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Analog Devices Inc. LTC2181IUP#PBF
- Part No.:
- LTC2181IUP#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 64-WFQFN Exposed Pad
- Datasheet:
-
LTC2181IUP#PBF.pdf
- Description:
- IC ADC 16BIT PIPELINED 64QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,848
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Product details
Overview
LTC2181IUP#PBF from Analog Devices (formerly Linear Technology) is a 16-bit, 40Msps dual-channel simultaneous-sampling analog-to-digital converter optimized for high-dynamic-range signal digitization in communications infrastructure. It delivers 77dB SNR, 90dB SFDR, and ultralow 0.07psRMS jitter, enabling undersampling of IF signals up to 140MHz in cellular base stations and software-defined radios.
For engineers reviewing the LTC2181IUP#PBF datasheet, LTC2181IUP#PBF pinout, LTC2181IUP#PBF application, or LTC2181IUP#PBF equivalent, key selection criteria include its dual-channel synchronization capability, selectable CMOS/DDR-CMOS/DDR-LVDS output interface, 1.8V single-supply operation, 550MHz full-power bandwidth, and industrial temperature range (–40°C to +85°C).
Technical Context
The LTC2181IUP#PBF implements two independent 16-bit SAR-based ADC cores with shared clocking and synchronized sampling control, ensuring precise channel-to-channel timing alignment critical for I/Q demodulation and beamforming. Its sample-and-hold front-end supports differential analog inputs from 1VP-P to 2VP-P with 0.7V–1.25V common-mode range and 80dB CMRR.
Digital interface flexibility includes full-rate CMOS, DDR-CMOS, or DDR-LVDS outputs with configurable OVDD (1.2V/1.5V/1.8V), plus an SPI port for configuration of randomizer, duty-cycle stabilizer, nap/shutdown modes, and input range. Internal reference provides 1.25V ±25ppm/°C drift; external reference mode accepts 0.625V–1.3V at SENSE pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit with no missing codes over temperature - guarantees monotonicity and full code coverage in precision measurement systems. |
| Sampling Rate | 40Msps - supports Nyquist sampling of baseband signals up to 20MHz or undersampling of IF bands up to 140MHz. |
| SNR / SFDR | 77dB SNR and 90dB SFDR at 70MHz input - enables high-fidelity digitization of narrowband carriers in dense spectral environments. |
| Power Dissipation | 115mW total (58mW per channel) at 40Msps with CMOS outputs - reduces thermal load in densely packed RF front-ends. |
| Input Bandwidth | 550MHz full-power bandwidth - preserves signal integrity for wideband modulated waveforms without attenuation. |
| Jitter | 0.07psRMS acquisition jitter - limits aperture uncertainty to <0.002 LSB at 70MHz, essential for high-IF sampling accuracy. |
| INL / DNL | ±2LSB INL and ±0.5LSB DNL (typ) - ensures linearity for calibration-critical applications like medical imaging and NDT. |
Pinout & Package
64-lead (9mm × 9mm) plastic QFN package with exposed thermal pad (Pin 65 = GND, must be soldered). Pin assignments are validated per Linear Technology datasheet 218210f Rev. C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (1,16,17,64) | Analog supply input | 1.7V–1.9V single supply; requires local 0.1µF ceramic bypass to GND for noise suppression. |
| AIN1+/AIN1– (4,5) | Differential analog input CH1 | Accepts 1VP-P to 2VP-P signals with 0.7V–1.25V common-mode bias via VCM1. |
| AIN2+/AIN2– (12,13) | Differential analog input CH2 | Matched path to CH1; enables true simultaneous sampling for phase-coherent applications. |
| ENC+/ENC– (18,19) | Differential encode clock input | Accepts sine, PECL, LVDS, TTL, or CMOS; falling edge on ENC– triggers conversion when used differentially. |
| D1_0–D1_15 / D2_0–D2_15 (23–32,43–58) | Parallel digital data outputs | Configurable as full-rate CMOS, DDR-CMOS, or DDR-LVDS; OVDD determines swing (1.2V/1.5V/1.8V). |
