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Texas Instruments LM311PW
- Part No.:
- LM311PW
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM311PW.pdf
- Description:
- IC COMPARATOR 1 GEN PUR 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,296
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Product details
Overview
LM311PW 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 LM311PW datasheet, LM311PW pinout, LM311PW application, or LM311PW equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternatives, and supply-chain support for production deployment.
Technical Context
The LM311PW uses a PNP input stage enabling common-mode operation down to VCC− − 0.7 V, and features dual output terminals (COL OUT and EMIT OUT) allowing flexible load referencing to ground, VCC+, or VCC−. Its strobe (BAL/STRB) and balance (BALANCE) pins enable external offset trimming and synchronous gating.
It operates as a voltage comparator only - no internal hysteresis or latch functionality - with differential input voltage range of ±30 V and input bias current ≤300 nA at 25°C. Output logic state is determined solely by polarity of IN+ vs IN−, with low-state VOL = 0.75 V at 50 mA (VCC+ = ±15 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Response time | 165 ns high-to-low; enables sub-6 MHz comparator-based oscillators and fast edge detection |
| Input bias current | Max 300 nA at 25°C; minimizes loading on high-impedance sensor or reference sources |
| Input offset voltage | Max 7.5 mV at 25°C; defines minimum detectable voltage difference without trimming |
| Output voltage swing | COL OUT sinks up to 50 mA at ≤40 V; supports direct relay, lamp, or MOSFET gate drive |
| Supply voltage range | 3.5 V to 30 V total (VCC+ − VCC−); compatible with ±15 V op-amp rails or +5 V logic supplies |
| Operating temperature | 0°C to +70°C; qualified for commercial-grade embedded control and instrumentation |
| Common-mode input range | −14.7 V to +13.8 V (at ±15 V supply); allows inputs near supply rails without phase reversal |
Pinout & Package
TSSOP-8 package (3.00 mm × 4.40 mm), moisture-sensitive level 1, lead-free and RoHS compliant.
| 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 rail |
| 2: IN+ | Noninverting input | Accepts reference or signal input; common-mode range extends to VCC− − 0.7 V |
| 3: IN− | Inverting input | Accepts signal or threshold input; differential comparison determines output state |
| 4: VCC− | Negative supply | Reference for internal circuitry and EMIT OUT; may be connected to ground in single-supply use |
| 5: BALANCE | Offset null adjustment | Connects to potentiometer wiper for manual input offset cancellation (typically 10 kΩ trimmer) |
| 6: BAL/STRB | Strobe control input | Sinking ≥3 mA forces output into high-impedance state - enables time-gated comparisons |
| 7: COL OUT | Collector output terminal | Open-collector NPN output; requires external pullup to define logic-high level and sink current |
| 8: VCC+ | Positive supply | Power rail for internal circuitry; sets upper limit for COL OUT voltage swing and load drive |
Key Features
| Feature | Design Value |
|---|---|
| Strobe-enabled gating | External current-driven control (–3 mA) disables output regardless of input state - critical for synchronized sampling |
| Isolated dual outputs | COL OUT and EMIT OUT allow load connection to ground, VCC+, or VCC− - eliminates need for level-shifting buffers |
| Wide supply compatibility | Operates from 3.5 V to 30 V total supply - supports legacy ±15 V systems and modern 5 V microcontroller interfaces |
| High-voltage output drive | COL OUT switches up to 40 V at 50 mA - directly drives relays, LEDs, and logic families without external transistors |
| Low input bias current | ≤300 nA max ensures minimal error in high-impedance voltage divider or photodiode applications |
Applications
| Zero-Crossing Detection | Oscillator Circuits |
|---|---|
|
Use Scenario: Detecting AC waveform polarity transitions in power monitoring or motor control. IC Role / Device Role / Timing Role: Voltage comparator comparing sine wave against 0 V reference; output toggles at each crossing. Use Value: Enables precise timing for TRIAC triggering or digital sampling synchronization with line frequency. |
Use Scenario: Generating square-wave clock signals using RC feedback networks. IC Role / Device Role / Timing Role: Core comparator in free-running multivibrator topology with hysteresis via feedback resistors. Use Value: Delivers stable 100-kHz output with <1% duty cycle variation across temperature and supply voltage. |
| Peak Detection | TTL/MOS Interface Level Shifting |
|
Use Scenario: Capturing maximum amplitude of analog sensor outputs in data acquisition systems. IC Role / Device Role / Timing Role: Comparator driving diode-capacitor hold circuit; strobe pin freezes capture on command. Use Value: Achieves <10 µs capture window and <0.5% droop over 100 ms using EMIT OUT for low-leakage discharge control. |
Use Scenario: Converting 3.3 V or 5 V logic signals to higher-voltage control lines (e.g., 12 V solenoid drivers). IC Role / Device Role / Timing Role: Open-collector output pulled to 12 V or 24 V rail; acts as bidirectional level translator. Use Value: Eliminates need for dedicated level-shifter ICs while maintaining <165 ns propagation delay and noise immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM393DR | Dual comparator, lower speed (1.3 µs), no strobe or balance pins, 2-mA max supply current | Lacks strobe gating and offset trimming; suited for cost-sensitive dual-threshold detection only | Choose LM393DR only when dual channels are needed and speed/strobe are unnecessary |
| TL331IDBVR | Single comparator, rail-to-rail input, 200-ns response, no emitter output or strobe, 60-µA supply current | No isolated outputs or external offset control; optimized for ultra-low-power battery systems | Prefer TL331IDBVR for portable devices where quiescent current <100 µA is mandatory |
Compared with LM311PW, LM393DR offers dual-channel integration but sacrifices speed, strobe control, and high-voltage drive; TL331IDBVR reduces power consumption dramatically but removes critical analog trimming and load-flexibility features required in precision industrial designs.
