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Texas Instruments LM3814MX-7.0
- Part No.:
- LM3814MX-7.0
- Manufacturer:
- Texas Instruments
- Category:
- Current Regulation/Management
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM3814MX-7.0.pdf
- Description:
- IC CURRENT GAUGE 6% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,232
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Product details
Overview
LM3814MX-7.0 from Texas Instruments is a high-side current gauge IC implementing delta-sigma sensing with PWM output, ±7 A full-scale range, 0.004 Ω typical insertion loss, and 6 ms sampling interval-used for battery charge/discharge monitoring and smart fuse applications in portable power systems.
For engineers reviewing the LM3814MX-7.0 datasheet, LM3814MX-7.0 pinout, LM3814MX-7.0 application, or LM3814MX-7.0 equivalent, key selection considerations include high-side sensing topology, PWM duty-cycle–to-current conversion linearity, shutdown quiescent current (2.5 µA), thermal layout sensitivity for ±7 A accuracy, and SO-8 package compatibility with standard PCB assembly processes.
Technical Context
The LM3814MX-7.0 integrates a precision internal sense element and delta-sigma analog-to-digital converter to average current over fixed 6 ms intervals, rejecting transient spikes while delivering a PWM output whose duty cycle linearly encodes magnitude and direction (50% = zero current). It operates from 2 V to 5.25 V and features internal power-on-reset and filtering to suppress false trips.
As a high-side sensing device, it places SENSE+ at VDD potential and requires copper thermal management under pins 1 and 2 to maintain ±3.5% room-temperature accuracy at ±7 A. Its PWM frequency is nominally 160 Hz (100–250 Hz range), with logic-level output compatible with microcontroller GPIO inputs without external level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Full-Scale Range | ±7 A continuous; supports accurate measurement of bidirectional load currents up to 7 A without external shunt. |
| Insertion Loss | 0.004 Ω typical - minimizes voltage drop and power loss in high-current paths, critical for efficiency-sensitive battery systems. |
| Sampling Interval | 6 ms - provides immunity to sub-6 ms transients while enabling real-time current feedback for protection algorithms. |
| Accuracy (25°C) | ±3.5% - includes internal sense element error; validated at 2.5 A test point per LM3814-7.0 electrical characteristics table. |
| Shutdown Current | 2.5 µA typical - enables ultra-low-power mode during system sleep or fault lockout without removing supply. |
| PWM Frequency | 160 Hz nominal (100–250 Hz) - ensures sufficient resolution for microcontroller capture while avoiding aliasing in sampled-data systems. |
| Supply Range | 2.0 V to 5.25 V - compatible with single-cell Li-ion, USB-powered, and low-voltage industrial rails. |
Pinout & Package
LM3814MX-7.0 is housed in an SO-8 surface-mount package (TI package code M08A), with dual ground pins (7 and 8) and integrated high-side sense architecture requiring careful thermal layout on pins 1 (SENSE+, VDD) and 2 (SENSE−).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | SENSE+, VDD | High-side current sense terminal and primary supply input; must be connected to high-side rail; thermal coupling to PCB copper affects ±7 A accuracy. |
| 2 | SENSE− | Low-side current sense terminal; forms Kelvin connection with Pin 1 across internal 0.004 Ω sense element. |
| 3 | FLTR+ | Positive input to anti-aliasing filter for delta-sigma modulator; requires 0.1 µF ceramic capacitor to Pin 4. |
| 4 | FLTR− | Negative input to anti-aliasing filter; referenced to GND; completes RC filter network with Pin 3. |
| 5 | SD | Active-low shutdown control; pulled high via 10 kΩ resistor for normal operation; reduces IQ to 2.5 µA when driven low. |
| 6 | PWM | Open-drain PWM output; duty cycle encodes current magnitude/direction (50% = 0 A); sinks ≤1 mA; logic-compatible with 2–5.25 V supplies. |
| 7 | GND | Analog ground reference for internal circuitry and filter network; must be low-impedance connection. |
| 8 | GND | Dedicated second ground pin; improves thermal dissipation and reduces ground bounce in high-dI/dt applications. |
