D16) - indicates that the audio output is muted. The MUTE LED is also used during CRD44800-ST-FB initialization (see below). FAULT LED (D19) - indicates several types of fault conditions. If one (or more) of the PWM outputs is shorted, or the PWM back end overheats, the FAULT LED will light. Also, if either the Optical or Coax digital input is selected as the system input and a valid digital signal is not present, the FAULT LED will light. The FAULT LED is also used during CRD44800-ST-FB initialization (see below). S/PDIF ERROR LED (D6) - indicates the absence of a valid S/PDIF signal into the CS8416. Stand-alone Operation The CRD44800-ST-FB evaluation system is prewired for stand-alone operation. The SMPS is a universal input, 90-260VAC, 50/60Hz. 1) Attach the supplied power cord to the power entry module. Do not turn on the power yet. 2) Configure jumper J10 for the desired volume control mode. If J10 is in, the gain of the CS44800 will be forced to 0dB, irrespective of the position of the volume control pot. If J10 is out, the volume control pot determines the CS44800 gain. 3) Configure jumpers J17 and J18 for the desired mode of operation. The first three options are stand-alone, while the final option is remote. Function J17 J18 Analog Inputs 1-2 1-2 Coaxial S/PDIF 2-3 1-2 Optical S/PDIF 1-2 2-3 Remote Mode 2-3 2-3 4) If the Analog input mode is selected, configure jumpers J6 and J7 to select the sampling frequency for the CS5341s. Sample Rate (Fs) J6 J7 48 kHz 2-3 2-3 96 kHz 1-2 2-3 192 kHz 2-3 1-2 5) Supply either analog signals (if the Analog input option is selected) or either coaxial or optical digital PCM inputs (if the digital S/PDIF option is selected). 4 CRD44800-ST-FB 6) Connect loudspeakers to the speaker output terminals. The Red terminal is speaker positive, and the Black terminal is speaker negative. Note that in a full-bridge system like the CDRD44800-ST-FB, neither speaker terminal is grounded. As a result, speaker switch boxes with common negative terminals should not be used. Rx Lx Rs Ls S C R L Figure 1. Speaker Terminal Configuration Turn the volume control fully counterclockwise and apply power using the power switch on the power entry module. The Fault and Mute LEDs will both light briefly as the system is initialized. Note that if either the Coax or the Optical input is selected, a valid digital signal must be provided to the selected input so that the CRD44800-ST-FB can complete initialization. If a valid signal is not present at the selected input, both the Fault and Mute LEDs will remain lit. If one of the stand-alone modes is selected, the amplifiers should now be operating. Slowly advance the volume control clockwise until the desired volume is achieved. The MUTE pushbutton (S2) may be used to mute and unmute the audio output. The RAMP UP/DN pushbutton (S3) will enable or disable switching on the PWM back end. Note that in the stand-alone mode, several system faults are indicated by the lighting of the red Fault LED, D19. Typical causes for fault conditions are short circuited speaker outputs, thermal shutoff of the power back end, or lack of a S/PDIF signal when either of the S/PDIF inputs is selected. Remote Operation The CRD44800-ST-FB may also be operated remotely via the Cirrus FlexGUI for complete control of all the features of the CS44800. Note that the Fault and Mute LEDs operate differently in the remote mode. They indicate the selected audio signal input as explained below. Follow the procedure below to set up remote operation. 1) Attach the supplied power cord to the power entry module. Do not turn on the power yet. 2) Configure jumpers J17 and J18 for remote operation. Jumpers J17 and J18 should have pins 2 and 3 connected for remote operation. Jumpers J6 and J7 should be removed completely. 3) Turn on the AC power. Press the Reset button on the driver board. Select the desired audio input source by pressing the Mute button. The following table shows the inputs selections: Selected Input Mute LED Fault LED Analog Inputs On Off Optical S/PDIF Off On 5 CRD44800-ST-FB Selected Input Mute LED Fault LED Coaxial S/PDIF On On 4) Connect the DB-9 RS-232 port (J14) on the CRD44800-ST-FB Driver board to a PC serial port. 5) Copy the CRD44800-ST-FB directory from the included CD-ROM to the users local hard drive. Note that FlexGUI is only compatible with systems running Windows 98 or better (i.e. Windows 98, ME, 2000, XP, etc.). 