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Analog Devices Inc. LTC2945HUD-1#TRPBF
- Part No.:
- LTC2945HUD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Supply Controllers, Monitors
- Package:
- 12-WFQFN Exposed Pad
- Datasheet:
-
LTC2945HUD-1#TRPBF.pdf
- Description:
- IC POWER MONITOR I2C 12QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,907
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Product details
Overview
LTC2945HUD-1#TRPBF 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, onboard min/max tracking, programmable alert thresholds, and operates from 2.7V to 80V supply. It is used in automotive battery monitoring systems where high-side current sensing and wide common-mode voltage tolerance are required.
For engineers reviewing the LTC2945HUD-1#TRPBF datasheet, LTC2945HUD-1#TRPBF pinout, LTC2945HUD-1#TRPBF application, or LTC2945HUD-1#TRPBF equivalent, key selection criteria include its inverted SDAO output for opto-isolated I²C, AEC-Q100 qualification (H-grade, –40°C to +125°C), 12-lead 3mm × 3mm QFN package, and ability to monitor 0V–80V rails without external level-shifting.
Technical Context
The LTC2945HUD-1#TRPBF implements a dedicated 12-bit delta-sigma ADC with three-channel sequential sampling: differential sense voltage (ΔSENSE), supply voltage (VIN or VDD), and auxiliary analog input (ADIN). Its internal multiplier computes 24-bit power values by digitally multiplying synchronized 12-bit current and voltage samples.
It supports two I²C operating modes: continuous scan (7.5 Hz typical update rate) and snapshot mode (single-shot per command), with separate SDAI (input) and SDAO (inverted output) pins enabling robust opto-isolation. The device includes an integrated shunt regulator on INTVCC for >80V operation and undervoltage lockout on both VDD and INTVCC pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Rail-to-rail input range | 0V to 80V common-mode on SENSE+/SENSE− - enables direct high-side or low-side current sensing across full battery or bus voltage range without external attenuators. |
| ADC resolution & accuracy | 12-bit with ±0.75% total unadjusted error - ensures ≤0.75% full-scale measurement uncertainty for current, voltage, and derived power values. |
| Power calculation | 24-bit digital multiplication of 12-bit current and voltage - delivers high dynamic range for accurate watt-hour energy accumulation over wide load conditions. |
| Operating temperature | –40°C to +125°C (H-grade) - qualified per AEC-Q100 for under-hood automotive applications including 12V/48V battery management. |
| I²C interface | Split SDAI/SDAO with inverted SDAO (LTC2945-1 variant) - allows direct connection to inverting opto-isolators without external logic inversion. |
| Supply flexibility | VDD = 4V–80V with internal 5V linear regulator on INTVCC; optional shunt regulator mode up to 100V - eliminates need for external bias supplies in high-voltage systems. |
| Quiescent current | <80 µA in shutdown - enables always-on monitoring in low-power automotive subsystems without significant battery drain. |
Pinout & Package
Package: 12-lead (3 mm × 3 mm) plastic QFN with exposed pad (Pin 13, optional GND connection). Thermal resistance θJA = 58.7°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE+ | High-side current sense and voltage monitor input | Accepts 0V–80V common-mode voltage; used with SENSE− to measure shunt voltage drop (full-scale 102.4 mV) or directly monitor supply rail (full-scale 102.4 V). |
| SENSE− | Current sense reference input | Differential partner to SENSE+; supports Kelvin connection for precision low-value shunt measurement. |
| VDD | Main high-voltage supply input | Powers internal series regulator (4V–80V); generates 5V at INTVCC when VDD > 7V; absolute max = 100V. |
| INTVCC | Internal low-voltage supply pin | Configurable as input (2.7V–5.9V), linear regulator output (5V/10mA), or shunt regulator (6.3V clamp); UVLO at 2.5V disables ADC. |
| SDAI | I²C data input | Open-collector input for I²C commands and addresses; clamped to 6.4V max; requires external pull-up. |
| SDAO | Inverted I²C data output | Open-drain output with inverted logic (LTC2945-1 function); enables direct opto-isolator coupling without external inverters. |
| ALERT | Programmable fault alert output | Open-drain active-low signal triggered when measured values exceed user-defined min/max thresholds; SMBus-compatible. |
| ADR0 / ADR1 | I²C address configuration inputs | Three-state inputs (INTVCC/GND/open) select one of nine I²C addresses; enable multi-device bus configurations. |
| ADIN | Auxiliary analog input | Measures external voltage 0V–2.048V (0.5 mV LSB); used for auxiliary rail or temperature sensor monitoring. |
