SAA2500, Elektronika, elementy
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INTEGRATED CIRCUITS DATA SHEET SAA2500 MPEG Audio Source Decoder Preliminary specication File under Integrated Circuits, IC01 September 1994 Philips Semiconductors Philips Semiconductors Preliminary specication MPEG Audio Source Decoder SAA2500 FEATURES APPLICATIONS · Advanced error protection · Cable and satellite digital radio decoders · Integrated audio post processing for control of signal level and inter-channel crosstalk · Video CD · Compact Disc Interactive (CD-I) · Demultiplexing of ancillary data in the input bitstream · Sold-state audio · Automatic digital de-emphasis of the decoded audio signal · Multimedia Personal Computer (PC). · Separate master and slave inputs GENERAL DESCRIPTION · Automatic sample frequency and bit-rate switching in master input mode The SAA2500 supports all audio modes (joint stereo, stereo, single channel and dual channel) bit rates and sample frequencies of ISO/MPEG-1 layers I and II, as standardized in “ISO/IEC11172-3”. · Automatic synchronization of input and output interface clocks in master input mode · Selectable audio output precision; 16, 18, 20 or 22 bit · Low power consumption. ORDERING INFORMATION TYPE NUMBER PACKAGE NAME DESCRIPTION VERSION SAA2500H QFP44 (1) Plastic quad flat package; 44 leads (lead length 1.3 mm); body 10 SOT307-2 ´ 10 ´ 1.75 mm Note 1. When using IR reflow soldering it is recommended that the Drypack instructions in the “Quality Reference Pocketbook” (order number 9398 510 34011) are followed. Supply of this “ISO/IEC11172-3” audio standard Layer I or layer II compatible IC does not convey a licence nor imply a right under any patent, or any Industrial or Intellectual Property Right, to use this IC in any ready-to-use electronic product. September 1994 2 Philips Semiconductors Preliminary specication MPEG Audio Source Decoder SAA2500 BLOCK DIAGRAM handbook, full pagewidth 54 8 7444 10 9 3242 43 24 25 23 11 12 TDI 41 37 39 40 38 1 TDO CLOCK GENERATOR DECODING CONTROL RESET TCK TMS TRST CDS 19 20 SAA2500 CDSEF 18 CDSCL SYNTHESYS SUBBAND FILTER BANK AND OUTPUT PROCESSING 21 CDSWA DEQUANTI- ZATION AND SCALING PROCESSOR 22 CDSSY 26 INPUT PROCESSOR SD 15 CDM 14 CDMEF 16 CDMCL 13 CDMWS 36 35 17 GND 28 GND 6 GND 27 33 31 32 29 30 MGB489 TC0 TC1 TA TB TO TI SCK WS Fig.1 Functional block diagram. September 1994 3 Philips Semiconductors Preliminary specication MPEG Audio Source Decoder SAA2500 PINNING SYMBOL PIN DESCRIPTION TYPE RESET 1 master reset I FSCLK 2 sample rate clock; buffered signal O FSCLKIN 3 sample rate clock input I MCLK 4 master clock; buffered signal O V DD1 5 supply voltage - GND 6 supply ground - MCLKOUT 7 master clock oscillator output O MCLKIN 8 master clock oscillator input or signal input I X22OUT 9 22.579 MHz clock oscillator output O X22IN 10 22.579 MHz clock oscillator input or signal input I STOP 11 stop decoding I URDA 12 unreliable data input; interrupt decoding I CDMWS 13 coded data (master input) word select output O CDMEF 14 coded data (master input) error ag input I CDM 15 ISO/MPEG coded data (master input) I CDMCL 16 coded data (master input) bit clock output O GND 17 supply ground - CDSCL 18 coded data (slave input) bit clock I CDS 19 ISO/MPEG coded data (slave input) I CDSEF 20 coded data (slave input) error ag I CDSWA 21 coded data (slave input) window signal I CDSSY 22 coded data (slave input) frame sync I L3CLK 23 L3 interface bit clock I L3DATA 24 L3 interface serial data I/O L3MODE 25 L3 interface address/data select input I SD 26 baseband audio I 2 S data output O TA 27 do not connect; reserved O GND 28 supply ground - SCK 29 baseband audio data I 2 S clock output O WS 30 baseband audio data I 2 S word select output O TO 31 connect to TI (pin 32) O TI 32 connect to TO (pin 31) I TB 33 do not connect; reserved O V DD2 34 supply voltage - TC1 35 do not connect; factory test control 1 input, with integrated pull-down resistor I TC0 36 do not connect; factory test control 0 input, with integrated pull-down resistor I TDO 37 boundary scan test data output O TRST 38 boundary scan test reset input; this pin should be connected to ground for normal operation I TCK 39 boundary scan test clock input I September 1994 4 Philips Semiconductors Preliminary specication MPEG Audio Source Decoder SAA2500 SYMBOL PIN DESCRIPTION TYPE TMS 40 boundary scan test mode select input I TDI 41 boundary scan test data input I FSCLK384 42 sample rate clock frequency indication input I FSCLKM 43 sample rate clock source selection for the master input I MCLK24 44 master clock frequency indication I handbook, full pagewidth handbook, full pagewidth RESET FSCLK 1 2 33 32 31 TB TI TO FSCLKIN MCLK V 3 4 5 DD 30 29 WS SCK SAA2500 (QFP44) GND 6 7 28 27 GND TA MCLKOUT MCLKIN 8 26 25 SD L3MODE X22OUT X22IN 9 10 24 23 L3DATA L3CLK STOP 11 MGB490 Fig.2 Pin configuration. FUNCTIONAL DESCRIPTION For layers I and II of ISO/MPEG the broadband audio signal spectrum is split into 32 sub-bands of equal bandwidth. For each sub-band signal a masking threshold is calculated. The sub-band samples are then re-quantized to such an accuracy that the spectral distribution of the re-quantization noise does not exceed the masking threshold. It is this reduction of representation accuracy which yields the data reduction. The re-quantized sub-band signals are multiplexed, together with ancillary information regarding the actual re-quantization, into a MPEG audio bitstream. Coding system The perceptual audio encoding/decoding scheme defined within the “ISO/IEC 11172-3 MPEG Standard” allows for a high reduction in the amount of data needed for digital audio whilst maintaining a high perceived sound quality. The coding is based upon a psycho-acoustic model of the human auditory system. The coding scheme exploits the fact that the human ear does not perceive weak spectral components that are in the proximity (both in time and frequency) of loud components. This phenomenon is called masking. September 1994 5 [ Pobierz całość w formacie PDF ] |