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Texas Instruments LP38691DTX-1.8/NOPB
- Part No.:
- LP38691DTX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
LP38691DTX-1.8/NOPB.pdf
- Description:
- IC REG LINEAR 1.8V 500MA TO252-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,870
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Product details
Overview
LP38691DTX-1.8/NOPB from Texas Instruments is a 500-mA, 1.8-V fixed-output low-dropout CMOS linear regulator in WSON-6 package, featuring 2% output accuracy at 25°C, 250 mV dropout at 500 mA (VOUT = 5 V), and stable operation with only 1-µF ceramic output capacitor. It delivers precision voltage regulation for battery-powered microcontroller cores in portable instrumentation.
For engineers reviewing the LP38691DTX-1.8/NOPB datasheet, LP38691DTX-1.8/NOPB pinout, LP38691DTX-1.8/NOPB application, or LP38691DTX-1.8/NOPB equivalent, key selection criteria include dropout voltage at 1.8 V output, ground pin current under full load, thermal shutdown threshold, ripple rejection at 120 Hz, and compatibility with ultra-low-ESR ceramic capacitors.
Technical Context
The LP38691DTX-1.8/NOPB uses a PMOS pass transistor architecture enabling sub-100 µA ground pin current across load, input voltage, and temperature - eliminating base-drive losses inherent in NPN-based regulators. Its trimmed bandgap reference and internal feedback resistors fix VOUT at 1.8 V without external components.
No enable pin is integrated; the device operates continuously when VIN ≥ 2.7 V and VIN ≥ (VOUT + VDO). Thermal shutdown activates at 160°C junction temperature with 10°C hysteresis, and foldback current limiting engages based on VIN–VOUT differential - limiting to ~350 mA above 5 V differential and ~850 mA below 4 V differential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±2% at 25°C; ensures stable core supply for 1.8-V logic and RF ICs |
| Max Output Current | 500 mA continuous; supports single-core MCU or sensor subsystems without derating |
| Dropout Voltage | 250 mV typical at 500 mA (for 5 V output); at 1.8 V output, dropout is ≤450 mV per datasheet curves |
| Ground Pin Current | 55 µA typical at full load; enables high-efficiency operation in battery-critical systems |
| Ripple Rejection | 55 dB at 120 Hz with 1-Vp-p input ripple; suppresses switching noise from upstream DC/DC converters |
| Quiescent Current | 100 µA typical over full temperature range; maintains low standby power in always-on applications |
| Thermal Shutdown | Activates at 160°C junction temp with 10°C hysteresis; protects against sustained overload in compact layouts |
Pinout & Package
LP38691DTX-1.8/NOPB is housed in a thermally enhanced 6-pin WSON package (3.0 mm × 3.0 mm) with exposed thermal pad (DAP) on bottom. The DAP must be soldered to a PCB copper plane for effective heat dissipation and meets AEC-Q100 Grade 1 reliability requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pins 1, 6) | Input supply connection | Both pins must be tied together for full 500-mA operation; each rated for 250 mA max |
| OUT (Pin 3) | Regulated output node | Delivers stable 1.8 V; connects directly to load or local decoupling capacitor |
| GND (Pin 5) | Power and signal reference | Internally connected to die substrate and thermal pad; requires low-impedance PCB return path |
| SNS (Pin 4) | Remote output sense | WSON-only; must be shorted to OUT to enable remote sensing and eliminate trace IR drop error |
| DAP (Exposed Pad) | Thermal interface | Functions as primary heat sink; must be soldered to ≥100 mm² copper area for RθJB = 24.9°C/W |
Key Features
| Feature | Design Value |
|---|---|
| Ceramic-capacitor stability | Stable with ≥1-µF X5R/X7R ceramic output capacitor - eliminates need for tantalum or electrolytic |
| Precision trimmed reference | 2% output tolerance over –40°C to 125°C ensures reliable operation in industrial environments |
| Ultra-low ground current | 55 µA typical at full load enables >99% efficiency at light loads and extends battery life |
| Thermal protection with hysteresis | 160°C shutdown / 150°C recovery prevents latch-up and allows safe auto-recovery after transient overloads |
| Low-noise regulation | 0.7 µV/√Hz output noise (at 3.3 V) - suitable for noise-sensitive analog and RF circuitry |
Applications
| Portable Medical Sensors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Powering low-power ADCs and wireless transceivers in handheld glucose meters and pulse oximeters. IC Role / Device Role / Timing Role: Primary 1.8-V LDO supplying analog front-end and BLE SoC core rails. Use Value: 250-mV dropout enables operation down to 2.05 V input, extending usable battery range from two alkaline cells. | Use Scenario: Regulating 1.8-V supply for isolated digital I/O ASICs in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Local point-of-load regulator delivering clean, stable voltage to FPGA configuration banks. Use Value: 55 dB ripple rejection attenuates 120-Hz noise from AC/DC front-end, preventing logic errors in timing-critical interfaces. |
| Automotive Body Control Units | Test & Measurement Handhelds |
Use Scenario: Supplying 1.8-V rail to LIN transceiver and microcontroller in door module ECUs. IC Role / Device Role / Timing Role: AEC-Q100 Grade 1 qualified LDO ensuring functional safety compliance for non-safety-critical domains. Use Value: Guaranteed operation from –40°C to 125°C ambient enables placement near heat-generating power stages. | Use Scenario: Providing regulated 1.8-V bias to high-resolution SAR ADCs and precision op-amps in portable DMMs. IC Role / Device Role / Timing Role: Low-noise, low-drift voltage source minimizing measurement offset and quantization error. Use Value: 0.7 µV/√Hz noise floor preserves ENOB in 16-bit+ data acquisition paths without additional filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL7407LPGQDRQ1 | 7-channel high-side driver with integrated 1.8-V LDO; not a standalone regulator | Designed for LED/relay driving with auxiliary bias - lacks precision output tolerance and ceramic-stability specs | Select only if system requires integrated driver functionality alongside regulation |
| TPS7A0518PDQNR | 200-mA, 1.8-V LDO in X2SON-4; 170 mV dropout at 200 mA, 25 µA IQ | Lower current rating and smaller package - insufficient for 500-mA MCU core loads | Choose when board space is critical and load current ≤200 mA |
Compared with TPL7407LPGQDRQ1 and TPS7A0518PDQNR, LP38691DTX-1.8/NOPB uniquely balances 500-mA capability, 2% accuracy, ceramic stability, and WSON thermal performance - making it the only direct fit for space-constrained, high-current 1.8-V core supplies requiring industrial temperature support.
