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Texas Instruments LP3981ILD-2.5
- Part No.:
- LP3981ILD-2.5
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP3981ILD-2.5.pdf
- Description:
- IC REG LINEAR 2.5V 300MA 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,169
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Product details
Overview
LP3981ILD-2.5 from Texas Instruments is a micropower, ultra-low-dropout CMOS voltage regulator delivering 300 mA at fixed 2.5 V output with 132 mV typical dropout at full load, ≤1 µA shutdown quiescent current, and 35 µVRMS output noise (10 Hz–100 kHz). It serves as a precision power supply for RF front-ends and baseband ICs in battery-powered cellular handsets.
For engineers reviewing the LP3981ILD-2.5 datasheet, LP3981ILD-2.5 pinout, LP3981ILD-2.5 application, or LP3981ILD-2.5 equivalent, key selection criteria include its WSON-6 package thermal performance (RθJA = 56.5°C/W), logic-controlled enable with 1.4 V VIH threshold, ceramic-capacitor stability (2.2 µF COUT), and 60 dB PSRR at 1 kHz under 50 mA load.
Technical Context
The LP3981ILD-2.5 employs a PMOS pass transistor architecture enabling ultra-low dropout and minimal ground current increase in dropout-critical for extending battery life in portable systems. Its internal bandgap reference (1.23 V) feeds an error amplifier driving the pass device, with fast turnon circuitry reducing tON to 240 µs (typical) when using a 0.033 µF BYPASS capacitor.
It integrates thermal shutdown (160°C trip, 20°C hysteresis) and short-circuit current limiting (600 mA steady-state), while maintaining stability with low-ESR ceramic output capacitors (5–500 mΩ) and supporting both OUT-SENSE feedback (for remote sensing) and standard OUT configuration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5 V ±3% over −40°C to +125°C; enables direct replacement of 2.5 V logic rails without external resistors. |
| Max Output Current | 300 mA continuous; supports high-current digital baseband processors and RF power amplifiers in CDMA/GSM handsets. |
| Dropout Voltage | 132 mV typical at 300 mA; allows regulation from 2.63 V input-critical for single-cell Li-ion operation down to end-of-discharge. |
| Quiescent Current | 70 µA typical at 1 mA load; increases only slightly under load, preserving battery runtime in standby modes. |
| PSRR | 60 dB at 1 kHz; suppresses switching noise from DC/DC converters feeding the LDO input, protecting sensitive analog circuits. |
| Output Noise | 35 µVRMS (10 Hz–100 kHz); meets low-noise requirements for ADC references and RF synthesizer VCO supplies. |
| Enable Threshold | VIH = 1.4 V, VIL = 0.4 V; compatible with 1.8 V and 3.3 V GPIOs for precise system-level power sequencing. |
| Thermal Resistance | RθJA = 56.5°C/W (WSON-6); enables 1.77 W max power dissipation at TA = 25°C, supporting high ambient industrial environments. |
Pinout & Package
LP3981ILD-2.5 is packaged in a thermally enhanced 6-pin WSON (NGC) package measuring 4.00 mm × 3.00 mm with exposed thermal pad connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pin 2) | Input voltage supply | Accepts 2.5–6 V input; requires 2.2 µF ceramic decoupling within 1 cm of pin for stability and noise reduction. |
| EN (Pin 6) | Logic enable input | Active-high control: ≥1.4 V enables regulation; ≤0.4 V disables output and reduces IQ to ≤1.5 µA. |
| BYPASS (Pin 5) | Noise reduction node | Connects 0.033 µF capacitor to GND to reduce output noise by filtering internal reference; does not affect transient response. |
| OUT (Pin 1) | Regulated output | Delivers 2.5 V at up to 300 mA; must be connected to OUT-SENSE for standard operation unless remote sensing is used. |
| OUT-SENSE (Pin 3) | Feedback sense input | Monitors output voltage at load point; ties directly to OUT for local regulation or routes separately for remote sensing accuracy. |
| GND (Pin 4) | Power and signal ground | Common return for IN, OUT, EN, BYPASS, and OUT-SENSE; must connect to exposed thermal pad for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 35 µVRMS output noise (10 Hz–100 kHz) enables clean power for RF VCOs and high-resolution ADCs without additional filtering. |
