Analog Devices Inc. LTC4310IDD-2#PBF

Overview

LTC4310IDD-2#PBF from Analog Devices (formerly Linear Technology) is a bidirectional I²C isolator IC designed for hot-swappable, galvanically isolated communication between two I²C buses with separated grounds. It supports 400kHz maximum SCL frequency, provides ±5kV HBM ESD protection, features rise time accelerators (2–6mA), and operates across –40°C to +85°C in a 10-lead 3mm × 3mm DFN package. It enables robust I²C isolation in Power-over-Ethernet and industrial backplane systems.

For engineers reviewing the LTC4310IDD-2#PBF datasheet, LTC4310IDD-2#PBF pinout, LTC4310IDD-2#PBF application, or LTC4310IDD-2#PBF equivalent, key selection criteria include its 400kHz I²C compliance, transformer- or capacitor-based isolation barrier support, stuck-bus recovery (37ms timeout), thermal shutdown (150°C), and dual-rail level-shifting capability across isolated domains.

Technical Context

The LTC4310IDD-2#PBF implements event-driven differential pulse encoding across an isolation barrier using TXP/TXN outputs and RXP/RXN inputs, supporting up to 1500V isolation with Ethernet transformers or capacitors. Its logic detection circuitry distinguishes local bus signals from self-driven outputs, enabling seamless clock stretching, arbitration, and ACK/NACK propagation across isolation.

It integrates rise rate limiting (dV/dtRISE = 2–6.9 V/µs at VCC = 3–5.5V), slew-limited rise time acceleration (IBOOST = 2–6 mA), and active stuck-bus recovery (16 clocks + STOP). READY output asserts low only after synchronized bus idle detection on both sides, ensuring deterministic link establishment.

Key Specifications

Pinout & Package

Package: 10-lead (3mm × 3mm) plastic DFN with exposed pad (Pin 11), rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISO1540DR and ADUM1250ARZ, the LTC4310IDD-2#PBF delivers native 400kHz I²C isolation with autonomous stuck-bus recovery, rise time acceleration, and hot-swap resilience - reducing BOM count and firmware overhead in industrial and telecom systems requiring guaranteed protocol transparency.

Availability

LTC4310IDD-2#PBF is available at Aetrix Electronics and suitable for industrial backplane monitoring, Power-over-Ethernet controllers, and modular server blade management requiring stable component supply across extended temperature ranges.

Supply support for LTC4310IDD-2#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC4310 product line was developed specifically for robust, protocol-transparent I²C isolation in hot-swap-capable industrial, telecom, and PoE infrastructure - addressing limitations of generic digital isolators in multi-master, clock-stretching environments.

FAQ

What is the maximum I²C clock frequency supported by the LTC4310IDD-2#PBF?

The LTC4310IDD-2#PBF supports a maximum SCL clock frequency of 400kHz, as specified in its Electrical Characteristics table. This distinguishes it from the LTC4310-1 variant (100kHz) and enables compatibility with fast-mode Plus I²C peripherals and PMBus devices without protocol translation or timing adjustments.

How does the LTC4310IDD-2#PBF handle a stuck I²C bus condition?

The LTC4310IDD-2#PBF monitors SDA and SCL for low states exceeding 37ms. Upon detection, it disables its drivers, transmits a recovery command to the paired device, then issues up to sixteen SCL clock pulses followed by a STOP bit. The LTC4310IDD-2#PBF resumes normal operation only after detecting synchronized bus idle or STOP on both sides.

Can the LTC4310IDD-2#PBF be used with capacitor-based isolation instead of transformers?

Yes - the LTC4310IDD-2#PBF supports both transformer-coupled (e.g., 10/100Base-TX magnetics) and capacitor-coupled isolation barriers. For capacitor coupling, use ≥47pF ceramic capacitors on RXP/RXN and TXP/TXN, with board trace parasitics minimized to ensure CRXP/CRXN ≥ 10×CPAR per the Applications Information section.

What is the purpose of the READY pin on the LTC4310IDD-2#PBF?

The READY pin on the LTC4310IDD-2#PBF is an open-drain output that pulls low only after successful synchronization - i.e., when both local and remote I²C buses have been idle for ≥115µs or a STOP bit has occurred on both sides. It signals to the host system that the isolation link is fully established and bidirectional communication is active.

Does the LTC4310IDD-2#PBF support level shifting between different supply voltages?

Yes - the LTC4310IDD-2#PBF inherently supports level shifting: its SDA and SCL pins on one side can operate at 3.3V while the other side runs at 5V, provided external pull-ups match their respective bus voltages. The isolation barrier decouples ground references, enabling safe communication between positive-to-negative rail or mixed-voltage domains.