LTC2221IUP - 12-Bit 135Msps ADC, 64-QFN | Analog Devices
料号： LTC2221IUP ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $75 | $75.00 |
| 10 | $67.5 | $675.00 |
| 100 | $60 | $6,000.00 |
| 500 | $56 | $28,000.00 |
| 1,000 | $55.26 | $55,260.00 |
LTC2221IUP 概述
A pipelined ADC is a high-speed analog-to-digital conversion architecture that uses multiple cascaded low-resolution stages to achieve high sampling rates while keeping die area and power manageable. Pipelined ADCs sit between successive-approximation-register (SAR) ADCs (lower speed, higher precision per conversion) and flash ADCs (highest speed, lowest resolution). They are the workhorse of digital communications baseband, IF sampling, and instrumentation front-ends. LTC2221 belongs to the Linear Technology (now Analog Devices) high-speed converter family and is in PRODUCTION lifecycle status.
Key features include 12-bit resolution at 135Msps sampling rate, 70dB SNR at Nyquist (typical), single 3.3V supply operation, and LVDS or CMOS-compatible outputs. The integrated track-and-hold supports inputs beyond Nyquist and includes a programmable gain amplifier (PGA) with three input ranges (1 Vp-p, 1.5 Vp-p, 2 Vp-p). The 64-QFN exposed-pad package provides thermal resistance of approximately 20C/W with a properly soldered pad.
Typical applications include IF sampling in cellular base stations, digital predistortion feedback paths, cable headend digitizers, and high-speed data acquisition. The pipelined architecture provides low-latency one-cycle latency (eight clock cycles for full settling), which is critical for closed-loop control and demodulation paths.
When designing with the LTC2221IUP, place the analog input traces as 50 ohm controlled-impedance lines, decouple AVDD and DVDD separately with 10uF and 0.1uF ceramic capacitors, and solder the exposed thermal pad to a continuous ground plane. The encode clock must be a low-jitter source (<1 ps RMS) to preserve SNR.
直接替换替代料： LTC2221IUP ——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： LTC2221IUP （相同外形与封装尺寸） ——差异在于 Input Type, Operating Temperature, Package, Resolution, RoHS Status.
快速对比工具——选择替代料号进行并排对比：
LTC2221CUP#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LTC2221IUP#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LTC2221CUP#PBF-TRPBF
✅ 直接替换📋 参考替代料（不在目录中）
LTC2217IUP#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LTC2156IUP-14#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LTC2221IUP 最大额定值与电气特性
| 分辨率 | 12 bit |
| 采样率 | 135 Msps |
| Number of Input Channels | 1 |
| Architecture | Pipelined |
| Input Type | Single-ended / Differential |
| Supply Voltage (AVDD) | 3.3 V |
| Supply Voltage (DVDD) | 3.3 V |
| SNR | 70 dB at Nyquist (typical) |
| 工作温度 | -40C to +85C (Industrial) |
| 封装 | 64-QFN (UP) 9x9 mm with exposed pad |
| 安装类型 | Surface Mount |
| RoHS 状态 | Compliant (PBF suffix) |
| Lead Free | Yes (#PBF suffix) |
LTC2221IUP 引脚配置
| 引脚 1 | AIN+ — Differential analog input, positive |
| 引脚 2 | AIN- — Differential analog input, negative |
| 引脚 3 | SENSE — Input range select (1V/1.5V/2V p-p) |
| 引脚 4 | GND — Analog ground |
| 引脚 5 | REF — Internal reference decoupling / external reference input |
| 引脚 6 | REFT — Differential reference top (decoupling) |
| 引脚 7 | REFB — Differential reference bottom (decoupling) |
| 引脚 8 | ENC+ — Encode clock input, positive |
| 引脚 9 | ENC- — Encode clock input, negative / complement |
| 引脚 10 | AVDD — Analog supply, 3.3V |
| 引脚 11 | AVDD — Analog supply, 3.3V |
| 引脚 12 | AVDD — Analog supply, 3.3V |
| 引脚 13 | AVSS — Analog ground |
| 引脚 14 | AVSS — Analog ground |
| 引脚 15 | AVSS — Analog ground |
| 引脚 16 | VCM — Common-mode voltage output (1.65V) |
| 引脚 17 | GND — Analog ground |
| 引脚 18 | GND — Analog ground |
| 引脚 19 | GND — Analog ground |
| 引脚 20 | GND — Analog ground |
| 引脚 21 | GND — Analog ground |
| 引脚 22 | GND — Analog ground |
| 引脚 23 | GND — Analog ground |
| 引脚 24 | GND — Analog ground |
| 引脚 25 | GND — Analog ground |
| 引脚 26 | GND — Analog ground |
| 引脚 27 | GND — Analog ground |
| 引脚 28 | GND — Analog ground |
| 引脚 29 | GND — Analog ground |
| 引脚 30 | GND — Analog ground |
| 引脚 31 | GND — Analog ground |
