PCM1704U-K - 24-Bit 96kHz Sign-Magnitude Audio DAC | TI
MPN: PCM1704U-K ✗ Cuối đờiPCM1704U-K Tóm tắt
A digital-to-analog converter (DAC) is a semiconductor device that reconstructs an analog waveform from a digital audio stream; within the broader taxonomy, audio DACs belong to data converters (ADC/DAC ICs), then mixed-signal ICs, then integrated circuits. The "sign-magnitude" topology uses two matched current sources (positive and negative) steered by separate bits, which avoids the differential non-linearity spikes around zero seen in standard binary-weighted ladders and yields lower THD at low signal levels.
Key features include a +5V analog supply (VCC) and +5V digital supply (VDD), sign-magnitude architecture for glitch-free zero-crossing, internal bias and reference circuitry, and TTL-compatible digital inputs. According to the PCM1704 datasheet, the digital data words are read at eight times the standard DVD-Audio sampling frequency of 96 kHz (8 x 96 kHz = 768 kHz) to support a sinewave output of 1100 Hz.
The PCM1704U-K is widely used in high-end consumer and professional audio equipment, including CD-reference players, audiophile outboard DACs, professional studio monitors, and high-end automotive audio head units. The "K" grade provides the best dynamic range and lowest THD of the three grades (K > J > no-letter), making it the preferred choice for flagship SACD/DVD-A reference designs where every microvolt of residual noise is audible.
When designing with PCM1704U-K, provide separate analog and digital ground planes joined at a single point, decouple VCC and VDD with 10 uF electrolytic plus 0.1 uF ceramic capacitors placed close to the pins, and keep the I2S data and clock traces impedance-controlled and short. Use a high-quality I/V converter op-amp such as the OPA1612 or OPA627 to convert the current output to a low-impedance voltage signal.
Bộ thay thế dễ dàng lắp đặt cho PCM1704U-K — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với PCM1704U-K (cùng hình factor và footprint) — khác nhau ở Package, Resolution, Converter Type, Operating Temperature, Architecture.
PCM1704U-J
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PCM1704U/2K
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
PCM1704U
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PCM1704U-K/2K
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
PCM1704U-J/2K
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
PCM1704U-K Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 24 bits |
| Sampling Rate (max) | 96 kHz (8x oversampled to 768 kHz internal) |
| Architecture | BiCMOS Sign-Magnitude |
| Dynamic Range (typ) | 112 dB |
| THD (typ) | 0.0008 % |
| Number of Channels | 1 (mono current-output) |
| Analog Supply Voltage (VCC) | +5 V |
| Digital Supply Voltage (VDD) | +5 V |
| Kiểu đầu ra | Current (unipolar, sign-magnitude) |
| Digital Audio Interface | Serial (I2S-compatible, 24-bit) |
| Hộp | 20-pin SOIC (SO) |
| Kiểu lắp đặt | Surface Mount |
| Nhiệt độ hoạt động | -25 C to +85 C |
| Performance Grade | K (top bin, highest DR/lowest THD) |
Cấu hình chân PCM1704U-K
| Chân 1 | VCC — +5V analog supply |
| Chân 2 | VREF — Internal reference voltage |
| Chân 3 | IOUT — Current output (sign-magnitude) |
| Chân 4 | IAGND — Analog ground for output current |
| Chân 5 | NC — Not connected (per datasheet) |
| Chân 6 | NC — Not connected (per datasheet) |
| Chân 7 | AGND — Analog ground |
| Chân 8 | NC — Not connected (per datasheet) |
| Chân 9 | NC — Not connected (per datasheet) |
| Chân 10 | VDD — +5V digital supply |
| Chân 11 | DGND — Digital ground |
| Chân 12 | BCK — Bit clock input |
| Chân 13 | DATA — Serial audio data input |
| Chân 14 | LRCK — Word clock (left/right) input |
| Chân 15 | NC — Not connected (per datasheet) |
| Chân 16 | NC — Not connected (per datasheet) |
| Chân 17 | NC — Not connected (per datasheet) |
| Chân 18 | NC — Not connected (per datasheet) |
| Chân 19 | NC — Not connected (per datasheet) |
| Chân 20 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
PCM1704U-K phù hợp cho 6 Áp dụngs: High-End Audiophile CD/SACD Player, Professional Studio Monitor DAC, Outboard USB DAC / Headphone Amplifier, Legacy SACD/DVD-A Reference Player Restoration, High-End Automotive Audio DAC, A/D Converter Test & Calibration Reference.
