LTC2281CUP - Dual 10-Bit 125Msps 3V ADC | Analog Devices
MPN： LTC2281CUP ✗ 停產LTC2281CUP 概覽
A pipelined ADC is a multi-stage converter architecture where each stage samples and produces a multi-bit residue, with stages cascaded through low-resolution flash sub-ADCs and DACs. Pipelined ADCs are the dominant architecture for sampling rates above ~10 Msps because they achieve a favourable trade-off between conversion speed, resolution, and die area. The LTC2281CUP belongs to the hierarchy: ADC -> data converter -> signal chain IC -> semiconductor, occupying the dual-channel, low-power, high-speed segment.
Key features include 1.2 Vp-p or 2 Vp-p selectable input ranges, an internal 2.5V reference, low power dissipation that scales with sample rate, and a CMOS-compatible parallel digital output bus. The wideband differential front-end accepts single-ended or differential analog inputs and integrates input signal termination. A separate digital output supply (OVDD) allows the outputs to interface directly to 1.8V, 2.5V, or 3.3V logic without level translators.
The LTC2281CUP uses 9-stage pipelined cores per channel with digital error correction, providing spurious-free dynamic range strong enough for cellular base-station IF sampling and radar intermediate-frequency (IF) digitizers. The 125 Msps dual-channel throughput is sufficient for multi-antenna MIMO receivers where baseband I/Q must be captured in parallel. Per-channel power typically sits in the low hundreds of milliwatts, simplifying thermal design in dense multi-channel acquisitions.
Typical applications include medical and industrial imaging digitizers, base-station receiver IF strips, cable-head-end QAM/QPSK demodulators, multi-channel data acquisition front-ends, and software-defined radio (SDR) receiver IF/BB ADC stages. The combination of low power and high SFDR also suits portable instrumentation and spectrum-analyzer digitizer boards.
Designers should provide a low-noise, low-impedance analog input network (typically a differential driver such as the AD8138 or an RF transformer) and route the LVDS/CMOS outputs with controlled-impedance traces to avoid digital-coupling noise into the analog front-end. The exposed pad (UP package thermal pad) must be soldered to a solid ground plane to keep junction temperature within the 0C to +70C commercial range.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替換替代品，適用於 LTC2281CUP — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LTC2281CUP （相同外形與佔位） — 差異在於 Resolution, RoHS Status, Package, SFDR, Number of Channels.
LTC2281IUP
✅ 直接替換📋 參考替代品（不在目錄中）
LTC2285CUP
✅ 直接替換聯絡詢價
查看資料表 →LTC2283CUP
✅ 直接替換聯絡詢價
查看資料表 →LTC2280CUP
✅ 直接替換聯絡詢價
查看資料表 →LTC2286CUP
✅ 直接替換聯絡詢價
查看資料表 →LTC2281CUP 最大額定值與電氣特性
| 解析度 | 10 bits |
| Number of Channels | 2 (dual) |
| 取樣率 | 125 Msps |
| Supply Voltage (Analog) | 3 V (2.85 V to 3.4 V) |
| Output Supply Voltage (OVDD) | 1.8 V to 3.3 V |
| Input Range (Selectable) | 1.2 Vp-p or 2 Vp-p |
| Input Type | Differential / Single-Ended |
| Architecture | Pipelined |
| SNR at Nyquist | 61.6 dB |
| SFDR at Nyquist | 82 dB |
| Data Interface | Parallel CMOS |
| Reference | Internal 2.5 V (external optional) |
| 工作溫度範圍 | 0 C to +70 C (C grade) |
| 封裝 | 64-pin QFN (UP) 9 mm x 9 mm with exposed pad |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant (lead-free variants available) |
| AEC-Q100 | Not qualified |
LTC2281CUP 64-pin qfn (up) 9 mm x 9 mm with exposed pad 腳位配置指南
LTC2281CUP（64-pin qfn (up) 9 mm x 9 mm with exposed pad 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： LTC2281CUP.
請參閱 資料表 以查看完整腳位配置。
典型應用
LTC2281CUP 適用於 6 應用s: Cellular Base-Station IF Receiver, Medical Ultrasound Imaging, Industrial Imaging and Machine Vision, Test and Measurement Instrumentation, Software Defined Radio (SDR) Receivers, Multi-Channel Data Acquisition Boards.
Cellular Base-Station IF Receiver
The LTC2281CUP is well-suited to digitizing the IF stages of cellular base-station receivers, where its 82 dB SFDR at Nyquist preserves modulator linearity across the entire 30 MHz LTE bandwidth. Paired with an AD8138 differential driver, the dual channels sample I/Q at 125 Msps simultaneously, achieving the dynamic range required for 3GPP error-vector-magnitude (EVM) targets under multi-carrier loading. Compared to a 12/14-bit ADC running at 80 Msps, this part delivers the same dual-channel throughput at lower cost, suitable for macro-cell receiver chain. The 61.6 dB SNR satisfies the noise-figure budget for QPSK through 16-QAM modulations.
推薦
Medical Ultrasound Imaging
In medical ultrasound, the LTC2281CUP is used per channel to digitize returning acoustic echoes at baseband to intermediate frequency, where the 125 Msps dual-channel throughput supports 64-element phased-array beam-formers. Its 61.6 dB SNR allows dynamic-range budgets to be met at depths up to 15 cm, while the 82 dB SFDR prevents harmonic artefacts from interfering with adjacent tissue contrast. Compared to discrete 10-bit ADCs, the LTC2281CUP's pipelined structure maintains pipeline latency consistency across channels, ensuring beam-steering mathematics remain phase-coherent. The internal reference and small 64-QFN footprint simplify multi-channel board layout.
