RC8650 datasheet(12/48 Pages) ETC

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RC8650 VOICE SYNTHESIZER

RC SYSTEMS

Analog Audio Output

The analog output pins AO0 and AO1 are high impedance (10 kΩ

typical) outputs from the RC8650’s internal D/A converters. When us-

ing these outputs, the addition of an external low-pass ﬁlter is highly

recommended. When laying out the printed circuit board, avoid run-

ning digital lines near the AO lines in order to minimize induced noise

in the audio path. If space permits, run a guard ground next to the

AO traces.

The circuit shown in Figure 1.8 is a low-pass ﬁlter/power ampliﬁer ca-

pable of delivering 1.1 W to an 8

Ω load, when operating from a +5 V

power supply (power output will be less when operating from +3.3 V).

Figure 1.8. 3 kHz Low-Pass Filter/Power Ampliﬁer

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The ampliﬁer’s shutdown pin can be controlled by the TS0 pin to mini-

mize current drain when the RC8650 is inactive.

Digital Audio Output

The digital audio pin DAOUT outputs the RC8650’s audio signal as

a digital audio stream consisting of 8 data bits per sample. The nor-

malized sampling rate for all text to speech modes and the DTMF

generator is 84 kbs (10,500 bytes/sec). The sinusoidal generator, pre-

recorded and real time audio playback mode rates are user program-

mable, so their normalized rates will vary. See the Pin Descriptions and

Audio Control Register command description for further details.

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Figure 1.7. Method of Capturing Status Information for Driving External Circuitry

RC8650 Datasheet(PDF) 12 Page - List of Unclassifed Manufacturers