Availability
LM311PW is available at Aetrix Electronics and suitable for industrial automation, building control systems, and test equipment requiring stable component supply across extended production lifecycles.
Supply support for LM311PW 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 decades of expertise in precision signal chain components.
The LM311PW belongs to TI's legacy high-speed comparator product line, engineered for robust performance in noisy industrial environments, wide supply flexibility, and direct interface with electromechanical loads.
FAQ
What is the maximum output voltage swing capability of the LM311PW?
The LM311PW COL OUT terminal can switch up to 40 V relative to VCC−, per absolute maximum ratings. This allows direct drive of 24-V relays or 36-V logic interfaces when VCC− is grounded. The actual usable swing depends on load current and supply configuration - at 50 mA, VOL remains ≤1.5 V with ±15 V supplies. Always observe the 40-V collector-to-emitter limit specified for LM311PW in the datasheet.
Can the LM311PW operate from a single 5-V supply?
Yes, the LM311PW is explicitly rated for single 5-V operation (VCC+ = 5 V, VCC− = 0 V). Input common-mode range extends from 0.5 V to 3.5 V under these conditions, and output low voltage is guaranteed ≤0.4 V at 8 mA sink current. This makes LM311PW suitable for interfacing with 5-V microcontrollers and logic families without level shifters.
How does the BAL/STRB pin function in the LM311PW?
The BAL/STRB pin on the LM311PW serves dual purpose: as a strobe input when driven with ≥3 mA sink current, it forces the output into high-impedance state regardless of input differential; as a balance control, it connects to a potentiometer for manual input offset nulling. TI specifies it must never be shorted to ground - current drive is mandatory for reliable strobe action in LM311PW.
What is the purpose of the EMIT OUT pin on the LM311PW?
The EMIT OUT pin on the LM311PW provides an alternative output path referenced to VCC−, enabling loads to be connected between EMIT OUT and VCC+ (high-side switching) or between EMIT OUT and ground (low-side switching with VCC− grounded). Unlike COL OUT, EMIT OUT does not require an external pullup resistor and offers lower leakage in high-impedance hold circuits - a key advantage in peak detector designs using LM311PW.
Does the LM311PW include built-in hysteresis?
No, the LM311PW has no internal hysteresis. It is a pure differential comparator whose output changes state immediately upon input crossing the threshold defined by input offset voltage. External hysteresis must be added via positive feedback (e.g., resistor from COL OUT to IN+) for noise immunity in slow-moving or noisy input applications - a standard practice confirmed in TI's LM311PW application examples.
LM311PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Series:
- -
- Packaging:
- Tube
- 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-TSSOP
LM311PW FAQ
1.How can I place an order for LM311PW through Aetrix?
Please submit a Request for Quotation (RFQ) for LM311PW 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 LM311PW reliable?
The price and inventory of LM311PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM311PW is usually 5 days.
3.What payment methods are accepted for LM311PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM311PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM311PW?
LM311PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM311PW 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 LM311PW?
For technical support, including LM311PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM311PW requirements.
6.How does Aetrix verify that LM311PW is sourced from the original manufacturer or authorized distributors?
All LM311PW 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 LM311PW meets industry standards.
7.What is the process for return or replacement of LM311PW?
All LM311PW units undergo pre-shipment inspection (PSI). If there is an issue with LM311PW, 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 LM311PW part is unused and in its original packaging.
Return procedure for LM311PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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