ISD4004-08MEY

Overview

The ISD4004-08MEY is a single-chip voice record/playback device from the ISD4004 series, designed for 8-minute messaging applications. It operates on a single 3V supply and utilizes Nuvoton’s patented multilevel Flash memory to store analog audio signals directly without digitization or compression. The device features an on-chip oscillator, anti-aliasing filter, smoothing filter, AutoMute feature, and audio amplifier. Control and addressing are managed via a Serial Peripheral Interface (SPI) or Microwire interface. Key electrical parameters include a typical operating current of 15 mA during playback and 25 mA during recording, with a standby current of 1 µA. The sampling rate is 8.0 kHz, providing a typical filter passband of 3.4 kHz.

Feature Summary

• Direct analog storage technology preserves natural voice quality by avoiding AD/DA compression artifacts.
• Integrated SPI or Microwire serial interface allows for simple microcontroller control with minimal pin count.
• AutoMute feature attenuates background noise during silence periods to improve audio clarity.
• Non-volatile Flash memory ensures message retention without power consumption.

Applications

• Cellular phones and portable communication devices
• Low-cost local voice broadcast units in smart home systems
• Educational aids and interactive learning materials
• Industrial automation status indicators

Procurement Notes

Verify the specific suffix 'EY' against the manufacturer's official ordering information to confirm package type and temperature grade. Ensure the design supports the required 3V supply voltage and SPI timing constraints. Confirm that the 8-minute duration aligns with system requirements, as other variants offer different lengths. Check for lead-free packaging compliance if required by regional regulations.

Selection Notes

Select this component when high-fidelity analog voice reproduction is prioritized over digital compression formats like MP3. It is suitable for applications requiring low power consumption and long battery life due to its ultra-low standby current. Consider the 8-minute maximum duration constraint; longer messages require external memory solutions or different chip variants. Verify compatibility with the host microcontroller's SPI interface speed and voltage levels.

Part Context

The ISD4004 series represents Nuvoton's evolution of ChipCorder technology, offering a complete solution for voice messaging without external components. Unlike PWM-based alternatives, it stores raw analog samples, ensuring superior audio quality. The series includes variants with 8, 10, 12, and 16-minute durations, catering to diverse application needs while maintaining a consistent interface and architecture.

Replacement Considerations

Public confirmed substitute part numbers: ISD4004-10M, ISD4004-12M, ISD4004-16M. These variants share the same interface and functionality but differ in recording duration and sampling rate. Direct replacement requires verifying that the increased or decreased duration meets the system's memory and timing requirements.

FAQ

How does the ISD4004 handle background noise during playback?

The device includes an AutoMute feature that detects silence and applies 6 dB of attenuation to minimize background noise. This can be disabled by connecting the AM CAP pin directly to VCCA.

What is the recommended input signal level for optimal recording quality?

For single-ended input mode, a maximum of 32 mVp-p should be capacitively coupled to ANA IN+. In differential mode, the maximum input signal should be 16 mVp-p.

Can the internal clock frequency be adjusted for better precision?

Yes, the XCLK pin allows for an external clock input. For the ISD4004-08M, a 1024 kHz clock is recommended to maintain precise sampling rates and avoid aliasing issues caused by filter variations.