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Texas Instruments LM139FK
- Part No.:
- LM139FK
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 20-CLCC
- Datasheet:
-
LM139FK.pdf
- Description:
- QUAD DIFFERENTIAL COMPARATOR 20-
- Quantity:
- Payment:
- Shipping:
Inventory:1,991
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Product details
Overview
LM139FK from Texas Instruments is a military-grade quad differential comparator IC designed for high-reliability analog voltage comparison in harsh environments. It operates from single supplies (2 V to 30 V) or dual supplies (±1 V to ±15 V), features open-collector outputs compatible with TTL/MOS/CMOS, and delivers 2 mV typical input offset voltage, 25 nA typical input bias current, and 1.3 µs typical response time at 5 V - enabling precision level detection in power supervision and industrial control systems.
For engineers reviewing the LM139FK datasheet, LM139FK pinout, LM139FK application, or LM139FK equivalent, this page provides verified technical context, military-temperature-range specifications (–55°C to +125°C), LCCC-20 package details, and validated alternative options for ruggedized comparator designs requiring wide supply tolerance and ground-sensing capability.
Technical Context
The LM139FK implements four independent comparators using PNP Darlington-pair inputs, enabling accurate operation from ground up to (VCC – 1.5 V) at 25°C and (VCC – 2 V) across full temperature range. Its open-collector NPN output stage supports wired-AND logic and flexible pull-up voltage translation.
Input common-mode range includes ground, differential input voltage withstands ±36 V, and supply current remains stable at 0.8 mA (typ) regardless of supply voltage - critical for unregulated or battery-backed systems where rail stability cannot be assumed.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Range | Single: 2 V to 30 V; Dual: ±1 V to ±15 V - supports direct connection to 24 V industrial rails or ±12 V analog subsystems without regulation. |
| Input Offset Voltage | 2 mV (typ) - enables accurate threshold detection within ±2 mV error at room temperature, critical for precision reference comparison. |
| Input Bias Current | 25 nA (typ) - minimizes loading on high-impedance sensor sources like thermistors or photodiodes. |
| Response Time | 1.3 µs (typ, 100 mV overdrive) - ensures fast decision-making in oscillator timing and fault-detection circuits. |
| Output Type | Open-collector NPN - allows level-shifting to any logic rail (e.g., 3.3 V MCU interface from 24 V supply) and wired-AND bus configuration. |
| Operating Temperature | –55°C to +125°C - qualified per MIL-PRF-38535 for deployment in avionics, engine control, and space-qualified platforms. |
| Input Common-Mode Range | 0 V to (VCC – 1.5 V) at 25°C - permits direct ground-referenced sensing without level-shifting circuitry. |
Pinout & Package
LCCC (Leadless Ceramic Chip Carrier) 20-pin package, 8.90 mm × 8.90 mm body size, hermetically sealed ceramic construction with SNPB lead finish, rated for –55°C to +125°C operation and compatible with MIL-STD-883 reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1IN+, 2IN+, 3IN+, 4IN+ | Positive input (x = comparator 1–4) | Differential sense node for non-inverting comparison; accepts signals from 0 V to (VCC – 1.5 V). |
| 1IN−, 2IN−, 3IN−, 4IN− | Negative input (x = comparator 1–4) | Differential sense node for inverting comparison; same common-mode limits as positive inputs. |
| 1OUT, 2OUT, 3OUT, 4OUT | Open-collector output (x = comparator 1–4) | Sinks current when IN− > IN+ + VIO; requires external pull-up for logic-high state and voltage translation. |
| VCC | Positive supply | Primary power rail; supports up to 30 V DC; powers all four comparators and internal bias networks. |
| GND | Ground reference | System return path; defines 0 V reference for inputs, outputs, and supply decoupling. |
| NC (Pin 1) | No internal connection | Unbonded pad; must remain unconnected on PCB to avoid parasitic coupling or mechanical stress. |
Key Features
| Feature | Design Value |
|---|---|
| Wide supply range | Operates from 2 V to 30 V single supply - eliminates need for local regulators in 12 V or 24 V industrial systems. |
| Ground-sensing input | Common-mode range includes 0 V - enables direct interface with ground-referenced sensors (e.g., current shunts, RTDs). |
| Low input bias current | 25 nA typical - preserves signal integrity in high-Z source applications such as piezoelectric transducers or capacitive touch sensors. |
| Open-collector outputs | Supports mixed-voltage logic interfacing (e.g., 24 V comparator output driving 3.3 V microcontroller input via 3.3 V pull-up). |
| MIL-PRF-38535 qualification | All parameters tested across –55°C to +125°C - guarantees performance in mission-critical aerospace, defense, and downhole equipment. |
Applications
| Power Supervision | Oscillators |
|---|---|
Use Scenario: Monitoring 24 V DC bus voltage against 22.5 V and 25.5 V thresholds to trigger undervoltage/overvoltage alarms in railway traction control units. IC Role / Device Role / Timing Role: Quad comparator performing simultaneous high/low window detection with hysteresis added externally via feedback resistors. Use Value: Enables fail-safe shutdown before rail collapse or insulation breakdown, leveraging LM139FK's guaranteed operation at –55°C and 24 V without auxiliary regulation. |
Use Scenario: Building a relaxation oscillator for clock generation in radiation-hardened telemetry modules where crystal oscillators are prohibited. IC Role / Device Role / Timing Role: One comparator acts as threshold detector charging/discharging an RC network; output drives reset logic or data strobes. Use Value: Achieves stable 10 kHz oscillation using only LM139FK, capacitor, and two resistors - no external timing IC required, reducing BOM count and single-point failure risk. |
| Industrial Motor Control | Automotive Body Electronics |
Use Scenario: Detecting phase current imbalance in three-phase AC motor drives by comparing sensed currents against reference thresholds in real time. IC Role / Device Role / Timing Role: Three comparators monitor line-to-line current differences; fourth handles enable/disable sequencing based on thermal sensor input. Use Value: Provides sub-microsecond fault response (<1.3 µs) to prevent IGBT shoot-through, using LM139FK's consistent propagation delay across –40°C to +85°C industrial range. |
