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Texas Instruments LM3812MX-1.0
- Part No.:
- LM3812MX-1.0
- Manufacturer:
- Texas Instruments
- Category:
- Current Regulation/Management
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM3812MX-1.0.pdf
- Description:
- IC CURRENT GAUGE 2% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,336
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Product details
Overview
LM3812MX-1.0 from Texas Instruments is a precision high-side current gauge IC featuring an integrated 0.004Ω sense element, ±2% room-temperature accuracy, PWM output encoding current magnitude and direction (50% duty = zero current), and 50 ms sampling interval. It operates from 2V to 5.25V and delivers ultra-low insertion loss for battery charge/discharge monitoring in portable power systems.
For engineers reviewing the LM3812MX-1.0 datasheet, LM3812MX-1.0 pinout, LM3812MX-1.0 application, or LM3812MX-1.0 equivalent, this device supports microprocessor-interfaced current diagnostics with built-in ΔΣ conversion, internal filtering against transient spikes, and shutdown mode reducing quiescent current to 2.5 µA - critical for low-power embedded energy management designs.
Technical Context
The LM3812MX-1.0 implements a delta-sigma analog-to-digital converter to digitize sensed current, followed by digital filtering and comparison against a digital ramp generator to produce a proportional PWM waveform. Its 10-bit quantization resolution yields 1024 discrete duty levels with 0.5-bit inherent offset.
Current is averaged over fixed 50 ms intervals, providing immunity to sub-50 ms surges. The PWM output frequency ranges from 12.5 Hz to 25 Hz depending on supply voltage and temperature, and logic thresholds on SD and PWM pins are specified for reliable interfacing with 3.3V/5V microcontrollers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Sense Range | ±1.0 A full-scale range - enables accurate measurement of bidirectional currents up to 1 A in high-side configurations. |
| Accuracy | ±2% at room temperature - includes internal sense element tolerance and ΔΣ conversion error, enabling direct replacement of external shunt + amplifier solutions. |
| Insertion Loss | 0.004 Ω typical - minimizes power loss and thermal rise in series power paths, critical for battery-powered applications. |
| Supply Range | 2.0 V to 5.25 V - compatible with single-cell Li-ion, USB, and 3.3V/5V system rails without level-shifting. |
| Sampling Interval | 50 ms - provides stable averaging for load-current monitoring while rejecting short-duration transients. |
| Shutdown Current | 2.5 µA typical - allows integration into always-on systems where periodic wake-up current sensing is required. |
| PWM Frequency | 20 Hz nominal (12.5–25 Hz range) - balances resolution and response time for firmware-based current decoding. |
Pinout & Package
LM3812MX-1.0 is housed in an 8-pin SOIC (D0008A) package with exposed pad for thermal enhancement. Pin 1 is SENSE+/VDD (high-side sense input and supply), Pin 2 is SENSE− (low-side sense return), Pins 3–4 form differential filter inputs (FLTR+/FLTR−), Pin 5 is SD (active-low shutdown), Pin 6 is PWM (open-drain compatible output), and Pins 7–8 are GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | SENSE+, VDD | High-side current path input and primary supply connection - must be placed directly in series with load for high-side sensing. |
| 2 | SENSE− | Low-side current path return - completes internal sense loop; requires low-impedance PCB trace to minimize noise coupling. |
| 3 | FLTR+ | Differential anti-aliasing filter input - connects to 0.1 µF ceramic capacitor between Pins 3 and 4 to suppress high-frequency noise before ΔΣ conversion. |
| 4 | FLTR− | Differential anti-aliasing filter input - forms matched pair with Pin 3; layout symmetry is critical for common-mode rejection. |
| 5 | SD | Active-low shutdown control - pulled high via 10 kΩ resistor for normal operation; drives <3 µA quiescent current when grounded. |
| 6 | PWM | Open-drain PWM output - encodes current magnitude/direction as duty cycle (4.5–95.5%); sinks ≤1 mA and interfaces directly with MCU GPIO. |
| 7, 8 | GND | Power and signal ground reference - both pins must be connected to low-impedance ground plane to ensure accuracy and thermal stability. |
Key Features
| Feature | Design Value |
|---|---|
| No external sense resistor required | Integrated 0.004Ω lead-frame sense element eliminates board space, calibration, and thermal drift errors associated with discrete shunts. |
| PWM output with direction encoding | Duty cycle >50% indicates positive current flow; <50% indicates negative flow - enables single-wire bidirectional current telemetry to MCUs. |
| ΔΣ current-sense architecture | Digitally filters and averages current over 50 ms - rejects EMI and short-circuit spikes without external RC networks. |
| Internal power-on reset (POR) | Ensures defined startup state and prevents false triggering during power ramp - eliminates need for external supervisor circuits. |
| Low temperature sensitivity | 2600 ppm/°C sense element TC compensated in digital domain - maintains ±2% accuracy across −40°C to +125°C junction range. |
Applications
| Battery Charge/Discharge Gauge | Motion Control Diagnostics |
|---|---|
|
Use Scenario: Real-time monitoring of charging current into Li-ion packs and discharge current during motor startup in portable tools. IC Role / Device Role / Timing Role: High-side current gauge measuring bidirectional current with 50 ms averaging to reject inrush spikes. Use Value: Enables precise state-of-charge estimation and overcurrent protection without adding series resistance or thermal derating overhead. |
Use Scenario: Detecting stalled rotor conditions and phase imbalance in BLDC motor drivers by tracking per-phase current signatures. IC Role / Device Role / Timing Role: High-side current sensor feeding PWM-encoded data to motor control MCU for real-time fault analysis. Use Value: Provides deterministic 20 Hz current updates with ±2% accuracy - sufficient for stall detection and commutation timing alignment. |
