Analog Devices Inc. HMC856LC5TR-R5

Overview

HMC856LC5TR-R5 from Analog Devices is a 5-bit digital time delay IC designed for high-speed timing compensation and clock skew management in serial data paths. It delivers 28 Gbps data rate support, 3 ps delay resolution, 92 ps maximum programmable delay range, and programmable differential output voltage swing from 500 mV p-p to 1350 mV p-p - enabling precise signal alignment in SONET OC-192 and CDR systems.

For engineers reviewing the HMC856LC5TR-R5 datasheet, HMC856LC5TR-R5 pinout, HMC856LC5TR-R5 application, or HMC856LC5TR-R5 equivalent, key selection considerations include its −3.3 V single-supply CML interface, on-chip 50 Ω input/output terminations, VR-controlled output level tuning, temperature-stable monotonic delay, and 5 mm × 5 mm ceramic LCC package with exposed paddle grounding requirement.

Technical Context

The HMC856LC5TR-R5 implements a fully monotonic 5-bit digital delay architecture with 3 ps step resolution and <92 ps total control range, calibrated across −40°C to +85°C. Its CML I/O structure features on-die 50 Ω termination to GND on inputs/outputs and 600 Ω pull-up termination on B0–B4 control lines for low-power digital programming.

Delay stability is maintained via internal compensation against supply (−3.7 V to −2.9 V) and temperature variation, with propagation delay drift of only +4 ps to +12 ps over full operating range. The VR pin enables real-time output amplitude adjustment (500–1350 mV p-p), directly modulating both signal level and edge speed (20 ps/18 ps rise/fall at nominal VR = 0 V).

Key Specifications

Pinout & Package

Package: 5 mm × 5 mm, 32-terminal ceramic leadless chip carrier (LCC, HE-32-1) with exposed thermal pad requiring connection to VEE (−3.3 V). RoHS-compliant, MSL3 rated.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital time delay applications.

Compared with HMC987LP5E and LMK04832, the HMC856LC5TR-R5 uniquely balances 28 Gbps operation, 3 ps resolution, single −3.3 V supply, and VR-adjustable output swing - making it the only option for compact, low-power, high-data-rate skew correction in space-constrained telecom modules.

Availability

HMC856LC5TR-R5 is available at Aetrix Electronics and suitable for SONET OC-192 line cards, high-speed serial interconnects, and broadband test instrumentation requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for HMC856LC5TR-R5 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 is a global leader in high-performance analog, mixed-signal, and RF ICs, serving precision instrumentation, communications, and industrial markets since 1965.

The HMC856LC5TR-R5 belongs to Analog Devices' Hittite Microwave product line, engineered specifically for microwave and millimeter-wave timing, delay, and signal conditioning in 10–40 Gbps infrastructure systems.

FAQ

What is the absolute maximum supply voltage rating for the HMC856LC5TR-R5?

The HMC856LC5TR-R5 has an absolute maximum negative supply voltage of −3.75 V on VEE pins and exposed pad. Operation beyond −3.75 V risks permanent damage. The recommended operating range is −3.7 V to −2.9 V at TA = 25°C, with derating above 85°C. All VEE connections - pins 27, 30, and the exposed paddle - must be tied to the same −3.3 V rail.

How does the VR pin affect both output swing and timing performance of the HMC856LC5TR-R5?

The VR pin on the HMC856LC5TR-R5 directly controls differential output voltage swing from 500 mV p-p (VR = −1.2 V) to 1350 mV p-p (VR = +0.4 V), enabling loss compensation. However, increasing VR also increases rise/fall times - from 20/18 ps at VR = 0 V to ~26/24 ps at VR = +0.4 V - and raises current draw by up to 60 mA, impacting power budget and edge fidelity at 28 Gbps.

Is the HMC856LC5TR-R5 pin-compatible with earlier HMC856 variants like HMC856LC5 or HMC856LC5TR?

Yes, the HMC856LC5TR-R5 shares identical pinout, package (HE-32-1 LCC), electrical specifications, and thermal design requirements with HMC856LC5 and HMC856LC5TR. The "-R5" suffix denotes tape-and-reel packaging with 500-unit reels; all three part numbers are functionally and mechanically interchangeable in PCB layout and circuit design.

What is the role of the VB pin on the HMC856LC5TR-R5, and how must it be connected?

The VB pin on the HMC856LC5TR-R5 provides a DC bias reference for internal CML circuitry and must be connected directly to GND. Leaving VB floating or applying any voltage causes undefined operation and potential device malfunction. This connection is mandatory for stable 28 Gbps operation and correct interpretation of B0–B4 control inputs.

Does the HMC856LC5TR-R5 support dc-coupled inputs and outputs, and what are the interface requirements?

Yes, the HMC856LC5TR-R5 supports both ac- and dc-coupled interfaces. For dc coupling, connect I+/I− and O+/O− directly to other CML devices with matching 50 Ω terminations. For ac coupling, use series capacitors with 50 Ω ac load to GND. Input common-mode range is −1.5 V to +0.5 V; output swing is referenced to GND and requires 50 Ω termination at receiver end.