Analog Devices Inc. LTC2255CUH#PBF

Overview

LTC2255CUH#PBF from Analog Devices (formerly Linear Technology) is a 14-bit, 125Msps low-power pipelined analog-to-digital converter designed for high-frequency signal digitization in demanding 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 clock duty cycle stabilizer. It is used in ultrasound front-ends requiring wide dynamic range and precise timing fidelity.

For engineers reviewing the LTC2255CUH#PBF datasheet, LTC2255CUH#PBF pinout, LTC2255CUH#PBF application, or LTC2255CUH#PBF equivalent, key selection considerations include its 14-bit resolution at 125Msps, differential analog input support (±0.5V to ±1V range), flexible output voltage drive (0.5V–3.3V), and integrated reference programming via SENSE pin - all in a thermally enhanced 32-pin 5mm × 5mm QFN package.

Technical Context

The LTC2255CUH#PBF implements a six-stage CMOS pipelined ADC architecture with digital correction logic, achieving 5-cycle pipeline latency and no missing codes over temperature. Its sample-and-hold uses 3.5pF sampling capacitors with aperture jitter of 0.2psRMS, enabling high-fidelity digitization up to Nyquist frequency (62.5MHz).

It supports dual output formats (offset binary or 2's complement) selected via MODE pin, and configurable reference scaling via SENSE pin (±0.5V, ±1V, or ±V_SENSE). The internal 1.5V VCM buffer provides common-mode bias, while separate OVDD allows independent output driver voltage control (0.5V–3.6V).

Key Specifications

Pinout & Package

Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33, GND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9246BCPZ-125 and LTC2265IUP#PBF, the LTC2255CUH#PBF uniquely balances 125Msps speed, integrated duty cycle stabilization, and 395mW power efficiency in a compact QFN-32 - making it optimal for space-constrained, thermally sensitive, and clock-flexible wideband digitization systems.

Availability

LTC2255CUH#PBF is available at Aetrix Electronics and suitable for wireless infrastructure, medical ultrasound, portable instrumentation, and spectral analysis applications requiring stable component supply, long-term manufacturability, and consistent parametric performance across production lots.

Supply support for LTC2255CUH#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 LTC2255CUH#PBF belongs to ADI's high-speed precision ADC product line, engineered specifically for wideband digitization in communications receivers, medical imaging, and test equipment where SNR, SFDR, and thermal efficiency are critical.

FAQ

What is the maximum input frequency supported by the LTC2255CUH#PBF before signal attenuation occurs?

The LTC2255CUH#PBF specifies a 640MHz full-power bandwidth, meaning the analog input signal amplitude remains within 3dB of its low-frequency value up to 640MHz. This allows faithful digitization of IF signals well into the UHF band, provided the input drive circuitry maintains impedance matching and low parasitic reactance per the recommended front-end designs in the datasheet.

Does the LTC2255CUH#PBF require an external reference voltage, or does it include an internal reference?

The LTC2255CUH#PBF includes an internal 1.5V reference and VCM buffer, but it also supports external reference configurations. The SENSE pin determines reference mode: connecting SENSE to VCM selects ±0.5V input range with internal reference; connecting to VDD selects ±1V range; applying an external voltage (0.5V–1V) to SENSE sets a custom ±V_SENSE range - offering flexibility without mandatory external references.

How does the clock duty cycle stabilizer in the LTC2255CUH#PBF improve system design?

The clock duty cycle stabilizer in the LTC2255CUH#PBF actively corrects non-50% duty cycle clocks, enabling high AC performance (e.g., 72.4dB SNR) even with asymmetric clock sources such as PLLs or dividers with inherent duty cycle error. This eliminates the need for external duty cycle correction circuits, reducing BOM count, board area, and timing validation complexity in high-speed sampling systems.

Can the LTC2255CUH#PBF interface directly with a 1.8V FPGA I/O bank?

Yes. The LTC2255CUH#PBF supports independent output supply OVDD from 0.5V to 3.6V. Setting OVDD = 1.8V configures D0–D13 and OF outputs to swing between 0V and 1.8V, meeting standard 1.8V LVCMOS logic thresholds. Output drive strength (±50mA) and VOL/VOH specs are guaranteed at this voltage, enabling direct connection to 1.8V FPGA I/O without level-shifting components.

What thermal management guidance applies to the LTC2255CUH#PBF in continuous 125Msps operation?

The LTC2255CUH#PBF has a θ_JA of 34°C/W when the exposed thermal pad (Pin 33) is soldered to a minimum 100mm² copper pour connected to internal ground planes. At 395mW dissipation and 25°C ambient, junction temperature reaches ~158°C - exceeding the 125°C T_JMAX. Therefore, adequate PCB copper area, thermal vias (≥6×0.3mm), and optional airflow or heatspreading are required to maintain T_J ≤ 125°C under full-speed operation.