Texas Instruments LM3815M-1.0/NOPB

Overview

LM3815M-1.0/NOPB from Texas Instruments is a low-side current gauge IC delivering ±1 A sensing range with ultra-low insertion loss (0.004 Ω), PWM output encoding current magnitude and direction, and 6 ms sampling interval - used in battery charge/discharge monitoring and smart fuse applications where minimal power path disruption is critical.

For engineers reviewing the LM3815M-1.0/NOPB datasheet, LM3815M-1.0/NOPB pinout, LM3815M-1.0/NOPB application, or LM3815M-1.0/NOPB equivalent, this page delivers verified specifications, SO-8 package terminal mapping, real-world use cases, and two validated alternative parts for current-sense system design continuity.

Technical Context

The LM3815M-1.0/NOPB implements a delta-sigma analog-to-digital converter to digitize sensed current, enabling internal digital filtering that rejects transient spikes and provides 6 ms averaging - directly supporting immunity to short-duration load surges without external RC networks. Its PWM output encodes bidirectional current via duty cycle (50% = zero, >50% = positive, <50% = negative), with quantization resolution of 1/128 and inherent 0.5-bit offset requiring correction for high-accuracy readings.

Designed exclusively for low-side sensing, the device integrates its sense element between SENSE+ (pin 1, tied to GND) and SENSE− (pin 2), eliminating external shunts while maintaining thermal coupling between sense path and die. It operates from 2.0 V to 5.25 V, draws 100 µA quiescent current in active mode, and reduces to 2.5 µA in shutdown - activated by pulling SD (pin 5) low.

Key Specifications

Pinout & Package

LM3815M-1.0/NOPB is housed in an SO-8 surface-mount package (TI package code M08A), with exposed pad not electrically connected. Pin 1 is SENSE+/GND, pin 8 is VDD, and dual ground pins (7 and 1) provide low-impedance return paths for sense and power domains.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-sense applications.

Compared with LM3815M-1.0/NOPB, INA219BIDR offers superior accuracy and digital interface but adds external component dependency, while MAX40056ATA+T provides simpler analog readout yet lacks bidirectional PWM encoding and low-side flexibility - making LM3815M-1.0/NOPB optimal for cost-sensitive, low-component-count low-side current gauging.

Availability

LM3815M-1.0/NOPB 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 LM3815M-1.0/NOPB 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, designing and manufacturing analog ICs, embedded processors, and high-reliability components for industrial, automotive, and communications markets.

The LM3815M-1.0/NOPB belongs to TI's precision current-sense gauge family, engineered specifically for low-loss, low-side current measurement in battery-powered and safety-critical load monitoring systems - prioritizing simplicity, robustness, and minimal insertion impact.

FAQ

What is the sensing configuration supported by LM3815M-1.0/NOPB?

The LM3815M-1.0/NOPB is designed exclusively for low-side current sensing. Its pin 1 (SENSE+/GND) connects to system ground, and pin 2 (SENSE−) connects to the load side of the current path - enabling measurement without breaking the high-side power rail. This configuration avoids high common-mode voltage challenges and simplifies isolation requirements compared to high-side alternatives like the LM3814M-1.0/NOPB.

How does the PWM output of LM3815M-1.0/NOPB encode current magnitude and direction?

The LM3815M-1.0/NOPB outputs a 160 Hz PWM signal where duty cycle linearly represents average current over the prior 6 ms interval: 50% = 0 A, >50% = positive current (e.g., 95.5% = +1 A), and <50% = negative current (e.g., 4.5% = −1 A). The relationship is defined as ISENSE = 2.2 × (D − 0.5) × IMAX, with D as measured duty cycle and IMAX = 1 A for LM3815M-1.0/NOPB.

What is the accuracy specification for LM3815M-1.0/NOPB and under what conditions does it apply?

LM3815M-1.0/NOPB guarantees ±3.5 % accuracy at room temperature (25°C), including contributions from the internal sense element, delta-sigma ADC, and digital processing. This specification assumes VDD = 5.0 V, proper 1 µF bypass and 0.1 µF filter capacitors, and operation within the −40°C to +125°C junction temperature range - with accuracy degrading slightly at temperature extremes due to sense element TCR (2600 ppm/°C).

Can LM3815M-1.0/NOPB be used in shutdown mode, and what is its quiescent current in that state?

Yes, LM3815M-1.0/NOPB supports active-low shutdown via pin 5 (SD). When SD is pulled below 0.7 V, the device enters low-power mode with typical quiescent current of 2.5 µA - verified across 2.0 V to 5.25 V supply range. This mode disables PWM output and internal modulation, making LM3815M-1.0/NOPB suitable for battery-backed systems requiring multi-year standby operation.

What package type and footprint does LM3815M-1.0/NOPB use, and are there thermal considerations?

LM3815M-1.0/NOPB uses an SO-8 package (TI code M08A) with standard 1.27 mm pitch and no exposed thermal pad. Its thermal resistance θJA is 150°C/W; therefore, sustained 1 A current at elevated ambient requires adequate copper area under pins 1 and 2 to manage self-heating - especially critical for maintaining ±3.5 % accuracy, as sense element drift correlates with local die temperature rise.