Cirrus Logic AN260 - Manual

1
Copyright © Cirrus Logic, Inc. 2009
(All Rights Reserved)
http://www.cirrus.com
AN260
Transitioning from the CS4362 to the CS4362A or CS4365
1. Introduction
This application note describes how to transition easily to the CS4365 or CS4362A from an existing
design that uses the CS4362. The CS4362A was designed to give a simple upgrade path from the
CS4362, whereas the CS4365 adds some additional features. Please refer to the CS4362A and CS4365
data sheets for supplemental information and specifications concerning operation of the device. A brief
comparison between the product families is shown in Table 1.
1.1 What the CS4362A offers over the CS4362:
• Sixth order multi-bit delta-sigma modulator for lower out of band noise
• Increased full-scale output level for ease of board level noise management
• Improved lower latency PCM digital filter
• Non-decimating DSD processor with on chip 50 kHz filtering
• Uses identical register mapping
1.2 Changes from the CS4362 that the CS4362A requires:
• The VD supply must be changed to 2.5 V from either the 3.3 V or 5 V of the CS4362.
• Depending on the desired output voltage requirements, attenuation may need to be added to the off-chip filter.
• Loss of simultaneous support for two synchronous sample rates mode which was available in the CS4362.
This mode provided for dual sample rates such as 192 kHz front channels with 96 kHz surrounds for DVD
audio and required the use of LRCK2 and SCLK2. This mode is not offered in the CS4362A or CS4365.
• Additional resistors on MUTEC pins.
1.3 What the CS4365 offers over the CS4362A:
• Additional DSD functions of Volume control, Mute pattern detect, support for phase modulation mode, and
offers a direct to switched capacitor path
• 1/2 dB volume control steps (vs. 1 dB in CS4362/62A)
• One-Line and TDM modes
• Auto-mute polarity detection
• Auto-speed mode detection
1.4 Changes from the CS4362 that the CS4365 requires:
• The VD supply must be changed to 2.5 V from the either 3.3 V or 5 V of the CS4362.
• Depending on the desired output voltage requirements, attenuation may need to be added to the off-chip filter.
• Simultaneous support for two synchronous sample rates is no longer available.
• Additional resistors on MUTEC pins.
• Four pins change location or function for hardware mode. The changes aren't necessary for software mode.
• Requires different register mapping from the CS4362.
JAN ‘09
AN260REV2