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Texas Instruments LP38690DT-1.8
- Part No.:
- LP38690DT-1.8
- Manufacturer:
- Texas Instruments
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
LP38690DT-1.8.pdf
- Description:
- IC REG LINEAR 1.8V 1A TO252-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,926
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Product details
Overview
LP38690DT-1.8 from Texas Instruments is a 1-A, 1.8-V fixed-output low-dropout CMOS linear regulator in TO-252 (DP) package, featuring 2.5% output accuracy at 25°C, 950 mV dropout at 1 A load (VOUT = 1.8 V), and stable operation with only 1-µF ceramic output capacitance. It serves as a primary power rail for core logic in portable embedded systems requiring tight voltage regulation under varying load and temperature.
For engineers reviewing the LP38690DT-1.8 datasheet, LP38690DT-1.8 pinout, LP38690DT-1.8 application, or LP38690DT-1.8 equivalent, this page delivers verified technical context, validated pin functions, real-world application mappings, and two confirmed alternative parts - all grounded in TI's SNVS322M production data sheet (Rev M, Dec 2015).
Technical Context
The LP38690DT-1.8 uses a PMOS pass transistor architecture enabling ultra-low ground pin current (55 µA typical at full load) independent of input voltage, load, or temperature. Its trimmed bandgap reference and internal feedback network ensure ±2.5% output tolerance over –40°C to +125°C operating junction range.
No enable pin is present - unlike the LP38692 variant - making it a simple ON/OFF-controlled regulator via input supply only. It lacks remote sense (SNS) functionality in TO-252 packaging, and its foldback current limiting activates at 450 mA when VIN–VOUT > 5 V, rising to 1500 mA when differential drops below 4 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±2.5% at 25°C; maintains regulation across –40°C to +125°C junction range. |
| Max Output Current | 1 A continuous; limited by thermal design and dropout headroom - not current-source-limited. |
| Dropout Voltage | 950 mV at 1 A (VOUT = 1.8 V); defines minimum VIN = 2.75 V required for regulation at full load. |
| Quiescent Current | 55 µA typical at full load; remains ≤100 µA across full temperature and load range - enables battery longevity. |
| Stability Capacitor | Stable with ≥1 µF ceramic output capacitor (X5R/X7R); no ESR requirement - simplifies layout and cost. |
| Thermal Shutdown | Activates at ~160°C junction; hysteresis ~10°C - protects against sustained overload without PCB-level intervention. |
| PSRR | 55 dB at 120 Hz (1 Vp-p ripple); sufficient for post-regulation of noisy DC/DC converter outputs. |
Pinout & Package
LP38690DT-1.8 is supplied in a 3-pin TO-252 (DP) thermally enhanced package (6.58 mm × 6.10 mm), with exposed tab soldered to PCB ground plane for optimal thermal performance (RθJB = 29.7°C/W). No enable or sense pins are present in this variant.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Regulated output terminal | Delivers stable 1.8 V to load; connects directly to local bypass capacitor and load ground return path. |
| 2 (GND) | Power and thermal ground | Die substrate reference and primary heat conduction path; must be soldered to ≥1 cm² copper pour for full 1-A rating. |
| 3 (IN) | Unregulated input supply | Accepts 2.7 V to 10 V; requires ≥1 µF ceramic input capacitor placed within 5 mm of pin for transient immunity. |
Key Features
| Feature | Design Value |
|---|---|
| PMOS pass transistor | Eliminates base-drive current - keeps GND pin current ≤100 µA regardless of load, enabling accurate current-sense-free power budgeting. |
| Ceramic-capacitor stability | Validated with 1 µF X5R/X7R MLCC at output - removes need for tantalum or aluminum electrolytic, reducing size, cost, and failure risk. |
| Wide input range | Operates from 2.7 V to 10 V - supports single-cell Li-ion (2.7–4.2 V), 3.3 V rails, and 5 V/9 V wall adapters without external pre-regulation. |
| Industrial temp grade | Specified from –40°C to +125°C junction - suitable for automotive cabin, industrial control, and outdoor edge-node deployments. |
| Foldback current limit | Self-protecting under short-circuit: limits to 450 mA at high VIN–VOUT, scaling up to 1500 mA near dropout - balances safety and recovery capability. |
Applications
| Hard Disk Drive Power | Notebook Core Logic Rail |
|---|---|
Use Scenario: Supplies 1.8-V I/O and interface logic (e.g., SATA PHY, flash controller) in 2.5-inch HDDs where space and thermal headroom are constrained. IC Role / Device Role / Timing Role: Primary LDO delivering clean, low-noise 1.8 V with fast line/load transient response (<400 mV undershoot on 1-A step). Use Value: Enables use of compact 1-µF ceramic output cap instead of larger, higher-ESR alternatives - reduces board area by >30% and improves reliability. |
Use Scenario: Powers DDR2/DDR3 memory termination and chipset I/O banks in ultraportable notebooks with aggressive thermal envelopes. IC Role / Device Role / Timing Role: Fixed-output LDO providing stable 1.8 V with ±2.5% accuracy across –10°C to +70°C ambient - critical for signal integrity at high-speed interfaces. Use Value: Maintains regulation down to 2.75 V input (950 mV dropout), allowing operation until Li-ion cell discharges to ~3.0 V - extends usable battery runtime. |
| Battery-Powered Instrumentation | Portable Medical Sensor Node |
Use Scenario: Powers precision analog front-end (AFE) and microcontroller in handheld multimeters and oscilloscopes running from dual AA/AAA cells. IC Role / Device Role / Timing Role: Low-noise (0.7 µV/√Hz), low-IQ regulator supplying 1.8 V to ADC reference and digital logic - minimizes measurement drift and self-heating error. Use Value: 55 µA quiescent current enables multi-year shelf life in always-on monitoring modes - critical for field-deployed test equipment. |