| Low-dropout operation | 132 mV dropout at 300 mA allows use with aging Li-ion batteries (≥2.63 V input), maximizing usable cell voltage range. |
| Shutdown current | ≤1.5 µA max shutdown current extends shelf life and preserves battery charge during long-term storage or deep sleep. |
| Ceramic capacitor stability | Stable with 2.2–22 µF ceramic output capacitors (5–500 mΩ ESR), eliminating need for larger, costlier tantalum solutions. |
| Integrated protection | Thermal shutdown (160°C) and short-circuit current limit (600 mA) prevent damage during fault conditions without external components. |
| Fast enable response | 240 µs typical turnon time (with 0.033 µF BYPASS) supports rapid power-up sequences in burst-mode wireless transceivers. |
Applications
| CDMA Cellular Handset Power Rail | Wideband CDMA Baseband Processor Supply |
|---|---|
Use Scenario: Powers RF transceiver ICs and analog front-end modules requiring stable, low-noise 2.5 V supply in compact handset PCBs. IC Role / Device Role / Timing Role: Primary LDO delivering regulated 2.5 V to RF synthesizers and mixer stages; provides clean bias independent of noisy DC/DC converter outputs. Use Value: 60 dB PSRR at 1 kHz rejects switching noise from adjacent buck converters, preventing phase noise degradation in transmit paths. | Use Scenario: Supplies core voltage to baseband ASICs handling digital signal processing in WCDMA modems. IC Role / Device Role / Timing Role: High-current (300 mA) LDO with fast enable for dynamic power gating during sleep/wake cycles. Use Value: 240 µs turnon time ensures timely power delivery to processor cores upon wake interrupt, minimizing latency in real-time communication. |
| GSM Handset Audio Codec Bias | Portable Information Appliance Memory Backup |
Use Scenario: Provides ultra-low-noise 2.5 V bias to stereo audio DACs and headphone amplifiers in dual-mode GSM handsets. IC Role / Device Role / Timing Role: Low-noise LDO isolating analog audio path from digital switching noise; uses BYPASS pin for noise suppression. Use Value: 35 µVRMS output noise prevents audible hiss in high-gain audio playback, meeting SNR > 100 dB requirements. | Use Scenario: Maintains 2.5 V supply to SRAM or real-time clock (RTC) during main system power-down in PDAs and handheld terminals. IC Role / Device Role / Timing Role: Micropower LDO operating in no-load regulation mode with ≤1.5 µA shutdown current. Use Value: Enables multi-year battery backup life using coin-cell sources, supported by guaranteed stability at zero load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F25DRVR | 250 mA max output, 120 mV dropout at 250 mA, RθJA = 60.3°C/W (WSON-6), 20 µVRMS noise | Lower noise but reduced current capability; lacks OUT-SENSE pin for remote sensing | Preferred when ultra-low noise (<25 µVRMS) is prioritized over 300 mA load support |
| MCP1700T-2502E/MB | 250 mA max, 175 mV dropout at 250 mA, SOT-23-5 package, RθJA = 210°C/W, 40 µVRMS noise | Higher thermal resistance limits power handling; no BYPASS pin or OUT-SENSE option | Suitable for cost-sensitive, lower-power designs where board space permits larger thermal footprint |
Compared with LP3981ILD-2.5, TPL720F25DRVR offers lower noise but sacrifices 50 mA output capacity and remote sensing, while MCP1700T-2502E/MB trades thermal performance and feature set for lower unit cost in non-demanding applications.
Availability
LP3981ILD-2.5 is available at Aetrix Electronics and suitable for CDMA handset power management, WCDMA baseband supply, GSM audio biasing, and portable information appliance memory backup requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LP3981ILD-2.5 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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets.
The LP3981 family targets battery-powered wireless devices, delivering micropower efficiency, ultra-low dropout, and low-noise regulation optimized for cellular handset power architectures.
