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Texas Instruments LP3981ILDX-2.7
- Part No.:
- LP3981ILDX-2.7
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP3981ILDX-2.7.pdf
- Description:
- IC REG LINEAR 2.7V 300MA 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,490
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Product details
Overview
LP3981ILDX-2.7 from Texas Instruments is a micropower, ultra-low-dropout CMOS voltage regulator delivering 300 mA at fixed 2.7 V output, with 132 mV typical dropout at full load, ≤1 µA shutdown current, and 35 µVRMS output noise (10 Hz–100 kHz). It serves as the primary power rail for RF front-end ICs and baseband processors in battery-powered cellular handsets.
For engineers reviewing the LP3981ILDX-2.7 datasheet, LP3981ILDX-2.7 pinout, LP3981ILDX-2.7 application, or LP3981ILDX-2.7 equivalent, key selection criteria include low-noise operation under light loads, ceramic-capacitor stability, thermal performance in WSON-6, and enable-controlled power sequencing in space-constrained portable designs.
Technical Context
The LP3981ILDX-2.7 employs a PMOS pass transistor architecture enabling ultra-low dropout and minimal ground current increase in dropout-critical for extending battery runtime. Its internal bandgap reference (1.23 V) feeds a precision error amplifier driving the pass device, with fast turnon circuitry reducing tON to 240 µs (typical) when using a 0.033 µF BYPASS capacitor.
Power supply rejection exceeds 55 dB at 10 kHz and maintains ≥60 dB at 1 kHz across −40°C to +125°C, while output sensing via OUT-SENSE ensures regulation accuracy independent of PCB trace resistance. The device integrates thermal shutdown (160°C) and short-circuit current limiting (600 mA), with no external compensation required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.7 V ±3% over −40°C to +125°C - ensures stable core voltage for 2.7-V logic and RF ICs without external feedback. |
| Max Output Current | 300 mA continuous - sufficient to power dual-band GSM/CDMA transceivers and baseband ASICs simultaneously. |
| Dropout Voltage | 132 mV typical at 300 mA - enables regulation down to 2.832 V input, preserving battery life in single-cell Li-ion systems. |
| Quiescent Current | 70 µA typical at 1 mA load - minimizes standby power loss in always-on subsystems like real-time clocks or wake-up controllers. |
| PSRR @ 1 kHz | ≥60 dB - suppresses switching noise from DC/DC converters feeding the LDO input, preventing RF desense. |
| Output Noise | 35 µVRMS (10 Hz–100 kHz) - meets stringent spectral purity requirements for analog front-ends and ADC reference 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 control. |
Pinout & Package
LP3981ILDX-2.7 is packaged in a thermally enhanced 6-pin WSON (NGC) package measuring 4.00 mm × 3.00 mm with an exposed thermal pad connected to GND. This package delivers RθJA = 56.5°C/W, enabling high-power-density deployment in handheld form factors.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pin 2) | Input voltage supply | Accepts 2.7–6 V input; requires 2.2 µF ceramic capacitor placed ≤1 cm from pin to minimize high-frequency impedance. |
| OUT (Pin 1) | Regulated output | Delivers 2.7 V to load; connects directly to load and output capacitor; must be tied to OUT-SENSE for accurate regulation. |
| OUT-SENSE (Pin 3) | Output voltage sense | High-impedance feedback node; must be shorted to OUT to close regulation loop-no remote sensing capability. |
| EN (Pin 6) | Logic-enable input | Active-high control: >1.4 V enables regulator; <0.4 V disables it, reducing IQ to ≤1.5 µA. |
| BYPASS (Pin 5) | Noise reduction node | Connects to 0.033 µF capacitor to reduce reference noise; does not affect transient response or stability. |
| GND (Pin 4) | Ground reference | Primary return path for IN, OUT, and EN; thermal pad must be soldered to PCB ground plane for thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low-noise regulation | 35 µVRMS output noise with 0.033 µF BYPASS cap - eliminates need for post-LDO filtering in sensitive RF supply rails. |
| Ceramic-capacitor stability | Stable with 2.2–22 µF ceramic output caps (5–500 mΩ ESR) - reduces BOM count and board area vs. tantalum-based solutions. |
| Thermal-enhanced WSON-6 | RθJB = 30.9°C/W - enables 300 mA operation at ambient up to 85°C without heatsinking in compact layouts. |
| Fast enable response | 240 µs typical turnon time - supports rapid power cycling of peripherals during burst-mode communication. |
| Low-quiescent-current shutdown | ≤1.5 µA max shutdown current - extends shelf life and standby time in battery-backed applications like SIM card interfaces. |
Applications
| CDMA Cellular Handset Power Rail | Wideband CDMA Baseband Supply |
|---|---|
|
Use Scenario: Powers RF transceiver ICs requiring clean, low-noise 2.7 V supply during transmit bursts. IC Role / Device Role / Timing Role: Primary LDO supplying VCC_RF and VCC_SYNTH; regulates against battery sag and DC/DC ripple. Use Value: 60 dB PSRR at 1 kHz prevents AM-to-PM distortion in power amplifiers; 132 mV dropout maximizes usable battery range. |
Use Scenario: Supplies digital baseband processor core voltage where low noise avoids timing jitter in clock recovery circuits. IC Role / Device Role / Timing Role: Low-noise post-regulator for PLL/VCO biasing and ADC reference buffers. Use Value: 35 µVRMS noise ensures <1 ps RMS jitter on 26 MHz reference clocks; ceramic stability simplifies layout. |
| GSM Transceiver Bias Supply | Portable Information Appliance Core Rail |
|
