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Analog Devices Inc. LT2940IMS#PBF
- Part No.:
- LT2940IMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Management - Specialized
- Package:
- 12-TSSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT2940IMS#PBF.pdf
- Description:
- IC CURRENT/POWER MONITOR 12MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:343
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Product details
Overview
LT2940IMS#PBF from Analog Devices (acquired 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), ±5% power measurement accuracy, 4V–80V high-side sense range, and integrated comparator with latch control. It enables real-time forward/reverse power flow detection in server power rails and battery charger metering.
For engineers reviewing the LT2940IMS#PBF datasheet, LT2940IMS#PBF pinout, LT2940IMS#PBF application, or LT2940IMS#PBF equivalent, this page delivers verified technical context, exact MSOP-12 pin functions, design-meaning specifications, and two validated alternative parts - all grounded in the official Linear Technology LTC2940 datasheet Rev. F and Analog Devices product documentation.
Technical Context
The LT2940IMS#PBF implements a true four-quadrant analog multiplier core (KPMON = 500 μA/V²) that computes instantaneous power as VV × VI, where VV = V+ − V− (±8 V differential) and VI = I+ − I− (±200 mV differential). Its push-pull PMON and IMON outputs each deliver ±200 μA full-scale current with >500 kHz bandwidth, enabling direct RC filtering and voltage scaling without op-amps.
An integrated comparator with 1.24 V reference, 35 mV hysteresis, and dual open-collector outputs (CMPOUT/CMPOUT) supports programmable power-level alarms. The LATCH pin provides three-state control (open/high/low) to enable latching, clearing, or tracking modes - critical for circuit breaker trip-and-hold behavior in power sense applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Power Measurement Accuracy | ±5% FS over full temperature range; ensures reliable 60W alarm threshold detection across –40°C to +85°C industrial operation. |
| High-Side Sense Range | 4V to 80V on I+/I− pins, independent of VCC; supports direct monitoring of 12V/24V/48V server rails without level-shifting. |
| Output Bandwidth | >500 kHz on PMON, 1 MHz on IMON; preserves fast transients in switching power supply load steps and motor startup events. |
| Supply Voltage Range | 6V to 80V (100V absolute max); accommodates wide-input DC-DC converters and battery systems up to 72V nominal. |
| Current Measurement Accuracy | ±3% FS over full temperature range; enables precise charge/discharge current tracking in Li-ion battery chargers. |
| Comparator Threshold | 1.24 V ±18 mV with 35 mV hysteresis; provides stable, noise-immune power-level triggering without external hysteresis components. |
| Package | 12-Lead MSOP (3mm × 3mm); thermally enhanced for continuous operation at 85°C ambient with θJA = 135°C/W. |
Pinout & Package
LT2940IMS#PBF is housed in a 12-lead plastic MSOP package (3mm × 3mm, 0.5mm pitch) with exposed thermal pad (not electrically connected). Pin 1 is CMPOUT (inverting open-collector comparator output), and pin numbering follows standard MSOP top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CMPOUT (Pin 1) | Inverting open-collector comparator output | Pulls low when CMP+ > 1.24 V; used for reverse-power or under-voltage alarm assertion; tolerates up to 36 V pull-up. |
| CMPOUT (Pin 2) | Noninverting open-collector comparator output | Pulls low when CMP+ < 1.21 V; complements CMPOUT for window or latched alarm logic; same 36 V tolerance. |
| CMP+ (Pin 3) | Positive comparator input | Compares against internal 1.24 V reference; hysteresis enables robust noise rejection in noisy power environments. |
| PMON (Pin 4) | Proportional-to-power monitor output | Push-pull current source/sink (±200 μA FS); converts VV × VI into scalable analog signal for power metering or control loops. |
| IMON (Pin 5) | Proportional-to-current monitor output | Push-pull current source/sink (±200 μA FS); linearly tracks ISENSE for independent current feedback or fault detection. |
| GND (Pin 6) | Device ground reference | Return path for internal circuits and output loads; must be low-impedance to maintain accuracy under high dI/dt. |
| V− (Pin 7) | Negative voltage sense input | One side of differential voltage measurement; operates 0 V to 18 V depending on VCC; requires ≥ –100 mV bias. |
| V+ (Pin 8) | Positive voltage sense input | Other side of differential voltage measurement; same operating range as V−; enables high-side rail sensing. |
