Analog Devices Inc. LTC2248CUH#PBF

Overview

LTC2248CUH#PBF from Analog Devices (formerly Linear Technology) is a 14-bit, 65Msps low-power pipelined analog-to-digital converter designed for high-fidelity digitization of wideband RF and IF signals in communications and imaging systems. It operates from a single 3V supply (2.7V–3.4V), delivers 74.3dB SNR and 90dB SFDR at Nyquist, supports flexible ±0.5V to ±1V differential input range, and features a 575MHz full-power bandwidth sample-and-hold stage.

For engineers reviewing the LTC2248CUH#PBF datasheet, LTC2248CUH#PBF pinout, LTC2248CUH#PBF application, or LTC2248CUH#PBF equivalent, key selection criteria include its 65Msps sampling rate with 14-bit resolution, clock duty cycle stabilizer for robust timing margin, shutdown/nap modes for power management, and QFN-32 (5mm × 5mm) package compatibility with space-constrained RF front-ends.

Technical Context

The LTC2248CUH#PBF implements a six-stage CMOS pipelined ADC architecture with digital correction logic to achieve no missing codes and ±1LSB INL over temperature. Its sample-and-hold circuit uses differential NMOS switch-capacitor topology with 4pF sampling capacitors and supports both differential and single-ended input drive configurations.

Internal reference generation provides 1.5V common-mode bias (VCM) with ±25ppm/°C tempco, while the MODE pin selects output format (offset binary or 2's complement) and enables/disables the clock duty cycle stabilizer-critical for maintaining AC performance across non-50% clock waveforms.

Key Specifications

Pinout & Package

The LTC2248CUH#PBF is housed in a 32-lead (5mm × 5mm) plastic QFN package with exposed thermal pad (Pin 33) that must be soldered to PCB ground for thermal and electrical performance. Pin numbering follows standard top-view layout with AIN+, AIN−, CLK, and D0–D13 arranged for minimized trace length and coupling in high-speed layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9246BCPZ-65 and LTC2249CUK#PBF, the LTC2248CUH#PBF offers superior power efficiency (205mW vs 320mW) and built-in clock duty cycle stabilization-reducing BOM count and layout sensitivity in cost-sensitive RF designs-while maintaining best-in-class SFDR for its speed class.

Availability

LTC2248CUH#PBF is available at Aetrix Electronics and suitable for wireless infrastructure, medical imaging, portable instrumentation, and test equipment requiring stable component supply and long-term production continuity.

Supply support for LTC2248CUH#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 LTC2248CUH#PBF belongs to ADI's high-speed precision ADC product line, engineered specifically for demanding RF/IF digitization where SNR, SFDR, and power efficiency must coexist in compact form factors.

FAQ

What is the maximum input frequency supported by the LTC2248CUH#PBF before aliasing occurs?

The LTC2248CUH#PBF has a 65Msps sampling rate, so its Nyquist frequency is 32.5MHz. Signals above this frequency will alias into the first Nyquist zone. Its 575MHz full-power bandwidth ensures minimal amplitude roll-off up to 32.5MHz, making it suitable for direct IF sampling without aggressive anti-alias filtering. The LTC2248CUH#PBF maintains 74.3dB SNR at 5MHz and 73.4dB at 70MHz input-confirming usable bandwidth beyond Nyquist for undersampling applications.

Does the LTC2248CUH#PBF require an external reference voltage, or does it include an internal reference?

The LTC2248CUH#PBF includes an internal 1.5V reference and common-mode bias (VCM) generator, eliminating the need for an external reference in most applications. The SENSE pin allows configuration of input range (±0.5V to ±1V) using internal references. External references can be applied via REFL/REFH pins if higher accuracy or custom voltage levels are required. The LTC2248CUH#PBF specifies ±30ppm/°C drift for internal reference, ensuring stability across 0°C to 70°C operation.

How does the clock duty cycle stabilizer in the LTC2248CUH#PBF improve system design?

The clock duty cycle stabilizer in the LTC2248CUH#PBF actively corrects non-50% clock waveforms, enabling full 65Msps performance even with duty cycles from 30% to 70%. This relaxes clock source requirements, avoids costly precision clock buffers, and improves timing margin in noisy environments. Without it, SNR degrades significantly outside 45–55% duty cycle range. The LTC2248CUH#PBF's stabilizer maintains 74.3dB SNR and 90dB SFDR across the full operating range, verified in Figure 2248 G12 of the datasheet.

What are the power consumption differences between normal, nap, and shutdown modes of the LTC2248CUH#PBF?

In normal operation at 65Msps, the LTC2248CUH#PBF draws 205mW. In nap mode (SHDN = H, OE = L, no clock), power drops to 15mW while preserving internal state for fast wake-up. In shutdown mode (SHDN = H, OE = H, no clock), power falls to 2mW-fully disabling analog and digital circuits. These modes are controlled exclusively via SHDN and OE pins, with no software overhead. The LTC2248CUH#PBF's low nap-mode power enables periodic sampling architectures in portable spectrum analyzers without sacrificing restart latency.

Can the LTC2248CUH#PBF interface directly with common FPGA I/O standards?

Yes-the LTC2248CUH#PBF supports OVDD from 0.5V to 3.6V, allowing direct interfacing with LVCMOS, LVTTL, and sub-1V FPGA I/O banks. Its D0–D13 outputs drive ±50mA and specify VOH/VOL down to 1.8V OVDD (VOH = 1.79V, VOL = 0.09V at 1.6mA). The parallel 14-bit bus requires no serialization, reducing FPGA resource usage. The LTC2248CUH#PBF's 5ns max bus relinquish time after OE↓ ensures clean handoff to FPGA capture logic during multi-channel time-interleaved configurations.