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Texas Instruments LP2981IM5X-3.3
- Part No.:
- LP2981IM5X-3.3
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LP2981IM5X-3.3.pdf
- Description:
- IC REG LINEAR 3.3V 100MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,560
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Product details
Overview
LP2981IM5X-3.3 from Texas Instruments is a fixed-output, 3.3V, 100mA low-dropout (LDO) voltage regulator in SOT-23-5 package, featuring ±0.5% initial output accuracy, 175mV dropout at 100mA, 75dB PSRR at 1kHz, and operation from –40°C to +125°C. It delivers stable power to low-voltage microcontrollers in electricity meters and micro-inverters.
For engineers reviewing the LP2981IM5X-3.3 datasheet, LP2981IM5X-3.3 pinout, LP2981IM5X-3.3 application, or LP2981IM5X-3.3 equivalent, this page provides verified specifications, validated pin functions, confirmed thermal performance, and real-world design context for industrial-grade LDO selection and replacement.
Technical Context
The LP2981IM5X-3.3 implements a CMOS pass transistor architecture with internal bandgap reference and active feedback control, enabling precise 3.3V regulation across line, load, and temperature. Its soft-start circuit limits inrush current, while integrated overcurrent and thermal shutdown protect against fault conditions.
This "new chip" variant supports input voltages from 2.5V to 16V and maintains ±1% output accuracy over full load (0–100mA) and temperature (–40°C to +125°C). It achieves high PSRR (75dB @ 1kHz, 45dB @ 1MHz) and stable operation with ≥2.2µF ceramic output capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±0.5% (A-grade), enabling direct interface with 3.3V logic without external resistors. |
| Max Output Current | 100mA continuous - sufficient for MCU cores, sensors, and communication peripherals in space-constrained designs. |
| Dropout Voltage | 175mV at 100mA - allows operation from 3.475V input, supporting battery-backed or post-DC/DC regulation. |
| PSRR | 75dB at 1kHz, 45dB at 1MHz - effectively suppresses switching noise from upstream DC/DC converters. |
| Quiescent Current | 69μA at zero load - minimizes standby power in always-on industrial monitoring systems. |
| Operating Temperature | –40°C to +125°C junction - qualified for use in electricity meters and residential breakers exposed to ambient extremes. |
| Input Voltage Range | 2.5V to 16V - compatible with 3.3V, 5V, and 12V system rails without external level-shifting. |
| Enable Threshold | 0.85V (min) high-level, 0.15V (max) low-level - ensures reliable ON/OFF control with standard GPIOs or open-drain signals. |
Pinout & Package
LP2981IM5X-3.3 is housed in a 5-pin SOT-23 (DBV) package measuring 2.9mm × 2.8mm, optimized for high-density PCB layouts and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input supply | Accepts 2.5V–16V input; requires ≥1µF ceramic capacitor to GND for stability and transient response. |
| 2 (GND) | Ground reference | Common substrate return path for regulator core, enable logic, and protection circuits. |
| 3 (ON/OFF) | Active-high enable | Drives high (>0.85V) to enable output; pulls low (<0.15V) to disable with internal pulldown for controlled discharge. |
| 4 (NC) | No-connect | Reserved for factory calibration; must remain floating-no connection to GND, VOUT, or any potential. |
| 5 (OUT) | Regulated output | Delivers 3.3V ±0.5%; requires ≥2.2µF ceramic capacitor to GND for stability and ESR <1Ω. |
Key Features
| Feature | Design Value |
|---|---|
| Stable with 2.2µF ceramic capacitors | Eliminates need for tantalum or electrolytic caps-reducing BOM cost, size, and failure risk in long-life applications. |
| Internal soft-start | Controls inrush current during power-up, minimizing required input bulk capacitance and preventing upstream rail sag. |
| ±1% output accuracy over load & temp | Meets tight tolerance requirements of 3.3V MCUs and ADC references without external trimming or calibration. |
| High PSRR (75dB @ 1kHz) | Attenuates ripple from switching regulators, reducing need for additional LC filtering stages in compact PSU designs. |
| Thermal shutdown & current limiting | Self-protects under overload or poor heatsinking-ensures safe operation in sealed enclosures like smart meters. |
| Low shutdown current (≤1.75μA) | Enables ultra-low-power sleep modes in battery-assisted or energy-harvesting systems without compromising wake latency. |
Applications
| Electricity Meters | Micro Inverters |
|---|---|
Use Scenario: Powering metrology ICs, RTCs, and isolated communication interfaces in Class 0.5S revenue-grade meters. IC Role / Device Role / Timing Role: Primary 3.3V LDO supplying precision analog front-end and secure bootloader circuitry. Use Value: ±1% output accuracy over –40°C to +85°C ambient ensures consistent ADC reference and timing stability across seasonal temperature swings. |
Use Scenario: Biasing gate drivers, isolation controllers, and sensor signal chains in residential solar inverters. IC Role / Device Role / Timing Role: Post-regulator after 12V DC/DC stage, delivering clean 3.3V to MCU and isolated gate driver ICs. Use Value: 75dB PSRR at 1kHz suppresses 100kHz–500kHz switching noise from primary DC/DC, eliminating output filter complexity. |
| Server PSU Monitoring | Residential Breakers |
Use Scenario: Providing auxiliary 3.3V rail for PMBus/I²C monitoring ICs and hot-swap controllers in 12V server PSUs. IC Role / Device Role / Timing Role: Secondary LDO for digital health-monitoring subsystems requiring independent, low-noise bias. Use Value: 69μA quiescent current enables always-on telemetry without degrading overall PSU efficiency at light loads. |
