Analog Devices Inc. LTC2945CUD-1#TRPBF

Overview

LTC2945CUD-1#TRPBF from Analog Devices is a rail-to-rail I²C power monitor IC that measures current (0V–80V sense range), voltage (0V–80V common-mode), and calculates 24-bit power via internal digital multiplier. It features ±0.75% total unadjusted error, 12-bit ΔΣ ADC, and operates from 2.7V to 80V supply - used in telecom power shelves, automotive battery monitoring, and industrial DC bus supervision.

For engineers reviewing the LTC2945CUD-1#TRPBF datasheet, LTC2945CUD-1#TRPBF pinout, LTC2945CUD-1#TRPBF application, or LTC2945CUD-1#TRPBF equivalent, key selection criteria include its inverted SDAO for opto-isolated I²C, 0.02Ω shunt compatibility, programmable ALERT thresholds, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The LTC2945CUD-1#TRPBF integrates a 12-bit delta-sigma ADC with dedicated channels for differential current sense (∆SENSE), supply voltage (VDD/SENSE+), and auxiliary analog input (ADIN). Its onboard logic continuously computes real-time power (24-bit) by multiplying digitized current and voltage values, stores min/max registers per channel, and triggers ALERT on threshold violation.

It supports dual power architectures: linear regulation from VDD (4V–80V → 5V INTVCC) or shunt regulation at INTVCC (6.3V clamp) for >80V supplies. The inverted SDAO output enables direct interface with inverting opto-isolators without external logic inversion.

Key Specifications

Pinout & Package

Package: 12-lead (3mm × 3mm) plastic QFN (UD package) with optional exposed pad (Pin 13) for thermal management. RoHS-compliant, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA226AIDGST, LTC2945CUD-1#TRPBF provides native >80V capability and integrated shunt regulation; compared with LTC2946CUH#TRPBF, it offers cost-optimized 12-bit performance with identical footprint and inverted SDAO for opto-isolation - ideal for AEC-Q100-compliant automotive modules.

Availability

LTC2945CUD-1#TRPBF is available at Aetrix Electronics and suitable for telecom infrastructure, automotive battery monitoring, and industrial DC motor drive applications requiring stable component supply, long-term lifecycle support, and AEC-Q100-qualified parts.

Supply support for LTC2945CUD-1#TRPBF 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2945 product line delivers highly integrated, rail-to-rail power monitoring solutions targeting high-reliability systems where accuracy, wide voltage range, and autonomous fault detection are critical - especially in automotive and telecom infrastructure.

FAQ

What is the key functional difference between LTC2945CUD-1#TRPBF and the standard LTC2945CUD#TRPBF?

The LTC2945CUD-1#TRPBF features an inverted SDAO (I²C data output) pin, enabling direct interface with inverting opto-isolators without external logic gates. This simplifies isolated communication in high-voltage systems. The standard LTC2945CUD#TRPBF uses non-inverted SDAO. Both share identical measurement accuracy, power architecture, and register map - only the SDAO polarity differs.

Does LTC2945CUD-1#TRPBF support operation from a −48V telecom supply?

Yes. LTC2945CUD-1#TRPBF supports negative supply configurations: connect VDD to −48V, tie GND to system ground, and use the INTVCC shunt regulator mode with appropriate R_SHUNT. The SENSE+ and SENSE− pins tolerate −1V to 100V differential, enabling low-side current sensing on negative rails. Figure 4 in the datasheet confirms this topology.

How does the min/max tracking work in LTC2945CUD-1#TRPBF, and can it be reset?

LTC2945CUD-1#TRPBF autonomously updates dedicated min/max registers for ∆SENSE, VIN, and ADIN in continuous scan mode. These registers retain extremes until explicitly cleared via I²C write to the CONTROL register's "Clear Min/Max" bit (bit A0). No host polling is required - the hardware handles all tracking, reducing firmware overhead and ensuring no transient peaks are missed.

What is the maximum shunt resistor value supported for accurate current measurement with LTC2945CUD-1#TRPBF?

LTC2945CUD-1#TRPBF measures differential voltage across the shunt with 102.4mV full-scale range and 25µV LSB resolution. For 1% full-scale accuracy, the shunt must develop ≥1.024mV at minimum expected current. With typical 5.12A full-scale using 0.02Ω (per datasheet Fig 1), the practical upper limit is ~0.1Ω for ≤1A full-scale - constrained by noise floor and offset error (±3.1 LSB). Larger values require calibration.

Is LTC2945CUD-1#TRPBF compatible with standard I²C master controllers without modification?

Yes. LTC2945CUD-1#TRPBF uses standard I²C protocol (400kHz max) with SDAI (input) and SDAO (inverted output) pins. The master communicates normally using SDAI for writes and reads SDAO for responses. Inversion is handled internally - no software or timing changes are needed. Pull-up resistors on both lines are required, referenced to INTVCC or VDD as appropriate.