Use Scenario: Delivers regulated 2.7 V to GSM PA driver stages and IF mixers during TDMA slot transitions. IC Role / Device Role / Timing Role: Fast-response LDO handling 0–300 mA load steps within 10 µs without overshoot. Use Value: 240 µs enable time synchronizes with slot timing; 70 µA quiescent current extends talk time in idle slots. |
Use Scenario: Powers ARM Cortex-M microcontroller core in handheld PDAs and barcode scanners. IC Role / Device Role / Timing Role: Main system LDO enabling deep-sleep mode entry/exit with sub-µA leakage. Use Value: ≤1.5 µA shutdown current preserves battery for months in storage; WSON-6 footprint fits <100 mm² PCB area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL720F27DBVR | 200 mA max output, 120 mV dropout at 200 mA, 25 µVRMS noise, SOT-23-5 package | Lower current capacity; better noise but limited thermal headroom for sustained 300 mA loads | Select when board space is critical and peak load ≤200 mA; verify thermal derating in enclosed enclosures. |
| MCP1700T-2702E/MB | 250 mA max output, 175 mV dropout at 250 mA, 30 µVRMS noise, SOT-23-3 package | No EN or BYPASS pins; fixed 2.7 V only; lacks enable control and noise-reduction capability | Choose for cost-sensitive, non-sequenced applications where enable and ultra-low noise are unnecessary. |
Compared with TPL720F27DBVR and MCP1700T-2702E/MB, the LP3981ILDX-2.7 uniquely balances 300 mA delivery, 132 mV dropout, and 35 µVRMS noise in a thermally optimized WSON-6, making it optimal for high-performance cellular RF power domains requiring both current and spectral purity.
Availability
LP3981ILDX-2.7 is available at Aetrix Electronics and suitable for CDMA handset design, wideband CDMA baseband systems, and portable information appliance production requiring stable component supply, long-term lifecycle support, and consistent parametric performance across manufacturing lots.
Supply support for LP3981ILDX-2.7 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 system-on-chip solutions for industrial, automotive, and communications markets.
The LP3981 family was engineered specifically for battery-powered wireless infrastructure and mobile terminals, emphasizing micropower operation, ultra-low noise, and ceramic-capacitor compatibility to reduce size and cost in space-constrained RF subsystems.
FAQ
What is the minimum input voltage required for LP3981ILDX-2.7 to regulate at full 300 mA load?
The LP3981ILDX-2.7 requires VIN ≥ VOUT + 0.3 V for proper regulation, meaning a minimum input of 3.0 V is needed to sustain 300 mA output at 2.7 V. Below this threshold, dropout behavior begins and output voltage drops linearly with input; the 132 mV typical dropout specification applies at 300 mA with VIN = 2.832 V.
Can LP3981ILDX-2.7 operate without the BYPASS capacitor?
Yes, LP3981ILDX-2.7 functions without the BYPASS capacitor, delivering 2.7 V output with standard LDO performance. However, omitting the 0.033 µF capacitor increases output noise to ~120 µVRMS; the BYPASS pin is optional but essential for meeting 35 µVRMS noise spec in RF-sensitive applications.
Is LP3981ILDX-2.7 compatible with 1-µF ceramic output capacitors?
No-LP3981ILDX-2.7 requires a minimum 2.2 µF ceramic output capacitor for guaranteed stability per TI's validated design. Using 1 µF violates the specified 2.2–22 µF range and may cause oscillation or poor transient response; X7R dielectric is recommended for stable capacitance across temperature.
How does the OUT-SENSE pin function in LP3981ILDX-2.7, and what happens if left unconnected?
The OUT-SENSE pin in LP3981ILDX-2.7 is the feedback node for the internal error amplifier and must be shorted directly to the OUT pin. Leaving it unconnected breaks the regulation loop, causing the output to rise uncontrollably to near VIN; TI explicitly states "must be connected to OUT for proper operation" in the pin description.
Does LP3981ILDX-2.7 support reverse-voltage protection or input overvoltage clamp?
No, LP3981ILDX-2.7 provides neither reverse-voltage protection nor input overvoltage clamping. Absolute maximum input rating is 6.5 V; exceeding this risks permanent damage. External protection-such as a series Schottky diode for reverse polarity or TVS for surge-must be added per system requirements.
LP3981ILDX-2.7 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):
- 2.7V
- 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)
LP3981ILDX-2.7 FAQ
1.How can I place an order for LP3981ILDX-2.7 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3981ILDX-2.7 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 LP3981ILDX-2.7 reliable?
The price and inventory of LP3981ILDX-2.7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3981ILDX-2.7 is usually 5 days.
3.What payment methods are accepted for LP3981ILDX-2.7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3981ILDX-2.7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3981ILDX-2.7?
LP3981ILDX-2.7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3981ILDX-2.7 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 LP3981ILDX-2.7?
For technical support, including LP3981ILDX-2.7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3981ILDX-2.7 requirements.
6.How does Aetrix verify that LP3981ILDX-2.7 is sourced from the original manufacturer or authorized distributors?
All LP3981ILDX-2.7 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 LP3981ILDX-2.7 meets industry standards.
7.What is the process for return or replacement of LP3981ILDX-2.7?
All LP3981ILDX-2.7 units undergo pre-shipment inspection (PSI). If there is an issue with LP3981ILDX-2.7, 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 LP3981ILDX-2.7 part is unused and in its original packaging.
Return procedure for LP3981ILDX-2.7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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