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SAN3021 APPLICATION NOTE
SA2531/2 Single Chip Telephone: Using dynamic microphone as tone ringer
1 Scope
This Application Note describes how to modify the standard application AN1500A to use a dynamic microphone instead of the standard electret microphone. Additionally, an application is shown, which uses the dynamic microphone as tone ringer.
2 Key Features • Updating existing systems using dynamic handset microphone • No need for a piezo ringer when using the dynamic microphone as tone ringer
Table of Contents
1 2 3 4 5 6 SCOPE................................................................................................................................................................. 1 KEY FEATURES ................................................................................................................................................. 1 OTHER APPLICABLE DOCUMENTS AND PAPERS ........................................................................................ 1 REVISION STATUS............................................................................................................................................. 1 GENERAL DESCRIPTION .................................................................................................................................. 2 HARDWARE CONFIGURATION......................................................................................................................... 2
6.1 USING THE DYNAMIC MICROPHONE AS TONE RINGER (SCHEMATIC :A)................................................................. 2 6.1.1 Ringer part ............................................................................................................................................. 2 6.1.2 Microphone amplifier part ...................................................................................................................... 3 6.2 AMPLIFIER FOR GENERAL PURPOSE APPLICATIONS (SCHEMATIC :B) ................................................................... 3 7 APPLICATION SCHEMATIC:............................................................................................................................. 4 8 LIABILITY AND COPYRIGHT STATEMENT...................................................................................................... 5
3 Other applicable documents and papers
Application Note AN1500A: SA2532K Single Chip Telephone Demo Board
4 Revision status
SAN3021 Application Note (this document) SAN3021 Schematic Rev. 1.1
SAN3021
PDS038-SA2531/2-004
Rev. B
21-03-00
SAN3021
5 General description
Dynamic handset microphones have been widely replaced by electret microphones, mainly because of higher output level, low EMC sensitivity and price issues. Therefore, the standard Single Chip Telephone application, AN1500 is based on using an electret handset microphone. However, there are situations where usage of a dynamic microphone is still desired, e.g. • when updating an existing design , .