| PAR/SER (11) | Programming mode select | Ground = serial SPI interface (CS/SCK/SDI/SDO); VDD = parallel logic control of core functions. |
| CLKOUT+/CLKOUT– (40,39) | Output clock pair | Provides synchronous clock for data capture; skew to data ≤0.6ns supports tight timing margins. |
Key Features
| Feature | Design Value |
|---|---|
| Two-channel simultaneous sampling | Guarantees sub-picosecond inter-channel skew for coherent I/Q processing and MIMO antenna arrays. |
| Selectable output interface | CMOS/DDR-CMOS/DDR-LVDS options allow direct interfacing to FPGAs (LVDS) or ASICs (CMOS) without level-shifting. |
| Optional clock duty cycle stabilizer | Enables full-speed performance with non-50% clock duty cycles, relaxing clock generation requirements in system design. |
| Data output randomizer | Reduces deterministic EMI peaks in DDR output streams, easing EMC compliance in compact RF modules. |
| Nap and shutdown modes | Reduces power to 10mW (nap) or 1mW (shutdown) - extends battery life in portable medical or test equipment. |
Applications
| Cellular Base Stations | Software Defined Radios |
|---|---|
Use Scenario: Digitizing dual-channel IF signals (e.g., 70MHz/69MHz 2-tone) in macrocell remote radio heads. IC Role / Device Role / Timing Role: Simultaneous-sampling dual ADC providing phase-aligned I/Q data for digital predistortion and MIMO processing. Use Value: 90dB SFDR prevents adjacent-channel interference; 0.07psRMS jitter maintains EVM <1.5% at 256-QAM. | Use Scenario: Reconfigurable wideband receiver front-end supporting multiple air interfaces (LTE, 5G NR, Wi-Fi 6E) in field-deployable radios. IC Role / Device Role / Timing Role: High-linearity dual ADC enabling real-time spectrum analysis and adaptive filtering across 10MHz–140MHz instantaneous bandwidth. Use Value: 550MHz input bandwidth and 77dB SNR support >100dB spurious-free dynamic range for multi-standard coexistence. |
| Portable Medical Imaging | Multi-Channel Data Acquisition |
Use Scenario: Ultrasound beamformer digitizing echo returns from 128+ transducer elements with time-of-flight precision. IC Role / Device Role / Timing Role: Dual-channel ADC capturing synchronized RF echoes with matched gain/offset for synthetic aperture focusing. Use Value: ±0.5LSB DNL and ±2LSB INL ensure accurate tissue contrast; low 115mW power enables battery-operated handheld scanners. | Use Scenario: High-precision vibration monitoring in industrial predictive maintenance systems using 8–16 sensor channels. IC Role / Device Role / Timing Role: Dual ADC serving as master sampling engine for time-interleaved or multiplexed sensor array digitization. Use Value: Simultaneous sampling eliminates phase error between acceleration/temperature/strain measurements; –40°C to +85°C rating ensures field reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel, 16-bit, medium-speed ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD9269BCPZ-40 | 40Msps, 16-bit, dual-channel; 78.5dB SNR, 88dB SFDR; requires separate 3.3V/1.8V supplies; no internal reference. | Higher power (220mW), wider supply requirement, and external reference increase BOM count and layout complexity. | Choose AD9269BCPZ-40 only if higher SNR margin is required and dual-supply architecture is acceptable. |
| ADS52J90IRGCT | 40Msps, 16-bit, quad-channel; 76.5dB SNR, 89dB SFDR; JESD204B interface; 1.8V/1.0V supplies; integrated PLL. | Quad-channel density and JESD204B reduce FPGA pin count but require serializer-deserializer IP and higher PCB layer count. | Choose ADS52J90IRGCT when scaling beyond two channels or integrating into JESD204B-based systems. |
Compared with AD9269BCPZ-40 and ADS52J90IRGCT, the LTC2181IUP#PBF offers lowest system-level power (115mW), single 1.8V supply, integrated reference, and simpler CMOS/LVDS interfacing-making it optimal for space-constrained, thermally sensitive, or cost-sensitive dual-channel designs.