Key Features
| Feature | Design Value |
|---|---|
| No external sense resistor required | Integrated 0.004 Ω lead-frame sense element eliminates board space, solder joint reliability risk, and calibration drift of discrete shunts. |
| PWM output encoding current magnitude and direction | Duty cycle linearly maps −7 A to +7 A (4.5% to 95.5%), enabling bidirectional current monitoring with single digital input on MCU. |
| 6 ms current averaging | Internal delta-sigma sampling rejects short-duration spikes (e.g., motor commutation noise), improving robustness in motion control diagnostics. |
| Ultra-low shutdown current | 2.5 µA typical allows persistent current monitoring during standby without compromising battery runtime in portable devices. |
| Internal power-on-reset and filtering | Ensures deterministic startup behavior and prevents false triggering during power ramp-up or EMI events in noisy industrial environments. |
Applications
| Battery Charge/Discharge Gauge | Motion Control Diagnostics |
|---|---|
Use Scenario: Real-time monitoring of bidirectional current in lithium-ion battery packs during charging and discharging cycles. IC Role / Device Role / Timing Role: High-side current gauge providing PWM-encoded current data to host MCU every 6 ms for state-of-charge estimation and overcurrent protection. Use Value: Eliminates need for external shunt and amplifier, reducing BOM cost and PCB area while maintaining ±3.5% accuracy at ±7 A without thermal derating. | Use Scenario: Detecting abnormal current signatures in stepper or BLDC motor drivers during stall, phase loss, or winding short conditions. IC Role / Device Role / Timing Role: High-side sensing node feeding averaged current waveform to diagnostic firmware; 6 ms sampling aligns with motor control loop timing. Use Value: Internal filtering rejects commutation noise, enabling reliable fault detection without additional analog filtering components. |
| Resettable Smart Fuse | Power Supply Load Monitoring and Management |
Use Scenario: Replacing mechanical fuses in DC distribution units with programmable overcurrent trip and auto-recovery capability. IC Role / Device Role / Timing Role: Primary current sensor in protection IC chain; PWM output triggers digital comparator or MCU-based trip logic after configurable delay. Use Value: 0.004 Ω insertion loss minimizes voltage drop across fuse path, preserving system efficiency while enabling precise ±7 A trip threshold setting. | Use Scenario: Monitoring dynamic load current in telecom power shelves or server VRMs to detect overloads and enable graceful shutdown. IC Role / Device Role / Timing Role: High-side current monitor interfacing directly to baseboard management controller (BMC) via GPIO for real-time telemetry. Use Value: SO-8 package and 2–5.25 V supply range allow direct integration into existing 3.3 V or 5 V management subsystems without level translation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current gauge applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX40056ASA+T | High-side, ±50 A range, 1.5 mΩ sense, analog output (VOUT), 2.7–5.5 V supply. | Requires external ADC; higher full-scale range but lower resolution at ±7 A; no built-in averaging or PWM interface. | Choose for higher-current systems needing analog output and wider dynamic range; not drop-in due to different output format and pinout. |
| INA226AIDGST | I²C-output current/voltage/power monitor, ±16 V common-mode, 0.1% gain error, 10-bit ΔΣ ADC. | Digital interface only; requires I²C bus and firmware support; no native PWM; higher accuracy but slower update rate (up to 1.024 ksps). | Choose for systems with available I²C and need concurrent voltage/power telemetry; not functionally equivalent due to communication protocol and lack of PWM output. |
Compared with MAX40056ASA+T and INA226AIDGST, the LM3814MX-7.0 uniquely delivers direct PWM-encoded current data with integrated 6 ms averaging and zero external sense components-making it optimal for cost-sensitive, microcontroller-based protection and telemetry where simplicity and deterministic timing outweigh the need for digital bus interfaces or extended current ranges.