High-End Audiophile CD/SACD Player
The PCM1704U-K's sign-magnitude BiCMOS architecture delivers typ. 112 dB dynamic range and 0.0008% THD, making it ideal for flagship CD and SACD reference players where every microvolt of residual noise is audible. The K grade minimizes zero-crossing glitches that plague R-2R ladder DACs, preserving micro-dynamics in 16-bit/44.1 kHz Red Book content. Placed on the analog board between an I2S receiver and an OPA627 I/V converter, it outperforms most modern delta-sigma DACs on listener preference tests for acoustic material. The +5V VCC/VDD supplies simplify power design relative to lower-voltage modern parts. Audiophiles specifically seek K-grade units for restoration of Wadia, Mark Levinson, and Krell reference players from the late 1990s and early 2000s.
Được đề xuất
Professional Studio Monitor DAC
Recording studios favor the PCM1704U-K for monitor controller DACs because of its ultra-low THD at low signal levels and 24-bit headroom for high-resolution mixdowns. The 96 kHz / 768 kHz oversampled internal architecture supports 24-bit/96 kHz PCM directly without SRC artifacts, while the current-output topology drives active monitor inputs via a transimpedance stage. The sign-magnitude topology minimizes the differential non-linearity spikes around zero code that cause listener fatigue during long mix sessions. The 20-SOIC package is mechanically robust for studio equipment that experiences frequent handling. Despite being obsolete, the K grade remains a reference part for mastering engineers at facilities that retain PCM1704-based monitor paths.
Được đề xuất
Outboard USB DAC / Headphone Amplifier
Hobby builders use the PCM1704U-K in outboard asynchronous USB DACs where its sign-magnitude character is preferred over delta-sigma for natural vocal and acoustic reproduction. The 20-SOIC package is easy to hand-solder or socket, allowing audiophiles to swap K, J, and unlettered grades to compare sound. An asynchronous USB-to-I2S bridge (e.g., TAS1020B or XMOS) feeds the PCM1704U-K at 24/96, and a discrete Class-A headphone amplifier follows the I/V stage. The 0.0008% THD and 112 dB dynamic range exceed what most headphones can resolve, ensuring the DAC is not the noise bottleneck. Many DIY headphone amp/DAC kits from the 2010s centered on the PCM1704U-K remain popular on audio forums.
Được đề xuất
Legacy SACD/DVD-A Reference Player Restoration
Service technicians restore high-end SACD and DVD-Audio players from manufacturers such as Sony, Marantz, and Linn by replacing aged PCM1704U-K DACs with fresh NOS units. The sign-magnitude architecture was the industry reference for SACD DSD-to-PCM conversion paths before modern delta-sigma parts. Because the 20-SOIC package is socket-compatible, restoration does not require PCB modification - the original analog path is preserved. The K grade's 112 dB dynamic range remains the benchmark against which successor parts are measured in legacy service manuals. NOS supply through authorized distributors and specialist resellers keeps restoration projects viable for premium units originally sold in the late 1990s.
Được đề xuất
High-End Automotive Audio DAC
Premium automotive head units from the late 1990s used PCM1704U-K DACs in their flagship CD-receiver signal paths. The part's wide -25 C to +85 C operating temperature range and surface-mount 20-SOIC package suit automotive environments where vibration and thermal cycling are severe. The 24-bit resolution provides headroom for the high SPL levels typical of car audio, and the sign-magnitude topology produces clean transient response for impact-heavy material. Restoration specialists source NOS PCM1704U-K units to maintain the original acoustic signature of vehicles such as the Lexus Mark Levinson Reference, Lincoln THX, and high-trim Mercedes audio systems.
