Analog Devices Inc. LTC6955IUKG-1#TRPBF

Overview

LTC6955IUKG-1#TRPBF from Analog Devices is an ultralow-jitter, 7.5GHz, 11-output CML clock buffer with one ÷2 output (OUT10), operating from –40°C to 125°C, delivering 45fs RMS additive jitter (ADC SNR method), 100Ω differential output impedance, and <5fs RMS jitter (12kHz–20MHz BW) for high-speed data converter clocking in JESD204B subclass 1 systems.

For engineers reviewing the LTC6955IUKG-1#TRPBF datasheet, LTC6955IUKG-1#TRPBF pinout, LTC6955IUKG-1#TRPBF application, or LTC6955IUKG-1#TRPBF equivalent, key selection criteria include its integrated ÷2 SYSREF output, sub-5fs integrated jitter performance at 7.5GHz, parallel 4-bit SEL control for dynamic output enable/inversion, and guaranteed operation across industrial temperature range with QFN-52 package thermal management.

Technical Context

The LTC6955IUKG-1#TRPBF implements a fully differential CML distribution architecture with eleven outputs-ten buffered at up to 7.5GHz and one dedicated ÷2 output (OUT10) for synchronized SYSREF generation. Its input stage supports DC–7.5GHz operation with 250Ω differential termination and selectable broadband filtering via FILT pin.

Parallel 4-bit SEL control enables per-output configuration (ON/INV/OFF) across 16 states, allowing flexible fanout count (3–11 active outputs) and polarity assignment for top/bottom board routing. Propagation delay variation is ±0.23ps/°C, and output skew is ±10ps (same part, all outputs except OUT0/OUT10).

Key Specifications

Pinout & Package

Package: 52-lead (7mm × 8mm) plastic QFN (UKG) with exposed ground pad (Pin 53), θJC = 2°C/W, θJA = 31°C/W. Exposed pad must be soldered to PCB ground plane with multiple thermal vias.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock buffer applications.

Compared with LTC6955IUKG#TRPBF, the LTC6955IUKG-1#TRPBF trades one full-rate output for a synchronized ÷2 SYSREF-critical for deterministic JESD204B subclass 1-but lacks the LMK04832RHAT's jitter cleaning and synthesis flexibility, making it optimal for clean, fixed-frequency fanout with tight skew and jitter budgets.

Availability

LTC6955IUKG-1#TRPBF is available at Aetrix Electronics and suitable for high-speed data converter clocking, wireless infrastructure synchronization, and JESD204B subclass 1 SYSREF generation requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for LTC6955IUKG-1#TRPBF 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 industrial markets.

The LTC6955 family is designed for ultralow-jitter clock distribution in high-speed data acquisition, wireless infrastructure, and JESD204B-compliant systems-emphasizing deterministic timing, minimal additive phase noise, and robust industrial operation.

FAQ

What is the maximum input frequency supported by the LTC6955IUKG-1#TRPBF?

The LTC6955IUKG-1#TRPBF supports differential input frequencies from DC to 7.5GHz. This is specified in the Electrical Characteristics table under "fIN Frequency Range" with a minimum value of 7500MHz at full temperature range. Input amplitude must remain within 0.25–1.6VP-P, and slew rate should exceed 100V/µs for optimal phase noise performance.

How does the FILT pin affect jitter performance in the LTC6955IUKG-1#TRPBF?

The FILT pin (Pin 40) enables an internal broadband noise filter in the LTC6955IUKG-1#TRPBF input stage. When tied to V+, it improves phase noise for low-slew-rate inputs (<2V/ns); when tied to GND, it disables filtering for high-slew-rate inputs (≥2V/ns). Using FILT = V+ with slew rates >2V/ns degrades overall phase noise, so correct configuration is essential to achieve the specified <5fs RMS jitter.

Can the LTC6955IUKG-1#TRPBF generate JESD204B subclass 1 SYSREF signals?

Yes-the LTC6955IUKG-1#TRPBF integrates a dedicated ÷2 output (OUT10±) that generates a deterministic, low-skew SYSREF signal synchronized to the input clock. Unlike the standard LTC6955IUKG#TRPBF, this variant replaces one full-rate output with the divided output, enabling direct compliance with JESD204B subclass 1 timing requirements without external dividers or additional ICs.

What is the purpose of the SEL0–SEL3 pins on the LTC6955IUKG-1#TRPBF?

The SEL0–SEL3 pins (Pins 50–52 and 1) form a 4-bit parallel control port on the LTC6955IUKG-1#TRPBF that configures output enable, disable, or inversion state for each of the eleven outputs. With 16 possible codes, it supports activation of 3–11 outputs and allows alternating polarity assignment-critical for minimizing trace-length mismatches in multi-layer PCB routing.

Is the exposed pad (Pin 53) on the LTC6955IUKG-1#TRPBF electrically connected?

Yes-the exposed pad (Pin 53) on the LTC6955IUKG-1#TRPBF is internally connected to GND and must be soldered directly to the PCB ground plane using multiple thermal vias. This connection is mandatory for both electrical performance (low ground inductance) and thermal management (θJC = 2°C/W), as stated in the Absolute Maximum Ratings and Pin Functions sections of the datasheet.