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Texas Instruments LM311PSR
- Part No.:
- LM311PSR
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
LM311PSR.pdf
- Description:
- IC COMPARATOR 1 GEN PUR 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,718
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Product details
Overview
LM311PSR from Texas Instruments is a single high-speed voltage comparator with open-collector output, designed for precision level detection and signal conditioning in industrial and embedded systems. It delivers 165 ns response time, supports ±15 V or single 5-V supply operation, and drives loads up to 40 V at 50 mA - used in zero-crossing detectors, peak detectors, and oscillator circuits.
For engineers reviewing the LM311PSR datasheet, LM311PSR pinout, LM311PSR application, or LM311PSR equivalent, this page provides verified electrical parameters, thermal metrics for SO-8 package, strobe and balance functionality details, and real-world implementation guidance for TTL/MOS interfacing, relay driving, and noise-immune threshold detection.
Technical Context
The LM311PSR uses a PNP input stage enabling input common-mode range down to VCC− − 0.7 V, supporting rail-to-rail sensing near negative supply. Its high-gain internal stage ensures fast decision-making, while the isolated-emitter NPN output stage allows flexible load referencing - to ground, VCC+, or VCC− - unlike standard open-drain comparators.
Strobe (BAL/STRB) and offset balance (BALANCE) pins enable external timing control and trimming without feedback networks. The device operates over 0°C to +70°C, with input bias current ≤300 nA and input offset voltage ≤7.5 mV, making it suitable for low-power, high-precision analog thresholding where legacy comparators exhibit drift or slow settling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Response Time | 165 ns high-to-low; enables sub-microsecond decision latency in pulse-width modulation or clock recovery. |
| Supply Voltage Range | 3.5 V to 30 V total; supports single 5-V logic rails or dual ±15-V op-amp supplies without level-shifting circuitry. |
| Input Bias Current | Max 300 nA at 25°C; minimizes loading on high-impedance sources like photodiodes or RC timing networks. |
| Output Drive Capability | 40 V collector-to-emitter swing at 50 mA; directly switches relays, lamps, or MOSFET gates without buffer stages. |
| Input Offset Voltage | Max 7.5 mV over full temperature range; defines minimum detectable differential voltage before output transition. |
| Common-Mode Range | –14.7 V to +13.8 V (at ±15 V supply); allows valid comparison of signals referenced to negative rails or ground. |
| ESD Rating (HBM) | ±500 V; meets standard handling requirements for automated assembly in industrial PCB production. |
Pinout & Package
LM311PSR is housed in an 8-pin SOIC (SO) package measuring 6.20 mm × 5.30 mm, with surface-mount footprint compatible with IPC-7351B SOIC-8 standards. Thermal resistance RθJA = 121.8°C/W enables operation up to 70°C ambient without forced airflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: EMIT OUT | Emitter output terminal | Provides low-side switching path referenced to VCC−; used when load must be tied to positive supply or floating reference. |
| 2: IN+ | Noninverting input | Accepts reference or signal input; common-mode range extends to VCC− − 0.7 V for ground-referenced designs. |
| 3: IN− | Inverting input | Accepts signal to be compared; differential input voltage range ±30 V avoids clamping diode conduction. |
| 4: VCC− | Negative supply pin | Reference node for internal circuitry and emitter output; may be connected to ground in single-supply configurations. |
| 5: BALANCE | Offset null adjustment | Connects to potentiometer wiper for manual VIO trimming; required only in ultra-precision applications. |
| 6: BAL/STRB | Strobe control input | Sinks –3 mA to disable output regardless of input state; enables synchronized sampling or gated comparison windows. |
| 7: COL OUT | Collector output terminal | Open-collector NPN output; requires external pullup to define logic-high level and drive strength. |
| 8: VCC+ | Positive supply pin | Power source for internal circuitry; supports up to +18 V absolute maximum rating. |
Key Features
| Feature | Design Value |
|---|---|
| Strobe-enabled output disable | Allows precise temporal gating of comparator decisions without interrupting input signal paths or requiring external logic. |
| Isolated emitter output | Enables load connection between COL OUT and EMIT OUT - permitting bidirectional voltage translation or floating load switching. |
| Wide supply compatibility | Operates from 3.5 V to 30 V total supply range, eliminating need for dedicated bias rails in mixed-voltage systems. |
| Wire-OR output capability | Multiple LM311PSR outputs can share a single pullup resistor, simplifying multi-input OR logic or priority encoder designs. |
| Ground-isolated I/O | Both inputs and outputs function independently of system ground, supporting isolated sensing in motor drives or power converters. |
Applications
| Zero-Crossing Detection | Oscillator & Timing Circuit |
|---|---|
Use Scenario: Detecting AC line voltage polarity transitions in power supplies or motor controllers. IC Role / Device Role / Timing Role: High-speed comparator comparing sine wave against ground reference with strobe-synchronized sampling. Use Value: 165 ns response ensures accurate zero-crossing capture within 1% of 50/60 Hz cycle, reducing phase error in TRIAC firing. |
Use Scenario: Generating stable square-wave clocks in free-running multivibrator or crystal oscillator topologies. IC Role / Device Role / Timing Role: Core timing element in hysteresis-based relaxation oscillator using RC feedback and BAL/STRB for duty-cycle control. Use Value: Open-collector output interfaces directly with TTL logic; 40 V output swing accommodates 12 V or 24 V clock distribution buses. |
| Peak Detector | Relay & Solenoid Driver |
Use Scenario: Capturing maximum amplitude of transient sensor signals in test equipment or audio processing. IC Role / Device Role / Timing Role: Comparator latching capacitor charge via diode when input exceeds stored value; BALANCE pin adjusts threshold hysteresis. Use Value: Input bias current ≤300 nA prevents capacitor discharge during hold phase, enabling >1-second hold time with 100 nF storage. |
Use Scenario: Directly switching 12 V/24 V relays or solenoids in PLC I/O modules or HVAC control panels. IC Role / Device Role / Timing Role: High-current comparator output driving relay coil through COL OUT–EMIT OUT path with flyback protection. Use Value: 50 mA sink capability eliminates need for external driver transistor; 40 V output rating withstands inductive kickback up to 30 V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM311DR | Same SOIC-8 package, identical electrical specs, but rated for –40°C to +85°C operating range vs. LM311PSR's 0°C to +70°C. | Preferred for automotive or extended-temperature industrial environments where cold-start operation is required. | Select LM311DR when ambient temperature may fall below 0°C; otherwise LM311PSR offers cost-optimized performance for commercial-grade systems. |
| TLV3011DBVR | Low-voltage CMOS comparator (1.8 V to 5.5 V), 350 ns response, rail-to-rail I/O, but max output drive <10 mA and no strobe pin. | Suitable for battery-powered sensors or portable devices, but cannot replace LM311PSR in high-voltage relay or AC line sensing. | Choose TLV3011DBVR only for low-power, single-supply ≤5 V systems where 40 V output swing and strobe control are unnecessary. |
Compared with LM311DR and TLV3011DBVR, the LM311PSR uniquely combines wide supply range (3.5–30 V), 40 V output capability, strobe control, and SOIC-8 packaging - making it irreplaceable in AC line monitoring, industrial relay control, and mixed-voltage timing applications where robustness and flexibility are critical.