6) Modify the following line in the file "flexconfig.ini", which is found in the FlexLoader application directory. This line is found in the [CDB44800Comm] section of the ini file. SERIAL = PI_Serial.dll, 2500, COM1, 38400 Replace "COM1" with the number of the serial communications (RS-232) port you are using (COM1/COM2/COM3/COM4). 7) Start FlexGUI opening FlexLoader.exe. This application can be used to read and modify any CS44800 register, and provides easy control over individual channel volumes. The CS44800 Dialog tab provides high level control over the CS44800's registers. Controls are provided to change volume, mute, power down, ramp control, quantization level, SAI input format, minimum pulse width, and channel delay. 6 CRD44800-ST-FB Figure 2. CS44800 Dialog Tab The Advanced Register Debug tab provides low level control over the CS44800 and CS8416 individual register settings. Each device is displayed on a separate tab. Register values can be modified bitwise or bytewise. For bitwise, click the appropriate pushbutton for the desired bit. For bytewise, the desired hex value can be typed directly in the register address box in the register map. 7 CRD44800-ST-FB Figure 3. Advanced Register Debug Tab - CS44800 8 CRD44800-ST-FB System Issues 2.1 Power Supply Ratings The required power supply current rating can be estimated as follows. 45 W is used as the reference output power because this represents the typical full scale output with no clipping. Assume the efficiency, , is approximately 85% (this accounts for power to supply control electronics and overhead), then for 45 W / 8 channels: PTotal = P Supply = POut = 360 W = 424 W 0.85 P Total 424 W = = 212 W 2 2 Consequently the supply current is: ISupply = PSupply 212 W = = 7 .1 A VSupply 30 V The factor of 2 in the denominator of the PSupply calculation arises from the fact that for typical consumer applications in A/V or DVD receivers, the power supply should be capable of providing 1/2 the total requirement for all channels operating at full power. This design guide is still quite conservative, and gives more that adequate headroom in real applications. 2.2 Power Supply Decoupling Proper power supply decoupling is one key to maximizing the performance of a Class-D amplifier. Because the design uses an open loop output stage, noise on the power supply rail will be coupled to the output. While the PSR functionality of the CS44800 helps reduce power supply noise feedthrough to the output, careful decoupling of the power stage supply rails is essential. Referring to Figure 11, the top side of the CRD44800-ST-FB PWM amplifier board, good decoupling practice is shown. Notice that the 0.1 F ceramic capacitors are as close as physically possible to the power pins of the STA500. The ground side of the capacitors is connected directly to top side ground plane, which is also used by the power supply return pins. This keeps the high frequency current loop small to minimize power supply variations and EMI. 470 F electrolytic capacitors are also located in close proximity to the power supply pins to supply the current locally for each channel. These are not required to be expensive low ESR capacitors. General purpose electrolytic capacitors that are specified to handle the ripple current can be used. The real time PSR feedback of the CS44800/CS4461 can greatly attenuate the induced voltages due to the power supply ripple current. 