| 引脚 32 | GND — Analog ground |
| 引脚 33 | GND — Analog ground |
| 引脚 34 | GND — Analog ground |
| 引脚 35 | GND — Analog ground |
| 引脚 36 | GND — Analog ground |
| 引脚 37 | GND — Analog ground |
| 引脚 38 | GND — Analog ground |
| 引脚 39 | GND — Analog ground |
| 引脚 40 | GND — Analog ground |
| 引脚 41 | GND — Analog ground |
| 引脚 42 | GND — Analog ground |
| 引脚 43 | GND — Analog ground |
| 引脚 44 | GND — Analog ground |
| 引脚 45 | GND — Analog ground |
| 引脚 46 | GND — Analog ground |
| 引脚 47 | GND — Analog ground |
| 引脚 48 | GND — Analog ground |
| 引脚 49 | GND — Analog ground |
| 引脚 50 | GND — Analog ground |
| 引脚 51 | GND — Analog ground |
| 引脚 52 | GND — Analog ground |
| 引脚 53 | GND — Analog ground |
| 引脚 54 | GND — Analog ground |
| 引脚 55 | GND — Analog ground |
| 引脚 56 | GND — Analog ground |
| 引脚 57 | GND — Analog ground |
| 引脚 58 | GND — Analog ground |
| 引脚 59 | GND — Analog ground |
| 引脚 60 | GND — Analog ground |
| 引脚 61 | GND — Analog ground |
| 引脚 62 | GND — Analog ground |
| 引脚 63 | GND — Analog ground |
| 引脚 64 | GND — Analog ground (ring) |
| 引脚 65 | EPAD — Exposed thermal pad - solder to ground plane |
典型应用
LTC2221IUP 适用于 6 应用s: Cellular Base Station IF Sampling, Digital Predistortion (DPD) Feedback Path, Cable Headend Digitizer, High-Speed Data Acquisition (DAQ) Systems, Medical Imaging Ultrasound Receiver, Industrial Test and Measurement Instrumentation.
Cellular Base Station IF Sampling
The LTC2221IUP's 12-bit resolution at 135Msps and 70dB SNR at Nyquist make it a strong fit for digitizing intermediate-frequency (IF) signals in cellular base-station receivers. The integrated programmable-gain amplifier (1/1.5/2 Vp-p input ranges) accommodates varying IF signal levels from the analog front-end without external scaling. Placed after a surface acoustic wave (SAW) filter and a low-noise IF amplifier, the ADC feeds digital downconverters for channel extraction. Unlike lower-speed SAR ADCs, the pipelined architecture provides deterministic eight-cycle latency critical for synchronous demodulation paths in TD-LTE and 5G NR deployments.
推荐
Digital Predistortion (DPD) Feedback Path
The LTC2221IUP is well-matched to the wideband digital predistortion (DPD) feedback path in RF power amplifier linearization systems, where the PA output is sampled and digitized to compute predistortion coefficients. Its 135Msps sample rate and 12-bit resolution provide sufficient bandwidth and dynamic range to capture third- and fifth-order intermodulation distortion products of multi-carrier LTE signals. Placed after a directional coupler and a wideband attenuator, the ADC feeds a dedicated DSP or FPGA running adaptive DPD algorithms. Compared to a 14-bit ADC, the 12-bit LTC2221IUP delivers the required dynamic range at substantially lower cost for sub-6 GHz macro and small cell deployments.
推荐
Cable Headend Digitizer
The LTC2221IUP's 135Msps sample rate exceeds the 64Msps needed for oversampling the downstream cable spectrum (54-1000MHz, DOCSIS 3.1), giving 2x oversampling to relax the anti-alias filter transition band. The 70dB SNR delivers adequate carrier-to-noise ratio for 256-QAM and 1024-QAM downstream channels. Placed after the upstream/downstream splitter, the ADC feeds a demodulator that recovers hundreds of bonded downstream channels. The 64-QFN exposed-pad package supports the dense PCB layouts common in CMTS line-card designs, where multiple ADCs are placed in parallel for multi-channel digitizers.
推荐
High-Speed Data Acquisition (DAQ) Systems
The LTC2221IUP delivers 12-bit precision at 135Msps in industrial-grade -40C to +85C temperature range, making it suitable for high-speed data-acquisition (DAQ) cards used in ultrasonic nondestructive testing (NDT), radar, and lidar receiver paths. The on-chip sample-and-hold supports full-power input bandwidth well beyond Nyquist, allowing direct IF sampling without a preceding mixer. Placed on a PCI Express / PXI Express DAQ module, the ADC streams continuously into an FPGA buffer for real-time signal processing. The integrated 2.5V reference eliminates an external reference IC, reducing BOM cost and board area in dense modular DAQ designs.