Use Scenario: Implementing door lock status monitoring in automotive body control modules by comparing Hall-effect sensor outputs against calibrated thresholds. IC Role / Device Role / Timing Role: Comparator converts analog magnetic field strength into clean digital lock/unlock signals for CAN gateway arbitration. Use Value: Delivers reliable operation at 125°C under hood conditions while maintaining <2 mV offset drift - ensuring correct latch state detection despite thermal gradients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM139J | CDIP-14 package, identical electrical specs, same MIL-PRF-38535 qualification, but larger footprint (21.30 mm × 7.60 mm) and through-hole mounting. | Preferred for legacy board designs with existing CDIP footprints or manual assembly requirements; lacks LCCC's thermal performance and vibration resistance. | Select LM139J only when board layout constraints or procurement continuity require through-hole compatibility. |
| LM2901FK | Same LCCC-20 package and pinout, commercial temperature range (–40°C to +125°C), lower cost, but not MIL-PRF-38535 tested - parameters verified only across commercial range. | Suitable for non-safety-critical industrial automation where full military screening is unnecessary; not approved for flight hardware or nuclear instrumentation. | Choose LM2901FK for cost-sensitive volume production where extended temperature validation is not mandated by system safety standards. |
Compared with LM139J and LM2901FK, the LM139FK uniquely combines hermetic LCCC packaging, full MIL-PRF-38535 test coverage across –55°C to +125°C, and 20-pin pinout optimized for high-density routing - making it the sole option for new designs requiring both extreme environmental resilience and compact surface-mount integration.
Availability
LM139FK is available at Aetrix Electronics and suitable for power supervision, industrial motor control, automotive body electronics, and aerospace telemetry systems requiring stable component supply under extended temperature and long-lifecycle commitments.
Supply support for LM139FK 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 and embedded processing technologies, with over 90 years of innovation in high-reliability components for industrial, automotive, and defense markets.
The LM139-MIL product line was engineered specifically for mission-critical applications demanding guaranteed performance across extreme temperatures and radiation environments - delivering proven comparator functionality in hermetically sealed ceramic packages compliant with MIL-PRF-38535.
FAQ
What is the maximum supply voltage rating for LM139FK?
The LM139FK has an absolute maximum supply voltage of 36 V, but its recommended operating range is 2 V to 30 V per the datasheet. Operation above 30 V risks exceeding safe junction temperature limits and invalidates parametric guarantees - always limit VCC to ≤30 V in production designs using LM139FK.
Does LM139FK support dual-supply operation?
Yes, LM139FK supports dual-supply operation with ±1 V to ±15 V (tested), provided the total differential supply voltage remains between 2 V and 36 V and VCC is at least 1.5 V more positive than the input common-mode voltage. This enables use in bipolar analog front-ends while retaining ground-sensing capability.
What is the purpose of the NC pin on LM139FK?
The NC (No Connect) pin on LM139FK - Pin 1 in the LCCC-20 package - has no internal bond wire or silicon connection. It must remain unconnected on the PCB to prevent mechanical stress on the ceramic body and avoid unintended coupling paths that could degrade noise immunity in high-speed comparator applications using LM139FK.
Can LM139FK drive TTL logic directly?
Yes, LM139FK outputs are explicitly rated as TTL-compatible when used with appropriate pull-up resistors. With a 5 V pull-up, LM139FK sinks ≥6 mA at VOL ≤400 mV (25°C), meeting TTL input low-level voltage and current requirements - confirming direct interface capability without buffer stages in systems using LM139FK.
Is LM139FK RoHS-compliant?
No, LM139FK uses SNPB (tin-lead) lead finish and is not RoHS-compliant. Its packaging is exempt under RoHS Annex III for high-reliability military/aerospace applications where lead-free alternatives do not meet MIL-PRF-38535 qualification requirements - a documented exception applicable to LM139FK.
LM139FK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 20-CLCC
- Series:
- -
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- General Purpose
- Number of Elements:
- 4
- Output Type:
- Open-Collector, Open-Drain
- Voltage - Supply, Single/Dual (±):
- 2V ~ 30V, ±1V ~ 15V
- :
- 5mV @ 5V
- Voltage - Input Offset (Max):
- 0.1µA @ 5V
- Current - Input Bias (Max):
- 16mA @ 5V
- Current - Output (Typ):
- 2mA
- Current - Quiescent (Max):
- -
- CMRR, PSRR (Typ):
- 300ns (Typ)
- Propagation Delay (Max):
- -
- Hysteresis:
- -55°C ~ 125°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 20-LCCC (8.89x8.89)
LM139FK FAQ
1.How can I place an order for LM139FK through Aetrix?
Please submit a Request for Quotation (RFQ) for LM139FK 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 LM139FK reliable?
The price and inventory of LM139FK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM139FK is usually 5 days.
3.What payment methods are accepted for LM139FK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM139FK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM139FK?
LM139FK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM139FK 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 LM139FK?
For technical support, including LM139FK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM139FK requirements.
6.How does Aetrix verify that LM139FK is sourced from the original manufacturer or authorized distributors?
All LM139FK 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 LM139FK meets industry standards.
7.What is the process for return or replacement of LM139FK?
All LM139FK units undergo pre-shipment inspection (PSI). If there is an issue with LM139FK, 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 LM139FK part is unused and in its original packaging.
Return procedure for LM139FK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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