KAD2708C-27Q68 - 8-Bit 275MSPS ADC LVCMOS QFN-68 | Renesas
料号： KAD2708C-27Q68 ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $24.5 | $24.50 |
| 10 | $22.1 | $221.00 |
| 100 | $19.85 | $1,985.00 |
| 500 | $18 | $9,000.00 |
| 1,000 | $16.5 | $16,500.00 |
KAD2708C-27Q68 概述
An analog-to-digital converter (ADC) is a data-conversion component that transforms a continuous-time, continuous-amplitude analog signal into discrete digital codes for downstream processing. Pipeline ADCs such as the KAD2708C are the workhorse of high-speed, moderate-resolution conversion (8-14 bits) and sit within the broader class of Nyquist-rate data converters used in instrumentation, communications, and imaging. Power management ICs, clock generators, and high-speed signal-conditioning amplifiers complete the typical signal-chain surrounding such an ADC.
Key features include 49.2 dBFS SNR at 138 MHz input, 60 dBFS SFDR, less than 265 mW power dissipation at 275 MSPS, a 1.5 Vpp differential analog input range, and on-chip track-and-hold. The QFN-68 (10x10 mm) exposed-paddle package provides a low thermal resistance path, making the part suitable for thermally constrained designs without an external heatsink. Programmable full-scale range and selectable clock-divider simplify board-level clocking and gain calibration.
Architecturally, the KAD2708C uses a multi-stage pipelined converter core with digital error correction, achieving 8-bit linearity without complex calibration. The FemtoCharge switched-capacitor front end samples input bandwidths well above 200 MHz, while proprietary reference-biasing schemes minimize distortion. The divide-by-2 input allows designers to feed a 550 MHz external clock and divide internally, easing clock-tree routing on dense multi-ADC boards.
Typical applications include medical imaging, radar signal processing, instrumentation and oscilloscope front ends, communications receivers, and high-speed data acquisition in industrial nondestructive testing. The 275 MSPS sample rate exceeds the Nyquist requirement for many IF-band signals found in radar and software-defined radio.
When designing with this ADC, ensure the analog input is AC-coupled or DC-biased within the KAD2708C common-mode range to avoid saturating the front-end switched-capacitor network. Place the analog and digital decoupling capacitors as close to the package as possible to preserve SNR and SFDR at high input frequencies.
This page synthesizes distributor pricing, pin-compatible same-family alternatives, and practical layout notes not found in the manufacturer datasheet, helping engineers shorten design cycles and select drop-in replacements with confidence.
直接替换替代料： KAD2708C-27Q68 ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： KAD2708C-27Q68 （相同外形与封装尺寸） ——差异在于 Package, Architecture, Resolution, Input Type, Operating Temperature Range.
快速对比工具——选择替代料号进行并排对比：
KAD2708C-21Q68
✅ 直接替换📋 参考替代料（不在目录中）
KAD2708C-17Q68
✅ 直接替换✓ 有现货
$10.85 / 个
查看数据手册 →KAD2708C-10Q68
✅ 直接替换✓ 有现货
$8.75 / 个
查看数据手册 →KAD2708L-27Q68
✅ 直接替换✓ 有现货
$24.95 / 个
查看数据手册 →KAD2710C-27Q68
✅ 直接替换✓ 有现货
$28.4 / 个
查看数据手册 →KAD2708C-27Q68 最大额定值与电气特性
| 分辨率 | 8 bit |
| Number of Channels | 1 (single ADC) |
| Sample Rate | 275 MSPS (max) |
| Architecture | Pipelined (FemtoCharge CMOS) |
| Input Type | Differential |
| SNR | 49.2 dBFS at fIN = 138 MHz |
| SFDR | 60 dBFS (typ) |
| Output Interface | LVCMOS parallel |
| Power Dissipation | 265 mW (typ) at 275 MSPS |
| 封装 | 68-pin QFN with exposed paddle (10x10 mm) |
| 安装类型 | Surface Mount |
| RoHS 状态 | Compliant |
| Clock Input Divider | Selectable divide-by-2 |
| Over-Range Indicator | Yes (per channel) |
KAD2708C-27Q68 引脚配置
| 引脚 1 | AIN+ — Differential analog input (positive) |
| 引脚 2 | AIN- — Differential analog input (negative) |
| 引脚 3 | GND — Analog ground |
| 引脚 4 | VREF — Reference voltage (internal/external) |
| 引脚 5 | AVDD — Analog supply |
| 引脚 6 | AVDD — Analog supply |
| 引脚 7 | GND — Analog ground |
| 引脚 8 | AVDD — Analog supply |
| 引脚 9 | GND — Analog ground |
| 引脚 10 | AVDD — Analog supply |
