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Texas Instruments LP311DR
- Part No.:
- LP311DR
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LP311DR.pdf
- Description:
- IC COMPARATOR 1 DIFF 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,378
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Product details
Overview
LP311DR from Texas Instruments is a low-power differential comparator with strobe capability in an 8-pin SOIC package. It features 1.2 μs typical response time, ±15 V or single 3–30 V supply operation, 900 μW typical power dissipation at 5 V, and emitter-collector open-drain outputs capable of 25 mA sink current. It is used in battery-powered voltage monitoring, threshold detection, and analog-to-digital interface circuits.
For engineers reviewing the LP311DR datasheet, LP311DR pinout, LP311DR application, or LP311DR equivalent, key selection considerations include its strobe-enabled output disable function, wide common-mode input range (−14.5 V to 13.5 V with ±15 V supplies), low input bias current (15 nA typ), and compatibility with LM311-based designs requiring reduced power consumption.
Technical Context
The LP311DR implements a bipolar comparator core with ion-implanted precision resistors enabling 30× lower power versus LM311 while retaining functional pinout and strobe control. Its dual-output structure (emitter and collector) supports flexible pull-up configurations and rail-to-rail output swing below VCC−.
Strobe functionality is implemented via a current-sinking input (100–300 μA at 0.3 V) that forces output high-impedance regardless of input states. Offset balancing is supported through dedicated BALANCE and BAL/STRB pins, allowing trimming of input offset voltage down to 2 mV typ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | Single 3 V to 30 V or dual ±15 V - enables direct integration into 3.3 V, 5 V, and industrial ±12 V systems without level-shifting. |
| Response Time | 1.2 μs typ (100 mV step, 5 mV overdrive) - suitable for medium-speed window detection and slow-control-loop feedback. |
| Input Offset Voltage | 7.5 mV max at 25°C - defines worst-case DC error in precision threshold applications; trimmed to 2 mV typ with external balance. |
| Input Bias Current | 15 nA typ - minimizes loading on high-impedance sensor sources such as thermistors or photodiodes. |
| Output Sink Current | 25 mA - drives LEDs, relays, or logic inputs directly without external buffer transistors. |
| Power Dissipation | 900 μW typ at 5 V - extends battery life in portable instrumentation and remote sensors. |
| Common-Mode Input Range | −14.5 V to 13.5 V (±15 V supply) - supports direct sensing of signals referenced to negative rails or ground-referenced AC signals. |
Pinout & Package
LP311DR is housed in an 8-pin SOIC (D) package per JEDEC MS-012AA, 3.9 mm body width, 1.75 mm max height, with standard 1.27 mm pitch and Q1 pin-1 quadrant orientation in tape-and-reel packaging.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BALANCE | Offset null adjustment terminal | Connects to external potentiometer wiper for trimming input offset voltage; unused pins must be shorted to BAL/STRB. |
| 2 - IN− | Inverting input | Differential input node; accepts signals within −14.5 V to 13.5 V common-mode range under ±15 V supply. |
| 3 - IN+ | Non-inverting input | Differential input node; same common-mode range as IN−; used for reference or signal comparison. |
| 4 - VCC− | Negative supply rail | Ground or negative supply connection; emitter output swings below this rail by up to 30 V. |
| 5 - VCC+ | Positive supply rail | Positive supply connection; supports single-supply (3–30 V) or split-supply (±15 V) operation. |
| 6 - COL OUT | Collector output | Open-collector NPN output; requires external pull-up; sinks up to 25 mA when active low. |
| 7 - BAL/STRB | Strobe / balance control | Current-sinking input (100–300 μA); pulling low disables output (high-Z); also serves as balance node when shorted to BALANCE. |
| 8 - EMIT OUT | Emitter output | Open-emitter NPN output; connects to VCC− for active-low sinking; allows output swing below VCC−. |
Key Features
| Feature | Design Value |
|---|---|
| Strobe-enabled output disable | Hardware-controlled high-impedance state via 100–300 μA current sink on BAL/STRB - eliminates need for external logic gating in sequencing or safety-critical shutdown paths. |
| Low-power operation | 900 μW typical at 5 V - reduces thermal load and extends runtime in coin-cell or energy-harvesting systems. |
| Dual-output configuration | Separate emitter and collector outputs - enables flexible termination: COL OUT for pull-up to higher voltage, EMIT OUT for sinking below ground or negative rail. |
| Wide supply range | Operates from 3 V single supply to ±15 V dual supply - supports legacy industrial, automotive, and portable designs without redesign. |
| Offset balancing | Two-pin trim interface (BALANCE + BAL/STRB) - achieves <2 mV offset after calibration, critical for precision zero-crossing or window detection. |
Applications
| Battery Voltage Monitor | Industrial Threshold Detector |
|---|---|
|
Use Scenario: Monitoring Li-ion cell voltage during charging/discharging to trigger cutoff at 4.2 V or 2.8 V thresholds. IC Role / Device Role / Timing Role: Differential comparator comparing sensed cell voltage against precision reference; strobe used to disable during charge-phase transitions. Use Value: 15 nA input bias avoids loading high-resistance voltage divider networks; 25 mA sink drives protection FET gate directly. |
Use Scenario: Detecting overtemperature condition in motor drive using PT100 bridge output. IC Role / Device Role / Timing Role: High-common-mode comparator rejecting noise on long sensor leads; operates from ±12 V supply shared with control logic. Use Value: −14.5 V to 13.5 V input range accommodates bridge output centered at −6 V; 7.5 mV max offset ensures <0.5°C error at 10 mV/°C gain. |