推薦
Industrial Imaging and Machine Vision
For industrial machine-vision cameras and inspection systems, the LTC2281CUP digitizes the analog output of line-scan or area-array image sensors, supporting line rates above 100 kHz. The dual-channel architecture is useful for stereo vision or RGB/YCC simultaneous capture, where the 10-bit depth preserves subtle shading transitions critical for defect classification. Internal 2.5V reference stabilizes gain across the inspection system, eliminating the warm-up drift of external references. Its 64-QFN footprint integrates neatly into CoaXPress or GigE-Vision camera boards.
推薦
Test and Measurement Instrumentation
Test-and-measurement digitizer boards benefit from the LTC2281CUP's 82 dB SFDR, which dominates harmonic distortion in spectrum-analyzer and oscilloscope IF paths. At 125 Msps dual channel, two ADC inputs capture time-interleaved oscilloscope channels without the bandwidth penalty of mechanical relays. Compared to 8-bit alternatives the LTC2281CUP delivers 4 dB more dynamic range for cable-reach fade measurements, while 3V AVDD enables portable battery-powered bench tools. The exposed pad simplifies thermal management in densely populated PXI/cPCI modules.
推薦
Software Defined Radio (SDR) Receivers
The LTC2281CUP performs baseband or low-IF digitization in SDR platforms where its dual channels enable direct I/Q sampling at 125 Msps. At ~470 mW total, it fits battery-powered handheld SDRs while preserving dynamic range for narrow-band signal detection below the noise floor. The 61.6 dB SNR sustains 9 effective ENOBs, well above the 7-8 ENOB threshold typical of demodulator algorithms. Compared to audio CODEC ADCs, the LTC2281CUP reaches far higher sample rates needed for wide-bandwidth SDR captures.
推薦
Multi-Channel Data Acquisition Boards
Multi-channel DAQ systems rely on the LTC2281CUP's dual-channel density to scale 16- or 32-channel boards without exceeding the carrier-board's power budget. Per the datasheet, each part draws ~235 mW per channel, summing to manageable thermal density even with 4 parts in close proximity. The exposed pad allows heat to flow into the carrier's ground plane, keeping junction rises below 20C. Compared to discrete single-channel ADCs the LTC2281CUP halves the FPGA I/O pin count and reduces trace-congestion on the digital routing layer.
推薦
推薦產品摘要
工程參考資料，適用於 LTC2281CUP — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LTC2281IUP | LTC2285CUP | LTC2283CUP | LTC2280CUP | LTC2286CUP |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 64-QFN (UP) 9x9 | 64-QFN (UP) 9x9 - same | 64-QFN (UP) 9x9 - same | 64-QFN (UP) 9x9 - same | 64-QFN (UP) 9x9 - same | 64-QFN (UP) 9x9 - same |
| Resolution (bits) | 10 | 10 | 14 | 12 | 10 | 14 |
| Sampling Rate (Msps) | 125 | 125 | 125 | 125 | 105 | 80 |
| SNR at Nyquist (dB) | 61.6 | 61.6 | 73.0 | 67.0 | 61.6 | 75.0 |
| SFDR at Nyquist (dB) | 82 | 82 | 85 | 82 | 82 | 90 |
| Supply Voltage (V) | 3 | 3 | 3 | 3 | 3 | 3 |
| Operating Temperature Range | 0C to +70C | -40C to +85C | 0C to +70C | 0C to +70C | 0C to +70C | 0C to +70C |
主要差異化特點
- Drop-in dual-channel 64-QFN pinout across the LTC2281/2283/2285/2286 family (對比LTC2285CUP)
- Lowest cost/performance position in the ADI 125 Msps 64-QFN family (對比LTC2285CUP)
- Specified at -3 dBFS 82 dBc SFDR at Nyquist input (對比LTC2280CUP)
設計說明
The 64-QFN exposed pad is the primary thermal and ground-return path. Per the LTC2281 datasheet, the PCB land pattern must include at least 8 thermal vias under the pad, stitched to a continuous ground plane on inner layers. Without sufficient vias, junction temperature can rise above spec, triggering built-in thermal shutdown or shift in ADC linearity. A solid top-layer copper pour of at least 25 sq mm surrounding the package further reduces ground-bounce and digital-coupling noise.
Route the 14-bit CMOS output bus with 50 ohm controlled-impedance traces and add 22 ohm damping resistors close to the LTC2281CUP outputs to dampen capacitive ringing. Keep digital traces routed on opposite layers from the analog input network, separated by a continuous ground plane to provide 60-80 dB isolation. According to the datasheet, switching output currents exceeding 10 mA total per bit edge event can couple to analog inputs without proper separation, degrading SNR by up to 8 dB.
AVDD analog supply must be decoupled with a 10 uF tantalum + 0.1 uF X7R ceramic pair within 5 mm of each supply pin, plus a 100 nF high-frequency X7R per pin. The OVDD digital supply shares the ferrite bead-isolated branch and requires its own 0.1 uF per-pin bypass. A common-board star-grounding topology prevents load-current spikes from generating AVDD droop. Per the datasheet, AVDD noise above 30 mV peak-peak couples directly through the input network into spurious-tone generation.
Do not drive the analog inputs beyond 1.2 or 2 Vp-p full scale while the LTC2281CUP is in shutdown mode. The input ESD structure does not clamp inputs above AVDD + 0.3 V; inrush currents can latch up the device. Per the datasheet, drive an idle-mode external buffer to bias inputs when not in use. Also avoid floating REFH pins even when using the internal reference - the 0.1 uF ceramic bypass cap is required for stable conversion at 125 Msps.
合規資訊
RoHS-compliant and lead-free. Not AEC-Q100 qualified (commercial grade only). Datasheet reference: LTC2281 datasheet 2281fb.pdf on analog.com.
