PCM1704U/2K

ADCs/DACs - Special Purpose Overview

The PCM1704U/2K is a precision, 24-bit digital-to-analog converter utilizing BiCMOS sign-magnitude architecture. It supports sampling frequencies from 16kHz to 96kHz with 8x oversampling capability at the maximum rate. The device accepts 20-bit or 24-bit audio data via a serial interface and features glitch-free current outputs of ±1.2mA with a settling time of 200ns. Key performance metrics include a typical dynamic range of 112dB (K grade), signal-to-noise ratio of 120dB, and total harmonic distortion plus noise as low as 0.0008%. It operates on dual ±5V supplies within a 20-lead SOIC package.

ADCs/DACs - Special Purpose Feature Summary

• BiCMOS sign-magnitude architecture eliminates glitches around bipolar zero for high linearity.
• Supports 20-bit and 24-bit input data formats with pin-programmable selection.
• High-performance audio specifications including 120dB SNR and 0.0008% THD+N (K grade).
• Fast current output stage providing ±1.2mA with 200ns settling time.

ADCs/DACs - Special Purpose Applications

• High-end consumer audio systems requiring ultra-low distortion.
• Professional audio equipment demanding high dynamic range.
• Waveform synthesis applications requiring precise low-level signal reproduction.

ADCs/DACs - Special Purpose Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm the specific grade suffix (e.g., U, J, K) matches design requirements, as performance parameters vary by grade. Ensure the /2K suffix corresponds to the required tape and reel packaging quantity of 2000 units. Check for RoHS compliance status if environmental regulations apply to the final assembly.

ADCs/DACs - Special Purpose Selection Notes

Select the appropriate grade suffix based on required dynamic range and distortion levels; the K grade offers the highest performance. Ensure the system provides dual ±5V power supplies, as the device does not support single-supply operation. Verify that the host processor can generate the necessary serial clock rates up to 25MHz for 8x oversampling at 96kHz. Consider external I/V conversion and filtering components to fully realize the specified analog performance.

ADCs/DACs - Special Purpose Part Context

The PCM1704 was originally developed by Burr-Brown Corporation before its acquisition by Texas Instruments. It represents a high-performance segment of the PCM170 series, distinguished by its sign-magnitude architecture which differs from delta-sigma converters. The /2K designation indicates a specific packaging configuration optimized for automated surface-mount assembly lines.

ADCs/DACs - Special Purpose Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should consult Texas Instruments for current alternatives compatible with 24-bit audio DAC requirements and similar pin configurations.

ADCs/DACs - Special Purpose FAQ

What is the maximum supported bit clock frequency?

The maximum bit clock (BCLK) rate is 25MHz, derived from the 8x oversampling requirement at a 96kHz sampling frequency.

How is the input data word length selected?

The 20BIT pin (Pin 9) selects the input word length. Connecting it to DGND selects 24-bit data, while connecting it to –VDD selects 20-bit data.

Does the PCM1704 require separate analog and digital power supplies?

No, both positive supplies (+VDD and +VCC) should be tied together to a single +5V source, and both negative supplies (–VDD and –VCC) to a single –5V source.