Digchip : Database on electronics components
Electronics components database



Details, datasheet, quote on part number: SAN2202B
 
 
Part numberSAN2202B
CategoryAnalog & Mixed-Signal Processing => Amplifiers
DescriptionSingle Chip Speakerphone With 8 - Ohm LouDSPeaker Amplifier
CompanySouth African Micro-Electronic Systems
DatasheetDownload SAN2202B datasheet
 


 
Specifications, Features, Applications

SINGLE CHIP "SPEAKERPHONE" WITH 8 - OHM LOUDSPEAKER AMPLIFIER

This application note describes a low-cost add-on circuit for driving 8-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 8 - 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

SCOPE.............................................................................................................................................................................................................1 2 KEY FEATURES..............................................................................................................................................................................................1 3 OTHER APPLICABLE DOCUMENTS AND PAPERS......................................................................................................................................3 4 REVISION STATUS.........................................................................................................................................................................................3 5 GENERAL DESCRIPTION...............................................................................................................................................................................3 5.1 AMPLIFIER SUPPLY: COMPARISON OF SAN2202A AND SAN2202B:..............................................................................................................3 6 BLOCK DIAGRAM...........................................................................................................................................................................................4 6.1 HOW TO AVOID HOWLING.............................................................................................................................................................................4 7 CIRCUIT 7.1 8 LOUDSPEAKER AMPLIFIER.......................................................................................................................................................................5 7.2 AMPLIFIER SUPPLY IN SHUNT TRANSISTOR PATH............................................................................................................................................5 7.3 AMPLIFIER SUPPLY BY POWER EXTRACTION CIRCUIT SAN3020......................................................................................................................5 8 MEASUREMENT RESULTS CURVES.........................................................................................................................................................6 8.1 FREQUENCY RESPONSE..............................................................................................................................................................................6 8.2 MAXIMUM SENDING LEVEL............................................................................................................................................................................6 8.3 MAXIMUM OUTPUT POWER...........................................................................................................................................................................6 8.4 ON-RESISTANCE IN PULSE DIALING...............................................................................................................................................................7 9 APPLICATION SCHEMATIC............................................................................................................................................................................8 10 LIABILITY AND COPYRIGHT STATEMENT..................................................................................................................................................9

1. Data Sheet SA2531/2 Single Chip Telephone 2. Application Note SAN3020: Power extraction for external loads

The amplifier is a simple, low cost add-on circuit to the SA253x single chip telephone family. It is supplied by the line current and amplifies the receive signal, taken from either or RO2 (Receive outputs), see Fig.1. Compared to more complex "real" handsfree circuits there is no channel switching or anti-larsen circuit implemented, therefore the receive and transmit gains must be lower to avoid howling. However, at short distances between user and telephone (<2m, which is adequate for normal office work) there is even full duplex "handsfree" operation possible, when the handset is placed next to the telephone with the microphone facing to the user. Due to the excellent sidetone cancellation of the SA253x circuits, howling between handset microphone and loudspeaker will only occur, when both are put very close to each other. In normal operation, no howling will occur, even with maximum loudspeaker volume. Due to the unique structure of the SA253x family's line adaption, adding the amplifier has no influence on the important PTT related parameters, like AC-impedance, DC-mask, etc. (see Pt. 5.1 below).

Note: all subsequent component numbering refers to the schematic, shown in Pt. 9

5.1 Amplifier supply: Comparison of SAN2202a and SAN2202b: The following table describes the difference between the two types of amplifier supply: while the simple SAN2202a supply shows slight influence in maximum sending level and "Make"-resistance in pulse dialing , the SAN2202b (3 extra components) supply has no influence in these parameters and has a more stable maximum output driving capability at high line currents (see & 5).

Parameter AC impedance off -hook DC mask Tx-/Rx-gains "Make"-resistance in pulse dialing max. sending level (soft clip level = 4Vpp) max. 8 output power; THD <2% max. 8 output power; THD <3% number of extra components

SAN2202a (Shunt path supply) no influence no influence no influence 20mA no influence for ILine <40mA <4Vpp for ILine 26mW 32mW none

SAN2202b (Power extraction) no influence no influence no influence @20mA no influence ; soft clip level 1 transistor,1diode,1resistor




Related products with the same datasheet
SAN2202A  


Some Part number from the same manufacture South African Micro-Electronic Systems
SAN3010 Single Chip Telephone Interface For Keyboard Entry Via uc
SAN3020 Single Chip Telephone Power Extraction For External Loads
SAN3021 Single Chip Telephone: Using Dynamic Microphone as Tone Ringer
SAN3022
LD29300D2M90R 3A, Very low drop Voltage Regulators
SA9604 Three Phase Bidirectional Power/energy Metering IC WITH Serial SPI Interface
SA9903 Single Phase Power / Energy IC with SPI Interface
SA9602 Single Phase Bidirectional Power/energy Metering IC WITH Instantaneous Pulse Output
SA2005 Programmable Three Phase Power / Energy Metering IC for Stepper Motor / Impulse Counter Applications
SA9642E Single Phase Unidirectional Power/energy Metering AND Earth Leakage Protection IC
D2022UK GOLD Metallised Multi-purpose Silicon DMOS RF FET 45W - 28V - 500mhz Push-pull
SA9605 Three Phase Power/energy Metering IC WITH Instantaneous Pulse Output
SA2002 Single Phase Bi-directional Power / Energy Metering IC with Instantaneous Pulse Output