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Texas Instruments LP3990SD-2.8/NOPB
- Part No.:
- LP3990SD-2.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP3990SD-2.8/NOPB.pdf
- Description:
- IC REG LINEAR 2.8V 150MA 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,086
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Product details
Overview
LP3990SD-2.8/NOPB from Texas Instruments (formerly National Semiconductor) is a 150mA low-noise linear voltage regulator delivering a precise 2.8V output from 2.0–6.0V input, featuring 43µA quiescent current in active mode, <10nA shutdown current, and stability with 1.0µF ceramic output capacitors. It serves as a power supply for core logic and I/O rails in space-constrained portable digital systems.
For engineers reviewing the LP3990SD-2.8/NOPB datasheet, LP3990SD-2.8/NOPB pinout, LP3990SD-2.8/NOPB application, or LP3990SD-2.8/NOPB equivalent, key selection criteria include dropout voltage (120mV typ. at 150mA), PSRR (55dB @ 1kHz), fast startup (105µs), thermal/short-circuit protection, and micro SMD or LLP-6 package compatibility with high-density PCB layouts.
Technical Context
The LP3990SD-2.8/NOPB employs a PMOS pass transistor architecture enabling ultra-low dropout and near-zero quiescent current in shutdown. Its internal reference and error amplifier maintain ±1% output accuracy over −40°C to +125°C junction temperature.
It integrates logic-controlled enable (VIH = 0.95V, VIL = 0.4V) with 1MΩ internal pulldown, supports no-bypass-capacitor operation, and achieves 150µVRMS output noise (10Hz–100kHz) without external noise-reduction components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.8V ±1.5% over full temperature and load range - ensures stable core/I/O rail for ASICs and baseband processors. |
| Max Output Current | 150mA continuous - sufficient for powering low-power microcontrollers, RF transceivers, and sensor interfaces. |
| Dropout Voltage | 120mV typical at 150mA - enables operation from single-cell Li-ion (2.8V out from ~3.0V input) with minimal headroom loss. |
| Quiescent Current | 43µA active / <10nA shutdown - extends battery life in always-on standby modes of handheld devices. |
| PSRR | 55dB @ 1kHz - suppresses switching noise from upstream DC/DC converters feeding the LP3990SD-2.8/NOPB input. |
| Output Noise | 150µVRMS (10Hz–100kHz) - meets stringent noise requirements for analog sections and PLL power domains. |
| Startup Time | 105µs to 95% VOUT - supports rapid wake-up sequences in power-managed mobile systems. |
Pinout & Package
LP3990SD-2.8/NOPB is supplied in the LLP-6 (Leadless Leadframe Package) with SOT23 footprint, measuring 2.0mm × 2.0mm × 0.8mm, lead-free and RoHS-compliant. The package features exposed thermal pad for enhanced heat dissipation (θJA = 88°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | Accepts 2.0–6.0V; requires 1.0µF ceramic capacitor placed ≤1cm from pin to minimize input inductance and ensure stability. |
| GND | Power ground reference | Common return path for input/output currents; must be connected to PCB ground plane and thermal pad for optimal thermal performance. |
| VOUT | Regulated output | Delivers fixed 2.8V; requires 1.0µF ceramic capacitor (X7R, 5–500mΩ ESR) directly at pin for loop stability and transient response. |
| VEN | Enable control input | Active-high logic interface (VIH ≥ 0.95V); internal 1MΩ pulldown ensures default-off state; drives shutdown current to <10nA. |
| N/C | No connection | Unbonded terminal; must remain floating - no routing or soldering permitted. |
| N/C | No connection | Unbonded terminal; must remain floating - no routing or soldering permitted. |
Key Features
| Feature | Design Value |
|---|---|
| Stable with 1.0µF ceramic output capacitor | Eliminates need for large tantalum or electrolytic caps, reducing board area by >50% vs legacy LDOs and enabling 0402/0603 footprint designs. |
| 1% initial output accuracy | Guarantees system-level voltage margin compliance without post-production calibration, critical for memory I/O and processor core rails. |
| Logic-controlled enable with internal pulldown | Removes need for external pull-down resistor, simplifying BOM and layout while ensuring fail-safe power-off during boot or reset. |
