ISD4004-10MSIR

Interface - Voice Record and Playback applications involve the conversion of analog audio signals into digital format for storage and retrieval. The ISD4004-10MSIR is a complete, integrated voice recording and playback system on a single chip. This device has been designed to allow communications systems, such as voicemail and conference telephones, to record and playback up to 10-seconds of digitally encoded voice at a high fidelity of 8-kHz sample rate.

The ISD4004-10MSIR integrates all of the functions necessary for record and playback applications, reducing the external components count and complexity of design. It is equipped with a microphone input and speaker output, analog-to-digital conversion, NON-VOLATILE memory, audio processing and power supply voltage regulation. It requires external power supplies and a printed circuit board with appropriate surface mount components.

Although optimized for communication systems, these ICs can also be utilized for a variety of other applications, such as toys and classroom audio recording. In all applications, the user is able to store, retrieve, and play back voice in an efficient, cost-effective manner. The ISD4004-10MSIR supports up to 10 seconds of recording in the internal memory with 512Kbits of RAM. When reading or writing to the memory, the device supports both a serial and parallel data bus interface.

The ISD4004-10MSIR has a built in microphone pre-amplifier and Analog-to-Digital Converter (ADC) to convert the audio signal into a digital 8 kHz 16-bit/sample word format. Additionally, the device contains a Digital Signal Processor (DSP) that supports digital filters and other audio processing functions. As samples are written to the NON-VOLATILE memory, a security bit can be written to prevent unauthorized tampering.

When it comes time to playback the audio, the device uses the built-in Digital-to-Analog Converter (DAC) to convert the digital samples back into an analog signal path for audio output. Additionally, the ISD4004-10MSIR provides the ability to mix the recording stored in memory with external audio signal inputs. These external signal inputs can be used to provide a wide variety of sound effects such as music, sound effects, or special messages.

For secure applications, the ISD4004-10MSIR supports password protected memory as well as external flash memory. The external flash memory can be used to store additional recordings or specialized messages. With the built-in speaker driver, the device is capable of driving large 8ohm loads, removing the need for an external amplifier.

The ISD4004-10MSIR is an ideal solution for applications requiring high quality, low cost, and low power voice recording and playback. By integrating all of the functions necessary into a single chip, it allows engineers to reduce the number of components, simplify the design process, and reduce design time and manufacturing costs.