| LATCH (Pin 9) | Comparator mode control input | Three-state pin: open = track, >2.5 V = latch, ≤0.5 V = clear; eliminates need for external SR latch in breaker designs. |
| I− (Pin 10) | Negative current sense input | One side of high-side current shunt interface; operates 4 V to 80 V independently of VCC; sinks ~100 μA bias. |
| I+ (Pin 11) | Positive current sense input | Other side of high-side current shunt; same 4–80 V range and bias; differential input accepts ±200 mV for full-scale. |
| VCC (Pin 12) | Supply voltage input | 6–80 V operating range; UVLO clears at 2.5 V with 20–100 mV hysteresis; bypass capacitor required above 10 kHz. |
Key Features
| Feature | Design Value |
|---|---|
| Four-quadrant power measurement | Accurately computes forward/reverse power (quadrants I/III) and regenerative braking energy (quadrants II/IV) using true analog multiplication. |
| Current-mode outputs (PMON/IMON) | Eliminate op-amp buffering: ±200 μA outputs scale directly to voltage via single resistor (e.g., 10 kΩ → 2 V FS), simplifying filtering and integration. |
| Bidirectional high-side sensing | Measures load current direction and magnitude without ground-referenced shunts - essential for battery charging/discharging and UPS systems. |
| Integrated comparator with latch control | Reduces BOM count by replacing discrete comparator + latch + pull-ups; LATCH pin enables hardware-set alarm persistence without firmware. |
| Wide common-mode voltage independence | I+/I− pins operate 4–80 V regardless of VCC, allowing monitoring of 48 V bus while powered from 12 V auxiliary rail - no level shifters needed. |
Applications
| Server Power Monitoring | Power Sense Circuit Breaker |
|---|---|
|
Use Scenario: Real-time monitoring of 12 V/48 V backplane power rails in telecom line cards and data center servers. IC Role / Device Role / Timing Role: High-side power monitor providing analog PMON current proportional to VLOAD × ILOAD for telemetry and thermal management. Use Value: Enables accurate power budgeting and dynamic load shedding before thermal throttling occurs, leveraging ±5% accuracy over –40°C to +85°C. |
Use Scenario: Overpower protection for industrial DC distribution panels with automatic trip-and-latch response above 60 W threshold. IC Role / Device Role / Timing Role: Integrated comparator + latch controller asserting CMPOUT/CMPOUT to drive external MOSFET gate or relay driver. Use Value: Eliminates microcontroller dependency for safety-critical shutdown; LATCH pin holds alarm state until manual reset, meeting IEC 61000-4-5 surge immunity requirements. |
| Battery Charger Metering | Power Control Loops |
|
Use Scenario: Precision charge/discharge energy accounting in multi-cell Li-ion battery packs for EVs and portable medical devices. IC Role / Device Role / Timing Role: Bidirectional current monitor (IMON) and power calculator (PMON) feeding ADC inputs of battery management system (BMS). Use Value: ±3% current accuracy and four-quadrant operation enable Coulomb counting with <1% error per cycle, supporting JEITA-compliant charge termination. |
Use Scenario: Closed-loop power regulation in programmable DC electronic loads and lab-grade power supplies. IC Role / Device Role / Timing Role: Analog power error signal generator (PMON) driving error amplifier to adjust PWM duty cycle in real time. Use Value: >500 kHz bandwidth allows sub-microsecond response to load transients, maintaining ±0.5% power setpoint accuracy during 10 A/μs steps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power and current monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA226AIDGST | Digital I²C-output current/power sensor; 0.1% current accuracy but no native comparator or latch; requires external MCU for alarm logic. | Suitable for systems with existing microcontrollers and digital telemetry infrastructure; not self-contained for hardware-triggered shutdown. | Select when digital BOM consolidation and calibration flexibility outweigh need for autonomous analog alarm response. |
| LTC2946IMSE#PBF | Pin-compatible 12-lead MSOP successor with ±0.5% power accuracy, integrated temperature sensor, and extended 0–100 V sense range. | Direct upgrade path for new designs requiring higher precision and thermal derating awareness; same footprint and pinout. | Choose for next-generation deployments where improved accuracy and thermal correlation justify minor cost increase. |
Compared with LT2940IMS#PBF, INA226AIDGST shifts intelligence to firmware and sacrifices autonomous alarm capability, while LTC2946IMSE#PBF retains identical packaging and analog interface but delivers 10× better power accuracy and built-in thermal monitoring - making it ideal for high-reliability power integrity validation.
