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Texas Instruments LP3981ILDX-2.8
- Part No.:
- LP3981ILDX-2.8
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP3981ILDX-2.8.pdf
- Description:
- IC REG LINEAR 2.8V 300MA 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,169
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Product details
Overview
LP3981ILDX-2.8 from Texas Instruments is a micropower, ultra-low-dropout CMOS voltage regulator delivering 300 mA at fixed 2.8 V output, optimized for battery-powered wireless systems. It features 132 mV typical dropout at full load, ≤1 µA shutdown current, 35 µVRMS output noise (10 Hz–100 kHz), and 60 dB PSRR at 1 kHz - enabling clean power for RF front-ends and baseband processors in cellular handsets.
For engineers reviewing the LP3981ILDX-2.8 datasheet, LP3981ILDX-2.8 pinout, LP3981ILDX-2.8 application, or LP3981ILDX-2.8 equivalent, key selection criteria include dropout performance under 300-mA load, ceramic-capacitor stability with 2.2-µF COUT, thermal resistance in WSON-6 package (RθJA = 56.5°C/W), and logic-controlled enable with 0.4 V/1.4 V thresholds.
Technical Context
The LP3981ILDX-2.8 employs a PMOS pass transistor architecture enabling ultra-low dropout and minimal ground current increase in dropout. Its internal bandgap reference (1.23 V) feeds a fast-turnon circuit that achieves 240 µs typical startup time with 0.033 µF bypass capacitor.
It integrates thermal shutdown (160°C trip, 20°C hysteresis) and short-circuit current limiting (600 mA peak), while maintaining stability with 2.2–22 µF ceramic output capacitors having 5–500 mΩ ESR - eliminating need for tantalum or electrolytic types.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8 V ±3% over −40°C to +125°C - ensures stable core voltage for 2.8-V logic rails without external feedback. |
| Max Output Current | 300 mA continuous - sufficient for GSM/CDMA transceiver ICs and baseband processors in compact handsets. |
| Dropout Voltage | 132 mV typical at 300 mA - enables operation down to VIN = 2.932 V, extending battery runtime in single-cell Li-ion systems. |
| Quiescent Current | 70 µA typical at 1 mA load; ≤1.5 µA in shutdown - minimizes standby drain in always-on subsystems. |
| PSRR | 60 dB at 1 kHz - suppresses switching noise from DC/DC converters feeding the LDO input. |
| Output Noise | 35 µVRMS (10 Hz–100 kHz) with 0.033 µF BYPASS cap - meets low-noise requirements for RF synthesizers and ADC references. |
| Enable Thresholds | VIL = 0.4 V max, VIH = 1.4 V min - compatible with 1.8-V and 3.3-V GPIO control without level-shifting. |
Pinout & Package
LP3981ILDX-2.8 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 2.7–6 V input; requires 2.2 µF ceramic capacitor placed ≤1 cm from pin with low-impedance analog ground return. |
| OUT (Pin 1) | Regulated output | Delivers fixed 2.8 V; connects directly to load and OUT-SENSE for accurate sensing; supports 2.2–22 µF ceramic COUT. |
| OUT-SENSE (Pin 3) | Output voltage sense | Must be shorted to OUT externally; enables remote-sense accuracy and improves load regulation by compensating trace IR drop. |
| EN (Pin 6) | Logic-enable input | Active-high control: <0.4 V disables (≤1.5 µA IQ), >1.4 V enables; ties to VIN if always-on operation required. |
| BYPASS (Pin 5) | Noise reduction node | Connects 0.033 µF ceramic/film cap to GND; reduces output noise without degrading transient response or regulation. |
| GND (Pin 4) | Power and signal ground | Common reference for IN, OUT, EN, BYPASS; must be tied to exposed thermal pad for optimal thermal performance (RθJB = 30.9°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 132 mV at 300 mA enables use with partially discharged Li-ion cells (down to ~2.93 V), maximizing usable battery capacity. |
| Ceramic-capacitor stable | Operates with 2.2 µF X7R/Z5U ceramic COUT (5–500 mΩ ESR), reducing BOM cost, board area, and failure risk vs. tantalum. |
| Low-noise regulation | 35 µVRMS output noise with BYPASS cap meets stringent requirements for RF PLLs, VCOs, and high-resolution ADCs. |
| Fast enable response | 240 µs typical turnon time (to 95% VOUT) supports dynamic power sequencing in multi-rail mobile SoCs. |
| Thermal protection | 160°C junction shutdown with 20°C hysteresis prevents damage during sustained overload or poor PCB heatsinking. |
Applications
| CDMA Cellular Handsets | Wideband CDMA Cellular Handsets |
|---|---|
|
Use Scenario: Powering RF transceiver ICs and analog baseband sections requiring low-noise, tightly regulated 2.8-V supply. IC Role / Device Role / Timing Role: Primary LDO delivering clean bias to PA driver stages and mixer cores; replaces noisier switching regulators in sensitive RF chains. Use Value: 60 dB PSRR at 1 kHz suppresses DC/DC ripple, while 35 µVRMS noise prevents EVM degradation in 16-QAM and 64-QAM modulation schemes. |
Use Scenario: Supplying 2.8-V core voltage to wideband digital baseband processors handling HSPA+ and LTE data bursts. IC Role / Device Role / Timing Role: High-current, low-dropout regulator supporting rapid load transients up to 300 mA during packet transmission. Use Value: 132-mV dropout preserves headroom during peak current draw, and fast 240-µs turnon enables burst-mode power gating for energy efficiency. |
| GSM Cellular Handsets | Portable Information Appliances |
|
Use Scenario: Providing stable 2.8-V rail to GSM power amplifier modules and SIM interface circuits. IC Role / Device Role / Timing Role: Always-on LDO with logic-enable for PA bias control; maintains regulation during deep discharge (VIN ≥ 2.93 V). Use Value: ≤1.5 µA shutdown current extends standby time; thermal shutdown protects against antenna mismatch-induced PA overheating. |
