LTC2261IUJ-14#PBF is a high-performance 14-bit analog-to-digital converter (ADC) designed by Analog Devices (formerly Linear Technology)

Optimized for high-speed signal processing, it combines precision, low power consumption, and flexibility, making it suitable for demanding applications in communications, medical devices, and industrial systems.

Functions

1. High-Speed Conversion
   • Achieves 125 MSPS sampling rate with a 5-cycle pipeline architecture, enabling real-time digitization of high-frequency signals up to 800 MHz full-power bandwidth
   • Features 73.4 dB SNR (Signal-to-Noise Ratio) and 85 dB SFDR (Spurious-Free Dynamic Range), ensuring accurate reconstruction of wide dynamic range signals
   • Ultra-low 0.17 ps RMS jitter supports undersampling of intermediate-frequency (IF) signals in wireless receivers
2. Flexible Input Configuration
   • Accepts differential or single-ended analog inputs with selectable ranges:
     • 1.0 V_P-P or 2.0 V_P-P full-scale input .
   • Supports various input signaling standards, including sine wave, PECL, LVDS, TTL, and CMOS
   • Optional clock duty cycle stabilizer maintains performance across a wide range of clock duty cycles
3. Digital Output Options
   • Configurable output modes via an SPI interface:
     • Full-rate CMOS (14 data lines).
     • Double-data-rate (DDR) CMOS (7 data lines) or DDR LVDS (14 differential pairs) for high-speed data transfer
   • LVDS outputs feature adjustable current (1.75–4.5 mA) and integrated 100Ω termination resistors to minimize reflections .
   • Supports straight binary or two’s complement data formats .
4. Low Power & Efficient Operation
   • Consumes 127 mW at full speed (1.8V analog supply), scaling down to 9 mW in nap mode and 0.5 mW in sleep mode
   • Power-saving features include shutdown control and dynamic power management for battery-powered systems
5. Precision & Stability
   • Integral nonlinearity (INL) of ±1 LSB and differential nonlinearity (DNL) of ±0.3 LSB ensure accurate signal reproduction .
   • Internal voltage reference with low drift (±30 ppm/°C) and external reference support for critical applications
6. SPI Configuration
   • A 3-wire SPI interface enables dynamic control of:
     • Data output randomizer (reduces digital feedback noise by 10–15 dB) .
     • LVDS swing, output termination, and power-saving modes .
   • On-chip registers allow real-time adjustments without external components .

Applications

1. Wireless Communications
   • Cellular Base Stations: Digitizes IF signals in LTE/5G receivers, supporting wideband channelization and beamforming .
   • Software-Defined Radios (SDRs): Enables multi-channel, multi-standard radios with high dynamic range and low latency .
   • RF Test Equipment: Accurately captures modulated signals for spectrum analysis and signal integrity testing .
2. Medical Imaging
   • Portable Ultrasound: Processes high-frequency echo signals with low noise, enhancing image resolution in compact devices
   • MRI/CT Scanners: Converts analog sensor data into digital streams for real-time image reconstruction .
3. Industrial & Instrumentation
   • Multichannel Data Acquisition: Ideal for systems requiring simultaneous sampling of multiple analog inputs (e.g., process control, test benches)
   • Non-Destructive Testing (NDT): Analyzes ultrasonic or radar signals to detect flaws in materials .
   • Aerospace Avionics: Processes high-speed sensor data in flight control systems and avionic displays .
4. High-Speed Instrumentation
   • Oscilloscopes & Logic Analyzers: Captures transient signals with sub-nanosecond precision .
   • Optical Communication: Converts analog outputs from photodetectors into digital data for fiber-optic links .
5. Automotive & Defense
   • ADAS (Advanced Driver Assistance Systems): Processes radar and LiDAR signals for collision avoidance .
   • Military Radios: Supports wideband frequency hopping and anti-jamming algorithms in tactical communication systems .

Key Technical Specifications

• Resolution: 14 bits
• Sampling Rate: 125 MSPS
• SNR: 73.4 dB
• SFDR: 85 dB
• Input Range: 1.0 V_P-P or 2.0 V_P-P (differential)
• Power Supply: 1.7–1.9 V (analog), 1.1–1.9 V (digital)
• Package: 40-pin QFN (6 mm × 6 mm)
• Temperature Range: –40°C to +85°C (industrial grade)

Design Considerations

• Clock Management: Use low-jitter clocks (e.g., LTC6946 PLL) to maximize ADC performance .
• Signal Conditioning: Pair with fully differential amplifiers like the LTC6409 for optimal noise suppression and gain control .
• Layout: Ensure proper grounding and decoupling to minimize noise coupling in high-speed traces