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Texas Instruments LP311D
- Part No.:
- LP311D
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LP311D.pdf
- Description:
- IC COMPARATOR 1 DIFF 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:810
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Product details
Overview
LP311D from Texas Instruments is a low-power differential comparator with strobe and offset balancing capability, designed for precision threshold detection in battery-powered and industrial systems. It operates from ±15 V or single 3-V supply, delivers 25 mA output drive, features 1.2 μs typical response time, and supports wide common-mode input range (−14.5 V to 13.5 V) - ideal for voltage monitoring and analog signal conditioning circuits.
For engineers reviewing the LP311D datasheet, LP311D pinout, LP311D application, or LP311D equivalent, key selection considerations include its 900 μW typical power consumption at 5 V, 7.5 mV max input offset voltage at 25°C, emitter-output swing below negative rail, and compatibility with LM211/LM311 PCB layouts.
Technical Context
The LP311D implements an open-collector/open-emitter output stage with dual independent outputs (COL OUT and EMIT OUT), enabling flexible interfacing with TTL, CMOS, or relay drivers. Its internal strobe function disables output regardless of input state when BAL/STRB is pulled low with 100–300 μA current - not direct grounding - providing precise timing control in multiplexed or synchronized systems.
Offset balancing is achieved via external resistors on BALANCE and BAL/STRB pins, allowing trimming of input offset voltage down to ≤2 mV typical. The device uses ion-implanted resistors for stable biasing, delivering 15 nA typical input bias current and 2 nA typical input offset current across 0°C to 70°C operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Range | Single 3 V to ±15 V - enables direct use in 3.3 V microcontroller systems or legacy ±15 V analog rails without level-shifting. |
| Input Offset Voltage | 7.5 mV max at 25°C - sets minimum detectable voltage difference in precision window comparators or zero-crossing detectors. |
| Response Time | 1.2 μs typical (100 mV step, 5 mV overdrive) - balances speed and ultra-low power for non-critical timing applications like battery charge-state indication. |
| Output Drive | 25 mA sink capability at COL OUT - directly drives LEDs, small relays, or logic inputs without external buffer transistors. |
| Power Consumption | 900 μW typical at 5 V - extends battery life in portable instrumentation and remote sensors where quiescent current is critical. |
| Common-Mode Range | −14.5 V to 13.5 V with ±15 V supply - allows direct sensing of signals referenced to negative rails or ground-referenced signals in mixed-supply systems. |
| Strobe Input Current | 100–300 μA required to activate strobe - mandates current-source drive (e.g., transistor or logic gate with series resistor), not direct logic-level connection. |
Pinout & Package
LP311D is housed in an 8-pin SOIC (D) package, 3.9 mm width, 1.75 mm max height, RoHS-compliant NIPDAU lead finish, MSL Level-1 (260°C peak reflow). Pin 1 identifier located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BALANCE | Offset null adjustment terminal | Connects to external potentiometer wiper for trimming input offset voltage; left floating or shorted to BAL/STRB if unused. |
| 2 - IN− | Inverting input | Differential input node; accepts signals up to ±15 V relative to midpoint of supplies; high impedance (15 nA bias current). |
| 3 - IN+ | Non-inverting input | Differential input node; same voltage range and impedance as IN−; used for reference or signal input in comparator configurations. |
| 4 - VCC− | Negative supply rail | Reference for emitter output and internal circuitry; EMIT OUT can swing below this rail by up to 30 V. |
| 5 - VCC+ | Positive supply rail | Reference for collector output and internal biasing; supports single-supply operation when VCC− = GND. |
| 6 - COL OUT | Open-collector output | Sinks up to 25 mA; requires external pull-up to define logic-high level; compatible with TTL/CMOS interface voltages. |
| 7 - BAL/STRB | Strobe and balance control | Pulling low with 100–300 μA disables both outputs; also serves as second offset trim terminal when used with BALANCE. |
| 8 - EMIT OUT | Open-emitter output | Sources current to VCC−; swings below VCC− rail; used for sinking loads referenced to negative supply or ground. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low power operation | 900 μW typical at 5 V supply - reduces thermal load and extends battery runtime in always-on sensor nodes. |
| Dual independent outputs | Separate COL OUT (sink) and EMIT OUT (source) terminals - enables bidirectional load control without external inverters or dual devices. |
| Strobe-enabled output disable | Hardware-controlled output blanking via BAL/STRB pin - eliminates race conditions in time-multiplexed sampling or synchronized shutdown sequences. |
| Offset voltage trimming | Two-terminal (BALANCE + BAL/STRB) nulling network - achieves <2 mV residual offset after calibration for high-accuracy threshold setting. |
| Wide supply and input range | Operates from 3 V single supply to ±15 V bipolar rails; inputs tolerate −14.5 V to 13.5 V common-mode - simplifies design across diverse power domains. |
Applications
| Battery Voltage Monitor | Industrial Threshold Detector |
|---|---|
|
Use Scenario: Monitoring Li-ion cell voltage during charging/discharging to trigger cutoff or alert at 3.0 V and 4.2 V thresholds. IC Role / Device Role / Timing Role: Dual LP311D comparators configured as window detector with independent strobe control per threshold. Use Value: 900 μW quiescent power minimizes self-discharge; emitter output swings below ground to drive low-side MOSFET switches directly. |
Use Scenario: Detecting overtemperature condition in motor drive using thermistor divider feeding into LP311D input. IC Role / Device Role / Timing Role: Precision comparator comparing thermistor voltage against trimmed reference; strobe synchronizes detection with PWM cycle. Use Value: 7.5 mV max offset ensures accurate trip point across temperature; 25 mA output drives optocoupler LED without buffer. |
