Texas Instruments DS125RT410SQ/NOPB

Overview

DS125RT410 from Texas Instruments is a four-channel, low-power retimer IC with integrated adaptive CTLE, CDR, and programmable de-emphasis driver. It operates independently per channel across 9.8–12.5 Gbps and submultiples (÷2/4/8), delivers ≈300 ps latency, supports BER < 1×10⁻¹⁵, and targets high-speed serial links in SFP+, QSFP, and backplane applications.

For engineers reviewing the DS125RT410 datasheet, DS125RT410 pinout, DS125RT410 application, or DS125RT410 equivalent, key selection considerations include multi-rate lock capability, 25-MHz reference-assisted fast CDR lock, adjustable VOD (600–1300 mV_p-p), –15 dB de-emphasis range, and WQFN-48 package compatibility with TI's retimer family.

Technical Context

The DS125RT410 implements a fully adaptive continuous-time linear equalizer (CTLE) with up to 34-dB boost at 5 GHz and a clock-and-data-recovery (CDR) block using a VCO calibrated via external 25-MHz reference for rapid lock. Each channel features independent rate detection and false-lock discrimination.

Its transmit path includes a CML-compatible differential driver with programmable output voltage (600–1300 mV_p-p) and analog de-emphasis (0 to –15 dB), while on-chip eye monitor (EOM) and PRBS generator support real-time link validation. Power delivery uses single 2.5-V ±5% supply with typical dissipation of 150 mW/channel.

Key Specifications

Pinout & Package

DS125RT410 is housed in a 7-mm × 7-mm, 0.5-mm pitch WQFN-48 package with exposed thermal pad (DAP) requiring ≥4 vias to ground for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS125DF410, DS125RT410 trades DFE-level crosstalk suppression for lower power and simpler implementation; compared with DS110RT410, it extends rate coverage to 12.5 Gbps and adds 6 dB CTLE headroom - making it the optimal choice for CPRI Option 7, 12.5-Gbps InfiniBand, and future-proof 10GbE+ systems.

Availability

DS125RT410 is available at Aetrix Electronics and suitable for high-speed serial interconnects requiring stable component supply, including optical module manufacturing, telecom line card assembly, and enterprise switch production.

Supply support for DS125RT410 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 company specializing in analog, embedded processing, and high-speed interface solutions for communications, industrial, and automotive markets.

The DS125RT410 belongs to TI's retimer product line designed specifically for multi-gigabit serial link integrity in optical modules, switch fabrics, and baseband fronthaul - emphasizing low latency, adaptive equalization, and protocol-agnostic rate agility.

FAQ

What data rates does the DS125RT410 support?

The DS125RT410 supports per-channel locking from 9.8 Gbps to 12.5 Gbps and all associated submultiples (÷2, ÷4, ÷8), covering standards including 10GbE, CPRI Options 3–7, Interlaken, and InfiniBand QDR. It does not support rates below 9.8 Gbps or above 12.5 Gbps. The DS125RT410 achieves this via VCO calibration using its 25-MHz reference clock and protocol-select lock mode.

How does the DS125RT410 differ from the DS125DF410?

The DS125RT410 uses an adaptive CTLE + CDR architecture, while the DS125DF410 replaces CTLE with a self-calibrating 5-tap DFE + CDR. This makes DS125DF410 better for crosstalk-dominated channels but increases power (200 mW/channel vs. 150 mW/channel for DS125RT410) and design complexity. Both share identical pinout, package, and rate range, but DS125RT410 offers lower latency and simpler loop-filter design.

Can the DS125RT410 operate without an external 25-MHz crystal?

No - the DS125RT410 requires a 24.9975–25.0025 MHz reference clock on REFCLK_IN for VCO calibration during power-up, CDR reset, or loss-of-lock recovery. This clock is not used for PLL training but enables fast, robust lock acquisition. Omitting it results in extended or failed CDR lock; REFCLK_OUT can buffer this signal to other DS125RT410 devices on the same board.

What is the purpose of the LPF_CP_n and LPF_REF_n pins on the DS125RT410?

The LPF_CP_n and LPF_REF_n pins (one pair per channel) connect to external 22-nF ±10% capacitors to configure the CDR loop filter. These components set the PLL bandwidth (~5 MHz) and directly impact jitter transfer, lock time, and stability. Incorrect capacitor values cause slow lock, excessive jitter, or loss of lock - TI specifies tight tolerance to ensure consistent performance across temperature and voltage.

Does the DS125RT410 support SMBus master mode configuration?

Yes - the DS125RT410 supports SMBus master mode, where it automatically reads initial configuration from an external EEPROM on power-up using READ_EN and ALL_DONE control signals. After boot, it transitions to SMBus slave mode for runtime updates. This dual-mode capability simplifies system initialization and enables field-upgradable retimer settings without host processor intervention.