Analog Devices Inc. LTC2221IUP#PBF

Overview

LTC2221IUP#PBF from Analog Devices (formerly Linear Technology) is a 12-bit, 135Msps analog-to-digital converter optimized for high-frequency, wide dynamic range signal digitization in communications infrastructure. It delivers 67.5dB SNR and 80dB SFDR up to 170MHz input frequency, with ultralow 0.15psRMS aperture jitter, enabling high-fidelity undersampling of IF signals in cable head-end and wireless baseband receivers.

For engineers reviewing the LTC2221IUP#PBF datasheet, LTC2221IUP#PBF pinout, LTC2221IUP#PBF application, or LTC2221IUP#PBF equivalent, key selection considerations include its 64-pin QFN package, dual LVDS/CMOS output flexibility, ±0.5V or ±1V selectable input range, internal reference option, and industrial temperature range (–40°C to +85°C).

Technical Context

The LTC2221IUP#PBF employs a 12-bit pipelined ADC core with integrated sample-and-hold, full-power bandwidth of 775MHz, and on-chip correction logic to achieve ±0.4LSB INL and ±0.2LSB DNL over temperature. Its flexible encode interface accepts differential LVDS, PECL, TTL, or CMOS clock inputs, with an optional duty cycle stabilizer ensuring performance across wide clock duty cycles.

Digital outputs support three configurations: single-bus CMOS at full data rate, or two demultiplexed CMOS buses (interleaved or simultaneous update), plus fully differential LVDS mode. A separate OVDD supply allows CMOS output swing adjustment from 0.5V to 3.6V, while dedicated REFHA/REFHB/REFLA/REFLB pins enable precise external reference routing or internal reference selection via SENSE pin.

Key Specifications

Pinout & Package

64-lead (9mm × 9mm) plastic QFN package with exposed thermal pad (Pin 65 = GND). Requires soldering of exposed pad to PCB ground plane 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 AD9230-125EBZ, LTC2221IUP#PBF offers superior input flexibility and jitter performance but consumes more power; compared with LTC2220IUP#PBF, it trades 35Msps sample rate for 230mW lower power and relaxed thermal requirements - ideal for cost- and power-sensitive 135Msps applications.

Availability

LTC2221IUP#PBF is available at Aetrix Electronics and suitable for cable head-end systems, wireless infrastructure equipment, and communications test instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC2221IUP#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 LTC2221IUP#PBF belongs to ADI's high-speed precision ADC product line, designed specifically for demanding communications infrastructure applications where dynamic range, jitter, and thermal stability are critical.

FAQ

What is the maximum analog input frequency supported by the LTC2221IUP#PBF?

The LTC2221IUP#PBF maintains 80dB SFDR up to 170MHz input frequency and 67.5dB SNR up to 140MHz input frequency under typical conditions (2V range, LVDS mode). Its 775MHz full-power bandwidth ensures minimal amplitude roll-off well beyond these frequencies, making it suitable for undersampling applications where the input signal resides in higher Nyquist zones.

Does the LTC2221IUP#PBF require an external reference voltage?

No, the LTC2221IUP#PBF includes an internal 1.6V reference and supports internal reference operation via the SENSE pin. Connecting SENSE to VCM selects ±0.5V input range; connecting to VDD selects ±1V range. External references can also be applied to SENSE (0.5V–1V) for custom ranges, but external REFHA/REFHB/REFLA/REFLB connections are only needed if using external reference buffers.

How does the LVDS output mode differ from CMOS mode on the LTC2221IUP#PBF?

In LVDS mode (LVDS pin = VDD), the LTC2221IUP#PBF drives 12-bit differential data pairs (D0± to D11±) and differential clock/data strobes (CLKOUT±, OF±) with 247–454mV differential swing and 1.125–1.375V common-mode voltage. In CMOS mode (LVDS pin = GND), it drives single-ended outputs (DA0–DA11, DB0–DB11) with configurable OVDD (0.5V–3.6V) and standard CMOS voltage thresholds - reducing FPGA I/O resource usage but increasing power and noise sensitivity.

Can the LTC2221IUP#PBF operate with a non-50% duty cycle clock?

Yes, the LTC2221IUP#PBF includes an optional clock duty cycle stabilizer enabled via the MODE pin. When activated, it corrects duty cycle distortion internally, allowing high-performance operation with clocks having duty cycles from 30% to 70%. This eliminates the need for external duty cycle correction circuits in systems using crystal oscillators or PLLs with asymmetric output stages.

What is the pipeline latency of the LTC2221IUP#PBF in LVDS mode?

The LTC2221IUP#PBF has a fixed pipeline latency of 5 clock cycles in LVDS mode, meaning the digital output corresponding to a given analog sample appears 5 sampling periods after the encode edge. This deterministic latency is critical for time-aligned feedback paths in digital predistortion and real-time signal processing applications, and is matched across all output formats (full-rate CMOS, demux interleaved, demux simultaneous).