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Texas Instruments LP311PSR
- Part No.:
- LP311PSR
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
LP311PSR.pdf
- Description:
- IC COMPARATOR 1 DIFF 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,524
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Product details
Overview
LP311PSR from Texas Instruments is a low-power differential comparator with strobe capability, designed for precision threshold detection in battery-powered and industrial sensing systems. It features 900 μW typical power consumption at 5 V, 1.2 μs typical response time, ±15 V or single 3 V operation, and emitter-collector open-drain outputs capable of 25 mA sink current.
For engineers reviewing the LP311PSR datasheet, LP311PSR pinout, LP311PSR application, or LP311PSR equivalent, this page delivers verified electrical parameters, true pin functionality, real-world use cases in voltage monitoring and level-shifting circuits, and validated alternative options for design continuity.
Technical Context
The LP311PSR implements a bipolar input stage with ion-implanted resistors enabling ultra-low quiescent current (150–300 μA total supply current) while maintaining wide common-mode input range (−14.5 V to 13.5 V with ±15 V supplies). Its dual-output structure-emitter output (EMIT OUT) and collector output (COL OUT)-supports flexible interfacing to TTL, CMOS, or relay drivers.
Strobe control (BAL/STRB pin) enables hardware-gated output disable independent of input states, and internal balance capability allows trimming of input offset voltage down to 2 mV typical. The device operates across 25°C to 85°C ambient, matching the extended temperature grade of the SOP-PS package variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | Single 3 V to ±15 V - supports direct integration into 3.3 V microcontroller systems or legacy ±15 V analog rails without level-shifting. |
| Quiescent Power | 900 μW typical at 5 V - enables multi-year operation on coin-cell batteries in portable sensors and IoT endpoints. |
| Response Time | 1.2 μs typical - sufficient for slow-to-moderate speed applications like battery charge-state monitoring or HVAC setpoint comparison. |
| Input Offset Voltage | 7.5 mV max at 25°C - defines minimum detectable voltage difference in precision window comparators or zero-crossing detectors. |
| Output Sink Current | 25 mA - directly drives LEDs, small relays, or logic inputs without external buffer transistors. |
| Input Bias Current | 15 nA typical - minimizes loading error when used with high-impedance sensor sources (e.g., thermistors, photodiodes). |
| Common-Mode Range | −14.5 V to 13.5 V (±15 V supply) - accommodates signals referenced below ground or above VCC in industrial signal conditioning. |
Pinout & Package
SOP (PS) package - 8-pin surface-mount small-outline package, 1.75 mm maximum height, RoHS-compliant NIPDAU lead finish, MSL Level-1 (260°C peak reflow), tape-and-reel packaging (2000 units/reel).
| 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 up to ±15 V relative to midpoint of supplies; high impedance (15 nA bias current). |
| 3 (IN+) | Non-inverting input | Differential input node; identical voltage range and impedance as IN−; used for reference or signal input depending on topology. |
| 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 | Primary power connection; supports single-supply (3–30 V) or split-supply (±15 V) configurations. |
| 6 (COL OUT) | Collector open-drain output | Active-low output; requires external pull-up to VCC+ or another logic rail; rated for 40 V collector-emitter breakdown. |
| 7 (BAL/STRB) | Strobe and balance control | Pulling low disables both outputs regardless of input state; also serves as balance terminal when used with external resistor network. |
| 8 (EMIT OUT) | Emitter open-drain output | Active-low output referenced to VCC−; can sink current while swinging below VCC−; complements COL OUT for push-pull-like behavior. |
Key Features
| Feature | Design Value |
|---|---|
| Low-power operation | 900 μW typical at 5 V enables energy-constrained designs such as wireless sensor nodes and portable medical devices. |
| Strobe-enabled output disable | Hardware-controlled output blanking via BAL/STRB pin eliminates need for software gating or external logic in time-critical sequencing. |
| Dual open-drain outputs | Independent EMIT OUT and COL OUT allow simultaneous driving of separate loads or creation of wired-OR logic functions. |
| Wide supply flexibility | Operates from single 3 V up to ±15 V, eliminating dedicated voltage regulators in mixed-signal systems with diverse rail requirements. |
| Offset voltage trimming | BALANCE and BAL/STRB pins support external nulling circuitry to reduce system-level offset errors in precision measurement paths. |
Applications
| Battery Voltage Monitor | Industrial Threshold Detector |
|---|---|
|
Use Scenario: Monitoring Li-ion cell voltage during charging/discharging to trigger cutoff or alert logic. IC Role / Device Role / Timing Role: Precision comparator detecting when cell voltage crosses 4.2 V (full) or 2.8 V (low) thresholds. Use Value: 7.5 mV max offset ensures accurate trip points; 900 μW quiescent power extends standby time between measurements. |
Use Scenario: Detecting overtemperature conditions in motor windings using a PT100 RTD bridge output. IC Role / Device Role / Timing Role: Differential comparator comparing RTD bridge voltage against a stable reference voltage. Use Value: −14.5 V to 13.5 V common-mode range accommodates bridge excitation and offset without level-shifting amplifiers. |
| Power Supply Sequencing | Opto-Isolated Feedback Comparator |
|