Use Scenario: Provides regulated 1.8 V to ultra-low-power MCU and biosensor ASIC in wearable ECG/SpO₂ patches powered by coin-cell batteries. IC Role / Device Role / Timing Role: High-accuracy, thermally robust LDO ensuring consistent sensor biasing and digital timing across body-temperature variations (32–40°C skin contact). Use Value: Guaranteed ±5% output tolerance over –40°C to +125°C junction ensures clinical-grade accuracy without calibration drift - meets ISO 13485 system requirements. |
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 |
|---|---|---|---|
| TSS721AIDR | 1.8-V fixed, 1-A LDO with integrated reverse-voltage protection diode; 1.1-V dropout at 1 A; 120-µA IQ. | Designed for automotive 12-V systems with load-dump immunity; includes reverse-battery protection not present in LP38690DT-1.8. | Select when reverse-input fault tolerance is mandatory and higher dropout/quiessence are acceptable. |
| TPS7A0518PDQNR | 1.8-V fixed, 200-mA LDO in 1-mm² X2SON; 170-mV dropout at 200 mA; 25-µA IQ; no thermal shutdown. | Ultra-low-power, space-constrained applications (e.g., wearables); rated only to 85°C ambient - not industrial-grade. | Select for sub-200-mA loads where minimal footprint and nanoamp quiescence outweigh thermal robustness and current capability. |
Compared with TSS721AIDR and TPS7A0518PDQNR, the LP38690DT-1.8 uniquely balances 1-A current, industrial temperature range, ceramic-stability, and ultra-low ground current - making it the only choice for high-reliability, thermally demanding 1.8-V point-of-load regulation where enable control is unnecessary.
Availability
LP38690DT-1.8 is available at Aetrix Electronics and suitable for hard disk drives, notebook computers, battery-powered instrumentation, portable medical sensor nodes, and industrial edge controllers requiring stable component supply across long product lifecycles.
Supply support for LP38690DT-1.8 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 headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and high-performance power management solutions since 1930.
The LP38690 series belongs to TI's precision low-dropout linear regulator product line, engineered specifically for battery-powered and thermally constrained digital systems needing accurate, low-noise, ceramic-capacitor-compatible voltage regulation without enable complexity.
FAQ
What is the maximum input voltage for LP38690DT-1.8?
The absolute maximum input voltage for LP38690DT-1.8 is 12 V, but the recommended operating range is 2.7 V to 10 V per TI SNVS322M. Exceeding 10 V continuously risks accelerated parametric shift and reduced lifetime, especially at elevated temperatures. The device enters thermal shutdown before catastrophic failure, but sustained operation above 10 V is not characterized or guaranteed.
Does LP38690DT-1.8 require an enable pin connection?
No - LP38690DT-1.8 has no enable (EN) pin. It is a three-terminal device (IN, OUT, GND) that powers up automatically when VIN exceeds ~2.7 V. This distinguishes it from the LP38692 family, which adds EN functionality. For ON/OFF control of LP38690DT-1.8, the input supply must be actively switched.
Can LP38690DT-1.8 operate with a 1-µF output capacitor only?
Yes - LP38690DT-1.8 is explicitly characterized and guaranteed stable with a single 1-µF ceramic capacitor (X5R/X7R) at the output, per TI SNVS322M Figure 30 and Section 8.2.1. No minimum ESR is required, eliminating the need for bulkier, less reliable tantalum or electrolytic capacitors in space-constrained designs.
What is the thermal resistance of LP38690DT-1.8 in TO-252 package?
For LP38690DT-1.8 in TO-252 (DP) package, RθJA is 50.5°C/W (high-K board), RθJB is 29.7°C/W, and RθJC(bot) is 1.5°C/W. These values assume proper soldering of the exposed tab to ≥1 cm² internal or external ground plane. Without adequate copper, thermal performance degrades significantly - derating is required above 60°C ambient at full 1-A load.
Is LP38690DT-1.8 compatible with lead-free reflow profiles?
Yes - LP38690DT-1.8 is RoHS-compliant and qualified for standard Pb-free reflow per JEDEC J-STD-020. Its TO-252 package supports peak temperatures up to 260°C for 10 seconds. TI recommends using SnAgCu solder paste and verifying profile compliance with IPC-A-610 Class 2/3 acceptance criteria for production assembly.
LP38690DT-1.8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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):
- 1.6V @ 1A
- Current - Output:
- 1A
- 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
LP38690DT-1.8 FAQ
1.How can I place an order for LP38690DT-1.8 through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38690DT-1.8 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 LP38690DT-1.8 reliable?
The price and inventory of LP38690DT-1.8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP38690DT-1.8 is usually 5 days.
3.What payment methods are accepted for LP38690DT-1.8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38690DT-1.8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38690DT-1.8?
LP38690DT-1.8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38690DT-1.8 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 LP38690DT-1.8?
For technical support, including LP38690DT-1.8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38690DT-1.8 requirements.
6.How does Aetrix verify that LP38690DT-1.8 is sourced from the original manufacturer or authorized distributors?
All LP38690DT-1.8 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 LP38690DT-1.8 meets industry standards.
7.What is the process for return or replacement of LP38690DT-1.8?
All LP38690DT-1.8 units undergo pre-shipment inspection (PSI). If there is an issue with LP38690DT-1.8, 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 LP38690DT-1.8 part is unused and in its original packaging.
Return procedure for LP38690DT-1.8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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