Texas Instruments DS125RT410SQE/NOPB

Overview

DS125RT410SQE/NOPB from Texas Instruments is a quad-channel, low-power retimer IC for high-speed serial links, featuring adaptive CTLE (up to 34-dB boost at 5 GHz), CDR with ≈300 ps latency, and programmable transmit de-emphasis (–15 dB) and VOD (600–1300 mV_p-p). It operates across 9.8–12.5 Gbps and submultiples (÷2/4/8) to support 10GbE, CPRI, and Interlaken in backplane and optical module interfaces.

For engineers reviewing the DS125RT410SQE/NOPB datasheet, DS125RT410SQE/NOPB pinout, DS125RT410SQE/NOPB application, or DS125RT410SQE/NOPB equivalent, key selection criteria include per-channel data-rate independence, 25-MHz reference-accelerated CDR lock time (as low as 12 ms), on-chip eye monitor + PRBS generator for system bring-up, and WQFN-48 (7 mm × 7 mm) thermal performance (R_θJB = 6.1 °C/W).

Technical Context

The DS125RT410SQE/NOPB implements four independent retiming channels, each integrating a fully adaptive continuous-time linear equalizer (CTLE), clock and data recovery (CDR) with PLL bandwidth of 5 MHz, and a CML-compatible differential driver with analog de-emphasis. Its CTLE adapts during lock acquisition using a figure-of-merit algorithm and freezes boost level post-lock unless manually re-triggered.

It uses a 25-MHz ±100-ppm crystal reference solely for VCO coarse calibration-not for PLL training-enabling rapid, robust lock without requiring synchronous input clocks. Signal detection, CDR lock status, and interrupt signaling (loss-of-signal, eye opening violation) are provided per channel via dedicated LVCMOS outputs.

Key Specifications

Pinout & Package

DS125RT410SQE/NOPB is housed in a thermally enhanced 48-pin WQFN package (7.00 mm × 7.00 mm, 0.5 mm pitch) with exposed thermal pad (DAP) requiring ≥4 vias to ground plane for optimal thermal performance (R_θJB = 6.1 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS125DF410, DS125RT410SQE/NOPB trades DFE-level crosstalk suppression for lower power and faster lock; compared with DS110RT410, it extends rate coverage to 12.5 Gbps while retaining identical footprint and configuration flow-making it the optimal choice for next-generation optical and wireless infrastructure requiring both performance headroom and thermal efficiency.

Availability

DS125RT410SQE/NOPB is available at Aetrix Electronics and suitable for high-speed optical module assembly, telecom base station backplane design, and switch fabric interconnect applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for DS125RT410SQE/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and high-speed interface solutions, with decades of expertise in signal integrity and timing ICs.

The DS125RT410SQE/NOPB belongs to TI's high-speed retimer product line-designed specifically for 10–12.5 Gbps serial link conditioning in optical communications, wireless infrastructure, and data center switching equipment.

FAQ

What data rates does the DS125RT410SQE/NOPB support, and how is rate selection implemented?

The DS125RT410SQE/NOPB supports per-channel locking from 9.8 to 12.5 Gbps and associated submultiples (÷2, ÷4, ÷8). Rate selection is configured via SMBus registers (e.g., Register 0x2F bits 7:4) or inferred automatically using the 25-MHz reference clock for VCO calibration. This enables seamless interoperability with 10GbE, CPRI Options 3–7, and Interlaken without firmware changes-each DS125RT410SQE/NOPB channel operates independently at its assigned rate.

Does the DS125RT410SQE/NOPB require an external reference clock, and what happens if it is omitted?

Yes, the DS125RT410SQE/NOPB requires a 25-MHz ±100-ppm crystal oscillator connected to REFCLK_IN for fast VCO calibration. If omitted, CDR lock time increases significantly (e.g., from 12 ms to >70 ms), and false lock risk rises under periodic input patterns. The reference clock is not used in the PLL feedback path-it only accelerates initial frequency acquisition. REFCLK_OUT provides a buffered copy for multi-device synchronization.

How does the adaptive CTLE in the DS125RT410SQE/NOPB differ from fixed-gain equalizers?

The DS125RT410SQE/NOPB's CTLE adapts during CDR lock acquisition using a figure-of-merit algorithm across 32 predefined boost profiles, then freezes the selected setting until manually reset. Unlike fixed-gain equalizers, this ensures optimal compensation for varying channel loss without over-equalization noise amplification. Post-lock stability prevents eye closure drift-critical for sustained BER < 1×10⁻¹⁵ operation in production systems.

Can the DS125RT410SQE/NOPB be configured without an external microcontroller?

Yes-the DS125RT410SQE/NOPB supports SMBus master mode, where it automatically loads configuration from an external EEPROM on power-up using READ_EN and ALL_DONE signals. This eliminates the need for host processor intervention during boot, making it ideal for headless optical modules and standalone retimer cards. Configuration registers-including VOD, de-emphasis, and rate settings-are retained in EEPROM for repeatable, deterministic startup.

What thermal management considerations apply to the DS125RT410SQE/NOPB in a 4-channel active configuration?

In full 4-channel operation, DS125RT410SQE/NOPB dissipates ~660 mW. Its WQFN-48 package relies on the exposed thermal pad (DAP) connected via ≥4 vias to an internal ground plane for heat dissipation. With R_θJB = 6.1 °C/W, a 20°C board temperature rise above ambient requires ~120 cm² of 2-oz copper area. Avoid placing thermal vias under adjacent components, and ensure uninterrupted thermal conduction path from DAP to system heatsink or airflow zone.