Availability
LTC2181IUP#PBF is available at Aetrix Electronics and suitable for cellular infrastructure, portable medical imaging, and industrial data acquisition requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC2181IUP#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, with deep expertise in precision data conversion and RF signal chain solutions.
The LTC218x family was designed specifically for demanding communications and instrumentation applications requiring simultaneous dual-channel sampling, ultra-low jitter, and flexible digital interfacing in compact QFN packages.
FAQ
What is the maximum input frequency supported by the LTC2181IUP#PBF while maintaining specified SNR?
The LTC2181IUP#PBF maintains 77dB SNR up to 70MHz input frequency at –1dBFS and 40Msps sampling rate, as verified in Figure G24 of the datasheet. At 140MHz input, SNR degrades to 76.3dB due to front-end bandwidth roll-off, but remains usable for undersampling architectures where aliasing is managed digitally.
Does the LTC2181IUP#PBF support external voltage reference, and what is the valid input range at the SENSE pin?
Yes, the LTC2181IUP#PBF supports external reference via the SENSE pin, with a valid input range of 0.625V to 1.300V (min/max) over temperature. This allows precise system-level calibration and improved gain matching in multi-ADC arrays, as confirmed in Table on page 5 of datasheet 218210f.
How does the duty cycle stabilizer in the LTC2181IUP#PBF improve system design flexibility?
The duty cycle stabilizer in the LTC2181IUP#PBF compensates for non-50% clock duty cycles, enabling full 40Msps performance even with asymmetric clocks from crystal oscillators or PLLs. This eliminates the need for external duty-cycle correction circuits, reducing component count and board area in base station and SDR designs.
What are the power consumption differences between CMOS and DDR-LVDS output modes for the LTC2181IUP#PBF?
In CMOS mode, the LTC2181IUP#PBF consumes 115mW total at 40Msps; in DDR-LVDS mode (3.5mA), it consumes 259mW. The 144mW increase reflects LVDS driver current and termination, but enables longer trace lengths and lower EMI-critical for high-density FPGA interfacing.
Can the LTC2181IUP#PBF operate with single-ended analog inputs, and how is this configured?
Yes, the LTC2181IUP#PBF supports single-ended analog inputs by tying ENC– to GND and driving ENC+ with a 1.8V square wave or sine wave. Channel inputs remain differential (AIN1+/AIN1–), but common-mode bias is set via VCM1/VCM2 outputs; no hardware modification is needed beyond encoder configuration.
LTC2181IUP#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 64-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 40M
- Number of Inputs:
- 2
- Input Type:
- Differential
- Data Interface:
- LVDS - Parallel, Parallel
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 2
- Architecture:
- Pipelined
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 1.7V ~ 1.9V
- Voltage - Supply, Digital:
- 1.7V ~ 1.9V
- Features:
- Simultaneous Sampling
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 64-QFN (9x9)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
LTC2181IUP#PBF FAQ
1.How can I place an order for LTC2181IUP#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2181IUP#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LTC2181IUP#PBF reliable?
The price and inventory of LTC2181IUP#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2181IUP#PBF is usually 5 days.
3.What payment methods are accepted for LTC2181IUP#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2181IUP#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2181IUP#PBF?
LTC2181IUP#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2181IUP#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LTC2181IUP#PBF?
For technical support, including LTC2181IUP#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2181IUP#PBF requirements.
6.How does Aetrix verify that LTC2181IUP#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2181IUP#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LTC2181IUP#PBF meets industry standards.
7.What is the process for return or replacement of LTC2181IUP#PBF?
All LTC2181IUP#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2181IUP#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LTC2181IUP#PBF part is unused and in its original packaging.
Return procedure for LTC2181IUP#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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