LM4549 National Semiconductor, LM4549 Datasheet
LM4549
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LM4549 Summary of contents
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... AC ’97 Rev 2.1 Codec with Sample Rate Conversion and National 3D Sound General Description The LM4549 is an audio codec for PC systems which is fully PC98 compliant and performs the analog intensive functions of the AC97 Rev2.1 architecture. Using 18-bit Sigma-Delta A/D’s and D/A’s, the LM4549 provides 90dB of Dynamic Range ...
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... R = 10k Left to Right CD Left to Right 0dB to 22.5dB +12dB to -34.5dB 2 215˚C 220˚C 74˚C/W −40˚C T 85˚C MAX A 4.2V AV 5.5V DD 3.0V DV 5.5V DD Units LM4549 (Limits) Typical Limit (Note 7) (Note 8) 4.2 V (min) 5.5 V (max) 3.0 V (min) 5.5 V (max 500 µA 30 µA 2.23 V ...
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... SDATA_IN, SDATA_OUT to falling edge of BIT_CLK Hold time of SDATA_IN, SDATA_OUT from falling edge of BIT_CLK BIT_CLK, SYNC, SDATA_IN or SDATA_OUT BIT_CLK, SYNC, SDATA_IN or SDATA_OUT For cold reset For cold reset 3 Units LM4549 (Limits) Typical Limit (Note 7) (Note (min) 20 kHz 18 Bits ...
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... Fs = 48kHz, single codec configuration, unless otherwise noted Conditions For warm reset For warm reset For ATE Test Mode For ATE Test Mode JMAX or the number given in Absolute Maximum Ratings, whichever is lower. For the LM4549 resistor. 4 Units LM4549 (Limits) Typical Limit ...
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Timing Diagrams Clocks DS101035-10 Data Setup and Hold DS101035-11 Digital Rise and Fall DS101035-12 Cold Reset DS101035-13 Warm Reset DS101035-14 5 www.national.com ...
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... Typical Application FIGURE 2. LM4549 Typical Application Circuit for a Single Codec Application www.national.com 6 DS101035-3 ...
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... The amount of AUX_L AUX_L 14 I signal mixed in the left output stream can be adjusted from +12dB to −34.5dB in 1.5dB steps as well as muted via register 16h. Top View Order Number LM4549VH See NS Package Number VBH48A 7 DS101035-2 www.national.com ...
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Pin Description (Continued) Analog I/O (Continued) Name Pin Functional Description This line level input can be routed through the Input Mux and recorded by the right ADC. In addition, this analog input gets summed into the right ...
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... Codec. This data stream contains both control data and ADC audio data. This output is clocked out SDATA_IN the LM4549 on the rising edge of BIT_CLK. 48kHz sync pulse which signifies the beginning of both the SDATA_IN and SDATA_OUT SYNC 10 I serial streams. SYNC must be synchronous to BIT_CLK. ...
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Typical Performance Characteristics ADC Noise Floor DS101035-15 ADC Frequency Response DS101035-19 www.national.com DAC Noise Floor DS101035-16 DAC Frequency Response DS101035-20 10 Analog Loopthru Noise Floor DS101035-18 True Line Level Out Noise Floor (Analog Loopthrough) DS101035-18 ...
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... The first bit of slot 0 is designated the Valid Frame bit. If this bit indicates that the current data frame contains at least one slot of valid data and the LM4549 will further sample the next four bits to determine which frames do in fact have valid data. Valid slots are signified their re- spective slot bit position ...
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... Reserved Set to 0 SDATA_OUT Slot 2: Control Data Slot 2 is used to transmit 16 bit control data to the LM4549 in the event that the current operation is a write operation. The least significant four bits should be stuffed with zeros by the AC ’97 controller. If the current operation is a register read, the entire slot, bits 19 through 0 should be stuffed with zeros ...
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Application Information FIGURE 7. Start of Audio Input Frame Bit Description Comment Codec Ready 15 0=Not Ready, 1=Ready Bit Slot 1 data 14 Status Address is valid valid Slot 2 data 13 Status Data is valid valid Slot 3 data ...
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... Writing any value to this register causes a register reset which changes all of the registers back to their default val- ues read is performed on this register, the LM4549 will return a value of 0D50h indicating that National 3D Sound is implemented, 18bit data is supported for both the ADC’s and DAC’ ...
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... Extended Audio ID Register (28h) This read only register identifies which AC97 Extended Au- dio features are supported. The LM4549 provides for VRA (Variable Rate Audio) and Multiple Codec support. VRA is in- dicated the LSB of register 28h. The two MSB’s, ID1 and ID0, show the current codec configuration as con- nected via external pins 45 and 46 ...
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... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. 48-Lead , TQFP 1.4mm, JEDEC (M) Order Number LM4549VH NS Package Number VBH48A 2 ...