Availability
LM311PSR is available at Aetrix Electronics and suitable for industrial automation, power supply monitoring, and embedded sensor interface applications requiring stable component supply across multi-year production cycles.
Supply support for LM311PSR 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 and embedded processing solutions, with over 90 years of innovation in precision analog ICs and industrial-grade components.
The LM311PSR belongs to TI's legacy high-speed comparator product line, engineered specifically for ruggedized signal conditioning in noisy industrial environments, power conversion feedback loops, and electromechanical control systems.
FAQ
What is the maximum supply voltage rating for LM311PSR?
The LM311PSR has an absolute maximum supply voltage rating of ±18 V (VCC+ ≤ +18 V, VCC− ≥ –18 V), with total supply range up to 36 V. Recommended operating range is 3.5 V to 30 V. Exceeding these limits risks permanent damage, per TI's SLCS007K datasheet Section 6.1. Always verify actual rail voltages in your design before finalizing LM311PSR usage.
Can LM311PSR operate from a single 5-V supply?
Yes, the LM311PSR is explicitly specified to operate from a single 5-V supply, as confirmed in its Features list and Recommended Operating Conditions (Section 6.3). In this configuration, connect VCC− to ground and use VCC+ = 5 V. Input common-mode range remains functional from 0.5 V to 3.5 V, and output swings from near ground to 5 V via external pullup - making LM311PSR ideal for direct TTL/MOS interfacing.
How does the BAL/STRB pin function in LM311PSR?
The BAL/STRB pin on LM311PSR serves dual purpose: as strobe input (sinking –3 mA to force output high-impedance) or as balance adjust node when used with external potentiometer. When strobed low, output is disabled regardless of input differential - enabling synchronized sampling. TI warns against shorting BAL/STRB to ground; it must be current-driven, not voltage-driven, per Section 6.6 footnote (4).
What is the output configuration of LM311PSR?
The LM311PSR features two independent output terminals: COL OUT (open-collector NPN) and EMIT OUT (emitter output). COL OUT sinks current to VCC− when active; EMIT OUT sources current from VCC+ when active. Together they allow bidirectional switching - e.g., driving loads between COL OUT and EMIT OUT - and support wire-OR connections. No internal pullup is present; external resistors define logic levels and current limits.
Does LM311PSR require external compensation or filtering?
No, the LM311PSR is internally compensated and requires no external frequency compensation. However, TI recommends 0.1 µF bypass capacitors on both VCC+ and VCC− pins (Section 10), especially in noisy environments or AC-coupled applications, to stabilize supply rails and prevent false triggering due to supply ripple affecting common-mode range. Layout guidelines also emphasize short, low-inductance ground paths.
LM311PSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- General Purpose
- Number of Elements:
- 1
- Output Type:
- DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL
- Voltage - Supply, Single/Dual (±):
- 3.5V ~ 30V, ±1.75V ~ 15V
- :
- 7.5mV @ ±15V
- Voltage - Input Offset (Max):
- 0.25µA @ ±15V
- Current - Input Bias (Max):
- 50mA
- Current - Output (Typ):
- 7.5mA
- Current - Quiescent (Max):
- -
- CMRR, PSRR (Typ):
- -
- Propagation Delay (Max):
- -
- Hysteresis:
- 0°C ~ 70°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 8-SO
LM311PSR FAQ
1.How can I place an order for LM311PSR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM311PSR 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 LM311PSR reliable?
The price and inventory of LM311PSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM311PSR is usually 5 days.
3.What payment methods are accepted for LM311PSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM311PSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM311PSR?
LM311PSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM311PSR 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 LM311PSR?
For technical support, including LM311PSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM311PSR requirements.
6.How does Aetrix verify that LM311PSR is sourced from the original manufacturer or authorized distributors?
All LM311PSR 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 LM311PSR meets industry standards.
7.What is the process for return or replacement of LM311PSR?
All LM311PSR units undergo pre-shipment inspection (PSI). If there is an issue with LM311PSR, 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 LM311PSR part is unused and in its original packaging.
Return procedure for LM311PSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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