Use Scenario: Regulating power for LCD controller, touch controller, and microSD interface in handheld PDAs and e-readers. IC Role / Device Role / Timing Role: Micropower LDO supplying mixed-signal peripherals with minimal quiescent drain during sleep modes. Use Value: 70 µA typical IQ at light load and ceramic-capacitor compatibility reduce system-level power and component count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL7407LDR | 7-channel 200-mA sink driver with integrated LDO; 2.8-V option available but not pin-compatible; higher IQ (25 µA typ). | Designed for LED/relay driving with built-in logic; lacks OUT-SENSE and BYPASS pins for precision regulation. | Choose only if multi-channel sinking and integrated logic are required; not a direct functional replacement for standalone LDO use. |
| TPS73228DBVR | 300-mA LDO with 2.8-V output; 150-mV dropout (typ), 30-µVRMS noise, but requires minimum 1-µF COUT and has no BYPASS pin. | Optimized for general-purpose low-noise apps; lacks dedicated noise-reduction node and remote-sense capability. | Select when lowest possible noise is critical and BYPASS functionality is unnecessary; verify thermal performance (RθJA = 260°C/W in SOT-23) for 300-mA loads. |
Compared with LP3981ILDX-2.8, TPL7407LDR trades LDO precision for multi-function integration, while TPS73228DBVR offers lower noise but sacrifices design flexibility in noise filtering and thermal management - making LP3981ILDX-2.8 optimal for space-constrained, battery-sensitive RF applications demanding both low dropout and configurable noise suppression.
Availability
LP3981ILDX-2.8 is available at Aetrix Electronics and suitable for CDMA/GSM handset design, portable information appliance development, and wideband cellular baseband power delivery requiring stable component supply across production lifecycles.
Supply support for LP3981ILDX-2.8 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 was engineered specifically for micropower, ultra-low-noise battery-powered wireless applications - emphasizing extended runtime, RF-friendly regulation, and compact ceramic-capacitor-based implementation.
FAQ
What is the minimum input voltage required for LP3981ILDX-2.8 to maintain regulation?
The LP3981ILDX-2.8 requires VIN ≥ VOUT + 0.3 V (i.e., ≥3.1 V) for guaranteed regulation per recommended operating conditions. However, it can sustain regulation down to VIN = VOUT + 132 mV (≥2.932 V) at 300 mA load due to its ultra-low dropout architecture - verified in electrical characteristics tables across temperature.
Can LP3981ILDX-2.8 operate without the BYPASS capacitor?
Yes, LP3981ILDX-2.8 functions without the BYPASS capacitor but with higher output noise: 35 µVRMS is specified *with* a 0.033 µF capacitor on the BYPASS pin. Omitting it increases noise - exact values are not characterized in the datasheet, so designs requiring low-noise RF supply must include it.
Is LP3981ILDX-2.8 stable with a 1-µF ceramic output capacitor?
No. The LP3981ILDX-2.8 requires a minimum 2.2 µF ceramic output capacitor (5–500 mΩ ESR) for guaranteed stability, as stated in Section 9.2.2.4 and Electrical Characteristics table. Using 1 µF violates the design specification and may cause oscillation or poor transient response.
What is the thermal pad connection requirement for LP3981ILDX-2.8 in the WSON-6 package?
The exposed thermal pad of LP3981ILDX-2.8 must be soldered to a PCB copper pour connected to GND. Per Pin Descriptions, it serves as common ground and is electrically tied to Pin 4 (GND); omitting this connection degrades thermal performance (RθJB rises from 30.9°C/W to unspecified levels) and risks thermal shutdown.
Does LP3981ILDX-2.8 support remote voltage sensing?
Yes. LP3981ILDX-2.8 implements remote sensing via the OUT-SENSE pin (Pin 3), which must be connected directly to the load-side of the output trace. This compensates for IR drop across PCB traces, improving load regulation accuracy - a feature absent in many standard LDOs and critical for high-current mobile applications.
LP3981ILDX-2.8 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):
- 2.8V
- 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-2.8 FAQ
1.How can I place an order for LP3981ILDX-2.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3981ILDX-2.8 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-2.8 reliable?
The price and inventory of LP3981ILDX-2.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3981ILDX-2.8 is usually 5 days.
3.What payment methods are accepted for LP3981ILDX-2.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3981ILDX-2.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3981ILDX-2.8?
LP3981ILDX-2.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3981ILDX-2.8 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-2.8?
For technical support, including LP3981ILDX-2.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3981ILDX-2.8 requirements.
6.How does Aetrix verify that LP3981ILDX-2.8 is sourced from the original manufacturer or authorized distributors?
All LP3981ILDX-2.8 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-2.8 meets industry standards.
7.What is the process for return or replacement of LP3981ILDX-2.8?
All LP3981ILDX-2.8 units undergo pre-shipment inspection (PSI). If there is an issue with LP3981ILDX-2.8, 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-2.8 part is unused and in its original packaging.
Return procedure for LP3981ILDX-2.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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