| SCL | I²C clock input | Open-collector input; supports standard/fast-mode I²C up to 400 kHz; clamped to 6.4V max. |
| GND | Analog/digital ground reference | Common return for all analog and digital circuitry; exposed pad may be connected to PCB ground for thermal improvement. |
Key Features
| Feature | Design Value |
|---|---|
| Onboard 24-bit power calculation | Digitally multiplies synchronized 12-bit current and voltage samples - eliminates need for host MCU to perform floating-point power math, reducing firmware overhead and latency. |
| Min/max value storage | Automatically tracks and stores historical min/max for all three ADC channels - enables peak-load analysis and fault diagnostics without continuous polling or external memory. |
| Inverted SDAO output | Hardware-level inversion of I²C data output - simplifies opto-isolated communication in high-noise automotive or industrial environments by removing external gate-level inversion. |
| AEC-Q100 H-grade qualification | Rated for –40°C to +125°C operation with validated reliability testing - meets automotive electronics requirements for engine control, battery monitoring, and ADAS power domains. |
| Flexible supply architecture | Supports three power configurations: direct VDD tie, external INTVCC supply, or shunt-regulated INTVCC - enables use in 12V, 48V, and >80V systems (e.g., telecom, industrial HVDC) with single BOM. |
Applications
| Automotive Battery Management | Industrial 48V DC Power Distribution |
|---|---|
|
Use Scenario: Monitoring charge/discharge current and bus voltage in 12V/48V dual-battery automotive systems with start-stop and mild-hybrid functionality. IC Role / Device Role / Timing Role: High-side current sense amplifier + rail voltage monitor + real-time power calculator; provides cycle-accurate energy accounting for state-of-charge estimation. Use Value: Enables precise coulomb counting and power budgeting using only one IC, eliminating separate current-sense amplifiers and voltage dividers while maintaining AEC-Q100 compliance. |
Use Scenario: Real-time power telemetry in factory automation PLCs and robotics drives powered from 48V intermediate bus architectures. IC Role / Device Role / Timing Role: System-level power monitor interfacing via isolated I²C to host controller; captures min/max current/voltage excursions during motor startup and fault events. Use Value: Delivers deterministic 7.5 Hz update rate with hardware min/max capture - reduces host CPU interrupt load and improves response to overcurrent transients compared to software-based polling. |
| Telecom Rectifier Monitoring | Energy-Efficient Server PSU Telemetry |
|
Use Scenario: Monitoring output current, voltage, and power of –48V telecom rectifiers where input can exceed 80V during surge conditions. IC Role / Device Role / Timing Role: High-voltage capable power monitor using INTVCC shunt regulator mode; measures bus voltage via ADIN with resistive divider. Use Value: Supports >80V operation without external regulators or Zener clamps; ±0.75% TUE ensures accurate billing-grade power reporting for network equipment. |
Use Scenario: Per-rail power monitoring in server motherboards with multiple 12V/5V/3.3V VRMs feeding CPUs, GPUs, and memory. IC Role / Device Role / Timing Role: Multi-rail telemetry node with snapshot mode for on-demand measurement of individual VRM outputs; ALERT pin signals out-of-spec conditions. Use Value: Reduces component count versus discrete ADC + multiplier solutions; 80 µA shutdown current enables always-on health monitoring without impacting server standby efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA226AIDGST | 16-bit current/voltage/power monitor; no shunt regulator; max common-mode 36V; no ADIN channel | Limited to ≤36V systems; lacks auxiliary analog input and >80V support; higher resolution but narrower voltage range | Select for high-precision, low-voltage (≤36V) applications where 16-bit resolution outweighs missing shunt regulator and ADIN capability. |
| LTC2946CUHD#TRPBF | Successor with 16-bit ADC, ±0.3% TUE, extended 0V–100V common-mode, and enhanced EEPROM-based threshold storage | Higher accuracy and wider voltage range; pin-compatible QFN but different register map and I²C timing | Select for new designs requiring improved accuracy and future-proofing; not drop-in compatible due to firmware register changes despite same footprint. |
Compared with INA226AIDGST and LTC2946CUHD#TRPBF, the LTC2945HUD-1#TRPBF uniquely balances AEC-Q100 H-grade operation, 0V–80V rail-to-rail sensing, inverted SDAO for opto-isolation, and integrated shunt regulator - making it optimal for cost-sensitive, high-reliability automotive and industrial power monitoring where 12-bit resolution suffices.
