7. FUNCTIONAL DESCRIPTION
7.1. DETAILED DESCRIPTION
The Winbond’s ISD2500 series includes devices offered at 4.0, 5.3, 6.4, and 8.0 kHz sampling
frequencies, allowing the user a choice of speech quality options. Increasing the duration within a
product series decreases the sampling frequency and bandwidth, which affects the sound quality.
Please refer to the ISD2532/40/48/64 Product Summary table below to compare the duration,
sampling frequency and filter pass band.
The speech samples are stored directly into the on-chip nonvolatile memory without any digitization
and compression associated like other solutions. Direct analog storage provides a very true, natural
sounding reproduction of voice, music, tones, and sound effects not available with most solid state
To meet various system requirements, the ISD2532/40/48/64 products offer single-chip solutions at
32, 40, 48, and 64 seconds. Parts may also be cascaded together for longer durations.
TABLE 1: ISD2532/40/48/64 PRODUCT SUMMARY
Typical Filter Pass
Band * (kHz)
* 3dB roll off point. This parameter is not checked during production testing and may vary due
to process variations and other factors. Therefore, customer should not rely on this value for
One of the benefits of Winbond’s ChipCorder® technology is the use of on-chip nonvolatile memory,
providing zero-power message storage. The message is retained for up to 100 years typically without
power. In addition, the device can be re-recorded typically over 100,000 times.
In addition to its simplicity and ease of use, the ISD2500 series includes all the interfaces necessary
for microcontroller-driven applications. The address and control lines can be interfaced to a
microcontroller and manipulated to perform a variety of tasks, including message assembly, message
concatenation, predefined fixed message segmentation, and message management.
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