Analog Devices Inc. LTC2945HMS-1#PBF

Overview

LTC2945HMS-1#PBF from Analog Devices is a rail-to-rail I²C power monitor IC that measures current (via shunt), input voltage (0V–80V), and calculates 24-bit power in real time. It features a 12-bit ΔΣ ADC with ±0.75% total unadjusted error, internal multiplier, min/max tracking, and programmable overrange alerts. Used in high-side or low-side power monitoring for telecom rectifiers, automotive battery management, and industrial DC power supplies.

For engineers reviewing the LTC2945HMS-1#PBF datasheet, LTC2945HMS-1#PBF pinout, LTC2945HMS-1#PBF application, or LTC2945HMS-1#PBF equivalent, key selection criteria include its 0V–80V common-mode sense range, split SDAI/SDAO pins for opto-isolation, AEC-Q100 H-grade (–40°C to 125°C), and support for shunt regulator operation above 80V.

Technical Context

The LTC2945HMS-1#PBF integrates a 12-bit delta-sigma ADC with three simultaneous measurement channels: differential shunt voltage (ΔSENSE, 102.4mV FS), supply voltage (VIN or SENSE+, 102.4V FS), and auxiliary external voltage (ADIN, 2.048V FS). Its onboard digital multiplier computes 24-bit power values by multiplying quantized current and voltage data.

It implements continuous scan mode (7.5Hz typical update rate) and snapshot mode, stores min/max values per channel, and asserts an open-drain ALERT signal when thresholds are exceeded. The I²C interface supports nine addresses via ADR1/ADR0 and uses inverted SDAO output (LTC2945-1 variant) for compatibility with inverting opto-isolators.

Key Specifications

Pinout & Package

Package: 12-lead plastic MSOP (3mm × 4.4mm), exposed pad optional, θJA = 135°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA226AIDGST and LTC2946IMS#PBF, the LTC2945HMS-1#PBF uniquely balances 0V–80V rail-to-rail operation, hardware power calculation, inverted SDAO for opto-isolation, and AEC-Q100 H-grade qualification - making it optimal for automotive and telecom systems requiring robust isolation and wide-input monitoring without host computation.

Availability

LTC2945HMS-1#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, automotive battery management, and industrial PLC power supervision requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC2945HMS-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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and power management.

The LTC2945 product line delivers integrated, rail-to-rail power monitoring ICs with on-chip ADCs, multipliers, and alert logic - designed specifically for high-reliability, wide-input-voltage applications in automotive, telecom, and industrial systems.

FAQ

What is the operating temperature range of the LTC2945HMS-1#PBF?

The LTC2945HMS-1#PBF is rated for –40°C to +125°C (H-grade) and is AEC-Q100 qualified for automotive use. This rating applies to the full electrical specification, including ±0.75% total unadjusted error and 7.5Hz conversion rate, across the entire range. The MSOP package's θJA of 135°C/W requires appropriate PCB copper area for thermal management at maximum ambient.

How does the LTC2945HMS-1#PBF differ from the standard LTC2945HMS#PBF?

The LTC2945HMS-1#PBF features an inverted SDAO output pin, enabling direct interface with inverting opto-isolators (e.g., PC817) without external inverters. All other specifications - including 0V–80V sense range, 12-bit ADC accuracy, min/max tracking, and AEC-Q100 H-grade qualification - are identical to the LTC2945HMS#PBF. The "-1" suffix denotes this specific I²C data polarity variant.

Can the LTC2945HMS-1#PBF monitor voltages above 80V?

Yes - the LTC2945HMS-1#PBF supports operation from supplies >80V via its INTVCC shunt regulator mode. When VDD exceeds 80V, INTVCC is configured as a 6.3V shunt node; an external resistor limits current to <35mA. The SENSE+ and SENSE– pins retain their 0V–80V common-mode range, so voltage sensing above 80V requires an external resistive divider referenced to the monitored rail.

What is the purpose of the split SDAI and SDAO pins on the LTC2945HMS-1#PBF?

The LTC2945HMS-1#PBF separates I²C data into SDAI (input-only) and SDAO (inverted output-only) to simplify opto-isolated I²C bus implementation. SDAI accepts commands from the master, while SDAO returns inverted data - allowing direct connection to inverting optocouplers without external logic. This eliminates timing skew and level-shifter complexity inherent in bidirectional SDA implementations.

Does the LTC2945HMS-1#PBF require external components for basic operation?

Yes - the LTC2945HMS-1#PBF requires at minimum: (1) 0.1µF bypass capacitors on VDD and INTVCC pins, (2) external pull-up resistors on SCL and SDAI (to VDD or INTVCC), (3) pull-up on SDAO (to VDD or INTVCC), and (4) a shunt resistor between SENSE+ and SENSE–. Optional components include resistive dividers for ADIN or high-voltage VIN sensing, and a shunt resistor for INTVCC when operating above 80V.