Use Scenario: Enabling downstream DC/DC converters only after primary rail reaches regulation. IC Role / Device Role / Timing Role: Window comparator verifying that +12 V rail stays within 11.4–12.6 V before asserting enable signal. Use Value: Strobe input synchronizes enable assertion with system reset timing; dual outputs simplify OR-ing multiple enable conditions. |
Use Scenario: Isolating feedback path in isolated flyback converter by comparing secondary-side error voltage to reference. IC Role / Device Role / Timing Role: High-impedance comparator interfacing optocoupler output to PWM controller's error amplifier input. Use Value: 15 nA input bias current prevents loading of high-impedance optocoupler output; 25 mA sink current drives controller reference pin directly. |
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 power draw, faster 115 ns response, wider −15.5 V to 14.5 V common-mode range. | Preferred where speed >100 kHz or rail-to-rail input swing is required; unsuitable for sub-μA battery systems. | Select LM311DR only if response time <200 ns is mandatory and power budget allows ≥2.5× increase. |
| TLV3011DBVR | CMOS input (0.5 pA bias), 1.8–5.5 V single-supply only, 300 μs response, 650 nA quiescent current. | Better for ultra-low-power, low-voltage (<3.3 V) systems but incompatible with ±15 V or fast edge detection. | Choose TLV3011DBVR for coin-cell-powered 3 V systems needing femtoampere input impedance; not drop-in for LP311PSR. |
Compared with LM311DR and TLV3011DBVR, the LP311PSR uniquely balances micropower operation (900 μW), robust ±15 V compatibility, and strobe control - making it optimal for industrial battery-backed monitoring where speed is secondary to supply flexibility and deterministic output gating.
Availability
LP311PSR is available at Aetrix Electronics and suitable for battery voltage monitoring, industrial threshold detection, power supply sequencing, and opto-isolated feedback circuits requiring stable component supply across extended temperature ranges.
Supply support for LP311PSR 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 LP311PSR belongs to TI's legacy precision analog comparator family, engineered specifically for low-power, high-reliability threshold detection in resource-constrained and mixed-voltage systems.
FAQ
What is the operating temperature range for the LP311PSR?
The LP311PSR is characterized for operation from 25°C to 85°C ambient temperature. This extended temperature grade distinguishes it from the standard LP311 (0°C to 70°C) and makes the LP311PSR suitable for industrial environments where board-level heating exceeds commercial-grade limits. The device maintains specified performance-including 7.5 mV max input offset voltage and 1.2 μs response time-across this full range.
Does the LP311PSR support single-supply operation?
Yes, the LP311PSR supports true single-supply operation from as low as 3 V up to 30 V total supply range (VCC+ to VCC−). When used with a single 5 V supply (VCC+ = 5 V, VCC− = 0 V), its emitter output can swing below ground (VCC−) by up to 30 V, and its common-mode input range extends from 0.5 V to 3.5 V-enabling direct interface with 3.3 V microcontrollers and sensors without level-shifting circuitry.
How does the strobe function work on the LP311PSR?
The BAL/STRB pin on the LP311PSR serves dual purpose: as a strobe input and balance terminal. When pulled low (≤0.3 V) with 100–300 μA current, it forces both EMIT OUT and COL OUT into high-impedance off-state-regardless of input voltages. This hardware gating avoids software delays and race conditions in critical timing sequences. The datasheet explicitly warns against shorting this pin to ground; it must be current-driven.
What package type is used for the LP311PSR?
The LP311PSR uses an SOP (PS) package: an 8-pin surface-mount small-outline package with 1.75 mm maximum height, 1.27 mm lead pitch, and RoHS-compliant NIPDAU lead finish. It is supplied in tape-and-reel format (2000 units per reel) and has moisture sensitivity level (MSL) rating of Level-1 (unlimited floor life at ≤30°C/60% RH), simplifying SMT assembly without baking requirements.
Can the LP311PSR replace the LM311 in existing designs?
The LP311PSR shares identical pinout and functional architecture with the LM311, but it is not a direct drop-in replacement due to key differences: lower power (900 μW vs. 2.5 mW), slower response (1.2 μs vs. 115 ns), and reduced input bias current (15 nA vs. 250 nA). It can replace LM311 in low-speed, low-power applications-but layout changes may be needed if thermal or speed margins were previously tight.
LP311PSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-SO
LP311PSR FAQ
1.How can I place an order for LP311PSR through Aetrix?
Please submit a Request for Quotation (RFQ) for LP311PSR 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 LP311PSR reliable?
The price and inventory of LP311PSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP311PSR is usually 5 days.
3.What payment methods are accepted for LP311PSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP311PSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP311PSR?
LP311PSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP311PSR 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 LP311PSR?
For technical support, including LP311PSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP311PSR requirements.
6.How does Aetrix verify that LP311PSR is sourced from the original manufacturer or authorized distributors?
All LP311PSR 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 LP311PSR meets industry standards.
7.What is the process for return or replacement of LP311PSR?
All LP311PSR units undergo pre-shipment inspection (PSI). If there is an issue with LP311PSR, 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 LP311PSR part is unused and in its original packaging.
Return procedure for LP311PSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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