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Texas Instruments LM397MFX/NOPB
- Part No.:
- LM397MFX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM397MFX/NOPB.pdf
- Description:
- IC COMPARATOR 1 GEN PUR SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,949
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Product details
Overview
LM397MFX/NOPB from Texas Instruments is a single general-purpose voltage comparator with bipolar input stage, open-collector NPN output, and rail-to-ground input common-mode range (0 V to VS – 1.5 V). It operates from 5 V to 30 V single or dual supply, draws only 300 µA typical supply current, and delivers 440 ns propagation delay (50-mV overdrive) - ideal for precision threshold detection in industrial sensor interfaces and A/D converter front-ends.
For engineers reviewing the LM397MFX/NOPB datasheet, LM397MFX/NOPB pinout, LM397MFX/NOPB application, or LM397MFX/NOPB equivalent, key selection considerations include its SOT-23 (DBV) 5-pin package, ±2 mV input offset voltage, 7 nA input bias current, open-collector output requiring external pull-up, and −40°C to +85°C industrial temperature range.
Technical Context
The LM397MFX/NOPB implements a bipolar-input comparator architecture enabling operation with inputs down to ground, unlike many CMOS comparators. Its input common-mode range extends from 0 V to VS – 1.5 V at 25°C (0 V to VS – 2 V across temperature), supporting direct sensing of low-side current shunts or battery monitoring below supply rails.
The open-collector output stage uses a grounded-emitter NPN transistor capable of sinking up to 13 mA, allowing level translation via external pull-up to logic supplies independent of VS (e.g., 3.3 V or 5 V), and enabling wired-OR configurations for multi-comparator logic functions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 5 V to 30 V - supports wide industrial power rails without regulation; compatible with unregulated 12 V/24 V systems. |
| Input Offset Voltage | ±2 mV (typ) - enables accurate threshold detection within ~2 mV error at room temperature. |
| Input Bias Current | 7 nA (typ) - minimizes loading on high-impedance reference or sensor sources (e.g., thermistors, photodiodes). |
| Propagation Delay | 440 ns (tPLH/tPHL, 50-mV overdrive) - suitable for medium-speed signal conditioning and pulse generation up to ~1 MHz. |
| Supply Current | 300 µA (typ, VS = 5 V) - enables low-power operation in battery-backed or energy-constrained systems. |
| Output Sink Current | 13 mA (max) - drives standard TTL/CMOS loads and small relays directly when paired with appropriate pull-up. |
| Operating Temperature | −40°C to +85°C - qualified for industrial environments including factory automation and motor control cabinets. |
Pinout & Package
LM397MFX/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm × 1.45 mm max height, optimized for space-constrained PCB layouts and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN– (Pin 1) | Inverting Input | Accepts reference or threshold voltage; differential comparison against VIN+ determines output state. |
| GND (Pin 2) | Ground Reference | System return path for supply and inputs; required for single-supply operation with ground-referenced signals. |
| VIN+ (Pin 3) | Noninverting Input | Accepts sensed analog signal (e.g., sensor output, voltage divider tap); comparison result drives output logic. |
| OUTPUT (Pin 4) | Open-Collector Output | Sinks current when active; requires external pull-up resistor to define logic-high level and drive strength. |
| VS (Pin 5) | Positive Supply | Connects to main supply rail (5–30 V); powers internal circuitry and sets upper limit of input common-mode range. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-ground input common-mode range | 0 V to VS – 1.5 V enables direct interface with ground-referenced sensors and shunt-based current monitors. |
| Open-collector output with 13 mA sink capability | Supports flexible level translation, wired-OR logic, and direct driving of LEDs, small relays, or logic gates. |
| Low 300 µA supply current | Reduces system power budget and thermal load in always-on industrial monitoring circuits. |
| ±2 mV input offset voltage (typ) | Ensures stable switching thresholds in precision window detectors and zero-crossing applications. |
