Key facts
- Brand
- Analog Devices
- Model
- AD1845
- Industry
- Industrial
- Documents
- 3
- Languages
- EN
- Last added
- 2012-08-02
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AN-404 Application Note: Designing a Compatible PCB Socket for AD1845 and CS4231 Codecs
Analog Devices' AD1845 Parallel-Port, 16-Bit, Sound-Port Stereo Codec is pin-for-pin compatible with Crystal Semiconductor's CS4231 Multimedia Audio Codec. However, customers have faced difficulties using them interchangeably due to slightly different external interface requirements and power supply circuitry recommendations. This document addresses these challenges by showing designers how to create a compatible PCB layout or 'socket' for both parts within PC motherboard or plug-in card designs.
The note details specific design considerations including input circuit design, power supply strategies (both recommended and alternative), and layout principles such as component placement and grounding. It also covers cost/performance tradeoffs that allow for a socket requiring no assembly differences between the two codecs.
Analog Devices AD1845 specifications
| Resolution (ADC) | 16 Bits |
|---|---|
| Input Impedance | 10‑17 kΩ |
| Sample Rate Range | 4.0 kHz to 50 kHz |
| Power Supply Range | 4.75 V to 5.25 V |
| Typical Power Supply Current | 130 mA |
| Package Options | 68‑Lead PLCC, 100‑Lead TQFP |
All Analog Devices AD1845 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
How to use the product for one specific task, with worked examples.
Questions answered in these manuals
What are the main differences between the AD1845 and CS4231 codecs?
The main differences involve external interface requirements, specifically crystal oscillator inputs (CS4231 requires two crystals while AD1845 uses one) and differing power supply circuitry recommendations.
From: AN-404 Application Note: Designing a Compatible PCB Socket for AD1845 and CS4231 Codecs
How do the crystal oscillator requirements differ between the two codecs?
The CS4231 requires two crystal inputs (XTAL1 at 24.575 MHz and XTAL2 at 16.9344 MHz), whereas the AD1845 defaults to a single crystal input (24.576 MHz) but can use other frequency sources.
From: AN-404 Application Note: Designing a Compatible PCB Socket for AD1845 and CS4231 Codecs
What is the input impedance of the AD1845?
The AD1845 input impedance is specified as 10 kΩ to 17 kΩ.
Which packages are available for the AD1845?
The device is offered in 68‑lead PLCC and 100‑lead TQFP packages.