| Programmable Logic Interface | AC Zero-Crossing Detector |
|
Use Scenario: Converting analog control signals (0–10 V) into TTL-compatible digital enable/disable commands for PLC I/O modules. IC Role / Device Role / Timing Role: Single-supply comparator with strobe synchronized to system clock to gate valid decision windows. Use Value: 3 V minimum supply allows direct use with 3.3 V microcontroller logic; 1.2 μs response ensures timing alignment within 10 μs control cycles. |
Use Scenario: Detecting zero crossings of 50/60 Hz mains voltage for phase-controlled dimming or synchronous switching. IC Role / Device Role / Timing Role: AC-coupled comparator with balanced inputs and offset trim to eliminate false triggers near zero crossing. Use Value: Dual outputs allow simultaneous driving of rising- and falling-edge-triggered logic; emitter output swings below neutral to ensure clean transition. |
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 supply current (5.5 mA vs. 0.3 mA), faster response (200 ns vs. 1.2 μs), no strobe pin, same SOIC-8 pinout. | Used where speed > power savings; unsuitable for battery operation; lacks hardware disable for sequencing. | Select LM311DR only when sub-microsecond response is required and power budget permits. |
| TLV3011DBVR | Rail-to-rail input, 1.8–5.5 V supply only, 350 nA supply current, no strobe, SOT-23-6 package (different pinout). | Optimized for ultra-low-power 3.3 V systems; lacks negative supply support and strobe; requires PCB redesign. | Choose TLV3011DBVR for new 3.3 V designs prioritizing nanoamp quiescent current over strobe or dual-supply flexibility. |
Compared with LM311DR and TLV3011DBVR, the LP311DR uniquely balances ultra-low power (900 μW), strobe control, and ±15 V compatibility - making it the only option among the three for legacy-replacement battery-powered industrial comparators requiring hardware-gated output disable.
Availability
LP311DR is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial voltage supervision, and analog interface circuits requiring stable component supply across extended temperature ranges (0°C to 70°C).
Supply support for LP311DR 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The LP311DR belongs to TI's legacy precision analog comparator family, designed specifically to provide drop-in low-power replacements for LM311 in cost-sensitive, thermally constrained, and battery-operated applications without sacrificing functional compatibility.
FAQ
What is the operating temperature range for the LP311DR?
The LP311DR is characterized for operation from 0°C to 70°C ambient temperature. This range is specified in TI's official ordering information and applies to all SOIC-packaged LP311 variants including LP311DR. It is not rated for extended industrial (−40°C to 85°C) or automotive temperature grades.
Does the LP311DR support single-supply operation?
Yes, the LP311DR supports true single-supply operation from 3 V to 30 V. The datasheet confirms functionality with VCC+ = 3 V and VCC− = 0 V, maintaining 25 mA output sink capability and 1.2 μs response time. Input common-mode range extends to within 0.5 V of either rail under these conditions.
How is the strobe function implemented on the LP311DR?
The strobe function on the LP311DR is implemented on Pin 7 (BAL/STRB) as a current-sinking input requiring 100–300 μA at 0.3 V to force the output into high-impedance state. It must not be shorted to ground; instead, it should be driven by a current source or logic buffer capable of sinking the specified current. This action overrides both inputs and disables both COL OUT and EMIT OUT.
Can the LP311DR replace the LM311 in existing designs?
Yes, the LP311DR is explicitly designed as a pin-compatible, functionally interchangeable replacement for the LM311 in SOIC-8 packages. TI's datasheet states "Same pinout as LM211, LM311" and "Designed To Be Interchangeable With Industry-Standard LP311". No PCB changes are required, though users should verify timing margins due to the slower 1.2 μs response versus LM311's 200 ns.
What is the maximum output sink current specification for the LP311DR?
The LP311DR specifies a guaranteed 25 mA output sink current for both COL OUT (Pin 6) and EMIT OUT (Pin 8) under typical conditions. This value is confirmed in the "Output Drive Capability" section of the datasheet and verified across the full operating temperature range with ±15 V supplies. It remains valid at lower voltages, though power dissipation must be checked per application.
LP311DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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
LP311DR FAQ
1.How can I place an order for LP311DR through Aetrix?
Please submit a Request for Quotation (RFQ) for LP311DR 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 LP311DR reliable?
The price and inventory of LP311DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP311DR is usually 5 days.
3.What payment methods are accepted for LP311DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP311DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP311DR?
LP311DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP311DR 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 LP311DR?
For technical support, including LP311DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP311DR requirements.
6.How does Aetrix verify that LP311DR is sourced from the original manufacturer or authorized distributors?
All LP311DR 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 LP311DR meets industry standards.
7.What is the process for return or replacement of LP311DR?
All LP311DR units undergo pre-shipment inspection (PSI). If there is an issue with LP311DR, 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 LP311DR part is unused and in its original packaging.
Return procedure for LP311DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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