FAQ
What is the maximum input voltage rating for the LP3981ILD-2.5?
The LP3981ILD-2.5 has an absolute maximum input voltage rating of 6.5 V, with recommended operating input range from 2.7 V to 6 V. Exceeding 6.5 V risks permanent damage. The device maintains regulation down to VIN = VOUT + 0.3 V (i.e., 2.8 V minimum for reliable 2.5 V output), making it suitable for single-cell Li-ion applications across full discharge curves. This specification is confirmed in Section 6.1 of the SNVS159H datasheet.
Does the LP3981ILD-2.5 require an external bypass capacitor for stable operation?
No-the LP3981ILD-2.5 operates stably without the BYPASS capacitor, but adding a 0.033 µF ceramic capacitor between BYPASS and GND reduces output noise from 50 µVRMS to 35 µVRMS (10 Hz–100 kHz) without degrading load transient response. The BYPASS pin connects to a high-impedance reference node; low-leakage NPO/COG ceramics are recommended. This behavior is verified in Section 9.2.2.6 and Figure 13 of the LP3981ILD-2.5 datasheet.
Can the LP3981ILD-2.5 be used with a 2.2 µF ceramic output capacitor?
Yes-the LP3981ILD-2.5 is explicitly designed and characterized for stability with 2.2 µF ceramic output capacitors (X7R/Z5U/Y5V dielectrics) having ESR between 5 mΩ and 500 mΩ. This is stated in Section 9.2.2.4 and Table 1 of the datasheet. Using 2.2 µF ceramic capacitors minimizes board area and cost while meeting all stability and transient response requirements across −40°C to +125°C.
What is the thermal shutdown behavior of the LP3981ILD-2.5?
The LP3981ILD-2.5 activates thermal shutdown at 160°C junction temperature and remains latched off until junction temperature falls by 20°C (hysteresis), resuming normal operation automatically. During shutdown, output is disabled and quiescent current drops to ≤1.5 µA. This protection is integrated and requires no external components, as specified in Section 6.5 (TSD parameter) and Section 8.4.1 of the SNVS159H datasheet.
Is the LP3981ILD-2.5 pin-compatible with other members of the LP3981 family?
Yes-all LP3981 variants-including LP3981ILD-2.5, LP3981ILD-2.7, and LP3981ILD-3.3-share identical WSON-6 (NGC) pinout and package dimensions (4.00 mm × 3.00 mm). Pin functions (IN, EN, BYPASS, OUT, OUT-SENSE, GND) and thermal pad connection are identical across output voltage options, enabling drop-in replacement during design iteration or voltage optimization. This is confirmed in the "Device Information" table on page 2 of the datasheet.
LP3981ILD-2.5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.2V @ 300mA
- Current - Output:
- 300mA
- Current - Quiescent (Iq):
- 120 µA
- Current - Supply (Max):
- 210 µA
- PSRR:
- 50dB ~ 55dB (1kHz ~ 10kHz)
- 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:
- 6-WSON (3x4)
LP3981ILD-2.5 FAQ
1.How can I place an order for LP3981ILD-2.5 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3981ILD-2.5 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 LP3981ILD-2.5 reliable?
The price and inventory of LP3981ILD-2.5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3981ILD-2.5 is usually 5 days.
3.What payment methods are accepted for LP3981ILD-2.5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3981ILD-2.5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3981ILD-2.5?
LP3981ILD-2.5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3981ILD-2.5 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 LP3981ILD-2.5?
For technical support, including LP3981ILD-2.5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3981ILD-2.5 requirements.
6.How does Aetrix verify that LP3981ILD-2.5 is sourced from the original manufacturer or authorized distributors?
All LP3981ILD-2.5 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 LP3981ILD-2.5 meets industry standards.
7.What is the process for return or replacement of LP3981ILD-2.5?
All LP3981ILD-2.5 units undergo pre-shipment inspection (PSI). If there is an issue with LP3981ILD-2.5, 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 LP3981ILD-2.5 part is unused and in its original packaging.
Return procedure for LP3981ILD-2.5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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