Analog Devices Inc./Maxim Integrated 73M1866B-IM/F

Overview

73M1866B-IM/F from Teridian Semiconductor is a single-package silicon Data Access Arrangement (MicroDAA®) for FXO VoIP interfaces, integrating PCM highway interface, G.711 μ-law/A-law codec, SPI control, and digital isolation barrier. It supports 8 kHz/16 kHz sampling, ±6 dB analog line-side transmit gain, +3 dB receive gain, and operates from 3.0–3.6 V across –40 °C to +85 °C in a 42-pin QFN package. Used in PSTN-connected VoIP gateways requiring emergency calling and redundancy.

For engineers reviewing the 73M1866B-IM/F datasheet, 73M1866B-IM/F pinout, 73M1866B-IM/F application, or 73M1866B-IM/F equivalent, key selection criteria include its integrated DAA compliance (FCC, ETSI ES 203 021-2), programmable TX/RX digital gain (–18 dB to +7.375 dB in 0.125 dB steps), THD of –80 dB, 6 kV isolation, and support for pulse dialing, ring detection, and Caller ID Type I/II.

Technical Context

The 73M1866B-IM/F implements a patented digital isolation barrier using a small pulse transformer to deliver both power and data to line-side circuitry, enabling fail-safe operation under line voltage variation and EMI. It embeds a full-featured FXO front-end with DC/AC termination, trans-hybrid cancellation, billing tone rejection, and polarity reversal detection.

Its PCM highway interface supports master/slave modes, automatic clock rate detection, and interoperability with E1/T1 framers and POTS codecs. Control is handled via SPI with daisy-chain capability for up to 16 devices, while GPIO pins enable user-configurable I/O and call progress monitoring.

Key Specifications

Pinout & Package

The 73M1866B-IM/F is housed in a 42-pin QFN package (7 mm × 7 mm) with an exposed bottom thermal pad requiring solder connection for thermal and electrical integrity per datasheet Section 2.5 and Figure 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si3050-C-FM and SLIC3710, the 73M1866B-IM/F delivers certified DAA functionality in one package-including isolation, regulation, and compliance logic-reducing time-to-certification by 6–9 months and eliminating transformer qualification overhead.

Availability

73M1866B-IM/F is available at Aetrix Electronics and suitable for VoIP gateways, PBX systems, computer telephony adapters, and voicemail appliances requiring stable component supply, long-lifecycle support, and global regulatory compliance.

Supply support for 73M1866B-IM/F 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

Teridian Semiconductor was a fabless analog/mixed-signal IC company specializing in highly integrated communications solutions before its acquisition by Maxim Integrated in 2011.

The 73M1866B-IM/F belongs to Teridian's MicroDAA™ family, designed specifically to replace discrete FXO interface circuits in VoIP equipment with a single IC meeting global PSTN interface and safety standards.

FAQ

What is the primary function of the 73M1866B-IM/F in a VoIP system?

The 73M1866B-IM/F serves as a fully integrated FXO Data Access Arrangement, enabling direct two-wire PSTN connection for VoIP gateways. It handles analog line interface, G.711 encoding/decoding, digital isolation, and regulatory-compliant signaling-replacing multiple discrete components. The 73M1866B-IM/F integrates all core DAA functions into a single 42-pin QFN package, reducing design complexity and certification risk.

Does the 73M1866B-IM/F support both μ-law and A-law companding?

Yes, the 73M1866B-IM/F includes an ITU-T G.711-compliant codec with software-selectable μ-law and A-law companding modes. This allows seamless interoperability with North American and European PSTN networks respectively. The 73M1866B-IM/F implements both algorithms in hardware, ensuring low-latency, bit-exact compliance without host processor overhead.

What isolation rating does the 73M1866B-IM/F provide, and how is it achieved?

The 73M1866B-IM/F provides 6 kV isolation via a patented digital barrier using a small pulse transformer to transfer both power and data across the line interface. This eliminates optocouplers and external isolated supplies while meeting FCC Part 68, ETSI ES 203 021-2, and JATE requirements. The 73M1866B-IM/F achieves this through on-chip transformer driver and receiver circuitry synchronized to maintain timing integrity across the barrier.

Can the 73M1866B-IM/F operate at 16 kHz sampling rate?

Yes, the 73M1866B-IM/F supports both 8 kHz and 16 kHz sampling rates. At 16 kHz, it operates in 16-bit linear mode-ideal for wideband voice applications such as HD voice messaging and speech analytics. The 73M1866B-IM/F automatically detects clock rate on PCM_CLK and configures internal paths accordingly, simplifying host interface design.

What regulatory standards does the 73M1866B-IM/F meet out-of-the-box?

The 73M1866B-IM/F is designed to meet FCC Part 68, ETSI ES 203 021-2, and JATE requirements for DAA compliance. Its programmable AC/DC termination, call progress monitor, and billing tone rejection are implemented to satisfy regional line interface specifications without external components. The 73M1866B-IM/F achieves this through factory-trimmed registers and configurable impedance tables mapped to international standards.