| Thermal overload and short-circuit protection | Auto-recovering shutdown prevents permanent damage during fault conditions (e.g., output short or ambient overtemperature), supporting unattended operation. |
| No noise bypass capacitor required | Reduces component count by one passive per rail, lowers cost and assembly complexity, and avoids parasitic resonance issues common with external bypass networks. |
Applications
| Smartphone Baseband Power | Wearable Sensor Hub Supply |
|---|---|
Use Scenario: Powers ARM Cortex-M4-based sensor fusion processor and integrated ADC/DAC in compact fitness tracker. IC Role / Device Role / Timing Role: Primary 2.8V LDO supplying digital core and analog front-end; provides clean, low-noise bias independent of main PMIC switching noise. Use Value: 150µVRMS noise and 55dB PSRR prevent signal corruption in 16-bit sensor data acquisition, enabling sub-milligal motion resolution. |
Use Scenario: Delivers regulated 2.8V to Bluetooth Low Energy SoC and MEMS accelerometer in coin-cell-powered hearable device. IC Role / Device Role / Timing Role: Standby-mode LDO activated only during BLE advertising intervals; enabled via host MCU GPIO. Use Value: 43µA IQ and <10nA shutdown current extend 180-day battery life; 105µs startup synchronizes with BLE radio wake-up timing. |
| Portable Medical Pulse Oximeter | Industrial Handheld Scanner |
Use Scenario: Supplies 2.8V to optical front-end (LED drivers, photodiode amp) and signal processing ASIC in FDA-cleared wearable oximeter. IC Role / Device Role / Timing Role: Low-noise analog rail LDO; decouples sensitive analog circuitry from noisy digital subsystems sharing same battery source. Use Value: 120mV dropout allows direct use of partially discharged 3.0V lithium coin cell across full operating life, eliminating intermediate buck stage. |
Use Scenario: Provides 2.8V logic supply to 32-bit RISC processor and CMOS image sensor in ruggedized barcode scanner with 10-year field deployment target. IC Role / Device Role / Timing Role: Main I/O voltage regulator; operates across −40°C to +85°C ambient with guaranteed ±1.5% tolerance. Use Value: Thermal shutdown (155°C) and short-circuit protection ensure reliability in sealed enclosures with limited airflow and intermittent high-current laser activation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A0528PDBVR | Lower IQ (25µA), smaller 1.5mm × 1.5mm X2SON package, but requires 2.2µF min. output capacitance and has higher 200mV dropout at 150mA. | Better suited for ultra-long-life coin-cell applications where size is paramount and input headroom exceeds 3.0V. | Select TPS7A0528PDBVR when board area is constrained and input voltage ≥3.0V; LP3990SD-2.8/NOPB remains preferred for 2.0–2.9V inputs or 1.0µF cap compatibility. |
| MCP1700T-2802E/TT | Higher IQ (2.5µA shutdown, 3.5µA active), wider input range (2.3–6.0V), but only 250mA rated and lacks thermal shutdown; ±2% output tolerance. | Targeted at cost-sensitive consumer electronics where absolute precision and fault protection are secondary to BOM cost. | Choose MCP1700T-2802E/TT for price-driven volume production with relaxed accuracy needs; LP3990SD-2.8/NOPB is specified for industrial-grade reliability and tighter regulation. |
Compared with TPS7A0528PDBVR and MCP1700T-2802E/TT, the LP3990SD-2.8/NOPB uniquely balances ultra-low-noise operation (150µVRMS), 1.0µF ceramic stability, and integrated fault protection - making it the optimal choice for analog-sensitive, thermally demanding, or battery-headroom-limited digital applications.
Availability
LP3990SD-2.8/NOPB is available at Aetrix Electronics and suitable for smartphone baseband power, wearable sensor hub supply, portable medical pulse oximeters, industrial handheld scanners, and other applications requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LP3990SD-2.8/NOPB 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 acquired National Semiconductor in 2011 and maintains its precision analog and power management portfolio. TI is a global semiconductor leader focused on analog, embedded processing, and connectivity solutions.
