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Texas Instruments LP38691SDX-2.5/NOPB
- Part No.:
- LP38691SDX-2.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP38691SDX-2.5/NOPB.pdf
- Description:
- IC REG LINEAR 2.5V 500MA 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,222
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Product details
Overview
LP38691SDX-2.5/NOPB from Texas Instruments is a 500-mA, 2.5-V fixed-output low-dropout CMOS linear regulator in WSON-6 package, featuring 250 mV dropout at 500 mA (VOUT = 5 V), ±2% output accuracy over –40°C to 125°C, and stable operation with only 1-µF ceramic output capacitor. It serves as a primary voltage rail for microcontroller cores and I/O in space-constrained portable instrumentation.
For engineers reviewing the LP38691SDX-2.5/NOPB datasheet, LP38691SDX-2.5/NOPB pinout, LP38691SDX-2.5/NOPB application, or LP38691SDX-2.5/NOPB equivalent, key selection criteria include dropout voltage at full load, ground current vs. load, thermal performance in WSON-6, remote sense capability (SNS pin), and enable functionality compatibility.
Technical Context
The LP38691SDX-2.5/NOPB uses a PMOS pass transistor architecture enabling ultra-low ground pin current (55 µA typical at full load) independent of input voltage or temperature. Its internal trimmed bandgap reference and feedback loop ensure ±2% output tolerance across –40°C to 125°C without external resistors.
No enable pin is present - unlike LP38693 variants - making it a permanently enabled regulator. The SNS pin is available only in WSON packages and must be tied directly to OUT for proper remote sensing; its inclusion enables compensation for PCB trace resistance between regulator and load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5 V ±2% (25°C), ±4% (–40°C to 125°C) - eliminates need for external feedback resistors and ensures precision for ADC references. |
| Max Output Current | 500 mA - supports mid-power digital loads such as Cortex-M4 microcontrollers or FPGA I/O banks. |
| Dropout Voltage | 250 mV at 500 mA (VOUT = 5 V); 450 mV at 500 mA (VOUT = 2.5 V) - enables regulation from 2.95-V input down to 2.5-V output in battery-powered systems. |
| Ground Current | 55 µA typical at full load - remains stable across input voltage and temperature, minimizing system quiescent power loss. |
| Input Voltage Range | 2.7 V to 10 V - compatible with single-cell Li-ion (fully charged), dual-cell alkaline, or intermediate DC/DC outputs. |
| Stability Capacitor | 1-µF ceramic output capacitor sufficient - reduces BOM count and board area vs. electrolytic/tantalum alternatives. |
| Thermal Shutdown | Activates at ~160°C junction temperature with ~10°C hysteresis - protects against sustained overload without requiring external thermal management. |
Pinout & Package
LP38691SDX-2.5/NOPB is housed in a 3.00 mm × 3.00 mm, 6-pin WSON package with exposed thermal pad (DAP) on bottom for enhanced heat dissipation. The DAP must be soldered to a PCB copper plane to achieve specified RθJB = 24.9°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pins 1 & 6) | Input supply connection | Both pins must be connected together externally; each rated for ≤250 mA - enables high-current routing while maintaining low-inductance path. |
| OUT (Pin 3) | Regulated output node | Main power delivery point; connects to load and output capacitor; SNS pin ties here for remote sensing. |
| SNS (Pin 5) | Remote output voltage sense | Must be shorted to OUT; enables compensation for voltage drop across PCB traces - critical for <1% load regulation in high-precision analog rails. |
| GND (Pin 2) | Power and signal reference | Primary ground return; thermally coupled to die - requires low-impedance connection to PCB ground plane. |
| DAP (Exposed Pad) | Thermal interface | Not electrically connected; must be soldered to ≥100 mm² copper pour for thermal performance - reduces θJA by >25°C/W vs. no-pad layout. |
Key Features
| Feature | Design Value |
|---|---|
| PMOS Pass Transistor | Eliminates base-drive current, keeping ground pin current below 100 µA regardless of load or input voltage - ideal for battery runtime optimization. |
| Trimmed Bandgap Reference | Ensures ±2% output accuracy at 25°C and ±4% over full industrial temperature range - meets requirements for precision analog subsystems. |
| Foldback Current Limiting | Reduces output current to ~350 mA when VIN–VOUT > 5 V, protecting against sustained short-circuit faults without external circuitry. |
| Thermal Overload Protection | Shuts down output at ~160°C junction temperature and recovers at ~150°C - prevents permanent damage during transient overloads or poor heatsinking. |
| Stable with Low-ESR Ceramic Caps | Operates reliably with 1-µF X7R/X5R ceramics (5–500 mΩ ESR) - avoids cost, size, and reliability drawbacks of tantalum or aluminum electrolytics. |
Applications
| Portable Instrumentation | Battery-Powered Microcontrollers |
|---|---|
Use Scenario: Handheld multimeter with 24-bit sigma-delta ADC and LCD display powered from two AA cells. IC Role / Device Role / Timing Role: Primary 2.5-V analog supply rail for ADC reference and sensor front-end amplifiers. Use Value: ±2% output tolerance and low noise (0.7 µV/√Hz) preserve measurement accuracy; 1-µF ceramic stability simplifies layout in tight enclosures. |
Use Scenario: Wireless sensor node using ARM Cortex-M0+ MCU, BLE radio, and environmental sensors. IC Role / Device Role / Timing Role: Core logic supply for MCU operating at 2.5 V, decoupled from noisy RF section. Use Value: 55 µA ground current extends battery life; 250 mV dropout allows operation down to 2.75-V input as batteries discharge. |
| Hard Disk Drive Servo Control | Notebook Computer I/O Rail |
