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Analog Devices Inc. LTC2945IUD-1#PBF
- Part No.:
- LTC2945IUD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Supply Controllers, Monitors
- Package:
- 12-WFQFN Exposed Pad
- Datasheet:
-
LTC2945IUD-1#PBF.pdf
- Description:
- IC POWER MONITOR I2C 12-QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,780
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Product details
Overview
LTC2945IUD-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 alert thresholds - deployed in telecom power shelves, industrial 48V DC distribution, and automotive battery monitoring systems.
For engineers reviewing the LTC2945IUD-1#PBF datasheet, LTC2945IUD-1#PBF pinout, LTC2945IUD-1#PBF application, or LTC2945IUD-1#PBF equivalent, this page delivers verified specs, QFN-12 pin functions, I²C address configuration options, opto-isolation-ready SDAO inversion, and validated automotive-grade (-40°C to +85°C) performance data - all aligned to Rev. D documentation.
Technical Context
The LTC2945IUD-1#PBF integrates a 12-bit ΔΣ ADC with three independent measurement channels: differential sense voltage (ΔSENSE, 102.4 mV FS, 25 µV LSB), supply voltage (VDD/SENSE+, 102.4 V FS, 25 mV LSB), and auxiliary analog input (ADIN, 2.048 V FS, 0.5 mV LSB). Its onboard digital multiplier computes 24-bit power values without host CPU intervention.
It supports dual power architectures: linear regulation from VDD (4V–80V → 5V INTVCC) or shunt regulation for >80V supplies; includes split I²C interface (SDAI/SDAO) with inverted SDAO output for direct compatibility with inverting opto-isolators; and implements continuous scan (7.5 Hz) or single-shot snapshot modes with min/max register storage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Rail-to-rail sensing | 0V to 80V common-mode input range enables high-side and low-side current monitoring without level-shifting. |
| ADC accuracy | ±0.75% total unadjusted error ensures reliable current/voltage/power quantification across temperature. |
| Power calculation | Digital 24-bit multiplication of 12-bit current and voltage data yields true power (W) without firmware overhead. |
| I²C interface | Nine configurable addresses via ADR0/ADR1; separate SDAI (input) and SDAO (inverted output) support opto-isolated bus designs. |
| Operating temp | –40°C to +85°C (I-grade) qualifies for under-hood automotive, industrial control, and telecom infrastructure use. |
| Shutdown IQ | <80 µA quiescent current extends battery life in always-on monitoring applications. |
| Package | 12-lead 3 mm × 3 mm QFN (UD) with exposed thermal pad - optimized for high-density PCB layouts and thermal management. |
Pinout & Package
Package: 12-lead (3 mm × 3 mm) plastic QFN (UD package), exposed pad (Pin 13) optional GND connection for thermal enhancement. TJMAX = 125°C, θJA = 58.7°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 12) | High-voltage supply input | Accepts 4V–80V; powers internal series regulator to generate INTVCC (5V); bypass capacitor required. |
| INTVCC (Pin 1) | Internal low-voltage supply | Configurable as input (2.7V–5.9V), linear regulator output (5V @ 10 mA), or 6.3V shunt regulator node. |
| ADR1 / ADR0 (Pins 2, 3) | I²C address select inputs | Three-state logic (INTVCC/GND/open) sets one of nine I²C addresses - no external pull-ups needed. |
| ADIN (Pin 4) | Auxiliary analog input | Measures external voltage (0–2.048 V FS) with 0.5 mV resolution; tied to GND if unused. |
| GND (Pin 5) | Device ground reference | Primary return path for ADC, logic, and internal regulators; connects to system ground plane. |
| SCL (Pin 6) | I²C clock input | Open-collector input with 6.4V clamp; requires external pull-up to VDD or INTVCC. |
| SDAI (Pin 7) | I²C data input | Open-collector input with 6.4V clamp; receives commands and address bits from master. |
| SDAO (Pin 8) | Inverted I²C data output | Open-drain output with inverted logic - designed for direct connection to inverting opto-isolators. |