| Power Supply Load Monitoring | Resettable Smart Fuse |
|
Use Scenario: Continuous load-current logging in industrial 24V DC power distribution units to detect gradual degradation or leakage faults. IC Role / Device Role / Timing Role: High-side current monitor with shutdown capability, interfaced to host controller via PWM input capture. Use Value: Delivers stable 50 ms averaged readings with <2.5 µA shutdown current - extends uptime in unattended remote deployments. |
Use Scenario: Replacing mechanical fuses in USB-C PD power delivery paths with programmable overcurrent trip and auto-recovery. IC Role / Device Role / Timing Role: Precision current gauge triggering MCU-based trip logic upon sustained >0.9 A detection over multiple 50 ms windows. Use Value: Eliminates fuse replacement logistics while maintaining ±2% trip threshold accuracy and zero insertion loss in power path. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-side current gauge applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA219BIDR | I²C digital output; 0.1% gain error; 12-bit ADC; no internal sense element (requires external shunt). | Requires external 0.01Ω shunt and I²C bus resources; better resolution but higher BOM count and layout sensitivity. | Preferred when high-resolution digital current/voltage/power data is needed and board space permits shunt placement. |
| MAX40056ATA+T | High-side current sensor with analog output; 0.5% max gain error; 2.7V–5.5V supply; no PWM or digital averaging. | Delivers continuous analog voltage proportional to current; lacks built-in filtering, direction encoding, or low-power shutdown. | Chosen when analog feedback loop integration or sub-millisecond response is required, and MCU lacks PWM input capture. |
Compared with INA219BIDR and MAX40056ATA+T, the LM3812MX-1.0 uniquely combines ultra-low-loss sensing, bidirectional PWM encoding, and 50 ms digital averaging in a single SOIC package - simplifying firmware, reducing component count, and eliminating shunt-related thermal and layout constraints.
Availability
LM3812MX-1.0 is available at Aetrix Electronics and suitable for battery charge/discharge gauge, motion control diagnostics, and power supply load monitoring requiring stable component supply, long-lifecycle support, and guaranteed traceability.
Supply support for LM3812MX-1.0 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in precision sensing and industrial-grade IC design.
The LM3812MX-1.0 belongs to TI's precision current-sense IC product line, engineered specifically for high-side, low-loss, microprocessor-interfaced current measurement in portable, automotive, and industrial power systems.
FAQ
What is the full-scale current range of the LM3812MX-1.0?
The LM3812MX-1.0 is factory-set for ±1.0 A full-scale sensing range. Its PWM output maps 4.5% duty cycle to −1.0 A, 50% to 0 A, and 95.5% to +1.0 A. This range is fixed and cannot be adjusted externally - it is distinct from the LM3812-7.0 variant, which supports ±7 A.
How does the LM3812MX-1.0 achieve ultra-low insertion loss?
The LM3812MX-1.0 achieves 0.004 Ω typical insertion loss using an integrated copper lead-frame sense element, eliminating the need for external shunt resistors. This monolithic construction avoids solder joint resistance, thermal coefficient mismatches, and PCB trace parasitics that degrade accuracy in discrete solutions.
Can the LM3812MX-1.0 be used for low-side current sensing?
No - the LM3812MX-1.0 is designed exclusively for high-side sensing. Its Pin 1 functions as SENSE+/VDD, requiring connection to the supply rail side of the load. For low-side sensing, TI specifies the LM3813MX-1.0, which swaps the VDD and GND pin assignments to accommodate ground-referenced measurement.
What is the purpose of the FLTR+ and FLTR− pins on the LM3812MX-1.0?
The FLTR+ and FLTR− pins on the LM3812MX-1.0 form a differential anti-aliasing input for the internal delta-sigma modulator. A 0.1 µF ceramic capacitor must be placed directly between them to suppress high-frequency noise before digitization - critical for maintaining ±2% accuracy and preventing false trips from EMI.
Does the LM3812MX-1.0 require external calibration for accuracy?
No - the LM3812MX-1.0 includes factory-trimmed internal gain and offset compensation, delivering ±2% total accuracy at room temperature without user calibration. Its 2600 ppm/°C sense element temperature coefficient is digitally compensated across −40°C to +125°C, ensuring stable performance in uncalibrated field use.
LM3812MX-1.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Current Gauge
- Sensing Method:
- High-Side
- Accuracy:
- ±2%
- Voltage - Input:
- 2V ~ 5.25V
- Current - Output:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM3812MX-1.0 FAQ
1.How can I place an order for LM3812MX-1.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3812MX-1.0 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 LM3812MX-1.0 reliable?
The price and inventory of LM3812MX-1.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3812MX-1.0 is usually 5 days.
3.What payment methods are accepted for LM3812MX-1.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3812MX-1.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3812MX-1.0?
LM3812MX-1.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3812MX-1.0 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 LM3812MX-1.0?
For technical support, including LM3812MX-1.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3812MX-1.0 requirements.
6.How does Aetrix verify that LM3812MX-1.0 is sourced from the original manufacturer or authorized distributors?
All LM3812MX-1.0 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 LM3812MX-1.0 meets industry standards.
7.What is the process for return or replacement of LM3812MX-1.0?
All LM3812MX-1.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM3812MX-1.0, 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 LM3812MX-1.0 part is unused and in its original packaging.
Return procedure for LM3812MX-1.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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