Analog Devices Inc. LTC4310CMS-1#PBF

Overview

LTC4310CMS-1#PBF from Analog Devices (formerly Linear Technology) is a bidirectional, transformer- or capacitor-coupled I²C isolator designed for 100kHz systems with galvanic isolation between two I²C buses. It features rise time accelerators (2–6mA pull-up), ±5kV HBM ESD protection, stuck bus recovery (37ms timeout), and thermal shutdown (150°C). It enables hot-swappable I²C communication in isolated power supplies and PoE systems.

For engineers reviewing the LTC4310CMS-1#PBF datasheet, LTC4310CMS-1#PBF pinout, LTC4310CMS-1#PBF application, or LTC4310CMS-1#PBF equivalent, key selection criteria include I²C frequency support (100kHz), MSOP-10 package compatibility, isolation barrier implementation (transformer vs. capacitor), READY signal behavior, and shutdown current (<0.1µA).

Technical Context

The LTC4310CMS-1#PBF implements event-driven differential pulse transmission across an isolation barrier using TXP/TXN outputs and RXP/RXN inputs. It decodes received pulses to drive local SDA/SCL while maintaining full I²C protocol transparency-including clock stretching, arbitration, and ACK/NACK-across isolated domains.

Its dual-stage rise control operates in sequence: first limiting dV/dt to 0.8–1.4 V/µs (LTC4310-1) during 0–0.35•VCC rise, then activating IBOOST (2–6mA) above 0.45•VCC. Bus idle detection (≥115µs high) and STOP-bit synchronization enable reliable hot-swap handshaking via the READY output.

Key Specifications

Pinout & Package

Package: 10-Lead Plastic MSOP (MS package), 3mm × 3mm footprint, exposed pad optional for thermal relief.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C isolation applications.

Compared with ISO1540DR and ADUM1250ARZ, the LTC4310CMS-1#PBF delivers turnkey I²C isolation with guaranteed timing compliance, autonomous bus recovery, and integrated rise enhancement-reducing validation effort and improving field reliability in high-noise industrial environments.

Availability

LTC4310CMS-1#PBF is available at Aetrix Electronics and suitable for industrial sensor hubs, Power-over-Ethernet nodes, and hot-swappable server blades requiring stable component supply with full production traceability and long-term lifecycle support.

Supply support for LTC4310CMS-1#PBF 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

Analog Devices acquired Linear Technology in 2017 and maintains its precision analog and interface IC portfolio with rigorous automotive and industrial qualification standards.

The LTC4310CMS-1#PBF belongs to Linear's Hot Swap™ and I²C isolation product line, engineered specifically for robust, protocol-transparent galvanic separation of two-wire buses in high-reliability power and communications systems.

FAQ

What is the maximum I²C clock frequency supported by the LTC4310CMS-1#PBF?

The LTC4310CMS-1#PBF is rated for 100kHz I²C operation, matching standard-mode I²C timing specifications. It is not rated for fast-mode (400kHz) operation-that capability is reserved for the LTC4310-2 variant. Using the LTC4310CMS-1#PBF beyond 100kHz may result in timing violations, missed ACKs, or arbitration failure due to fixed internal rise rate limits and propagation delays.

Does the LTC4310CMS-1#PBF require external components for basic operation?

Yes-the LTC4310CMS-1#PBF requires external pull-up resistors on SDA and SCL (≥VCC supply), a 0.01µF bypass capacitor on VCC-to-GND, and either an Ethernet transformer (e.g., EPF8119S) or coupling capacitors on TXP/TXN and RXP/RXN. The READY pin also needs a pull-up resistor (typically 10kΩ) to function as a valid status indicator.

How does the stuck bus recovery feature work in the LTC4310CMS-1#PBF?

When SDA and SCL remain low for 37ms, the LTC4310CMS-1#PBF disables its drivers, asserts READY high, and generates up to sixteen SCL clock pulses followed by a STOP bit. This sequence attempts to release a stuck slave device. Recovery completes automatically once both buses detect a STOP or idle condition simultaneously, reactivating SDA/SCL driving and READY low assertion.

Can the LTC4310CMS-1#PBF be used with capacitor-based isolation instead of a transformer?

Yes-the LTC4310CMS-1#PBF supports capacitor-coupled isolation for lower-voltage applications (e.g., <1kV). Coupling capacitors (≥47pF) must connect TXP→RXP and TXN→RXN between two devices, with parasitic trace capacitance minimized per Figure 6. Transformer coupling remains required for 1500V-rated isolation per the datasheet's typical application.

What is the role of the READY pin on the LTC4310CMS-1#PBF?

The READY pin is an open-drain output that pulls low only when the LTC4310CMS-1#PBF has completed startup, synchronized both local and remote I²C buses (via STOP/idle detection), and is actively driving SDA/SCL with decoded remote bus states. It remains high during shutdown, thermal fault, stuck bus disconnect, or startup filtering (900µs).