PCM1704U/2K Equivalent & Substitute Parts

Part Overview

The PCM1704U/2K is a 24-bit audio DAC manufactured by Texas Instruments, designed for high-fidelity audio applications with a 96 kHz sampling rate and dual-channel output. The device operates with dual ±5V supply and is housed in a 20-SOIC package. This part is currently classified as obsolete, making identification of compatible substitute components essential for ongoing system support and new design implementations.

Substiute Parts

PCM1704U/2K

Texas InstrumentsIn Stock: 962PCM1704U/2K Datasheet

Current PartRFQ

PCM1795DBR

Texas InstrumentsIn Stock: 15616PCM1795DBR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PCM1704U/2K requires evaluation based on the following critical parameters:

Functional Compatibility Criteria:

• Number of Channels: 2 channels (maintained)
• Type: DAC, Audio (maintained)
• Mounting Type: Surface Mount (maintained)
• Operating Temperature Range: -25°C ~ 85°C (maintained)
• RoHS Status: ROHS3 Compliant (maintained)

Performance Parameters (Allowable Variations):

• Resolution: 24-bit minimum (upgrades to 32-bit acceptable)
• Sampling Rate: 96 kHz minimum (upgrades to 200 kHz acceptable)
• Data Interface: Serial or equivalent digital audio protocols (DSD, PCM acceptable)
• Voltage Supply: Dual ±5V or equivalent supply architecture (3V ~ 3.6V, 5V acceptable)

The PCM1795DBR qualifies as a substitute based on these criteria, offering enhanced specifications while maintaining core functional compatibility.

Parameter Comparison

Engineering Selection Recommendations

The PCM1795DBR is an active product from Texas Instruments and represents the recommended substitute for the obsolete PCM1704U/2K. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment.

The PCM1795DBR offers enhanced specifications including 32-bit resolution, 200 kHz sampling rate capability, and support for both DSD and PCM data interfaces. The device features improved moisture sensitivity (MSL 1 versus MSL 3), reducing handling and storage constraints. Supply voltage flexibility (3V ~ 3.6V, 5V) accommodates diverse system architectures while maintaining compatibility with the original ±5V requirement.

Package transition from 20-SOIC to 28-SSOP requires PCB layout modification. Both packages maintain 5.30mm width, simplifying mechanical integration considerations.

Frequently Asked Questions (FAQ)

Q: Can the PCM1795DBR directly replace the PCM1704U/2K without circuit modifications?

A: Direct pin-for-pin replacement is not possible due to package differences (20-SOIC versus 28-SSOP). PCB layout redesign is required. However, the functional and electrical parameters are compatible, allowing system-level substitution with appropriate circuit redesign.

Q: What are the key differences in data interface capability?

A: The PCM1704U/2K supports serial data interface only. The PCM1795DBR supports both DSD and PCM protocols, providing expanded format compatibility. Existing serial implementations remain compatible with the substitute.

Q: How do the supply voltage requirements differ?

A: The PCM1704U/2K requires dual ±5V supply. The PCM1795DBR accepts 3V ~ 3.6V or 5V supplies with separate analog and digital supply pins, offering greater flexibility in power distribution design.

Q: What is the impact of the resolution upgrade from 24-bit to 32-bit?

A: The 32-bit resolution of the PCM1795DBR exceeds the original 24-bit specification, providing enhanced dynamic range and signal-to-noise performance. Existing 24-bit audio sources remain fully compatible.

Q: Are there moisture sensitivity implications for long-term storage?

A: The PCM1795DBR features MSL 1 (unlimited moisture sensitivity level) compared to the PCM1704U/2K MSL 3 (168 hours). This improvement reduces bake-out requirements and simplifies inventory management.

Q: Does the sampling rate increase from 96 kHz to 200 kHz affect compatibility?

A: The higher sampling rate capability of the PCM1795DBR is backward compatible with 96 kHz audio sources. No compatibility issues arise from this specification enhancement.