9 CRD44800-ST-FB 2.3 Electromagnetic Interference (EMI) The EMI challenges that face a maker of Class-D amplifiers are largely the same challenges that have been faced by the switch mode power supply industry for many years. The numerous EMI consulting firms that have arisen and the many books that have been written on the subject indicate the scope of potential problems and available solutions. They should be considered a resource - most makers of switch mode equipment would benefit from developing a working relationship with a qualified EMI lab and from bringing their experience to bear on design issues, preferably early in the design process. This reference design from Cirrus Logic is a board level solution which is meant to control emissions by minimizing and suppressing them at the source in contrast to containing them in an enclosure. The EMI requirements for an amplifier have added dimensions beyond those imposed on power supplies. Audio amplifiers are usually located in close proximity to radio receivers, particularly AM receivers which are notoriously sensitive to interference. Amplifiers also need to operate with speaker leads of unpredictable length and construction which make it possible for any high frequency currents that appear on the outputs to generate nuisance emissions. The criteria for judging successful EMI control is not as well defined for amplifier design as it is for power supplies. While the techniques of measuring conducted and radiated emissions are similar for both types of products, power supplies have a number of clearly defined (and legally imposed) thresholds that are useful mainly as guidelines when testing amplifiers. 2.3.1 Suppression of EMI at the Source Several techniques are used in the circuit design and board layout to minimize high frequency fields in the immediate vicinity of the high power components. Specific techniques include the following: 10 * As was mentioned in Section 2.2, effective power supply decoupling of high frequency currents, and minimizing the loop area of the decoupling loop is one aspect of minimizing EMI. * Each output of the STA500 includes "snubbing" components. For example, OUT1 of U4 includes snubber components R10 (20 ), and C46 (330 pF). These components serve to damp ringing on the switching outputs in the 30-50 MHz range. The snubbing components should be as close as practical to the output pins to maximize their effectiveness. Again, refer to Figure 11 for the preferred component layout. * A separate ground plane with a solid electrical connection to the chassis and which surrounds the speaker output connector should be implemented. This allows the speaker outputs to be RF decoupled to the chassis just before they exit the chassis from the speaker connector. Again, refer to Figure 11 for the preferred component layout. * Make use of source termination resistors on all digital signals whose traces are longer than about 25 mm. CRD44800-ST-FB It is extremely critical that the layout of the power amplifier section of the Cirrus Logic CS44800 Reference Design be copied as exactly as possible to assure best RF/EMI performance. 11 Figure 4. Power and Connectors CRD44800-ST-FB 3. SCHEMATICS 12 Figure 5. CS44800 CRD44800-ST-FB 13 Figure 6. Left/Right Back Surround Channels CRD44800-ST-FB 14 Figure 7. Left/Right Surround Channels CRD44800-ST-FB 15 Figure 8. LFE/Center Channels CRD44800-ST-FB 16 Figure 9. Left/Right Channels CRD44800-ST-FB 17 Figure 10. PSR Feedback CRD44800-ST-FB 18 Figure 11. Silk Screen Top CRD44800-ST-FB 4. LAYOUT 19 Figure 12. Topside Layer CRD44800-ST-FB 20 Figure 13. Bottomside Layer CRD44800-ST-FB 21 22 A A A A A A A 001-10097-01 001-01865-01 012-00035-01 001-03379-01 001-10043-01 011-00007-01 012-00071-01 012-00064-01 001-02189-01 001-04345-01 311-00001-01 110-00078-01 110-00091-01 110-00094-01 110-00095-01 040-00022-01 020-00788-01 020-00789-01 020-00902-01 020-01130-01 020-00911-01 020-01047-01 020-00934-01 020-01048-01 021-00718-01 020-01181-01 020-00867-01 020-01209-01 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 A A A A A A A A A A A A A A A A A A A A A A 001-07078-01 2 A 001-01790-01 Rev 1 Line Cirrus P/N Item 4 1 1 3 1 1 2 8 10 1 1 17 16 1 1 1 1 1 45 4 2 31 2 8 8 5 1 2 9 21 EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA Qty U/M Reference Designator C0805C104K5RAC KEMET R1 R2 R47 R50 R57 R49 DALE DALE DALE CRCW060349R9F CRCW06034992F CRCW06032942F CRCW06031210F CRCW06031961F CRCW06032000F CRCW06032001F CRCW1210200J ERJ3EKF1002V CRCW060310R0F CRCW060310R2F CRCW06031000F TMP50612CT PT-1222P-03 FH21-22S-1DSA B8B-EH-A PT-422-03 311-00001-01 ECA1VM471B ECEA1CKS470 C0603C104K4RAC C0603C390J5GAC 2222 370 11474 C0805C331J5GAC ECEA0JKS220 C0603C222K5RAC C0603C121J5GAC ECJ3YB1E105K ECJ1VB1H102K