| Programmable Logic Interface | Analog-to-Digital Signal Conditioning |
|
Use Scenario: Converting analog sensor output (0–5 V) into clean digital enable signal for FPGA I/O bank. IC Role / Device Role / Timing Role: Single-supply (5 V) comparator with hysteresis added externally; COL OUT interfaces directly to 3.3 V FPGA input via pull-up. Use Value: Open-collector output provides voltage-level flexibility; 1.2 μs response ensures timely assertion before next clock edge. |
Use Scenario: Preconditioning audio signal for ADC input by detecting clipping events and triggering gain reduction. IC Role / Device Role / Timing Role: Fast comparator detecting >95% full-scale excursions; strobe disables detection during ADC conversion window. Use Value: Strobe pin allows precise temporal masking of comparator output - prevents false triggers during sampling aperture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar differential comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM311DR | Higher 2.5 mW typical power at ±15 V; 115 ns response time; no strobe function; same SOIC-8 pinout. | Used where speed >10× faster is required and power budget allows; lacks strobe-based synchronization capability. | Select LM311DR only when sub-200 ns response is mandatory and strobe control is unnecessary. |
| TLV3011DBVR | Rail-to-rail input; 1.8–5.5 V single-supply only; 350 nA supply current; 1.5 μs response; integrated reference; SOT-23-6. | Targeted at ultra-low-power, space-constrained designs; no dual output or strobe; incompatible pinout and supply architecture. | Choose TLV3011DBVR for battery-powered wearables needing minimal footprint and sub-μA operation - not for bipolar or strobed systems. |
Compared with LM311DR and TLV3011DBVR, the LP311D uniquely combines strobe control, dual open-collector/emitter outputs, and ultra-low 900 μW power in a drop-in-compatible SOIC-8 package - making it optimal for cost-sensitive, battery-aware industrial systems requiring synchronized analog decision-making.
Availability
LP311D is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial voltage monitoring, programmable logic interfacing, and analog signal conditioning requiring stable component supply and long-term production continuity.
Supply support for LP311D 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, embedded processing, and connectivity technologies, with decades of expertise in precision analog ICs and industrial-grade components.
The LP311D belongs to TI's legacy low-power comparator product line, engineered specifically for energy-efficient threshold detection in battery-operated and mixed-signal industrial equipment where reliability and pin compatibility with industry-standard LM311 are essential.
FAQ
What is the maximum supply voltage rating for LP311D?
The LP311D supports absolute maximum supply voltages of +18 V on VCC+ and −18 V on VCC−. Recommended operating supply range is ±15 V or single 3 V to 30 V total differential. Exceeding ±18 V risks permanent damage per TI's SLCS003D datasheet Absolute Maximum Ratings table.
Can LP311D operate from a single 3.3 V supply?
Yes, LP311D operates from a single 3 V supply (minimum) up to 30 V total differential. At 3.3 V, it maintains 25 mA output drive and 1.2 μs typical response, though input common-mode range shrinks to approximately 0.5 V above VCC− to 1.5 V below VCC+, per Recommended Operating Conditions.
How is the strobe function implemented on LP311D?
The strobe function is activated by pulling the BAL/STRB pin low with 100–300 μA current - not by direct grounding. This disables both COL OUT and EMIT OUT regardless of input states. TI explicitly warns against shorting BAL/STRB to ground, as it may cause undefined behavior or excessive current draw.
Is LP311D pin-compatible with LM311?
Yes, LP311D shares identical pinout and footprint with LM311 in SOIC-8 (D) package, as confirmed in TI's SLCS003D datasheet functional diagram and ordering table. This enables direct replacement in existing LM311 designs without PCB changes, provided strobe and offset trimming functions are either unused or adapted.
What is the input bias current specification for LP311D?
LP311D has 15 nA typical input bias current at 25°C, with a maximum of 150 nA across its full 0°C to 70°C operating range. This low bias current minimizes loading errors in high-impedance sensor interfaces such as thermistor or photodiode amplifier networks.
LP311D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Differential
- Number of Elements:
- 1
- Output Type:
- Open-Collector, Open-Emitter
- Voltage - Supply, Single/Dual (±):
- 3.5V ~ 30V, ±1.75V ~ 15V
- :
- 7.5mV @ ±15V
- Voltage - Input Offset (Max):
- 0.1µA @ ±15V
- Current - Input Bias (Max):
- -
- Current - Output (Typ):
- 300µA
- Current - Quiescent (Max):
- -
- CMRR, PSRR (Typ):
- -
- Propagation Delay (Max):
- -
- Hysteresis:
- 0°C ~ 70°C
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- Surface Mount
- :
- 8-SOIC
LP311D FAQ
1.How can I place an order for LP311D through Aetrix?
Please submit a Request for Quotation (RFQ) for LP311D 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 LP311D reliable?
The price and inventory of LP311D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP311D is usually 5 days.
3.What payment methods are accepted for LP311D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP311D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP311D?
LP311D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP311D 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 LP311D?
For technical support, including LP311D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP311D requirements.
6.How does Aetrix verify that LP311D is sourced from the original manufacturer or authorized distributors?
All LP311D 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 LP311D meets industry standards.
7.What is the process for return or replacement of LP311D?
All LP311D units undergo pre-shipment inspection (PSI). If there is an issue with LP311D, 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 LP311D part is unused and in its original packaging.
Return procedure for LP311D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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