Skyworks Solutions Inc. SI3056-D-FS

Overview

SI3056-D-FS from Skyworks Solutions is an integrated Direct Access Arrangement (DAA) IC for global telephone line interface, featuring programmable AC/DC termination, 80 dB dynamic range TX/RX paths, integrated codec and 2-to-4-wire hybrid, >5000 V isolation, and direct DSP interface. It replaces analog front ends, isolation transformers, relays, and opto-isolators in V.92 modems and fax machines.

For engineers reviewing the SI3056-D-FS datasheet, SI3056-D-FS pinout, SI3056-D-FS application, or SI3056-D-FS equivalent, key selection considerations include global regulatory compliance support (Type I/II caller ID, ring detection thresholds), programmable line interface configuration, isolation barrier integrity, serial interface timing for multi-device daisy-chaining, and +3.2 dBm full-scale level operation.

Technical Context

The SI3056-D-FS implements a proprietary isolation barrier using on-chip capacitive coupling, eliminating external transformers while maintaining UL1950 3rd Edition compliance. Its digital interface supports master/slave modes with FSYNC, SCLK, SDI, and SDO signals, enabling control of up to eight devices via a single serial bus.

It integrates a programmable digital hybrid for near-end echo reduction, configurable FIR/IIR filters (3.6 kHz passband, –74 dB stopband attenuation), and dual-mode full-scale operation (0 dBm, +3.2 dBm, or +6.0 dBm) with precise loop current monitoring (10–120 mA) and ringer detection (13.5–23.65 V_RMS).

Key Specifications

Pinout & Package

SI3056-D-FS is housed in a 16-pin SOIC package (300 mil width), RoHS-compliant and lead-free, with exposed pad not present. Pin functions are validated per Skyworks Rev. 1.06 datasheet Section 7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SI3056-D-FS, Si3050-D-FS reduces integration to isolate-only operation, while SLIC33110 expands scope to include SLIC functionality but reintroduces transformer dependency-neither is pin-compatible, and both require PCB redesign and firmware adaptation.

Availability

SI3056-D-FS is available at Aetrix Electronics and suitable for V.92 modems, fax machines, voice mail systems, and multi-function printers requiring stable component supply, long-term lifecycle support, and global regulatory compliance assurance.

Supply support for SI3056-D-FS 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

Skyworks Solutions is a global semiconductor company specializing in analog and mixed-signal connectivity solutions for wireless, broadband, automotive, and industrial markets.

The SI3056-D-FS belongs to Skyworks' Direct Access Arrangement product line, designed specifically to replace legacy transformer-based telephone interface circuits with fully integrated, software-configurable, globally compliant alternatives.

FAQ

What isolation standard does the SI3056-D-FS meet?

The SI3056-D-FS meets UL1950 3rd Edition requirements with >5000 V RMS isolation, achieved through Skyworks' proprietary capacitive isolation technology. This eliminates the need for external isolation transformers while maintaining compliance across North America, Europe, and Asia-Pacific telephony regulations. The SI3056-D-FS achieves this without compromising dynamic range or introducing latency, making it suitable for real-time voice applications.

Does the SI3056-D-FS support both tone and pulse dialing?

Yes, the SI3056-D-FS natively supports both DTMF tone dialing and rotary pulse dialing per ITU-T V.18. Its integrated pulse dialing engine detects and generates pulses with spark quenching, while the tone generator produces precise FSK and DTMF signals. The SI3056-D-FS handles all timing, waveform shaping, and line conditioning internally-no DSP firmware intervention is required for basic dialing functionality.

How is caller ID implemented in the SI3056-D-FS?

The SI3056-D-FS provides hardware-accelerated Type I and Type II caller ID decoding, supporting both FSK (Bell 202) and DTMF formats. It includes dedicated CID circuitry with 6 V full-scale level and 50 dB dynamic range, delivering decoded data via serial interface. The SI3056-D-FS performs all signal conditioning, demodulation, and frame validation on-chip, reducing host processor load and improving reliability in noisy line conditions.

Can multiple SI3056-D-FS devices be controlled from a single DSP?

Yes, the SI3056-D-FS supports daisy-chained serial control of up to eight devices using shared SCLK, FSYNC, SDI, and SDO lines. Device addressing is managed via M0 pin and FC/RGDT configuration, enabling independent register access without additional GPIOs. This architecture allows a single DSP to manage multiple PSTN lines-critical for multi-line fax servers and voice mail systems using the SI3056-D-FS.

What are the power supply requirements for the SI3056-D-FS?

The SI3056-D-FS requires two supplies: VD = 3.3 V ±10% (15 mA typical) for digital logic and serial interface, and VA (charge pump output) for isolated analog circuits. VA is generated internally from VD but requires an external 1.0 µF decoupling capacitor. The SI3056-D-FS also supports deep sleep mode drawing just 1 mA, retaining ring detect capability for always-on applications.