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Texas Instruments LP311P
- Part No.:
- LP311P
- Manufacturer:
- Texas Instruments
- Category:
- Comparators
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LP311P.pdf
- Description:
- IC COMPARATOR 1 DIFF 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,606
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Product details
Overview
LP311P 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 in portable instrumentation and power management circuits.
For engineers reviewing the LP311P datasheet, LP311P pinout, LP311P application, or LP311P equivalent, key selection considerations include its 900 μW typical power consumption at 5 V, emitter-output swing below negative rail, ±7.5 mV max input offset voltage at 25°C, strobe-controlled output disable, and PDIP-8 package compatibility with legacy LM311 layouts.
Technical Context
The LP311P implements an open-collector/open-emitter output stage with independent collector (COL OUT) and emitter (EMIT OUT) terminals, enabling flexible pull-up/pull-down configurations and direct interface to TTL/CMOS logic. Its internal architecture uses ion-implanted resistors for stable biasing and offset trimming, achieving 30:1 power reduction versus LM311 while retaining functional interchangeability.
Strobe functionality is implemented via a current-sinking BAL/STRB pin that forces output high-impedance when driven with 100–300 μA; offset balancing is supported through external resistors on BALANCE and BAL/STRB pins. The device is characterized for 0°C to 70°C operation and specified for ±15 V or 3–30 V total supply range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Range | Single 3 V to ±15 V - enables use in low-voltage battery systems and standard industrial rails without level-shifting. |
| Quiescent Power | 900 μW typical at 5 V - extends battery life in portable comparators and sensor interfaces. |
| Response Time | 1.2 μs typical (100-mV step, 5-mV overdrive) - sufficient for slow-to-moderate speed threshold detection, not high-speed signal conditioning. |
| Input Offset Voltage | 7.5 mV max at 25°C - defines minimum detectable voltage difference in precision level-sensing applications. |
| Output Drive | 25 mA sink capability at COL OUT - directly drives LEDs, relays, or logic inputs without external buffers. |
| Common-Mode Range | −14.5 V to 13.5 V (±15 V supply) - allows input signals near or beyond supply rails, e.g., ground-referenced sensors in split-rail systems. |
| Strobe Current | 100–300 μA required to disable output - mandates current-source drive, not direct grounding, to prevent malfunction. |
Pinout & Package
LP311P is housed in an 8-pin plastic dual in-line package (PDIP), with 0.3-inch body width and standard through-hole mounting. Thermal resistance θJA is 85°C/W, supporting moderate-power dissipation in non-ventilated environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BALANCE | Offset null adjustment terminal | Connects to external potentiometer wiper for manual input offset compensation; 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; referenced to same common-mode limits as IN−; used for threshold or reference comparison. |
| 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 | Collector output | Open-collector NPN output; sinks up to 25 mA; requires external pull-up for logic-high state. |
| 7 - BAL/STRB | Balance/strobe control | Current-sink input: pulling ≥100 μA disables output (high-Z); also used with BALANCE for offset trim. |
| 8 - EMIT OUT | Emitter output | Open-emitter NPN output; sources current when active; swings below VCC−, enabling negative-rail referencing. |
Key Features
| Feature | Design Value |
|---|---|
| Low-power operation | 900 μW typical at 5 V supply - reduces thermal load and extends runtime in energy-constrained designs. |
| Strobe-enabled output disable | Current-driven BAL/STRB pin (100–300 μA) forces high-impedance state - enables time-gated comparisons without external switches. |
| Independent emitter/collector outputs | Separate EMIT OUT and COL OUT terminals allow simultaneous sourcing and sinking or rail-to-rail output flexibility. |
| Wide supply and input range | Operates from 3 V single supply to ±15 V; input common-mode extends to ±14.5 V - simplifies interfacing with diverse sensor and power domains. |
| Offset balancing | External resistor network on BALANCE/BAL/STRB pins reduces input offset to <2 mV - improves accuracy in precision threshold detection. |
Applications
| Battery Voltage Monitor | Power Supply Sequencing |
|---|---|
|
Use Scenario: Detecting low-battery condition in handheld medical devices using a resistive divider from Li-ion cell. IC Role / Device Role / Timing Role: Threshold comparator comparing divided battery voltage against stable reference; strobe disabled during measurement window. Use Value: 900 μW quiescent power minimizes standby drain; emitter output swings below ground to interface with microcontroller ADC reference. |
Use Scenario: Enabling downstream DC/DC converters only after primary rail reaches regulation in multi-rail embedded systems. IC Role / Device Role / Timing Role: Precision window comparator verifying VIN > 4.75 V before asserting enable signal; strobe synchronized to system reset. Use Value: 7.5 mV max offset ensures tight trip-point tolerance; COL OUT directly drives MOSFET gate with 25 mA sink capability. |
| Industrial Sensor Interface | Overvoltage Protection Circuit |
|
Use Scenario: Converting 4–20 mA loop current to digital alert when process variable exceeds setpoint in PLC analog input modules. IC Role / Device Role / Timing Role: Current-to-voltage converter followed by LP311P as level detector; offset balancing compensates for transducer drift. Use Value: −14.5 V to 13.5 V common-mode range accommodates loop-powered sensor return path; PDIP-8 eases prototyping and field replacement. |
Use Scenario: Shutting off power to sensitive loads when input voltage exceeds 16 V in automotive accessory circuits. IC Role / Device Role / Timing Role: High-side comparator monitoring battery rail; EMIT OUT pulls shutdown pin low when overvoltage detected. Use Value: EMIT OUT swing below VCC− allows direct connection to NMOS gate without level shifter; 1.2 μs response prevents transient damage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar differential comparator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM311P | Higher 4.5 mW typical power, faster 115 ns response, no strobe function, same PDIP-8 pinout. | Used where speed >10× greater is required and power budget allows; lacks strobe-based gating. | Select LM311P only if response time <200 ns is mandatory and strobe control is unnecessary. |
| LP311D | Identical electrical specs, SOIC-8 package, 0°C to 70°C rating, same 7.5 mV offset max, but surface-mount only. | Suitable for automated assembly and space-constrained PCBs; requires reflow-compatible layout. | Choose LP311D for volume production with SMT lines; LP311P remains preferred for through-hole prototyping or repair. |
Compared with LM311P, LP311P trades speed for 30× lower power and adds strobe control - critical for battery longevity and gated sensing. Against LP311D, it offers identical performance in a through-hole package, easing hand-soldering, test fixture integration, and legacy board upgrades.
