Analog Devices Inc. LT2940IMS#TRPBF

Overview

LT2940IMS#TRPBF from Analog Devices (formerly Linear Technology) is a high-side bidirectional power and current monitor IC featuring a four-quadrant analog multiplier, push-pull current-mode outputs for instantaneous power (PMON) and sensed current (IMON), and integrated comparator with latch control. It operates with 4V–80V high-side voltage sensing, ±200mV current sense differential input, ±5% power measurement accuracy, and supports industrial temperature range (–40°C to +85°C) in 12-lead MSOP package. It is used in server power monitoring, power sense circuit breakers, and battery charger metering.

For engineers reviewing the LT2940IMS#TRPBF datasheet, LT2940IMS#TRPBF pinout, LT2940IMS#TRPBF application, or LT2940IMS#TRPBF equivalent, key selection considerations include its ±5% full-scale power error over –40°C to +85°C, 500 kHz PMON bandwidth, 4V–80V independent current-sense input range, dual open-collector comparator outputs with 1.24 V threshold, and compatibility with high-voltage supply rails up to 80 V.

Technical Context

The LT2940IMS#TRPBF implements a true four-quadrant analog multiplier core (K_PMON = 500 μA/V²) that computes instantaneous power as the product of differential voltage (V_V = V₊ – V_–, ±8 V max) and differential current sense (V_I = V_I+ – V_I–, ±200 mV max), delivering ±200 μA full-scale PMON output. Its IMON output scales current sense voltage linearly (G_IMON = 1000 μA/V) with ±3% total error over temperature.

It integrates a precision comparator (1.24 V reference, ±35 mV hysteresis) with inverting/noninverting open-collector outputs (CMPOUT/CMPOUT), a three-state LATCH pin enabling latched or tracking mode, and independent 4V–80V current-sense input operation decoupled from V_CC (6V–80V). The device supports reverse power flow indication via bipolar PMON/IMON sourcing/sinking capability.

Key Specifications

Pinout & Package

LT2940IMS#TRPBF is housed in a 12-lead plastic MSOP package (3.0 mm × 4.0 mm, 0.65 mm pitch) with exposed pad optional for thermal enhancement. Pin 1 is CMPOUT (inverting open-collector comparator output), pin 2 is CMPOUT (noninverting), pin 3 is CMP+, pin 4 is PMON, pin 5 is IMON, pin 6 is GND, pins 7–8 are V– and V+, pin 9 is LATCH, pins 10–11 are I– and I+, and pin 12 is V_CC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA226AIDGST and MAX4008BAUD+, the LT2940IMS#TRPBF uniquely integrates analog power multiplication, bidirectional current sensing, and autonomous comparator-based alarming in a single analog IC-eliminating ADC, firmware, and external logic required by alternatives.

Availability

LT2940IMS#TRPBF is available at Aetrix Electronics and suitable for server power monitoring, power sense circuit breakers, and battery charger metering requiring stable component supply and guaranteed long-term industrial temperature grade availability.

Supply support for LT2940IMS#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.

The LT2940 product line was developed by Linear Technology specifically for high-voltage, high-accuracy analog power and current monitoring in industrial, telecom, and computing infrastructure where isolation, simplicity, and reliability are critical.

FAQ

What is the maximum common-mode voltage supported by the current sense inputs of the LT2940IMS#TRPBF?

The LT2940IMS#TRPBF supports a 4V to 80V common-mode voltage range on its I+ and I– pins-completely independent of the V_CC supply voltage. This allows direct high-side current sensing on rails up to 80 V without level-shifting circuitry. Absolute maximum rating is 100 V per pin, but operation above 80 V violates the specified accuracy range.

How does the LT2940IMS#TRPBF handle reverse power flow, and what output indicates it?

The LT2940IMS#TRPBF handles reverse power flow using its four-quadrant multiplier architecture. When voltage and current polarities oppose (e.g., regenerative braking), the PMON output sinks current (negative polarity), and IMON similarly reflects reversed current direction. Reverse power is indicated by negative PMON current relative to the defined positive convention-observable as a voltage drop across a grounded load resistor on PMON.

Can the LT2940IMS#TRPBF operate with a supply voltage below 6 V?

No. The LT2940IMS#TRPBF has a minimum specified supply voltage of 6 V and features an undervoltage lockout (UVLO) that clears at 2.5 V with 75 mV hysteresis. Operation below 6 V is outside the guaranteed specification range; below 2.5 V, the device disables outputs and enters reset state. Attempting operation at 5 V will result in undefined behavior and failure to meet accuracy or timing specs.

What is the purpose of the LATCH pin on the LT2940IMS#TRPBF, and how should it be configured for non-latching alarm operation?

The LATCH pin controls comparator output behavior: open (high-impedance) enables tracking mode; >2.5 V enables latched alarm; ≤0.5 V forces outputs clear. For non-latching (tracking) operation, leave the LATCH pin unconnected (open) or tie it to a high-impedance node. Do not tie directly to V_CC or GND unless latching or forced-clear behavior is intended. A 100 kΩ pull-up to V_CC is acceptable to ensure defined state.

Does the LT2940IMS#TRPBF require external passive components for basic power monitoring functionality?

Yes-basic operation requires external components: a sense resistor (R_SENSE) between I+ and I– to convert load current to voltage, a voltage divider (R1/R2) to scale bus voltage into the ±8 V V+–V– range, and load resistors (R_PMON, R_IMON) to convert PMON/IMON current outputs to measurable voltages. No active components (e.g., op-amps) are required for scaling or filtering due to the current-mode architecture of the LT2940IMS#TRPBF.