LM4540 National Semiconductor, LM4540 Datasheet
LM4540
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LM4540 Summary of contents
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... LM4540 AC ’97 Codec with National 3D Sound General Description The LM4540 is an audio codec for PC systems which per- forms the analog-intensive function of the Analog Codec ’97 Rev 1.03 architecture. Using 18-Bit A/D and D/A convert- ers, the LM4540 provides 90dB of dynamic range. The LM4540 was designed specifically to provide a high quality audio path and provide all analog functionality audio system. It features full duplex stereo A/D’ ...
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... L CD 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. 25˚C. The reference A Units LM4540 (Limits) Typical Limit (Note 7) (Note 8) 4.2 V (min) 5.5 V (max) 3.0 V (min) 5.5 V (max 1 ...
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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 = 25˚C. The reference A Units LM4540 (Limits) Typical Limit (Note 7) (Note (min) 20 kHz 18 Bits 89 ...
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... Limits apply for 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 LM4540 resistor 25˚C. The reference A Units LM4540 (Limits) ...
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Timing Diagrams Clocks DS100906-10 Data Setup and Hold DS100906-11 Digital Rise and Fall DS100906-12 Cold Reset DS100906-13 Warm Reset DS100906-14 5 www.national.com ...
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... Typical Application FIGURE 2. LM4540 Typical Application Circuit www.national.com 6 DS100906-3 ...
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... This input can be used to reject common mode signals on the CD_L or CD_R inputs. CD_GND 19 I CD_GND ground point not a DC ground point. This input must be AC-coupled to the CD input signal’s ground. Top View Order Number LM4540VH See NS Package Number VBH48A 7 DS100906-2 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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... This data stream contains both status data and ADC audio data. This output is clocked out SDATA_IN the LM4540 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 DS100906-15 ADC Frequency Response DS100906-19 www.national.com DAC Noise Floor DS100906-16 DAC Frequency Response DS100906-20 10 Analog Loopthru Noise Floor DS100906-18 ...
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11 www.national.com ...
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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 LM4540 will further sampled 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 SD_OUT Slot 2: Control Data Slot 2 is used to transmit 16 bit control data to the LM4540 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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... ADC/DAC loopback Powerdown Control / Status Register (26h) This read/write register is used to monitor subsystem readi- ness and program LM4540 powerdown states. The lower half of this register is read only with a 1 indicated the sub- section is ready. Writing to the lower 8 bits will have no effect. ...
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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 LM4540VH NS Package Number VBH48A 2 ...