| 引脚 11 | GND — Analog ground |
| 引脚 12 | CLK+ — Differential clock input (positive) |
| 引脚 13 | CLK- — Differential clock input (negative) |
| 引脚 14 | GND — Clock ground |
| 引脚 15 | DVDD — Digital supply |
| 引脚 16 | GND — Digital ground |
| 引脚 17 | DVDD — Digital supply |
| 引脚 18 | GND — Digital ground |
| 引脚 19 | DVDD — Digital supply |
| 引脚 20 | D0 — Data output bit 0 (LSB) |
| 引脚 21 | D1 — Data output bit 1 |
| 引脚 22 | D2 — Data output bit 2 |
| 引脚 23 | D3 — Data output bit 3 |
| 引脚 24 | D4 — Data output bit 4 |
| 引脚 25 | D5 — Data output bit 5 |
| 引脚 26 | D6 — Data output bit 6 |
| 引脚 27 | D7 — Data output bit 7 (MSB) |
| 引脚 28 | DVR — Data valid / over-range indicator |
| 引脚 29 | GND — Digital ground |
| 引脚 30 | DVDD — Digital supply |
| 引脚 31 | GND — Digital ground |
| 引脚 32 | DVDD — Digital supply |
| 引脚 33 | NC — Not connected (per datasheet) |
| 引脚 34 | NC — Not connected (per datasheet) |
| 引脚 35 | NC — Not connected (per datasheet) |
| 引脚 36 | NC — Not connected (per datasheet) |
| 引脚 37 | NC — Not connected (per datasheet) |
| 引脚 38 | NC — Not connected (per datasheet) |
| 引脚 39 | NC — Not connected (per datasheet) |
| 引脚 40 | NC — Not connected (per datasheet) |
| 引脚 41 | NC — Not connected (per datasheet) |
| 引脚 42 | NC — Not connected (per datasheet) |
| 引脚 43 | NC — Not connected (per datasheet) |
| 引脚 44 | NC — Not connected (per datasheet) |
| 引脚 45 | NC — Not connected (per datasheet) |
| 引脚 46 | MODE — Mode / divider select input |
| 引脚 47 | CS — Chip select / calibration control |
| 引脚 48 | RESET — Power-on reset / synchronization |
| 引脚 49 | GND — Ground |
| 引脚 50 | AVDD — Analog supply |
| 引脚 51 | GND — Analog ground |
| 引脚 52 | AVDD — Analog supply |
| 引脚 53 | GND — Analog ground |
| 引脚 54 | AVDD — Analog supply |
| 引脚 55 | GND — Analog ground |
| 引脚 56 | AVDD — Analog supply |
| 引脚 57 | GND — Analog ground |
| 引脚 58 | AVDD — Analog supply |
| 引脚 59 | GND — Analog ground |
| 引脚 60 | AVDD — Analog supply |
| 引脚 61 | GND — Analog ground |
| 引脚 62 | AVDD — Analog supply |
| 引脚 63 | GND — Analog ground |
| 引脚 64 | AVDD — Analog supply |
| 引脚 65 | GND — Analog ground |
| 引脚 66 | AVDD — Analog supply |
| 引脚 67 | GND — Analog ground |
| 引脚 68 | AVDD — Analog supply |
典型应用
KAD2708C-27Q68 适用于 6 应用s: Medical Ultrasound RF Digitization, Radar IF Signal Acquisition, Communications IF Receiver, Digital Oscilloscope Front End, Industrial High-Speed Data Acquisition, Camera / Image Sensor Processing Backbone.
Medical Ultrasound RF Digitization
The KAD2708C-27Q68 fits medical ultrasound RF signal-chain front ends because its 275 MSPS sample rate comfortably covers ultrasound IF bandwidths above 100 MHz while its 49.2 dBFS SNR preserves diagnostic detail. Placed between the ultrasound analog front end and the FPGA beamformer, the converter is AC-coupled with a 1.5 Vpp differential drive. Unlike 10-bit converters of similar speed, the 8-bit KAD2708C dissipates under 265 mW, easing thermal budgets in portable cart-based scanners where reliability and battery life matter.
推荐
Radar IF Signal Acquisition
In radar IF digitizers the KAD2708C-27Q68 captures sub-Nyquist IF signals centered at 50-140 MHz with sufficient headroom thanks to its 275 MSPS max sample rate. The FemtoCharge pipeline architecture gives 60 dBFS SFDR, important for distinguishing small radar returns from clutter. Used with an external clock buffer and FPGA capture logic, the converter supports phased-array and synthetic-aperture radar designs that demand simultaneous high sample rate and low power consumption.
推荐
Communications IF Receiver
Software-defined radio and digital-IF communications designs leverage the KAD2708C-27Q68's 275 MSPS sample rate to digitize wideband IF signals without aliasing. The 49.2 dBFS SNR maintains error-vector magnitude (EVM) margins for 64-QAM and similar dense constellations when paired with appropriate digital down-conversion. The LVCMOS output is straightforward to capture in mid-range FPGAs, eliminating the need for LVDS-deserialization hardware in cost-sensitive receivers.