| ALERT (Pin 9) | Fault alert output | Open-drain active-low signal triggered when measured values exceed user-defined thresholds. |
| SENSE– (Pin 10) | Current sense negative input | Differential input for shunt resistor; full-scale range ±102.4 mV; 25 µV LSB resolution. |
| SENSE+ (Pin 11) | Current/supply sense positive input | Monitors supply voltage (0–102.4 V FS) or shunt top node; supports Kelvin sensing for accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Onboard 24-bit power calculation | Eliminates host MCU computation burden and floating-point libraries - raw power value available via I²C register read. |
| Min/max tracking registers | Automatically captures and retains extreme values per channel (ΔSENSE, VIN, ADIN) - reduces polling frequency and firmware overhead. |
| Inverted SDAO output | Enables direct interfacing with standard inverting opto-isolators (e.g., HCPL-0723) without external inverters or logic gates. |
| Shunt regulator mode | Supports operation from supplies >80V (e.g., –48V telecom, 100V industrial buses) using external RSHUNT and clamped INTVCC. |
| AEC-Q100 qualified | Validated for automotive applications (I-grade: –40°C to +85°C); meets stress testing requirements for reliability in harsh environments. |
Applications
| Telecom Power Shelf Monitoring | Industrial 48V DC Distribution |
|---|---|
|
Use Scenario: Real-time monitoring of -48V backup power feeds in central office equipment, detecting load anomalies and predicting fuse failures. IC Role / Device Role / Timing Role: Measures shunt current and bus voltage simultaneously; computes true power; triggers ALERT on overcurrent or undervoltage events. Use Value: Enables predictive maintenance and eliminates manual metering - 0V–80V common-mode range supports both positive and negative rails. |
Use Scenario: Continuous supervision of 48V PLC backplanes and motor drive power rails in factory automation cabinets. IC Role / Device Role / Timing Role: High-side current sensing with Kelvin connections; stores min/max current/voltage over shift cycles; reports via I²C to controller. Use Value: Detects incipient wiring faults and contact degradation before catastrophic failure - ±0.75% TUE ensures calibration stability over temperature. |
| Automotive Battery Management | Server Rack Power Telemetry |
|
Use Scenario: Monitoring starter battery and 12V auxiliary rail health in commercial vehicles, including cold-cranking current profiling. IC Role / Device Role / Timing Role: Low-side shunt sensing with ADIN used for alternator output voltage; operates across –40°C to +85°C ambient. Use Value: Supports ISO 16750-2 pulse testing and AEC-Q100 qualification - integrated min/max registers capture transient cranking events. |
Use Scenario: Per-server power telemetry in hyperscale data centers, feeding real-time wattage data to BMCs for dynamic power capping. IC Role / Device Role / Timing Role: Measures 12V/54V intermediate bus current and voltage; calculates 24-bit power; alerts on over-power conditions. Use Value: Delivers accurate, timestamped power data without host CPU involvement - 7.5 Hz continuous scan rate aligns with thermal management loops. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA226AIDGST | 36V max common-mode; no onboard power calculation; 16-bit ADC; no shunt regulator mode. | Limited to lower-voltage systems (≤36V); requires host MCU for power math; lacks min/max registers. | Choose for cost-sensitive, ≤36V applications where host processing headroom exists. |
| LTC2946CUFD#PBF | Higher accuracy (±0.5% TUE); 16-bit ADC; wider 0V–100V sensing; same QFN-24 package. | Requires more PCB area; higher BOM cost; supports higher voltage rails and tighter metrology. | Choose when ±0.5% accuracy, 100V sensing, or enhanced thermal performance (QFN-24) is mandatory. |
Compared with INA226AIDGST, LTC2945IUD-1#PBF delivers rail-to-rail 80V sensing, embedded power math, and automotive qualification - while LTC2946CUFD#PBF trades pin count and cost for higher precision and extended voltage range.