Use Scenario: Powering arc-fault detection logic, BLE radios, and status LEDs in smart residential circuit breakers. IC Role / Device Role / Timing Role: Main 3.3V regulator for mixed-signal SoC handling real-time current sampling and wireless reporting. Use Value: Stable operation up to +125°C junction enables mounting directly on current-sense shunt without derating or heatsink. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1700T-3302E/TT | 300mA rated, 6μA IQ, but only ±2% output accuracy and no enable pin. | Lacks ON/OFF control and tighter accuracy-unsuitable for MCU reset integrity or low-power sleep modes. | Choose only if higher current and ultra-low IQ outweigh need for enable functionality and ±0.5% tolerance. |
| TPS7A0533PDBVR | 200mA rated, 25μA IQ, ±1% accuracy, and enable pin-but requires ≥1µF output cap and has 250mV dropout at 100mA. | Higher dropout reduces usable input range; lower PSRR (60dB @ 1kHz) offers less switching noise rejection. | Prefer when 200mA headroom is critical and input headroom >250mV is available; avoid where 175mV dropout is essential. |
Compared with MCP1700T-3302E/TT and TPS7A0533PDBVR, LP2981IM5X-3.3 uniquely balances 100mA capability, ±0.5% accuracy, 175mV dropout, and 75dB PSRR in a 5-pin SOT-23-making it optimal for space-constrained, noise-sensitive industrial LDO applications where precision and reliability are non-negotiable.
Availability
LP2981IM5X-3.3 is available at Aetrix Electronics and suitable for electricity meters, micro inverters, and residential breakers requiring stable component supply, long-term lifecycle support, and guaranteed traceability for industrial deployments.
Supply support for LP2981IM5X-3.3 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 power management ICs for industrial, automotive, and enterprise applications.
The LP2981-N product line was designed specifically for high-reliability, low-noise LDO regulation in utility infrastructure and distributed energy systems-emphasizing accuracy, thermal robustness, and compatibility with ceramic capacitors.
FAQ
What is the maximum input voltage rating for LP2981IM5X-3.3?
The LP2981IM5X-3.3 supports a continuous input voltage range of –0.3V to 18V (absolute maximum), with recommended operation from 2.5V to 16V. Exceeding 16V in normal use risks violating recommended operating conditions, though the device withstands brief transients up to 18V per absolute ratings.
Does LP2981IM5X-3.3 require an external pull-up on the ON/OFF pin?
No-LP2981IM5X-3.3 includes an internal pulldown on the ON/OFF pin. When unused, the pin may be tied directly to VIN to enable the device permanently. External pull-up is unnecessary and not recommended, as it conflicts with the internal enable logic and may increase leakage.
Can LP2981IM5X-3.3 operate stably with a 1µF output capacitor?
No-LP2981IM5X-3.3 requires a minimum of 2.2µF ceramic output capacitance for guaranteed stability per TI's datasheet. Using 1µF violates the recommended condition and may cause oscillation or degraded transient response, especially under load steps or temperature variation.
What is the thermal resistance (RθJA) of LP2981IM5X-3.3 in its SOT-23-5 package?
The junction-to-ambient thermal resistance (RθJA) for LP2981IM5X-3.3 in the DBV (SOT-23-5) package is 178.6°C/W under JEDEC-standard 2s2p PCB conditions. Actual thermal performance improves significantly with copper pour, thermal vias, and optimized layout-enabling full 100mA operation at +125°C ambient in well-designed boards.
Is LP2981IM5X-3.3 pin-compatible with earlier LP2981 variants?
Yes-LP2981IM5X-3.3 shares identical pinout (IN, GND, ON/OFF, NC, OUT), footprint, and package (SOT-23-5 DBV) with legacy LP2981 devices. However, electrical differences-including tighter accuracy, lower dropout, and enhanced PSRR-mean functional substitution requires validation of system-level performance, particularly under worst-case line/load/temperature conditions.
LP2981IM5X-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.37V @ 100mA
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 95 µA
- Current - Supply (Max):
- 1.7 mA
- PSRR:
- 63dB (1kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LP2981IM5X-3.3 FAQ
1.How can I place an order for LP2981IM5X-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP2981IM5X-3.3 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 LP2981IM5X-3.3 reliable?
The price and inventory of LP2981IM5X-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP2981IM5X-3.3 is usually 5 days.
3.What payment methods are accepted for LP2981IM5X-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP2981IM5X-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP2981IM5X-3.3?
LP2981IM5X-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP2981IM5X-3.3 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 LP2981IM5X-3.3?
For technical support, including LP2981IM5X-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP2981IM5X-3.3 requirements.
6.How does Aetrix verify that LP2981IM5X-3.3 is sourced from the original manufacturer or authorized distributors?
All LP2981IM5X-3.3 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 LP2981IM5X-3.3 meets industry standards.
7.What is the process for return or replacement of LP2981IM5X-3.3?
All LP2981IM5X-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LP2981IM5X-3.3, 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 LP2981IM5X-3.3 part is unused and in its original packaging.
Return procedure for LP2981IM5X-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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