Analog Devices Inc. LTC2249IUH#PBF

Overview

LTC2249IUH#PBF from Analog Devices (formerly Linear Technology) is a 14-bit, 80Msps low-power pipelined analog-to-digital converter operating from a single 3V supply. It delivers 73dB SNR and 90dB SFDR at 70MHz input frequency, features a 575MHz full-power bandwidth sample-and-hold, clock duty cycle stabilizer, and shutdown/nap modes. It is used in high-performance ultrasound imaging front-ends requiring wide dynamic range digitization of RF signals.

For engineers reviewing the LTC2249IUH#PBF datasheet, LTC2249IUH#PBF pinout, LTC2249IUH#PBF application, or LTC2249IUH#PBF equivalent, key selection criteria include AC performance at Nyquist-plus frequencies, flexible 1V_P-P to 2V_P-P input range configuration, differential analog input interface, and QFN-32 package thermal and layout compatibility for high-speed signal integrity.

Technical Context

The LTC2249IUH#PBF implements a six-stage CMOS pipelined ADC architecture with digital correction logic, achieving 5-cycle pipeline latency. Its sample-and-hold uses 4pF sampling capacitors with linearized charging glitch design to minimize SFDR degradation from incomplete settling.

It supports both offset binary and 2's complement output formats via the MODE pin, and internal reference programming via SENSE pin to select ±0.5V or ±1V differential input ranges. The VCM pin provides a buffered 1.5V common-mode bias with ±25ppm/°C tempco and 4Ω output impedance.

Key Specifications

Pinout & Package

Package: 32-lead (5mm × 5mm) plastic QFN with exposed pad (GND, Pin 33), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2249IUH#PBF, AD9246BCPZ-80 offers marginally better SNR but adds design complexity with external reference routing, while LTC2255IUP#PBF trades 45Msps extra bandwidth for significantly higher power and thermal footprint - making LTC2249IUH#PBF optimal for 80Msps portable medical and test equipment where power, integration, and SNR/SFDR balance are critical.

Availability

LTC2249IUH#PBF is available at Aetrix Electronics and suitable for ultrasound imaging systems, wireless baseband receivers, and portable spectral analyzers requiring stable component supply across extended industrial temperature ranges.

Supply support for LTC2249IUH#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and healthcare markets.

The LTC2249IUH#PBF belongs to Linear Technology's high-speed ADC product line, designed specifically for demanding RF and IF digitization in medical imaging, test equipment, and broadband communications where low power, high SNR, and integrated biasing are essential.

FAQ

What is the operating temperature range for the LTC2249IUH#PBF?

The LTC2249IUH#PBF is rated for industrial temperature operation from –40°C to +85°C, as indicated by the "I" grade suffix in the part number. This makes it suitable for deployment in outdoor wireless infrastructure and portable medical devices exposed to ambient thermal variation. The device maintains full specification compliance-including ±1LSB INL and 73dB SNR-across this entire range without derating.

Does the LTC2249IUH#PBF require an external reference voltage?

No, the LTC2249IUH#PBF includes an internal 1.5V bandgap reference and programmable reference amplifier. The SENSE pin allows selection between ±0.5V and ±1V differential input ranges using only VDD or VCM connections-no external reference IC or resistor network is needed. External references may be applied to SENSE only if custom input ranges between 1V and 2V are required.

How does the clock duty cycle stabilizer in the LTC2249IUH#PBF improve system performance?

The clock duty cycle stabilizer in the LTC2249IUH#PBF reduces sensitivity to clock asymmetry by actively correcting duty cycle deviations before sampling. This lowers aperture jitter contribution, enabling consistent 73dB SNR performance even with 40%–60% input clock duty cycles-eliminating the need for external clock conditioners in cost-sensitive baseband receiver designs.

What is the purpose of the OF (Over/Under Flow) pin on the LTC2249IUH#PBF?

OF (Pin 28) is an asynchronous open-drain output that asserts high whenever the analog input exceeds the selected full-scale range-indicating either overrange (input > +FS) or underrange (input < –FS). This flag enables real-time gain control loop feedback in automatic ranging systems and prevents data corruption in ultrasound beamformers by signaling saturation events to the host processor.

Can the LTC2249IUH#PBF interface directly with a 1.8V FPGA I/O bank?

Yes, the LTC2249IUH#PBF supports variable OVDD from 0.5V to 3.6V. Setting OVDD = 1.8V configures all D0–D13 outputs and OF pin for 1.8V LVCMOS levels, including VOH ≥ 1.79V and VOL ≤ 0.09V at 1.6mA sink current. This allows direct connection to Xilinx Artix-7 or Intel Cyclone V FPGA banks without level-shifting circuitry.