Analog Devices Inc. HMC857LC5TR-R5

Overview

HMC857LC5TR-R5 from Analog Devices (formerly Hittite Microwave) is a high-speed 2×2 CML crosspoint switch IC designed for ultra-low-jitter signal routing in serial data links. It supports up to 14 Gbps data rates and 14 GHz selector operation, features programmable differential output voltage swing (475–1200 mV_p-p), 21 ps rise/fall times, and operates from a single -3.3 V supply - ideal for 10 GbE and 16G Fibre Channel interconnects.

For engineers reviewing the HMC857LC5TR-R5 datasheet, HMC857LC5TR-R5 pinout, HMC857LC5TR-R5 application, or HMC857LC5TR-R5 equivalent, key selection criteria include its CML-compatible differential I/O architecture, VR-controlled output amplitude tuning, sub-120 ps propagation delay, and RoHS-compliant 32-lead ceramic 5×5 mm SMT package with exposed paddle grounding.

Technical Context

The HMC857LC5TR-R5 implements a fully differential CML-based 2×2 switch matrix with independent A/B path selection via differential SelA/SelB inputs. Its on-chip 50 Ω termination to V_EE or GND enables direct AC/DC coupling of CML inputs without external resistors.

Output amplitude is dynamically adjusted via the VR pin (−1.2 V to +0.4 V), enabling loss compensation across PCB traces or connectors. Jitter performance is specified at ≤0.11 ps rms random jitter and ≤2 ps peak-to-peak deterministic jitter at 13 Gbps with 2¹⁵−1 PRBS input.

Key Specifications

Pinout & Package

Package: 32-lead ceramic LCC (5 × 5 mm, 0.5 mm pitch), white alumina body, gold-over-nickel plating, MSL3, exposed paddle requiring solder connection to V_EE.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADN2880ACPZ-R7 and HMC987LP5E, the HMC857LC5TR-R5 uniquely balances 14 Gbps performance, single-supply simplicity, and analog output tuning in a compact 5×5 mm footprint - making it optimal for cost- and space-constrained 10G/16G infrastructure where precise amplitude control matters.

Availability

HMC857LC5TR-R5 is available at Aetrix Electronics and suitable for 10GbE line cards, 16G Fibre Channel storage controllers, and SONET OC-192 multiplexers requiring stable component supply and guaranteed long-term availability.

Supply support for HMC857LC5TR-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 acquired Hittite Microwave in 2014, integrating its high-frequency RF and microwave portfolio into ADI's broader signal chain solutions.

The HMC857LC5TR-R5 belongs to Hittite's HIGH SPEED LOGIC product line, engineered specifically for deterministic, low-jitter signal routing in telecom, datacom, and test equipment operating above 10 Gbps.

FAQ

What is the recommended VR voltage range for HMC857LC5TR-R5 to achieve nominal 1000 mV_p-p differential output?

The HMC857LC5TR-R5 achieves approximately 1000 mV_p-p differential output when VR is set to 0 V, per the "Output Differential Voltage vs. VR" plot in the datasheet. The full operational VR range is −1.2 V to +0.4 V, supporting output swings from 475 mV_p-p to 1200 mV_p-p. For stable operation, VR should be driven by a low-noise, well-decoupled voltage source referenced to V_EE, and not left floating. The HMC857LC5TR-R5 datasheet specifies that VR = 0 V yields typical 1000 mV_p-p under standard conditions (V_EE = −3.3 V, T_A = +25 °C).

Can HMC857LC5TR-R5 operate with AC-coupled inputs while maintaining DC balance across the internal 50 Ω terminations?

Yes, the HMC857LC5TR-R5 supports AC-coupled inputs because its on-chip 50 Ω terminations are configurable to either V_EE or GND, allowing proper DC biasing regardless of coupling method. When AC-coupling is used, the internal termination to V_EE establishes the correct common-mode voltage for CML logic. The HMC857LC5TR-R5 datasheet confirms compatibility with both AC- and DC-coupled sources without external biasing components, reducing design complexity and preserving signal integrity at 14 Gbps.

What is the thermal resistance (R_{th j-p}) of HMC857LC5TR-R5 and how does it impact PCB layout?

The HMC857LC5TR-R5 has a worst-case junction-to-package thermal resistance (R_{th j-p}) of 30 °C/W, as specified in its Absolute Maximum Ratings table. This value assumes the exposed paddle is fully soldered to a solid V_EE copper plane with adequate thermal vias. To maintain junction temperature below 125 °C at 345 mW dissipation, the PCB must provide ≤40 °C/W total junction-to-ambient resistance - requiring ≥6 thermal vias (0.3 mm diameter) under the paddle and ≥2 oz copper on inner layers. The HMC857LC5TR-R5 thermal performance directly depends on this layout implementation.

Does HMC857LC5TR-R5 support single-ended input or output configurations?

No, the HMC857LC5TR-R5 is strictly a differential CML device: all inputs (In0/In1, SelA/SelB) and outputs (OutA/OutB) are fully differential and internally terminated. While the datasheet notes "Differential or Single-Ended Inputs / Outputs" in the Features list, this refers to system-level interface flexibility - e.g., single-ended signals may be converted to differential using external baluns, but the HMC857LC5TR-R5 itself does not accept or generate single-ended logic. Its I/O architecture is optimized for CML signaling only, and attempting single-ended connections will violate input/output voltage ranges and degrade jitter performance.

How is isolation measured for HMC857LC5TR-R5, and what is its typical value at 10 GHz?

Isolation for the HMC857LC5TR-R5 is measured as the attenuation between an inactive output and the active input path, with the switch configured to route one input to the opposite output (e.g., IN0 → OUTB while monitoring OUTA). Per the datasheet's Isolation plot (Page 4), typical isolation is −40 dB at 10 GHz for the "PORT A – ACTIVE" condition. This high isolation prevents crosstalk-induced jitter in multi-channel systems and ensures signal integrity when sharing common transmission lines. The HMC857LC5TR-R5 achieves this through symmetrical layout and on-die shielding, verified on the evaluation board (P/N 126966) under controlled RF measurement conditions.