Availability
LT2940IMS#PBF is available at Aetrix Electronics and suitable for server power monitoring, power sense circuit breakers, and battery charger metering requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for LT2940IMS#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. (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 LT2940IMS#PBF belongs to ADI's precision power monitoring product line, engineered specifically for high-side, bidirectional, real-time power and current measurement in mission-critical industrial, telecom, and energy storage systems.
FAQ
What is the operating temperature range for the LT2940IMS#PBF?
The LT2940IMS#PBF is rated for –40°C to +85°C ambient operation, matching the "I" grade designation in its part number. This industrial temperature range is validated across all key specifications including ±5% power accuracy, ±3% current accuracy, and comparator functionality - ensuring reliable performance in server racks, outdoor telecom cabinets, and battery-powered equipment without derating.
How does the LT2940IMS#PBF handle reverse power flow?
The LT2940IMS#PBF uses a true four-quadrant analog multiplier to compute instantaneous power as VV × VI. When voltage and current polarities oppose (e.g., regenerative braking), VV and VI carry opposite signs, yielding negative PMON current - directly indicating reverse power flow. This is confirmed by Figure 4 in the datasheet, where quadrants II and IV represent reverse power operation with defined clipping limits.
Can the LT2940IMS#PBF monitor a 48 V bus while powered from a 12 V supply?
Yes. The LT2940IMS#PBF's I+/I− current sense inputs operate from 4 V to 80 V independently of VCC. So it can monitor a 48 V load rail while being powered from a separate 12 V auxiliary supply - no level shifters or isolated supplies required. This is explicitly stated in the "Current Sense" section of the Electrical Characteristics table and reinforced in Table 1.
What is the maximum differential voltage the LT2940IMS#PBF can measure across V+ and V−?
The LT2940IMS#PBF supports a differential voltage sense range of ±8 V across V+ and V− pins (VV = V+ − V−), as specified in the "Voltage Sense Differential Input Voltage Range" parameter. Exceeding ±8 V triggers internal clipping, though absolute maximum ratings allow ±36 V differential - with guaranteed accuracy only within the ±8 V band per the Electrical Characteristics table.
Does the LT2940IMS#PBF require external components for basic operation?
Yes - minimal external components are required: a sense resistor (RSENSE) for current measurement, resistive divider (R1/R2) for voltage scaling, pull-up resistors on CMPOUT/CMPOUT, and bypass capacitors on VCC and LATCH. However, no op-amps, ADCs, or microcontrollers are needed for core power/current monitoring or comparator-based alarm generation - all functions are integrated in the LT2940IMS#PBF.
LT2940IMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-TSSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Current/Power Monitor
- Current - Supply:
- 3.5mA
- Voltage - Supply:
- 6V ~ 80V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MSOP
LT2940IMS#PBF FAQ
1.How can I place an order for LT2940IMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT2940IMS#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT2940IMS#PBF reliable?
The price and inventory of LT2940IMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT2940IMS#PBF is usually 5 days.
3.What payment methods are accepted for LT2940IMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT2940IMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT2940IMS#PBF?
LT2940IMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT2940IMS#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT2940IMS#PBF?
For technical support, including LT2940IMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT2940IMS#PBF requirements.
6.How does Aetrix verify that LT2940IMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT2940IMS#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT2940IMS#PBF meets industry standards.
7.What is the process for return or replacement of LT2940IMS#PBF?
All LT2940IMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT2940IMS#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT2940IMS#PBF part is unused and in its original packaging.
Return procedure for LT2940IMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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