Broadcom Limited AFBR-FS13B25

Overview

AFBR-FS13B25 from Broadcom is a free-space optical transceiver enabling full-duplex bidirectional wireless data transmission at rates from 125 Mb/s to 1.25 Gb/s over distances of 20–100 mm. It integrates an 850-nm VCSEL transmitter and high-speed PIN photodiode receiver, operates from a single 3.3 V supply, and maintains full functionality across 360° rotation-ideal for rotary optical data feedthroughs in industrial encoders and board-to-board interconnects.

For engineers reviewing the AFBR-FS13B25 datasheet, pinout, applications, or equivalent options, key selection considerations include its differential Tx/Rx I/O, signal detect (SD) and monitor current (Imon) outputs, laser Class 1 safety compliance, SMT-compatible 5.25 × 5.25 × 4.83 mm package, and immunity to RF fields up to 10 V/m (80 MHz–6 GHz).

Technical Context

The AFBR-FS13B25 implements independent transmitter and receiver signal chains: the Tx IC converts LVDS differential inputs (0.2–1.4 V_p-p) into analog drive current for an 850-nm VCSEL (λ_c = 830–870 nm), while the Rx IC integrates a transimpedance amplifier and limiting amplifier to deliver differential logic outputs (0.18–0.33 V_p) with <200 ps rise/fall times.

It supports active control via Tx EN and Rx EN pins (active-HIGH), provides real-time optical link monitoring via Imon (mirrored PD current) and SD (logic HIGH when Imon ≥ 3 µA), and uses dedicated decoupling pins (FILT, VDD15) to stabilize Tx and Rx power domains-enabling robust operation in noisy industrial environments without enclosure shielding.

Key Specifications

Pinout & Package

AFBR-FS13B25 uses a compact 28-pin surface-mount package measuring 5.25 mm × 5.25 mm × 4.83 mm (L × W × H), with exposed thermal pad on bottom side connected to GND. Pin 1 is located at upper-left corner (top view); all GND pins (1, 2, 5, 7, 15, 17, 20, 21, 22, 24, 28) provide low-inductance return paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar optical wireless transceiver applications.

Compared with AFBR-13B25Z (identical function, packaging variant) and TFDU4301 (lower-speed, discrete-component architecture), the AFBR-FS13B25 delivers 312× higher data throughput, integrated diagnostics, and guaranteed Class 1 safety-making it the sole option for industrial motion control and certified hazardous-area wireless interfaces.

Availability

AFBR-FS13B25 is available at Aetrix Electronics and suitable for rotary optical data feedthroughs, board-to-board wireless interconnects, and through-window optical communication systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant SMT assembly.

Supply support for AFBR-FS13B25 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

Broadcom Inc. is a global semiconductor leader designing connectivity, networking, and optical components for enterprise, industrial, and communications infrastructure.

The AFBR-FS13B25 belongs to Broadcom's Free-Space Optical Transceiver product line, engineered specifically for high-reliability, alignment-tolerant wireless data transfer in motion-critical and safety-certified systems.

FAQ

What is the maximum supported data rate and corresponding bit error rate for AFBR-FS13B25?

The AFBR-FS13B25 supports up to 1.25 Gb/s with a guaranteed bit error rate of ≤2.5×10⁻¹⁰ under ideal alignment conditions using 8b10b encoding. At this rate, total jitter at the receiver is ≤0.35 UI. Performance degrades predictably with lateral misalignment or tilt-lateral tolerance is ≤1.0 mm at 30 mm link distance. The AFBR-FS13B25 datasheet specifies these values under recommended operating conditions (3.3 V, 25°C).

Does AFBR-FS13B25 require external biasing or termination resistors for its differential I/O?

No, the AFBR-FS13B25 incorporates self-biasing differential inputs and outputs. Its Tx input accepts LVDS signals (0.2–1.4 V_p-p) without external biasing, and its Rx output drives a 100 Ω differential load with common-mode voltage of 180–330 mV. External 100 nF decoupling capacitors are required at VDDRx and VDDTx, but no pull-ups, pull-downs, or termination resistors are needed on Tx+/Tx− or Rx+/Rx− lines.

How is optical link health monitored using AFBR-FS13B25?

The AFBR-FS13B25 provides two dedicated monitoring outputs: Imon (pin 10) delivers a current proportional to received optical power, enabling quantitative link margin assessment; SD (pin 9) outputs a logic HIGH (≥1.1 V) when Imon ≥ 3 µA-indicating a valid optical signal. These signals allow real-time diagnostics, automatic retraining, and predictive maintenance without external photodetectors or ADCs.

What is the significance of the FILT and VDD15 pins on AFBR-FS13B25?

FILT (pin 23) is a dedicated Tx power supply decoupling node requiring a local 100 nF capacitor to suppress high-frequency switching noise from the VCSEL driver. VDD15 (pin 27) supplies an internal 1.5 V LDO; it must be left open or connected to a 1 nF capacitor (recommended) to stabilize the internal bias network. Both pins are essential for achieving specified jitter and EMI performance-omitting either degrades signal integrity and increases BER.

Is AFBR-FS13B25 compatible with lead-free reflow processes?

Yes, AFBR-FS13B25 is qualified for lead-free reflow with a peak temperature of +245°C for ≤10 seconds (MSL 5a). Its recommended profile includes preheat, soak, and reflow stages aligned to JEDEC J-STD-020. Thermal overstress beyond these limits may damage the VCSEL or lens bond. The device's SMT solderability has been validated per IPC-J-STD-002 and IPC-J-STD-003 standards.