The LP3990SD-2.8/NOPB belongs to National Semiconductor's legacy LDO family designed specifically for portable digital systems - emphasizing low noise, minimal quiescent current, ceramic capacitor compatibility, and robust protection in ultra-thin form factors.
FAQ
What is the minimum input voltage required for LP3990SD-2.8/NOPB to regulate at 2.8V?
The LP3990SD-2.8/NOPB requires a minimum input voltage of 2.0V, but for reliable regulation at full 150mA load, VIN must be at least VOUT + dropout voltage. With a typical dropout of 120mV, the practical minimum is 2.92V. At lighter loads, regulation is maintained down to 2.0V input, though output accuracy degrades near the dropout boundary. This behavior is confirmed in the Electrical Characteristics table under VDO and Line Regulation specifications.
Does LP3990SD-2.8/NOPB require an external bypass capacitor for noise reduction?
No, the LP3990SD-2.8/NOPB does not require an external noise bypass capacitor. Its internal design achieves 150µVRMS output noise (10Hz–100kHz) without additional filtering components, as explicitly stated in the Features section and verified in the Electrical Characteristics table under "en". This eliminates one passive component and associated layout complexity versus traditional LDOs.
What is the thermal resistance (θJA) of LP3990SD-2.8/NOPB in its LLP-6 package?
The LP3990SD-2.8/NOPB in the LLP-6 package has a junction-to-ambient thermal resistance (θJA) of 88°C/W, as specified in the Thermal Properties section. This value assumes standard JEDEC 2-layer board conditions; actual θJA will vary with PCB copper area, thermal vias, and airflow. The exposed thermal pad must be soldered to a solid ground plane to achieve this rating.
Can LP3990SD-2.8/NOPB operate with a 0.47µF output capacitor?
No - the LP3990SD-2.8/NOPB requires a minimum 1.0µF ceramic output capacitor for guaranteed stability, as defined in both the General Description and Output Capacitor section. While 0.47µF may function in some lab conditions, it violates the recommended specification and risks oscillation or poor transient response. The datasheet explicitly states COUT = 1.0µF (min 0.7µF) with 5–500mΩ ESR.
Is LP3990SD-2.8/NOPB pin-compatible with other variants in the LP3990 family?
Yes - all LP3990 variants in the LLP-6 package (e.g., LP3990SD-1.8, LP3990SD-3.3) share identical pinout, footprint, and thermal pad configuration. The only differences are output voltage and top-side marking. This allows voltage-scaling flexibility within the same PCB layout, provided input voltage and load requirements remain compatible across variants.
LP3990SD-2.8/NOPB 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 @ 150mA
- Current - Output:
- 150mA
- Current - Quiescent (Iq):
- 80 µA
- Current - Supply (Max):
- 120 µA
- PSRR:
- 55dB ~ 35dB (1kHz ~ 10kHz)
- Control Features:
- Enable
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-WSON (3x3)
LP3990SD-2.8/NOPB FAQ
1.How can I place an order for LP3990SD-2.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP3990SD-2.8/NOPB 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 LP3990SD-2.8/NOPB reliable?
The price and inventory of LP3990SD-2.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3990SD-2.8/NOPB is usually 5 days.
3.What payment methods are accepted for LP3990SD-2.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3990SD-2.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP3990SD-2.8/NOPB?
LP3990SD-2.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP3990SD-2.8/NOPB 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 LP3990SD-2.8/NOPB?
For technical support, including LP3990SD-2.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3990SD-2.8/NOPB requirements.
6.How does Aetrix verify that LP3990SD-2.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LP3990SD-2.8/NOPB 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 LP3990SD-2.8/NOPB meets industry standards.
7.What is the process for return or replacement of LP3990SD-2.8/NOPB?
All LP3990SD-2.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3990SD-2.8/NOPB, 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 LP3990SD-2.8/NOPB part is unused and in its original packaging.
Return procedure for LP3990SD-2.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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