Use Scenario: Precision voice-coil motor driver IC requiring clean, stable 2.5-V bias voltage in HDD actuator assembly. IC Role / Device Role / Timing Role: Low-noise analog bias supply isolated from digital switching noise. Use Value: 55 dB PSRR at 120 Hz suppresses ripple from spindle motor drivers; SNS pin compensates for trace IR drop in compact flex PCB. |
Use Scenario: USB controller and card reader interface ICs requiring regulated 2.5-V I/O voltage in ultrabook design. IC Role / Device Role / Timing Role: Secondary I/O supply derived from main 3.3-V rail via local LDO. Use Value: WSON-6 footprint (3×3 mm) fits dense motherboard layouts; thermal pad enables 500-mA load without external heatsink. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLS850F0TESK | 500-mA automotive-grade LDO with integrated watchdog and reset logic; 300-mV dropout at 500 mA; AEC-Q100 Grade 1 qualified. | Requires additional control signals (RESET, WDI); designed for ASIL-B safety-critical domains like body control modules. | Select TLS850F0TESK only if functional safety compliance (ISO 26262) and system monitoring features are required. |
| TPS7A2025PDQNR | 500-mA, 2.5-V LDO in 1.0-mm² X2SON-4; 170-mV dropout at 500 mA; 25-µA quiescent current; no SNS pin. | Smaller footprint and lower IQ, but lacks remote sensing and has reduced thermal capability (RθJA = 160°C/W). | Choose TPS7A2025PDQNR for ultra-low-power wearables where board space is paramount and trace resistance is negligible. |
Compared with TLS850F0TESK and TPS7A2025PDQNR, LP38691SDX-2.5/NOPB provides balanced performance: superior thermal handling via WSON-6 DAP, remote sensing for precision loads, and industrial temperature support - without automotive overhead or ultra-miniaturization trade-offs.
Availability
LP38691SDX-2.5/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered microcontrollers, hard disk drive servo control, and notebook computer I/O rails requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LP38691SDX-2.5/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 is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
LP38691SDX-2.5/NOPB belongs to TI's LP3869x family of low-dropout CMOS regulators, engineered specifically for portable, battery-powered digital systems requiring fast start-up, high accuracy, and ceramic-capacitor stability in minimal PCB area.
FAQ
Does LP38691SDX-2.5/NOPB have an enable pin?
No, LP38691SDX-2.5/NOPB does not include an enable (EN) pin. It is a permanently enabled regulator - unlike the LP38693 variant which features EN control. Power sequencing must be managed externally via input voltage control. This simplifies design for always-on rails but removes dynamic power gating capability.
What is the function of the SNS pin on LP38691SDX-2.5/NOPB?
The SNS pin on LP38691SDX-2.5/NOPB is a remote output voltage sense terminal, available only in WSON packages. It must be connected directly to the OUT pin to enable compensation for voltage drop across PCB traces between the regulator and load. This maintains tight load regulation (<±0.5%) in high-current or long-trace applications.
Can LP38691SDX-2.5/NOPB operate with a 1-µF output capacitor?
Yes, LP38691SDX-2.5/NOPB is explicitly designed to be stable with a single 1-µF ceramic output capacitor (X7R/X5R, 5–500 mΩ ESR). This eliminates the need for larger, higher-ESR capacitors and reduces solution size - confirmed in TI's SNVS321O datasheet Section 9.2.2.3 and Figure 14.
What is the maximum junction temperature for LP38691SDX-2.5/NOPB?
The absolute maximum junction temperature for LP38691SDX-2.5/NOPB is 150°C, with thermal shutdown activating at approximately 160°C. The device enters hysteresis recovery at ~150°C. Continuous operation near thermal limit degrades reliability; design must ensure PD ≤ ((125°C – TA) / RθJA) per datasheet Equation 1.
Is LP38691SDX-2.5/NOPB pin-compatible with LP38693 variants?
No, LP38691SDX-2.5/NOPB is not pin-compatible with LP38693 variants. While both use the same WSON-6 package, LP38691SDX-2.5/NOPB assigns Pin 4 to GND and Pin 5 to SNS, whereas LP38693SD uses Pin 4 for EN and Pin 5 for SNS - altering the functional pin mapping and preventing direct substitution without PCB revision.
LP38691SDX-2.5/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):
- 10V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.73V @ 500mA
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 55 µA
- Current - Supply (Max):
- 100 µA
- PSRR:
- 55dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-WSON (3x3)
LP38691SDX-2.5/NOPB FAQ
1.How can I place an order for LP38691SDX-2.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38691SDX-2.5/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 LP38691SDX-2.5/NOPB reliable?
The price and inventory of LP38691SDX-2.5/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP38691SDX-2.5/NOPB is usually 5 days.
3.What payment methods are accepted for LP38691SDX-2.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38691SDX-2.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38691SDX-2.5/NOPB?
LP38691SDX-2.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38691SDX-2.5/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 LP38691SDX-2.5/NOPB?
For technical support, including LP38691SDX-2.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38691SDX-2.5/NOPB requirements.
6.How does Aetrix verify that LP38691SDX-2.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LP38691SDX-2.5/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 LP38691SDX-2.5/NOPB meets industry standards.
7.What is the process for return or replacement of LP38691SDX-2.5/NOPB?
All LP38691SDX-2.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP38691SDX-2.5/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 LP38691SDX-2.5/NOPB part is unused and in its original packaging.
Return procedure for LP38691SDX-2.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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