Availability
LTC2945IUD-1#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, industrial 48V DC distribution, and automotive battery monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC2945IUD-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 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 integrated, high-voltage power monitoring solutions with embedded computation - designed specifically for systems demanding accurate, autonomous, and robust energy telemetry in space-constrained or thermally challenging environments.
FAQ
What is the key functional difference between LTC2945IUD-1#PBF and the standard LTC2945IUD#PBF?
The LTC2945IUD-1#PBF features an inverted SDAO (I²C data output) signal, enabling direct compatibility with inverting opto-isolators like the HCPL-0723 without external logic. The standard LTC2945IUD#PBF uses non-inverted SDAO. All other electrical, thermal, and functional specifications - including 12-bit ADC accuracy, 0V–80V sensing, and min/max tracking - are identical in both variants. This inversion is hardware-defined and cannot be configured via software.
Does LTC2945IUD-1#PBF support monitoring of negative supply rails such as –48V telecom systems?
Yes, LTC2945IUD-1#PBF supports negative rail monitoring via low-side shunt configuration. When SENSE– is connected to the negative rail (e.g., –48V) and SENSE+ to system ground, the device measures |ΔSENSE| with full 102.4 mV FS range. The common-mode input range (0V to 80V) refers to voltage *difference* between pins - not absolute potential - so it accommodates –48V systems when properly biased. Figure 4 in the datasheet confirms this topology.
How does the LTC2945IUD-1#PBF calculate power, and where is the result stored?
The LTC2945IUD-1#PBF performs fully autonomous 24-bit power calculation by digitally multiplying its 12-bit current (ΔSENSE) and 12-bit voltage (VIN or SENSE+) measurements. The resulting 24-bit value is stored in dedicated POWER MSB/LSB registers (addresses 0x06–0x07). No host MCU computation is required - the value is updated after each conversion cycle and accessible via standard I²C read operations.
Can LTC2945IUD-1#PBF operate from a supply above 80V, and if so, how?
Yes, LTC2945IUD-1#PBF can operate from supplies >80V using its INTVCC shunt regulator mode. Connect the high-voltage supply to INTVCC through an external shunt resistor (RSHUNT) sized per Equation 1 in the datasheet to limit current to <35 mA. The internal shunt clamps INTVCC at ~6.3V, powering internal circuitry safely. VDD is left unconnected or grounded in this configuration - confirmed in Absolute Maximum Ratings and Applications Information sections.
What I²C address options are available for LTC2945IUD-1#PBF, and how are they set?
LTC2945IUD-1#PBF supports nine I²C addresses determined by ADR0 and ADR1 pin states (INTVCC, GND, or open). For example: ADR1=INTVCC/ADR0=INTVCC → 0x60; ADR1=GND/ADR0=GND → 0x64; ADR1=open/ADR0=open → 0x6F. These combinations are defined in Table 1 of the Applications Information section. No external pull-up resistors are needed on ADR pins - internal biasing enables direct connection.
LTC2945IUD-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Applications:
- General Purpose
- Voltage - Input:
- 4V ~ 80V
- Voltage - Supply:
- 2.7V ~ 5.9V
- Current - Supply:
- 800 µA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-QFN (3x3)
LTC2945IUD-1#PBF FAQ
1.How can I place an order for LTC2945IUD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2945IUD-1#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 LTC2945IUD-1#PBF reliable?
The price and inventory of LTC2945IUD-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2945IUD-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC2945IUD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2945IUD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2945IUD-1#PBF?
LTC2945IUD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2945IUD-1#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 LTC2945IUD-1#PBF?
For technical support, including LTC2945IUD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2945IUD-1#PBF requirements.
6.How does Aetrix verify that LTC2945IUD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2945IUD-1#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 LTC2945IUD-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC2945IUD-1#PBF?
All LTC2945IUD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2945IUD-1#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 LTC2945IUD-1#PBF part is unused and in its original packaging.
Return procedure for LTC2945IUD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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