Availability
LTC2945HUD-1#TRPBF is available at Aetrix Electronics and suitable for automotive battery management, industrial 48V power distribution, and telecom rectifier monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC2945HUD-1#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC2945 belongs to Analog Devices' precision system monitoring product line, designed specifically for real-time current, voltage, and power measurement in harsh, high-voltage environments such as automotive under-hood systems and telecom infrastructure.
FAQ
What is the key functional difference between LTC2945HUD-1#TRPBF and the standard LTC2945HUD#TRPBF?
The LTC2945HUD-1#TRPBF features an inverted SDAO (I²C data output) signal, whereas the standard LTC2945HUD#TRPBF has a non-inverted SDAO. This inversion allows direct interface with inverting opto-isolators (e.g., 6N137, HCPL-0723) without external logic gates - a critical feature for noise-immune automotive and industrial I²C isolation. All other electrical and functional specifications remain identical between the two variants.
Does LTC2945HUD-1#TRPBF support operation above 80V input voltage?
Yes, the LTC2945HUD-1#TRPBF supports input voltages beyond 80V by configuring the INTVCC pin as a shunt regulator. When the supply exceeds 80V, connect it to INTVCC through an appropriately sized shunt resistor (calculated per Equation 1 in the datasheet) to clamp INTVCC at ~6.3V. This allows operation up to 100V absolute maximum on VDD or SENSE+ while maintaining safe internal biasing - a capability confirmed in the Absolute Maximum Ratings table and Applications Information section.
What is the purpose of the ADIN pin on LTC2945HUD-1#TRPBF, and what voltage range does it accept?
The ADIN pin on LTC2945HUD-1#TRPBF is an auxiliary analog input that measures external voltages from 0V to 2.048V with 0.5 mV LSB resolution. It is commonly used to monitor auxiliary rails (e.g., 3.3V or 5V logic supplies), temperature sensor outputs (e.g., LM35), or divided high-voltage buses. The pin has 3 MΩ minimum input resistance and ±1 µA input current, enabling direct connection to high-impedance sources without loading errors.
How does the min/max tracking feature work in LTC2945HUD-1#TRPBF, and which parameters does it monitor?
The LTC2945HUD-1#TRPBF automatically tracks and stores the minimum and maximum values for all three ADC channels: ΔSENSE (current), VIN/VDD (voltage), and ADIN (auxiliary voltage). These values persist across conversions and are updated in real time without host intervention. They are stored in dedicated registers (MIN_SENSE, MAX_SENSE, etc.) and can be read via I²C. This eliminates the need for continuous polling or external firmware-based tracking, reducing host processor overhead significantly.
Is LTC2945HUD-1#TRPBF pin-compatible with other members of the LTC294x family, such as LTC2943 or LTC2944?
No, the LTC2945HUD-1#TRPBF is not pin-compatible with LTC2943 or LTC2944. While all share the 12-lead QFN/MSOP footprint, pin assignments differ significantly - for example, LTC2943 uses a single SDA pin (bidirectional), whereas LTC2945HUD-1#TRPBF separates SDAI and SDAO (inverted). Additionally, ALERT, ADR0/ADR1, and ADIN functions are allocated differently. Board redesign is required for substitution; refer to respective pin configuration diagrams in each datasheet.
LTC2945HUD-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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 ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-QFN (3x3)
LTC2945HUD-1#TRPBF FAQ
1.How can I place an order for LTC2945HUD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2945HUD-1#TRPBF 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 LTC2945HUD-1#TRPBF reliable?
The price and inventory of LTC2945HUD-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2945HUD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC2945HUD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2945HUD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2945HUD-1#TRPBF?
LTC2945HUD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2945HUD-1#TRPBF 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 LTC2945HUD-1#TRPBF?
For technical support, including LTC2945HUD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2945HUD-1#TRPBF requirements.
6.How does Aetrix verify that LTC2945HUD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC2945HUD-1#TRPBF 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 LTC2945HUD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC2945HUD-1#TRPBF?
All LTC2945HUD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2945HUD-1#TRPBF, 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 LTC2945HUD-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC2945HUD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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