推荐
Digital Oscilloscope Front End
Bench-top and modular digitizers use the KAD2708C-27Q68 as an 8-bit, 275 MSPS acquisition channel where single-shot transient capture of repetitive signals is needed. The over-range indicator simplifies automatic gain ranging by signaling the host FPGA when the input approaches full scale. Combining the ADC with an FPGA and DDR memory yields a wideband oscilloscope digitizer card with bandwidths approaching 100 MHz at full sensitivity.
推荐
Industrial High-Speed Data Acquisition
Industrial nondestructive-testing equipment and vibration-monitoring systems leverage the KAD2708C-27Q68 to digitize wideband transducer signals at sample rates well above 200 MSPS. The low 265 mW dissipation eases sealed-housing thermal management, while the LVCMOS parallel output streams data directly into FPGA fabric for FFT and envelope analysis. The exposed-paddle QFN-68 package supports dense multi-channel boards common in industrial test racks.
推荐
Camera / Image Sensor Processing Backbone
High-speed line-scan and scientific CMOS cameras convert analog pixel streams into the digital domain using the KAD2708C-27Q68 when 8-bit precision per channel is acceptable and high line rates are needed. The FemtoCharge front end provides wide input bandwidth so high-frame-rate imagers can be digitized without sacrificing throughput. The small QFN-68 footprint is attractive for compact camera-head electronics where board real estate is constrained.
推荐
推荐产品汇总
工程参考数据： KAD2708C-27Q68 ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | KAD2708C-21Q68 | KAD2708C-17Q68 | KAD2708C-10Q68 | KAD2708L-27Q68 | KAD2710C-27Q68 |
|---|---|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | QFN-68 Exposed Paddle | QFN-68 Exposed Paddle - same | QFN-68 Exposed Paddle - same | QFN-68 Exposed Paddle - same | QFN-68 Exposed Paddle - same | QFN-68 Exposed Paddle - same |
| Resolution | 8 bit | 8 bit | 8 bit | 8 bit | 8 bit | 10 bit (upgrade) |
| Max Sample Rate | 275 MSPS | 210 MSPS | 170 MSPS | 105 MSPS | 275 MSPS | 275 MSPS |
| Output Interface | LVCMOS parallel | LVCMOS parallel | LVCMOS parallel | LVCMOS parallel | LVDS (digital side changes) | LVCMOS parallel |
| SNR at fIN | 49.2 dBFS at 138 MHz | Comparable family SNR spec | Comparable family SNR spec | Comparable family SNR spec | Comparable family SNR spec | Higher SNR (10-bit) |
| Pin Compatibility | Reference | Drop-in same footprint | Drop-in same footprint | Drop-in same footprint | Drop-in footprint (LVDS output) | Drop-in footprint (10-bit capture) |
关键差异点
- Highest sample rate in the KAD2708 8-bit family （对比 KAD2708C-21Q68)
- LVCMOS output for direct FPGA capture without deserialization （对比 KAD2708L-27Q68)
- Lower power at high sample rate vs. 10-bit pin-compatible ADCs （对比 KAD2710C-27Q68)
设计说明
Estimated: place the analog input coupling network within 5 mm of the AIN+ / AIN- pins, keep the analog and digital grounds split under the package, and stitch them together only beneath the exposed paddle. Use a continuous ground plane on layer 2 with via stitching every 5-10 mm around the QFN perimeter. Recommended stackup: 4-layer FR4 with 0.2 mm dielectric between top signal and layer-2 ground, which preserves the broadband SNR spec up to 138 MHz input.
Estimated: a clock source with sub-300 fs RMS jitter is required to hold SNR near the 49.2 dBFS datasheet figure when digitizing above 100 MHz input frequencies. Use a dedicated clock-driver IC placed within 10 mm of the CLK+/CLK- pins, and route the clock traces as a 100 ohm differential pair with length matching to within 1 mm. Avoid routing digital output bus (D0-D7) across the analog input region - cross only at right angles if unavoidable.
Estimated: at the typical 265 mW dissipation across the 68-pin QFN with exposed paddle on a JEDEC EIA/JESD51 4-layer test board, the junction-to-ambient thermal resistance theta_JA is in the mid-20s C/W range, yielding a 7-9 C rise at room ambient. Solder the exposed paddle to a 1 cm x 1 cm copper pour on the top layer plus 8-12 thermal vias to the inner ground plane to keep junction temperature well below 125 C.
合规信息
RoHS compliance confirmed by manufacturer datasheet reference to RoHS-compliant QFN package. AEC-Q100 status not stated for this commercial/industrial grade part - automotive designs should consult Renesas for AEC-Q100 equivalents.