Availability
LM3814MX-7.0 is available at Aetrix Electronics and suitable for battery charge/discharge gauge, motion control diagnostics, and resettable smart fuse applications requiring stable component supply and long-term industrial availability.
Supply support for LM3814MX-7.0 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and consumer markets.
The LM3814MX-7.0 belongs to TI's legacy current-sensing analog front-end product line, designed specifically for high-side, low-loss, PWM-output current gauging in portable power and protection systems where minimal insertion loss and microcontroller-friendly digital output are prioritized.
FAQ
What is the full-scale current range of the LM3814MX-7.0?
The LM3814MX-7.0 is factory-set for a ±7 A full-scale current range, supporting continuous bidirectional current measurement from −7 A to +7 A. Its PWM output duty cycle scales linearly between 4.5% (−7 A) and 95.5% (+7 A), with 50% representing zero current. This range is distinct from the ±1 A variant (e.g., LM3814MX-1.0) and is specified in TI's SNVS045D datasheet ordering table.
How does the LM3814MX-7.0 achieve ultra-low insertion loss?
The LM3814MX-7.0 achieves 0.004 Ω typical insertion loss using an integrated precision lead-frame sense element-eliminating external shunt resistors and associated parasitic resistance. This internal structure is calibrated and temperature-compensated, enabling high-side current sensing with minimal voltage drop and power dissipation, critical for efficiency-critical battery and power-distribution applications.
Can the LM3814MX-7.0 be used in low-side sensing configurations?
No-the LM3814MX-7.0 is specifically designed and characterized for high-side sensing only. For low-side sensing, TI offers the pin-compatible LM3815MX-7.0 variant, which swaps the VDD and GND pin assignments (Pin 1 = SENSE+, GND; Pin 8 = VDD) and adjusts internal biasing. Using LM3814MX-7.0 in low-side configuration violates its absolute maximum ratings and invalidates accuracy specifications.
What is the role of the FLTR+ and FLTR− pins on the LM3814MX-7.0?
The FLTR+ and FLTR− pins on the LM3814MX-7.0 form the differential input to an on-chip anti-aliasing filter for the delta-sigma modulator. A 0.1 µF ceramic capacitor must be placed between these pins to set the filter cutoff frequency, preventing aliasing of high-frequency noise into the 6 ms current average. This external capacitor is mandatory for stable operation and specified in TI's typical application circuits.
Is the LM3814MX-7.0 still in active production?
The LM3814MX-7.0 is marked "OBSOLETE" in TI's official SNVS045D datasheet (revised April 2013), indicating it is no longer manufactured by Texas Instruments. However, Aetrix Electronics maintains verified legacy inventory with full traceability and supports continued use in maintenance, repair, and legacy system production where functional equivalence and long-term supply stability are required.
LM3814MX-7.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Function:
- Current Gauge
- Sensing Method:
- High-Side
- Accuracy:
- ±6%
- Voltage - Input:
- 2V ~ 5.25V
- Current - Output:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM3814MX-7.0 FAQ
1.How can I place an order for LM3814MX-7.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3814MX-7.0 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 LM3814MX-7.0 reliable?
The price and inventory of LM3814MX-7.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3814MX-7.0 is usually 5 days.
3.What payment methods are accepted for LM3814MX-7.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3814MX-7.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3814MX-7.0?
LM3814MX-7.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3814MX-7.0 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 LM3814MX-7.0?
For technical support, including LM3814MX-7.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3814MX-7.0 requirements.
6.How does Aetrix verify that LM3814MX-7.0 is sourced from the original manufacturer or authorized distributors?
All LM3814MX-7.0 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 LM3814MX-7.0 meets industry standards.
7.What is the process for return or replacement of LM3814MX-7.0?
All LM3814MX-7.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM3814MX-7.0, 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 LM3814MX-7.0 part is unused and in its original packaging.
Return procedure for LM3814MX-7.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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