ANALOG DEVICES Engineer To Engineer Note EE-59 Codec Soundbytes Manual

This engineer’s note covers crystal requirements for clocking Analog Devices’ AC97 codecs.

Brand: Analog Devices
Category: Other Electronics
Document type: Application Note
Language: English
Pages: 4
File format: PDF
File size: 30 KB
Published: 02 August, 2012
Updated: 30 September, 2023
Models: AD1819B, AD1819, AD1819A, AD1881
MD5 checksum: 154137A5A4E6464739CA0BBA1EB7659A
PDF: ANALOG DEVICES Engineer To Engineer Note EE-59 Codec Soundbytes Manual PDF

About this manual

This Engineer's Note covers the crystal requirements for clocking Analog Devices AC97 codecs, including the AD1819 and AD1881 models. It specifies that a 24.576MHz quartz crystal is required for AC97 1.03 compliance, with a frequency tolerance of less than +100 PPM. The document advises against using ceramic crystals or LC resonators due to their higher frequency tolerances, which can degrade audio performance.

What's inside

Frequency Range
Frequency Tolerance and Stability
Operating temperature
Series vs. Parallel Crystals
Load Capacitance
Equivalent Series Resistance
Drive Level
Aging
Spurious Modes

Specifications

Required Crystal Frequency	24.576MHz
Frequency Tolerance	less +100 PPM
Operating Temperature Range	0°C to 70°C
Recommended Load Capacitance	18pF
Maximum Drive Level	1 mw

Frequently asked questions

What type of crystal is recommended for AC97 codecs?

ADI recommends QUARTZ crystals only because they meet the required frequency tolerance and stability.

Can ceramic crystals be used for AC97 codecs?

Ceramic crystals are not recommended as they have frequency tolerances greater than +5000 PPM, which may result in audio performance less than AC97.

What is the formula for calculating the sample rate?

The sample rate is calculated as: SAMPLE RATE = (SRG SETTING)*(XTAL RATE).

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