AS2521 Austria Mikro Systeme International AG, AS2521 Datasheet
AS2521
Related parts for AS2521
AS2521 Summary of contents
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... The AS2520 series incorporate volume control for the earpiece and the loudspeaker (AS2520 digital with +/- keys and AS2521 analogue with potentiometer). The volume control circuit automatically compensates the loop gain to ensure acoustic stability. Package Available in 28 pin SOP and DIP ...
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Preliminary Pin Description Pin # Name Type Supply Supply GND 6 STB AI 7 LLC DI 8 LSI RTH AI ...
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... These are the input pins for the handsfree microphone (electret). Volume Control Input Volume control for the receive signal. AS2520: Digital control with +/– keys or from µC; AS2521: Analogue dc control with potentiometer. Supply Source Control Output This N-channel open drain output controls the external high power source transistor for supplying (V loudhearing/handsfree mode ...
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Preliminary Functional Description The AS252x contains all the voice circuits needed in a high feature telephone instrument, i .e.: line adaptation (ac impedance, dc characteristics, 2/4-wire conversion, power extraction) handset speech circuit loudhearing with enhanced anti-Larsen handsfree with dynamic loop ...
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... The gain is reset by next off-hook. The volume can also be controlled via a microcontroller. The AS2521 uses a potentiometer to control the receive gain. The volume is an indirect dc control to avoid that noise is introduced from the potentiometer. The volume control is common for both the earpiece ...
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Preliminary The acoustic stability is provided as follows: When the volume is increased, e. dB, the receive gain maintains the same as long as no receive signal is applied. Applying a receive signal will cause ...
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Preliminary This approach has some disadvantages. It requires a high degree of discipline, since the three state channel control gives a very distinct half duplex with a relative high switching time constant to avoid chopper effects. Furthermore, the system is ...
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Preliminary The speech compression allows a higher gain in the transmit channel, i.e. the microphone gets more sensitive at low sound pressure levels on the microphone, which enables the user to move further away from the telephone. This means that ...
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Preliminary Electrical Characteristics Absolute Maximum Ratings* Supply Voltage............................................................................................................................... -0.3 Input Current..........................................................................................................................................+/- 25 mA Input Voltage (LS) ....................................................................................................................... -0.3V Input Voltage (LI, CS, SS).............................................................................................................-0.3V Input Voltage (STB, RI).........................................................................................................-2V Digital Input Voltage .......................................................................................................... -0.3V Electrostatic Discharge ..........................................................................................................................+/- 1000V Storage Temperature Range........................................................................................................... -65 ...
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Preliminary AC Electrical Characteristics mA 800 Hz; recommended operating conditions unless otherwise specified. LINE Transmit Symbol Parameter A Gain (M1/M2 to LS) TX Gain (M3/M4 to LS) A Gain ( Variation ...
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Preliminary Receive Symbol Parameter A Gain (LS to RO), Default RX LSP Gain (LSI to LO) A Variation with Frequency TX/F A Gain Range, LLC LLC A Volume Range RX THD Distortion V Soft Clip Level (RO) SC Soft Clip ...
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Preliminary Test Circuit Rev. 5.1 AS252x Figure 8: Test Circuit Page 12 AS2520/21/20B/21B May 1999 ...
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... Side tone balance network 7k5 µ 100 n 100 n 8 LSI 10 RTH 21 100 n M3 100 100 µ High A GND 7 Low LLC Off 100 k 23 AS2521 VOL AS2520 of AS252x. The digital inputs (HS, LE, PD, and 1k2 1k2 1k8 1k8 VOL+ VOL- May 1999 ...
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... AS2520 T 28 pin SOP AS2520 P 28 pin DIP AS2520B T 28 pin SOP AS2520B 28 pin DIP P AS2521 T 28 pin SOP AS2521 P 28 pin DIP AS2521B T 28 pin SOP AS2521B 28 pin DIP P Page 14 AS2520/21/20B/21B Volume Soft Clip Control Loudspk. Digital Yes Digital Yes ...