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Analog Devices Inc. LT2940CMS#PBF
- Part No.:
- LT2940CMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Management - Specialized
- Package:
- 12-TSSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT2940CMS#PBF.pdf
- Description:
- IC CURRENT/POWER MONITOR 12MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:543
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Product details
Overview
LT2940CMS#PBF from Analog Devices (acquired Linear Technology) is a high-side 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 open-collector outputs. It enables bidirectional power flow detection in server power rails and battery charger metering.
For engineers reviewing the LT2940CMS#PBF datasheet, LT2940CMS#PBF pinout, LT2940CMS#PBF application, or LT2940CMS#PBF equivalent, this page delivers verified specifications, MSOP-12 pin functions, real-world use cases in line-card monitoring and power-sense circuit breakers, and two validated alternative parts with documented technical differences.
Technical Context
The LT2940CMS#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 PMON and IMON outputs are push-pull current sources/sinks (±200 μA full-scale) with >500 kHz bandwidth and independent compliance voltage limits tied to VCC.
It integrates a precision comparator (1.24 V threshold, ±35 mV hysteresis) with dual open-collector outputs (CMPOUT/CMPOUT) and a three-state LATCH pin enabling latched alarm mode. The current sense inputs (I+/I−) operate from 4 V to 80 V independently of VCC, supporting high-side sensing in 12 V–48 V systems without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Power Measurement Accuracy | ±5% full-scale error over ±0.4 V² input product range; enables reliable 60 W alarm triggering in load monitor circuits. |
| High-Side Sense Range | 4 V to 80 V on I+/I− pins, independent of VCC; supports direct sensing across 12 V, 24 V, and 48 V industrial/server rails. |
| Output Bandwidth | >500 kHz for PMON, 1 MHz for IMON; preserves fast transients in switching power supply feedback or motor current profiling. |
| Supply Voltage Range | 6 V to 80 V (100 V absolute max); accommodates wide-input DC-DC converters and battery stacks up to 72 V. |
| Current Monitor Accuracy | ±3% full-scale error; ensures precise charge/discharge current tracking in battery management systems. |
| Comparator Threshold | 1.24 V with ±35 mV hysteresis; provides stable over-power trip at defined VCC-independent reference. |
| Package | 12-lead MSOP (3 mm × 4.4 mm); compatible with standard surface-mount assembly and thermal relief pads. |
Pinout & Package
LT2940CMS#PBF is housed in a 12-lead plastic MSOP package (0°C to 70°C operating range) 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−/V+, pins 9 is LATCH, pins 10–11 are I−/I+, and pin 12 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CMPOUT (1) | Inverting comparator output | Pulls low when CMP+ > 1.24 V; drives external LED or latch logic; tolerates up to 36 V pull-up. |
| CMPOUT (2) | Noninverting comparator output | Pulls low when CMP+ < 1.21 V; complements CMPOUT for window or polarity-sensitive alarms. |
| CMP+ (3) | Comparator positive input | Compares against internal 1.24 V reference; hysteresis prevents chatter during slow-rising power thresholds. |
| PMON (4) | Proportional-to-power output | Sources/sinks ±200 μA proportional to VV × VI; converts to voltage via RPMON resistor for analog power readout. |
| IMON (5) | Proportional-to-current output | Sources/sinks ±200 μA proportional to VI; enables simultaneous current monitoring without extra op-amps. |
| GND (6) | Device ground reference | Return path for all analog and digital circuitry; must be low-impedance for accurate high-side sensing. |
| V− (7), V+ (8) | Voltage sense differential inputs | Measure load voltage drop across series resistor or direct rail sense; ±8 V differential range. |
| LATCH (9) | Comparator mode control | Three-state input: open = tracking, >2.5 V = latched alarm, ≤0.5 V = cleared outputs. |
| I− (10), I+ (11) | Current sense differential inputs | Accept 4–80 V common-mode; bias current ~100 μA; ±200 mV differential range for shunt-based current sensing. |
| VCC (12) | Supply voltage input | 6–80 V operation; UVLO clears at 2.5 V with 75 mV hysteresis; bypass capacitor required above 10 kHz. |
Key Features
| Feature | Design Value |
|---|---|
| Four-quadrant power measurement | Accurately computes forward/reverse power (quadrants I–IV) using true analog multiplication - essential for regenerative braking or bidirectional DC-DC monitoring. |
| Independent high-side current sense range | I+/I− pins operate from 4 V to 80 V regardless of VCC, eliminating need for isolated supplies or level shifters in high-voltage rail monitoring. |
| Push-pull current-mode outputs | PMON and IMON drive resistive loads directly - scaling, filtering, and integration require only external R/C components, reducing BOM count. |
| Integrated comparator with latch control | Dual open-collector outputs + LATCH pin enable self-holding over-power alarms without external flip-flops or microcontroller intervention. |
| Guaranteed accuracy over ±0.4 V² input product | Delivers ±5% power error within defined VV × VI envelope (e.g., 8 V × 50 mV), ensuring consistent trip points across voltage/current variations. |
Applications
| Server Line Card Power Monitoring | Power-Sense Circuit Breaker |
|---|---|
Use Scenario: Real-time power consumption tracking on telecom line cards with variable 12 V/48 V input and dynamic load profiles. IC Role / Device Role / Timing Role: LT2940CMS#PBF measures high-side voltage and current simultaneously, multiplies them into instantaneous power, and feeds analog output to ADC or comparator for overload detection. Use Value: Enables per-card power budgeting and graceful shutdown before system-level brownout; ±5% accuracy ensures reliable 60 W alarm threshold per card. | Use Scenario: Overload protection in industrial DC distribution panels where fast response to >60 W fault conditions is required. IC Role / Device Role / Timing Role: LT2940CMS#PBF's comparator triggers latch mode upon exceeding threshold, holding CMPOUT low to activate solid-state relay or MOSFET gate driver. Use Value: Eliminates software polling delay; hardware-latched alarm responds in <2 μs propagation time, preventing thermal damage during short-circuit events. |
