Analog Devices Inc. LTC2255IUH#PBF

Overview

LTC2255IUH#PBF from Analog Devices (formerly Linear Technology) is a 14-bit, 125Msps low-power pipelined analog-to-digital converter optimized for high-frequency signal digitization in communications and imaging systems. It operates from a single 3V supply (2.85V–3.4V), delivers 72.4dB SNR at 5MHz input, 88dB SFDR, and features a 640MHz full-power bandwidth sample-and-hold with integrated clock duty cycle stabilizer. It is used in ultrasound front-ends requiring precise wideband dynamic range capture.

For engineers reviewing the LTC2255IUH#PBF datasheet, LTC2255IUH#PBF pinout, LTC2255IUH#PBF application, or LTC2255IUH#PBF equivalent, key selection criteria include its guaranteed no-missing-codes performance over –40°C to +85°C, flexible ±0.5V to ±1V differential input range, and dual-mode output format (offset binary or 2's complement) controlled via the MODE pin.

Technical Context

The LTC2255IUH#PBF implements a six-stage CMOS pipelined ADC architecture with digital correction logic, achieving 5-cycle pipeline latency and deterministic timing. Its sample-and-hold uses matched 3.5pF sampling capacitors and supports both transformer-coupled and active differential drive topologies with strict 100Ω max source impedance per input for optimal SFDR.

It integrates a programmable internal reference (via SENSE pin), 1.5V VCM bias output, and independent OVDD supply (0.5V–3.6V) enabling direct interfacing with LVDS, CMOS, or low-voltage logic families. Shutdown and nap modes reduce power to 2mW and 15mW respectively, while maintaining fast wake-up capability.

Key Specifications

Pinout & Package

Package: 32-lead (5mm × 5mm) plastic QFN with exposed pad (Pin 33 = GND), RoHS-compliant, lead-free (PBF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9246BCPZ-125 and ADS5463IPFP, the LTC2255IUH#PBF uniquely balances 14-bit resolution, 125Msps speed, single 3V supply, and on-chip clock stabilization-making it optimal for space-constrained, thermally sensitive, and cost-sensitive wideband digitization where SNR and design simplicity are critical.

Availability

LTC2255IUH#PBF is available at Aetrix Electronics and suitable for wireless infrastructure, medical ultrasound, and portable instrumentation requiring stable component supply with industrial temperature qualification and long-term production continuity.

Supply support for LTC2255IUH#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, serving industrial, automotive, communications, and healthcare markets.

The LTC2255IUH#PBF belongs to ADI's high-speed precision ADC product line, designed specifically for demanding digitization tasks in communications infrastructure and medical imaging where dynamic range, low power, and ease of integration are essential.

FAQ

What is the operating temperature range of the LTC2255IUH#PBF?

The LTC2255IUH#PBF is rated for industrial operation from –40°C to +85°C. This specification is guaranteed across all key AC and DC parameters including SNR, SFDR, INL, and DNL, making it suitable for deployment in base station radios, portable ultrasound devices, and outdoor test equipment where ambient conditions vary widely. The "I" suffix in the part number explicitly denotes this extended temperature grade.

Does the LTC2255IUH#PBF require an external reference voltage?

No, the LTC2255IUH#PBF includes an internal reference and does not require an external reference. Its SENSE pin allows configuration of the input range (±0.5V to ±1V) using the internal reference, or supports external reference voltages between 0.5V and 1V. External reference is optional and used only when higher accuracy or specific voltage scaling is needed beyond the internal reference's ±0.5% tolerance.

How does the MODE pin affect the output format and clock functionality of the LTC2255IUH#PBF?

The MODE pin on the LTC2255IUH#PBF controls two functions simultaneously: output data format (offset binary or 2's complement) and clock duty cycle stabilizer enable/disable. Ground = offset binary + stabilizer off; 1/3 VDD = offset binary + stabilizer on; 2/3 VDD = 2's complement + stabilizer on; VDD = 2's complement + stabilizer off. This dual function simplifies board design by eliminating separate control lines.

What is the purpose of the exposed pad (Pin 33) on the LTC2255IUH#PBF QFN package?

The exposed pad (Pin 33) on the LTC2255IUH#PBF is electrically connected to GND and serves as the primary thermal and electrical ground path. It must be soldered directly to a large PCB copper pour for effective heat dissipation (θ_JA = 34°C/W) and low-impedance grounding. Failure to connect it compromises thermal performance, increases junction temperature, and may degrade SNR and long-term reliability.

Can the LTC2255IUH#PBF interface directly with an FPGA using 1.8V I/O banks?

Yes, the LTC2255IUH#PBF supports direct interface with 1.8V FPGA I/O banks via its independent OVDD supply pin (Pin 21). When OVDD is set to 1.8V, the D0–D13 outputs meet 1.8V CMOS logic thresholds (VOH ≥ 1.79V, VOL ≤ 0.09V at 1.6mA), eliminating level-shifting components. This feature simplifies interconnect and reduces board area in high-density digital acquisition systems.