Availability
LP311P is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial sensor interfaces, and power supply monitoring requiring stable component supply across extended product lifecycles.
Supply support for LP311P 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, embedded processing, and connectivity solutions with emphasis on reliability, scalability, and long-term support.
The LP311P belongs to TI's legacy precision comparator family, engineered for low-power, rail-flexible threshold detection in cost-sensitive industrial and portable applications where speed is secondary to efficiency and design simplicity.
FAQ
What is the maximum supply voltage range supported by the LP311P?
The LP311P supports total supply voltage (VCC+ to VCC−) from 3.5 V to 30 V, including single-supply operation down to 3 V (with VCC− = GND) and dual-supply operation up to ±15 V. Absolute maximum ratings extend to ±18 V, but recommended operation stays within ±15 V for reliability and parameter guarantee. This wide range makes LP311P suitable for both low-voltage battery systems and standard industrial rails.
Can the LP311P drive a relay coil directly?
Yes, the LP311P can drive a relay coil directly via its COL OUT pin, which sinks up to 25 mA with a low-level output voltage of ≤0.4 V at 25°C. For typical 5 V, 20 mA relays, a pull-up resistor to VCC+ completes the circuit. Ensure relay coil flyback protection (e.g., diode across coil) is included, as LP311P does not integrate clamp circuitry. Always verify coil resistance and voltage compliance per LP311P's VOL and supply specifications.
How does the strobe function work on the LP311P?
The BAL/STRB pin on the LP311P serves dual purpose: as strobe input or balance terminal. To disable the output, drive BAL/STRB with 100–300 μA sink current (not direct ground), forcing high-impedance state regardless of input conditions. This requires a current source - e.g., transistor or logic buffer with series resistor - because shorting to ground causes undefined behavior. When unused for strobing, BAL/STRB must be shorted to BALANCE for offset trimming.
Is the LP311P pin-compatible with the LM311?
Yes, the LP311P has identical pinout and footprint to the LM311 in PDIP-8 packaging, as explicitly stated in the datasheet: "Same pinout as LM211, LM311" and "Designed To Be Interchangeable With Industry-Standard LP311". Electrical differences - notably 30× lower power and 6× slower response - mean LP311P can replace LM311 in low-speed, low-power applications without PCB changes, but not where nanosecond response is required.
What is the operating temperature range for the LP311P?
The LP311P is characterized for operation from 0°C to 70°C ambient temperature, as confirmed in the ordering information table and absolute maximum ratings section. This commercial-grade rating distinguishes it from the LP211 (−25°C to 85°C) and aligns with standard industrial control and consumer electronics requirements. Derating guidelines apply above 70°C; junction temperature must remain ≤150°C under all conditions.
LP311P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Series:
- -
- Packaging:
- Tube
- 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:
- Through Hole
- :
- 8-PDIP
LP311P FAQ
1.How can I place an order for LP311P through Aetrix?
Please submit a Request for Quotation (RFQ) for LP311P 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 LP311P reliable?
The price and inventory of LP311P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP311P is usually 5 days.
3.What payment methods are accepted for LP311P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP311P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP311P?
LP311P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP311P 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 LP311P?
For technical support, including LP311P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP311P requirements.
6.How does Aetrix verify that LP311P is sourced from the original manufacturer or authorized distributors?
All LP311P 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 LP311P meets industry standards.
7.What is the process for return or replacement of LP311P?
All LP311P units undergo pre-shipment inspection (PSI). If there is an issue with LP311P, 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 LP311P part is unused and in its original packaging.
Return procedure for LP311P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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