SAN2202 Datasheet, PDF (1/9 Pages) Sames – SINGLE CHIP SPEAKERPHONE WITH 8 - OHM LOUDSPEAKER AMPLIFIER

sames
SAN2202
APPLICATION NOTE
SINGLE CHIP “SPEAKERPHONE” WITH
8 - OHM LOUDSPEAKER AMPLIFIER
1 Scope
This application note describes a low-cost add-on circuit for driving an 8Ω-Loudspeaker to get a simple loudhearing
(“Speakerphone”) Telephone.
To possible ways of supplying the amplifier are shown:
SAN2202a:
SAN2202b:
Amplifier supply in shunt transistor path
Amplifier supply by power extraction circuit (SAN3020)
It can be added to any SA253x application without interfering with PTT-relevant parameters, like AC-impedance,
Sidetone cancellation or DC-mask.
2 Key Features
• Low cost additional circuit enables use of loudhearing function
• Full duplex “handsfree” operation via handset microphone and loudspeaker (at distances <2m between
telephone and user)
• Can be added to any SA253x- application
• Enables use of low cost 8Ω - Loudspeaker
• High output power with low distortion
• Entirely powered from the telephone line
• No influence of loudspeaker amplifier in AC-impedance, sidetone cancellation or DC-mask
• Loudspeaker volume adjustable by potentiometer
• Excellent sidetone cancellation of SAS253x circuits enables high loudspeaker volume without howling between
handset microphone and loudspeaker
SAN2202
PDS038-SA2531/2-001 Rev. B 21-03-00