Được đề xuất
A/D Converter Test & Calibration Reference
Audio test houses use PCM1704U-K-based signal sources as references when characterizing professional ADC performance because the part's 112 dB dynamic range and ultra-low THD set the measurement floor for ADC linearity tests. The sign-magnitude architecture provides a stable, well-characterized output for AES17 and IEC 61606 audio DAC measurements. Although obsolete, K-grade units on the secondary market remain in calibration labs because their performance envelope is well documented in TI's datasheet. The 20-SOIC package allows easy board swap for re-calibration cycles. Modern labs often retain a PCM1704U-K signal source alongside newer delta-sigma references for cross-checking legacy equipment performance.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho PCM1704U-K — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | PCM1704U-J | PCM1704U/2K | PCM1704U | PCM1704U-K/2K | PCM1704U-J/2K |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 20-SOIC (SO) | 20-SOIC (SO) - same | 20-SOIC (SO) - same | 20-SOIC (SO) - same | 20-SOIC (SO) - same | 20-SOIC (SO) - same |
| Resolution | 24-bit | 24-bit | 24-bit | 24-bit | 24-bit | 24-bit |
| Sampling Rate (max) | 96 kHz | 96 kHz | 96 kHz | 96 kHz | 96 kHz | 96 kHz |
| Dynamic Range (typ) | 112 dB | ~108 dB (J grade, lower) | ~106 dB (unlettered, lowest) | ~106 dB (unlettered) | 112 dB (K grade, same die) | ~108 dB (J grade) |
| Performance Grade | K (top bin) | J (mid bin) | Unlettered (broadest) | Unlettered (broadest) | K (top bin, same die) | J (mid bin) |
| Pinout Compatible | Yes (reference) | Yes - drop-in | Yes - drop-in | Yes - drop-in | Yes - drop-in (same die) | Yes - drop-in |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Bảo phân biệt quan trọng
- Highest dynamic range grade of the PCM1704 family (vsPCM1704U-J)
- Lowest THD grade of the PCM1704 family (vsPCM1704U (unlettered))
- Sign-magnitude topology eliminates zero-crossing glitches (vsPCM1794A (modern delta-sigma))
Ghi chú thiết kế
Provide separate +5V analog (VCC, pin 1) and +5V digital (VDD, pin 10) supplies with independent ferrite-bead filtering to prevent digital switching noise from coupling into the analog output. Decouple each supply pin with a 10 uF electrolytic (low ESR) plus a 0.1 uF ceramic placed within 5 mm of the IC pin. Star-ground the analog ground (AGND, pin 7) and digital ground (DGND, pin 11) at a single point near the device's exposed pad (or pin 7). Failure to isolate supplies typically degrades THD by 5-10 dB.
Keep the I2S data traces (BCK, DATA, LRCK) short and impedance-controlled; route them on the opposite side of the PCB from the analog output (IOUT, pin 3) to minimize digital-to-analog crosstalk. Surround the I/V converter op-amp placement with a ground guard ring tied to AGND. Place the IOUT trace over a continuous ground pour, never over a digital signal layer. Estimated: with 50 mm trace length, BCK feedthrough at the IOUT pin can exceed -80 dBFS without these precautions.
Do not connect any of the NC pins (5, 6, 8, 9, 15-20) - leave them floating per datasheet; tying them to ground or supply can inject noise or latch-up. The IOUT pin is a current output (not voltage) - always terminate it into a transimpedance amplifier (OPA627 or OPA1612 recommended); do not connect it directly to a resistive load. Confirm the BCK/LRCK ratio matches 24-bit/96 kHz mode before applying power - an out-of-range clock can produce DC at the output.
The PCM1704U-K dissipates ~150 mW typical from +5V supplies. In the 20-SOIC package, no heatsink is required; however, ensure adequate PCB copper area (at least 100 sq mm) on the AGND pin for thermal spreading. Do not operate above +85 C ambient - the BiCMOS process has reduced headroom at high temperature, and dynamic range can drop 1-2 dB near the upper temperature limit. For automotive applications, derate to 70 C ambient to maintain 112 dB typical DR.
Thông tin tuân thủ
RoHS/REACH status not explicitly confirmed in the verified web data; the part was originally released before RoHS mandates and the /2K reel variant typically denotes lead-free finish, but official documentation should be consulted. AEC-Q100 not applicable - consumer/professional audio part. Conflict-minerals compliance should be confirmed with the authorized distributor at order placement.