| 440 ns response time (50-mV overdrive) | Meets timing requirements for fast pulse shaping, overvoltage protection latching, and clock recovery circuits. |
Applications
| Industrial Sensor Interface | A/D Converter Front-End |
|---|---|
Use Scenario: Detecting temperature threshold crossings from an NTC thermistor network in a PLC I/O module. IC Role / Device Role / Timing Role: Voltage comparator converting analog resistance change into clean digital flag for microcontroller interrupt. Use Value: Rail-to-ground input range allows direct connection to thermistor divider without level-shifting; low bias current prevents measurement error. |
Use Scenario: Providing precise start-of-conversion trigger for a SAR ADC sampling motor phase currents. IC Role / Device Role / Timing Role: Comparator generating synchronized sample-enable pulse when current exceeds programmable threshold. Use Value: 440 ns propagation delay ensures sub-microsecond timing accuracy; open-collector output interfaces directly to ADC's CMOS control input. |
| Pulse/Square-Wave Generator | Peak Detector Hold Circuit |
Use Scenario: Building a relaxation oscillator using hysteresis feedback to generate fixed-frequency clock signals for legacy peripherals. IC Role / Device Role / Timing Role: Core comparator element in inverting hysteresis configuration defining upper/lower switching thresholds. Use Value: Stable ±2 mV offset and predictable 440 ns delay enable repeatable frequency tuning across temperature and supply variations. |
Use Scenario: Capturing and holding maximum voltage from a rectified AC waveform in a power supply monitor. IC Role / Device Role / Timing Role: Comparator controlling MOSFET gate to charge storage capacitor only when input exceeds held value. Use Value: 7 nA input bias current minimizes capacitor discharge during hold phase, extending retention time beyond 100 ms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL331IDBVR | Pin-compatible SOT-23 single comparator; slightly higher input offset (±3 mV typ), lower supply current (60 µA typ), same open-collector output. | Better suited for ultra-low-power battery applications; less ideal for high-accuracy thresholding due to higher offset. | Select TL331IDBVR when supply current <100 µA is critical and ±3 mV offset is acceptable. |
| LMV331IDBVR | CMOS-input single comparator in same SOT-23 package; rail-to-rail input, 36 µA supply current, push-pull output (no pull-up needed). | Eliminates external pull-up but lacks true ground-sensing capability; input common-mode does not include negative rail. | Choose LMV331IDBVR for low-power, rail-to-rail input designs where ground-referenced sensing is not required. |
Compared with TL331IDBVR and LMV331IDBVR, LM397MFX/NOPB uniquely combines ground-sensing input capability, robust 13 mA sink strength, and industrial temperature rating - making it the preferred choice for legacy-compatible, high-reliability industrial threshold detection where input must reach 0 V.
Availability
LM397MFX/NOPB is available at Aetrix Electronics and suitable for industrial sensor interfaces, A/D converter front-ends, and pulse generator circuits requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM397MFX/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 leader delivering analog, embedded processing, and connectivity solutions with deep expertise in precision analog design and industrial-grade reliability.
The LM397MFX/NOPB belongs to TI's general-purpose comparator product line, engineered specifically for robust, cost-effective threshold detection in industrial automation, power management, and test equipment where ground-referenced sensing and open-collector flexibility are essential.
FAQ
What is the maximum supply voltage for LM397MFX/NOPB?
The absolute maximum supply voltage for LM397MFX/NOPB is 30 V, with recommended operating range specified from 5 V to 30 V. Exceeding 30 V risks permanent damage per Absolute Maximum Ratings. For reliable long-term operation, maintain VS within 5–30 V and ensure proper decoupling with a 0.1-μF ceramic capacitor near the VS pin. LM397MFX/NOPB maintains full functionality across this range, including consistent input common-mode behavior and output sink capability.
Does LM397MFX/NOPB support single-supply operation with inputs at ground?