| Battery Charger Metering | Power Control Loop Feedback |
Use Scenario: Bidirectional energy accounting in Li-ion fast chargers supporting both CC/CV charging and discharge testing. IC Role / Device Role / Timing Role: LT2940CMS#PBF monitors charger output voltage and current, computes real-time power, and outputs PMON/IMON for MCU integration or analog integrator. Use Value: Four-quadrant operation captures charging (positive power) and discharging (negative power), enabling net energy calculation with ±3% current accuracy. | Use Scenario: Closed-loop power regulation in programmable DC loads or active dummy loads used for power supply validation. IC Role / Device Role / Timing Role: LT2940CMS#PBF provides analog power feedback signal (PMON) to error amplifier controlling MOSFET conduction in real time. Use Value: >500 kHz bandwidth maintains loop stability at high switching frequencies; current-mode output avoids ADC latency in fast-response control paths. |
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 | 16-bit ΔΣ ADC with I²C interface; 0.1% power accuracy; 36 V max common-mode; no integrated comparator. | Digital-output only; requires MCU firmware for alarm logic; better accuracy but slower update rate (up to 1 kHz). | Select for systems needing high-precision digital power telemetry and existing I²C infrastructure; not suitable for analog-only or sub-microsecond alarm response. |
| LTC2946IMS#PBF | 24-bit ΣΔ ADC, integrated temperature sensor, 100 V max common-mode, ±0.5% power accuracy, SPI interface. | Full digital power/energy metering SOC; includes Coulomb counting and energy accumulation registers; no analog PMON/IMON outputs. | Select for energy metering applications requiring kWh integration and long-term logging; lacks LT2940CMS#PBF's analog immediacy and comparator hardware latch. |
Compared with INA226AIDGST and LTC2946IMS#PBF, LT2940CMS#PBF offers unique analog immediacy-its current-mode PMON/IMON outputs and hardware comparator enable deterministic, zero-software-overhead power monitoring and alarm triggering, critical in safety-critical or resource-constrained embedded systems.
Availability
LT2940CMS#PBF is available at Aetrix Electronics and suitable for server line card monitoring, power-sense circuit breakers, and battery charger metering requiring stable component supply and guaranteed 0°C to 70°C industrial temperature performance.
Supply support for LT2940CMS#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 LT2940CMS#PBF belongs to ADI's precision power monitoring product line, designed specifically for high-side, wide-common-mode, analog-domain power and current measurement in telecom, industrial, and battery-powered systems where deterministic response and minimal external components are essential.
FAQ
What is the operating temperature range for the LT2940CMS#PBF?
The LT2940CMS#PBF is rated for 0°C to 70°C ambient operation, as confirmed by its "C" grade designation in the order information table. This makes it suitable for commercial and industrial environments where extended temperature tolerance is not required, unlike the "I" grade (–40°C to 85°C) variants such as LT2940IMS#PBF.
Can the LT2940CMS#PBF measure reverse power flow?
Yes, the LT2940CMS#PBF supports true four-quadrant operation: its analog multiplier correctly handles bidirectional high-side currents and bipolar voltage differences, allowing it to indicate forward (quadrants I/III) and reverse (quadrants II/IV) power flow via polarity-reversing PMON output current.
What is the maximum common-mode voltage on the I+ and I− pins of the LT2940CMS#PBF?
The I+ and I− pins of the LT2940CMS#PBF operate over a 4 V to 80 V common-mode range, independent of VCC, with absolute maximum rating of 100 V per pin. This enables direct high-side sensing on 48 V server rails without auxiliary level-shifting circuitry.
How does the LATCH pin function in the LT2940CMS#PBF?
The LATCH pin on the LT2940CMS#PBF controls comparator behavior: when open, outputs track CMP+; when pulled >2.5 V, outputs latch on over-threshold condition; when ≤0.5 V or VCC < 2.5 V, outputs clear regardless of CMP+. This enables hardware-set/hardware-reset alarm states without MCU involvement.
What are the full-scale output ranges for PMON and IMON on the LT2940CMS#PBF?
Both PMON and IMON deliver ±200 μA full-scale output current. PMON scales to ±0.4 V² input product (e.g., 8 V × 50 mV), while IMON scales to ±200 mV differential input. Each output has defined compliance voltage limits dependent on VCC, ensuring proper operation across the 6 V–80 V supply range.
LT2940CMS#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:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MSOP
LT2940CMS#PBF FAQ
1.How can I place an order for LT2940CMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT2940CMS#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 LT2940CMS#PBF reliable?
The price and inventory of LT2940CMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT2940CMS#PBF is usually 5 days.
3.What payment methods are accepted for LT2940CMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT2940CMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT2940CMS#PBF?
LT2940CMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT2940CMS#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 LT2940CMS#PBF?
For technical support, including LT2940CMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT2940CMS#PBF requirements.
6.How does Aetrix verify that LT2940CMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT2940CMS#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 LT2940CMS#PBF meets industry standards.
7.What is the process for return or replacement of LT2940CMS#PBF?
All LT2940CMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT2940CMS#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 LT2940CMS#PBF part is unused and in its original packaging.
Return procedure for LT2940CMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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