MFG. P/N PANASONIC PANASONIC KEMET KEMET BC COMPONENTS KEMET PANASONIC KEMET KEMET PANASONIC PANASONIC MFG SUMMIT HEAT SINKS CO LTD J2 HIROSE ELECTRIC J12 JST J5 DRAGON CITY INDUSTRIES J4 DRAGON CITY INDUSTRIES L5 L6 L7 L8 L9 L10 L11 L12 L13 L14 TRANSTEK MAGNETICS L15 L16 L17 L18 L19 L20 R71 DALE R56 DALE DALE R58 R75 R85 R86 R87 R88 R89 R108 R110 R111 R112 R113 R114 R115 R116 R117 R118 R4 R5 R9 R16 R23 R30 R37 R38 PANASONIC R65 R109 R7 R8 R45 DALE R48 DALE R6 DALE R54 R55 DALE R10 R11 R17 R18 R24 R25 R31 R32 DALE C46 C47 C73 C74 C100 C101 C127 C128 C11 C30 C56 C57 C83 C84 C110 C111 C137 C138 C41 C69 C96 C123 C12 C16 C2 C7 C18 C20 C22 C23 C24 C25 C26 C27 C34 C35 C36 C37 C38 C43 C62 C63 C64 C65 C66 C89 C90 C91 C92 C93 C116 C117 C118 C119 C120 C13 C15 C17 C21 C31 C39 C42 C48 C49 C50 C51 C52 C53 C54 C55 C67 C70 C75 C76 C77 C78 C79 C80 C81 C82 C94 C97 C102 C103 C104 C105 C106 C107 C108 C109 C121 C124 C129 C130 C131 C132 C133 C134 C135 C136 HS1 C1 C4 C6 C32 C33 C10 C3 C5 C19 C28 C29 C58 C59 C60 C61 C85 C86 C87 C88 C112 C113 C114 C115 C139 C140 C141 C142 C14 C40 C44 C68 C71 C95 C98 C122 C125 C8 C9 Figure 14. Bill of Materials RES 29.4k OHM 1/16W 1% 0603 FILM DELETED LINE ITEM RES 49.9 OHM 1/16W 1% 0603 FILM RES 49.9k OHM 1/16W 1% 0603 FILM RES 121 OHM 1/16W 1% 0603 FILM RES 1.96k OHM 1/16W 1% 0603 FILM RES 200 OHM 1/16W 1% 0603 FILM RES 2k OHM 1/16W 1% 0603 FILM RES 20 OHM 1/4W 5% 1210 FILM RES 10k OHM 1/16W 1% 0603 FILM RES 10 OHM 1/16W 1% 0603 FILM RES 10.2 OHM 1/16W 1% 0603 FILM RES 100 OHM 1/16W 1% 0603 FILM IND 22uH 3.5A 10% 400 DIA TH CONN, 6x2 SPKR TERMINAL CONN, FLEX 22PIN, ST, I mm PITCH CONN, 8PIN EH 2.5MM PTCH PWR HDR CONN, 2x2 SPKR TERMINAL HEATSINK, 30W, APOGEE PWM CAP 0.1uF 10% 50V X7R 0805 CAP 470uF 20% 35V ELEC RAD CAP 47uF 20% 16V ELEC RAD 6.3x11MM CAP 0.1uF 10% 16V X7R 0603 CAP 39pF 5% 50V C0G 0603 CAP 0.47uF 10% 63V MTL FLM RAD CAP 330pF 5% 50V C0G 0805 CAP 22uF 20% 6.3V ELEC RAD CAP 2200pF 10% 50V X7R 0603 CAP 120pF 5% 50V C0G 0603 CAP 1uF 10% 25V X7R 1206 CAP 1000pF 10% 50V X7R 0603 Description CRD44800-ST-FB 5. BILL OF MATERIALS 021-00358-01 020-00995-01 020-00897-01 065-00125-02 065-00085-01 060-00098-01 060-00286-01 060-00292-01 102-00028-01 300-00009-01 32 33 34 35 36 37 38 39 40 41 Line Cirrus P/N Item D A A A A A A A A A Rev 1 1 2 1 4 1 5 1 2 16 EA EA EA EA EA EA EA EA EA EA Qty U/M Reference Designator R51 R52 R53 R3 R39 R40 R41 X1 U9 U11 U3 U8 U2 U4 U5 U6 U7 U14 MFG CIRRUS LOGIC CIRRUS LOGIC NJR NJR ST MICROELECTRONICS CITIZEN BUILDING FASTENERS DALE PANASONIC R12 R13 R14 R15 R19 R20 R21 R22 DALE R26 R27 R28 R29 R33 R34 R35 R36 Figure 15. Bill of Materials RES 649 OHM 1/16W 1% 0603 FILM RES 90.9 OHM 1/16W 1% 0603 FILM NO POP IC CRUS A/D PSR FEEDBACK TSSOP24 IC CRUS, MULTI CHNL PWM CONTR QFP64 IC, 1.5A ADJ V REG, TO-252 IC LNR DUAL OP AMP LOW V RRO VSP8 IC 30V 3.5A QUAD PWR BRDG POWERSO36 OSC, 24.576MHz 100ppm 5V, SG-531 SCREW PANHEAD, 4-40, PH, 1/2"L RES 6.2 OHM 1/8W 5% 0805 FILM Description CS4461-CZZ/D CS44800-CQ/A NJM317DL1 NJM2140R STA500 CMX309FLC24.576MT PMS 440 0050 PH CRCW06036490F ERJ3EKF90R9V CRCW08056R2J MFG. P/N CRD44800-ST-FB 23 24 -2.5 A -5 20 -4.5 -4 -3.5 -3 -2 -1.5 d B r -1 -0.5 -0 +0.5 +1 50 100 Hz 500 1k Figure 16. Frequency Response 200 2k 5k 10k 20k CRD44800-ST-FB 6. TYPICAL PERFORMANCE PLOTS % 0.001 20 0.002 0.005 0.01 0.02 0.05 0.1 0.2 0.5 1 50 200 Hz 500 1k 2k Figure 17. THD+N vs. Frequency at 1 W, 10 W, and 20 W 100 1W 10 W 20 W 5k 10k 20k CRD44800-ST-FB 25 26 % 0.01 100m 0.02 0.05 0.1 0.2 0.5 1 2 5 10 200m 500m 2 W 5 Figure 18. THD+N vs. Power at 1 kHz 1 10 20 50 80 CRD44800-ST-FB A d B r -140 20 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 +0 50 100 Hz 500 1k Figure 19. FFT at -60 dBFS and 1 kHz 200 2k 5k 10k 20k CRD44800-ST-FB 27 CRD44800-ST-FB 7. REVISION HISTORY Release RD1 Date December 2004 Changes 1st Release Table 1. Revision History Contacting Cirrus Logic Support For all product questions and inquiries contact a Cirrus Logic Sales Representative. To find one nearest you go to: http://www.cirrus.com/ IMPORTANT NOTICE Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised 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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