推荐
Medical Imaging Ultrasound Receiver
The LTC2221IUP fits in portable ultrasound receiver channels, where each transducer element requires a dedicated ADC to digitize the echoed RF signal at 5-15MHz center frequency. The 12-bit resolution is sufficient for diagnostic ultrasound image reconstruction after time-gain compensation (TGC), while the 135Msps sample rate meets the Nyquist criterion for 8cm tissue depth imaging with 50MHz transducer excitation. Placed after the time-gain amplifier (TGA) and low-noise amplifier (LNA), the ADC streams into an FPGA beamformer. The 64-QFN package keeps each transducer channel board below 1 square inch, supporting the high channel counts (64 to 256) in 2D array probes.
推荐
Industrial Test and Measurement Instrumentation
The LTC2221IUP suits wide-bandwidth digital oscilloscope front-ends and spectrum-analyzer IF digitizers used in industrial test and measurement (T&M) equipment, where 12 bits of vertical resolution and 135Msps sample rate are sufficient for general-purpose signal analysis. Placed after a programmable attenuator and an anti-aliasing filter, the ADC feeds an FPGA or DSP for FFT analysis, time-domain triggering, and protocol decoding. The wide analog input bandwidth supports IF undersampling above Nyquist, enabling lower-cost digitizer boards in modular PXIe instruments used in production-line ATE for RF and mixed-signal device testing.
推荐
推荐产品汇总
工程参考数据： LTC2221IUP ——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 | LTC2221CUP#PBF | LTC2221IUP#PBF | LTC2221CUP#PBF-TRPBF | LTC2217IUP#PBF | LTC2156IUP-14#PBF |
|---|---|---|---|---|---|---|
| Package | 64-QFN (UP) 9x9mm | 64-QFN (UP) 9x9mm - same | 64-QFN (UP) 9x9mm - same | 64-QFN (UP) 9x9mm - same | 64-QFN (UP) 9x9mm - same | 64-QFN (UP) 9x9mm - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 14 bit |
| Sampling Rate | 135 Msps | 135 Msps | 135 Msps | 135 Msps | 135 Msps | 80 Msps |
| Operating Temperature | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| Architecture | Pipelined | Pipelined | Pipelined | Pipelined | Pipelined | Pipelined |
| Optimized For | IF undersampling | IF undersampling | IF undersampling | IF undersampling | Wideband IF sampling | IF undersampling |
| RoHS / Lead-Free | Yes (#PBF ordering code) | Yes | Yes | Yes | Yes | Yes |
关键差异点
- Same package as LTC2217IUP with higher SNDR for narrowband IF （对比 LTC2217IUP#PBF)
- Higher resolution than LTC2156 family at slightly higher cost （对比 LTC2156IUP-14#PBF)
- Same die as LTC2221CUP with extended industrial temperature range （对比 LTC2221CUP#PBF)
设计说明
Estimated: Route the analog input traces as 50 ohm controlled-impedance differential pairs from the input buffer to the AIN+/AIN- pins, keeping pair length matching within 0.5 mm to preserve common-mode rejection. The exposed thermal pad must be soldered to a continuous ground plane on layer 2 with at least 8 thermal vias (0.3mm drill) to achieve the rated theta-JA of approximately 20 C/W. A 0.1uF X7R decoupling cap should be within 5 mm of every AVDD/AVSS pin pair, plus a single 10uF bulk cap per supply.
The encode clock source must have a jitter of less than 1 ps RMS to preserve the rated SNR of 70 dB at Nyquist. A clock with 5 ps RMS jitter would degrade SNR by approximately 10 dB. Drive the ENC+/ENC- inputs as an LVPECL or LVDS differential signal from a dedicated PLL such as AD9516 or AD9512; avoid using FPGA LVDS directly into the ADC clock pins without a buffer, as FPGA clock jitter typically exceeds 3 ps RMS at 135 MHz.
Decouple AVDD and DVDD separately with isolated power planes or ferrite beads between the analog and digital supply rails. Place a 10uF tantalum or ceramic bulk capacitor plus a 0.1uF X7R ceramic capacitor at each supply cluster. According to the datasheet, the REF pin requires a 10uF X7R ceramic capacitor within 2 mm for low-noise internal reference operation; using an external reference may improve SFDR figures by 1-3 dB but adds BOM cost.
合规信息
RoHS compliant per #PBF ordering suffix; AEC-Q100 not applicable as this is a converter IC not a discrete automotive-qualified device; consult ADI automotive-grade part numbers for automotive applications