Availability
LP38691DTX-1.8/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, automotive body electronics, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LP38691DTX-1.8/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 is a global semiconductor company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets.
The LP3869x family was developed specifically for portable, battery-powered digital systems requiring fast start-up, tight output tolerance, and ultra-low ground current - targeting applications where efficiency, size, and thermal performance are critical.
FAQ
What is the minimum input voltage required for LP38691DTX-1.8/NOPB to regulate 1.8 V output?
The LP38691DTX-1.8/NOPB requires VIN ≥ 2.7 V per datasheet operating conditions, and VIN must also exceed (VOUT + VDO) - i.e., ≥2.25 V for typical 1.8-V operation. However, guaranteed regulation begins only when VIN reaches 2.7 V, as internal circuitry is not fully functional below that threshold. LP38691DTX-1.8/NOPB does not include UVLO, so output is unregulated until this condition is met.
Does LP38691DTX-1.8/NOPB have an enable pin?
No, LP38691DTX-1.8/NOPB does not include an enable (EN) pin. It is a permanently enabled regulator - unlike the LP38693 variant, which features an active-high EN input. To disable LP38691DTX-1.8/NOPB, the input supply must be removed or switched externally. This simplifies design for always-on applications but removes dynamic power control capability.
Can LP38691DTX-1.8/NOPB be used with a 1-µF ceramic output capacitor?
Yes, LP38691DTX-1.8/NOPB is explicitly designed and characterized for stability with a single 1-µF ceramic output capacitor - no ESR requirement or damping network needed. This is confirmed in the datasheet's "Stable With Ceramic Output Capacitors" feature and Typical Application Circuits. Larger values (e.g., 10 µF) improve PSRR but are not required for stability.
What is the purpose of the SNS pin on LP38691DTX-1.8/NOPB?
The SNS (sense) pin on LP38691DTX-1.8/NOPB enables remote output voltage sensing at the load to compensate for IR drop in PCB traces. For standard operation, SNS must be connected directly to the OUT pin. If routed to the load, it improves output voltage accuracy under varying load currents - critical for precision analog circuits powered by LP38691DTX-1.8/NOPB.
How does thermal performance differ between LP38691DTX-1.8/NOPB and TO-252-packaged variants?
LP38691DTX-1.8/NOPB in WSON-6 achieves RθJB = 24.9°C/W (junction-to-board), significantly better than TO-252's 29.7°C/W. Its exposed thermal pad (DAP) provides lower thermal resistance to PCB copper, enabling higher power dissipation in compact layouts. Unlike TO-252, WSON requires careful solder paste stencil design and reflow profiling to ensure void-free DAP attachment for optimal LP38691DTX-1.8/NOPB thermal performance.
LP38691DTX-1.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 10V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-252-3
LP38691DTX-1.8/NOPB FAQ
1.How can I place an order for LP38691DTX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38691DTX-1.8/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 LP38691DTX-1.8/NOPB reliable?
The price and inventory of LP38691DTX-1.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP38691DTX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LP38691DTX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38691DTX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38691DTX-1.8/NOPB?
LP38691DTX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38691DTX-1.8/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 LP38691DTX-1.8/NOPB?
For technical support, including LP38691DTX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38691DTX-1.8/NOPB requirements.
6.How does Aetrix verify that LP38691DTX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LP38691DTX-1.8/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 LP38691DTX-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LP38691DTX-1.8/NOPB?
All LP38691DTX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP38691DTX-1.8/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 LP38691DTX-1.8/NOPB part is unused and in its original packaging.
Return procedure for LP38691DTX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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