Texas Instruments FPC402RHUT

Overview

FPC402RHUT from Texas Instruments is a quad-port low-speed signal aggregator IC designed for SFP, QSFP, QSFP-DD, OSFP, and Mini-SAS HD pluggable module management. It consolidates I²C, status inputs (IN_A/B/C), and control outputs (OUT_A/B/C/D) across four ports into a single host interface-supporting either I²C up to 1 MHz or SPI up to 10 MHz-and enables placement under press-fit connectors on the PCB bottom side. It delivers programmable LED blinking/dimming, broadcast writes across cascaded devices, and prefetch of user-specified module registers.

For engineers reviewing the FPC402RHUT datasheet, FPC402RHUT pinout, FPC402RHUT application, or FPC402RHUT equivalent, this device addresses port-count scalability in high-density switch/router line cards, eliminates discrete I²C muxes and FPGA-based control logic, reduces routing congestion via localized port-side signal handling, and supports hot-plug-aware system management with interrupt-driven event reporting.

Technical Context

The FPC402RHUT implements a dual-domain architecture: a downstream I²C master per port (100/400 kHz compliant with SFF-8431/8436/8449) and an upstream configurable host interface (I²C or SPI). It integrates dedicated input de-glitching (30–50 µs pulse suppression on IN_* pins) and programmable interrupt generation triggered by user-defined port events (e.g., MOD_ABS, Tx_Fault, Rx_LOS).

Its GPIO[3:0] and four output banks per port (OUT_A/B/C/D) support flexible signal mapping: OUT_A drives Tx_Disable/ResetL, OUT_B controls RS/LPMode, while OUT_C/OUT_D provide current-limited, dimmable LED drivers with active-low polarity and built-in blink timing-enabling full status indication without external components.

Key Specifications

Pinout & Package

Package: WQFN-56 (RHU), 5.00 mm × 11.00 mm, thermally enhanced die attach pad (DAP = GND). Designed for bottom-side PCB placement beneath press-fit connectors to minimize trace length and layer count.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-port pluggable module management applications.

Compared with FPC401RHUT, FPC402RHUT adds full I²C address flexibility, broadcast capability, and register prefetch-making it essential for next-gen multi-rate optical modules. Against MAX5980ATJ+, FPC402RHUT addresses a fundamentally different function: signal aggregation versus power control-neither is substitutable without redesigning the port management architecture.

Availability

FPC402RHUT is available at Aetrix Electronics and suitable for ToR switch design, wireless infrastructure baseband units, and video transport routers requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.

Supply support for FPC402RHUT 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 delivering analog and embedded processing solutions, with leadership in interface, power management, and signal chain technologies for industrial, communications, and enterprise systems.

The FPC402RHUT belongs to TI's pluggable module controller product line, engineered specifically to simplify high-port-count optical interconnect management in networking and telecom infrastructure-reducing FPGA resource usage and PCB complexity.

FAQ

What host interface protocols does the FPC402RHUT support?

The FPC402RHUT supports two mutually exclusive host-side interfaces selected by the PROTOCOL_SEL pin: Inter-Integrated Circuit (I²C) up to 1 MHz Fast-mode Plus, or Serial Peripheral Interface (SPI) up to 10 MHz. In I²C mode, CTRL1–CTRL4 function as SCL, SDA, SET_ADDR_N, and ADDR_DONE_N; in SPI mode, they become SCK, SS_N, MOSI, and MISO. The FPC402RHUT does not support concurrent operation of both protocols.

How does the FPC402RHUT handle LED control for optical module status indication?

The FPC402RHUT provides dedicated OUT_C[0–3] and OUT_D[0–3] outputs per port, configured as active-low LED drivers with programmable blink rate, duty cycle, and dimming level. Each output requires a minimum 33 Ω series resistor and supports up to 18 mA sink current. These outputs are enabled and driven high at power-up-ensuring safe default state before host configuration.

Can multiple FPC402RHUT devices be synchronized for coordinated LED behavior?

Yes-when operating in SPI mode, the SPI_LED_SYNC pin (pin 30) must be connected across all FPC402RHUT devices to ensure synchronized LED blinking and dimming. In I²C mode, synchronization is achieved automatically via shared bus timing and broadcast commands; no external connection is needed. This enables uniform status indication across 56 ports using up to 14 cascaded FPC402RHUT units.

What is the power-on reset timing requirement for reliable FPC402RHUT initialization?

The FPC402RHUT requires a minimum TPOR (power-on reset time) of 30 ms after VDD1 reaches ≥3.135 V. During this interval, both port-side I²C masters and host-side interfaces remain non-operational. Host communication must wait until TPOR completes and EN is asserted (or left floating). If VDD2 ramps slower than VDD1, TPOR begins only after both supplies stabilize.

Does the FPC402RHUT support hot-plug detection for pluggable optical modules?

Yes-the FPC402RHUT integrates dedicated low-speed inputs IN_A[0–3], IN_B[0–3], and IN_C[0–3] with built-in 30–50 µs deglitch filtering to reliably detect module insertion/removal (Mod_ABS/ModPrsL), transmit faults (Tx_Fault/IntL), and receive loss-of-signal (Rx_LOS). These inputs trigger programmable interrupts via HOST_INT_N, enabling zero-polling hot-plug management in systems like ToR switches and BBUs.