Analog Devices Inc. DC854D-B

Overview

LTC2208 from Analog Devices (acquired Linear Technology) is a 16-bit, 130Msps analog-to-digital converter optimized for high-frequency undersampling applications up to 700MHz full-power bandwidth, featuring 78dBFS noise floor, 100dB spurious-free dynamic range (SFDR), and 70fsRMS aperture jitter. It integrates a programmable gain amplifier (PGA) front end supporting 1.5VP-P or 2.25VP-P input ranges and operates from a single 3.3V supply with 1.25W power dissipation.

For engineers reviewing the LTC2208 datasheet, LTC2208 pinout, LTC2208 application, or LTC2208 equivalent, this ADC is selected for RF receiver digitization where wide dynamic range, low noise at IF frequencies >100MHz, and flexible LVDS/CMOS output formatting are required - especially in cellular base station receivers, spectrum analyzers, and high-speed ATE systems.

Technical Context

The LTC2208 employs a 16-bit pipelined ADC core with integrated sample-and-hold (S/H) and PGA front end, enabling direct RF sampling without intermediate frequency conversion. Its 700MHz full-power bandwidth supports undersampling of signals up to 250MHz while maintaining ≥83dB SFDR at 250MHz with 1.5VP-P input range.

Digital outputs support multiple configurations: standard or low-power LVDS (differential, 100Ω-terminated), or CMOS (full-rate or demultiplexed half-rate buses), with selectable output swing (0.5V–3.6V). Clock interface accepts differential (LVDS/PECL) or single-ended (TTL/CMOS) inputs, and includes an optional duty cycle stabilizer for robust timing at full speed.

Key Specifications

Pinout & Package

Package: 64-lead (9mm × 9mm) plastic QFN with exposed thermal pad (Pin 65 = GND), requiring PCB soldering for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed ADC applications.

Compared with AD9268-130, the LTC2208 delivers +10dB SFDR at 250MHz and integrated PGA flexibility, justifying its use in demanding RF receivers; versus LTC2207, it provides +25Msps headroom for future-proofing wideband designs without layout change.

Availability

LTC2208 is available at Aetrix Electronics and suitable for cellular infrastructure, test equipment, and medical imaging systems requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for LTC2208 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, serving communications, industrial, automotive, and healthcare markets.

The LTC2208 belongs to ADI's high-speed precision ADC product line, designed specifically for RF-sampling receiver architectures where dynamic range, jitter performance, and flexible digital interfacing are critical.

FAQ

What is the maximum analog input frequency supported by the LTC2208?

The LTC2208 supports a full-power analog input bandwidth of 700MHz, enabling direct undersampling of RF signals up to 250MHz while maintaining ≥83dB SFDR. This makes the LTC2208 suitable for L-band and UHF digitization without external filtering or downconversion stages.

Does the LTC2208 require external reference components?

No - the LTC2208 includes an internal 2.5V bandgap reference. Tying the SENSE pin to VDD activates it, setting a full-scale range of 2.25VP-P (PGA=0). An external 1.25V or 2.5V reference may be used for improved accuracy or temperature stability, but is not required for basic operation of the LTC2208.

How does the PGA function affect input range and dynamic range in the LTC2208?

When PGA = low, the LTC2208 uses 1× gain with 2.25VP-P differential input range; when PGA = high, it applies 1.5× gain with 1.5VP-P range. The latter improves SNR for small signals by amplifying them before quantization, but reduces headroom - users must match PGA setting to expected signal amplitude to maximize effective bits in the LTC2208.

Can the LTC2208 operate with a single-ended clock input?

Yes - the ENC+ and ENC– inputs accept single-ended TTL, CMOS, or sine-wave clocks applied to ENC+ while tying ENC– to a 1.6V bias (via resistor divider or internal bias). The LTC2208's internal 6.2kΩ pull-up on ENC– supports this configuration, though differential clocking is recommended for lowest jitter in the LTC2208.

What is the purpose of the RAND pin on the LTC2208?

The RAND pin enables digital output randomization: when asserted high, it XORs D1–D15 with D0 (LSB), scrambling output patterns to reduce narrowband spectral energy from digital switching. This lowers EMI and crosstalk coupling into analog sections - a key feature for sensitive RF receiver designs using the LTC2208.