Yes, LM397MFX/NOPB explicitly supports single-supply operation with inputs referenced to ground. Its input common-mode voltage range extends from 0 V to VS – 1.5 V at 25°C (0 V to VS – 2 V over temperature), enabling direct connection of VIN– or VIN+ to ground or low-side shunt resistors. This feature is confirmed in the "Detailed Description" section and electrical specifications table of the official SNOS977F datasheet. LM397MFX/NOPB is designed for such use cases, distinguishing it from comparators requiring input bias above ground.
What external components are required for LM397MFX/NOPB to function?
LM397MFX/NOPB requires an external pull-up resistor on the OUTPUT (Pin 4) to establish a defined logic-high voltage level, as it features an open-collector NPN output stage. A 0.1-μF ceramic bypass capacitor between VS (Pin 5) and GND (Pin 2) is also mandatory to suppress supply noise and ensure stable operation. No other passive components are strictly required for basic comparator functionality, though hysteresis resistors may be added for noise immunity. LM397MFX/NOPB integrates all active circuitry internally - no external compensation or bias networks are needed.
How does the output stage of LM397MFX/NOPB differ from push-pull comparators?
LM397MFX/NOPB uses an open-collector NPN output transistor that can only sink current to ground - it cannot actively drive high. This requires an external pull-up resistor to set VOH, enabling level translation (e.g., 30 V supply with 3.3 V logic interface) and wired-OR logic. Push-pull comparators drive both high and low internally but lack this flexibility and voltage isolation. LM397MFX/NOPB's output stage is explicitly documented in Section 7.3.2 and Figure 7 of the SNOS977F datasheet, confirming its grounded-emitter NPN structure and 13 mA sink capability.
Is LM397MFX/NOPB pin-compatible with other Texas Instruments comparators?
Yes, LM397MFX/NOPB is pin-compatible with TI's TL331 single comparator in the SOT-23 (DBV) 5-pin package, sharing identical pinout: VIN– (1), GND (2), VIN+ (3), OUTPUT (4), VS (5). This compatibility is stated in the "Device Information" table and confirmed in the "Pin Configuration and Functions" section of the SNOS977F datasheet. Engineers may substitute LM397MFX/NOPB for TL331 in existing layouts without PCB changes, though differences in input offset, supply current, and temperature performance should be verified per application requirements. LM397MFX/NOPB retains full functional equivalence at the board level.
LM397MFX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- SC-74A, SOT-753
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- General Purpose
- Number of Elements:
- 1
- Output Type:
- Open-Collector, Rail-to-Rail
- Voltage - Supply, Single/Dual (±):
- 5V ~ 30V, ±2.5V ~ 15V
- :
- 7mV @ 30V
- Voltage - Input Offset (Max):
- 0.25µA @ 5V
- Current - Input Bias (Max):
- 13mA @ 5V
- Current - Output (Typ):
- 2mA
- Current - Quiescent (Max):
- -
- CMRR, PSRR (Typ):
- -
- Propagation Delay (Max):
- -
- Hysteresis:
- -40°C ~ 85°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- SOT-23-5
LM397MFX/NOPB FAQ
1.How can I place an order for LM397MFX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM397MFX/NOPB 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 LM397MFX/NOPB reliable?
The price and inventory of LM397MFX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM397MFX/NOPB is usually 5 days.
3.What payment methods are accepted for LM397MFX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM397MFX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM397MFX/NOPB?
LM397MFX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM397MFX/NOPB 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 LM397MFX/NOPB?
For technical support, including LM397MFX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM397MFX/NOPB requirements.
6.How does Aetrix verify that LM397MFX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM397MFX/NOPB 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 LM397MFX/NOPB meets industry standards.
7.What is the process for return or replacement of LM397MFX/NOPB?
All LM397MFX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM397MFX/NOPB, 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 LM397MFX/NOPB part is unused and in its original packaging.
Return procedure for LM397MFX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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