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Texas Instruments LP38690SDX-ADJ/NOPB
- Part No.:
- LP38690SDX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP38690SDX-ADJ/NOPB.pdf
- Description:
- IC REG LINEAR POS ADJ 1A 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,895
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Product details
Overview
LP38690SDX-ADJ/NOPB from Texas Instruments is a 1-A adjustable-output low-dropout CMOS linear regulator with PMOS pass transistor, stable with 1-µF ceramic output capacitors, 450-mV dropout at 1 A (5-V output), and ±2.5% ADJ pin voltage accuracy at 25°C - used in battery-powered portable instrumentation and notebook computer power rails.
For engineers reviewing the LP38690SDX-ADJ/NOPB datasheet, LP38690SDX-ADJ/NOPB pinout, LP38690SDX-ADJ/NOPB application, or LP38690SDX-ADJ/NOPB equivalent, key selection criteria include dropout voltage vs. load current, ground pin current under full load, thermal performance in WSON-6, ADJ pin leakage (<100 nA), and compatibility with ultralow-ESR ceramic capacitors down to 0 Ω.
Technical Context
The LP38690SDX-ADJ/NOPB uses a PMOS pass element enabling ground pin current ≤55 µA across full load, input voltage, and temperature range - eliminating base-drive losses typical of NPN-based regulators. Its trimmed bandgap reference ensures 2.5% VADJ accuracy over –40°C to +125°C.
It integrates foldback current limiting (450 mA at VIN–VOUT > 5 V; 1500 mA at VIN–VOUT < 4 V) and thermal shutdown activation at 160°C with 10°C hysteresis. Unlike the LP38692-ADJ, it lacks an enable pin and includes a no-connect (NC) terminal on Pin 3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | 1 A maximum continuous - supports high-current digital loads without external heat sinking in ambient ≤85°C with proper PCB copper area. |
| Dropout voltage | 450 mV typical at 1 A, 5-V output - enables regulation from 5.45-V input, critical for Li-ion single-cell systems near end-of-discharge. |
| VADJ accuracy | ±2.5% at 25°C (1.219–1.281 V) - sets output voltage tolerance via R1/R2 divider; enables 1.25–9-V programmable range with <0.5% error contribution from reference. |
| Ground pin 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 (2.7–4.2 V), 3.3-V/5-V rails, and industrial 9-V supplies. |
| Thermal resistance | RθJA = 50.6°C/W (WSON-6, 4 thermal vias) - allows full 1-A operation up to +85°C ambient with standard 2-layer PCB layout. |
| PSRR | 55 dB at 120 Hz - suppresses ripple from upstream switching converters feeding the LDO input. |
| Output noise | 0.7 µV/√Hz (10 Hz–10 kHz, 3.3-V output) - suitable for noise-sensitive analog circuitry like ADC references or RF bias rails. |
Pinout & Package
LP38690SDX-ADJ/NOPB is housed in a 6-pin WSON package (3.00 mm × 3.00 mm) with exposed thermal pad (DAP) soldered to PCB ground plane for enhanced thermal dissipation. Pin 3 is NC (no internal connection); EN pin is absent - distinguishing it from LP38692-ADJ.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pins 1, 6) | Input supply connection | Both pins must be tied together externally; each rated for ≤250 mA - enables robust current handling and low-inductance input path. |
| GND (Pin 2) | Circuit ground reference | Primary ground return for control circuitry; thermally coupled to die - requires direct connection to large copper pour for thermal management. |
| NC (Pin 3) | No internal connection | Must be left unconnected; not electrically active - avoids unintended coupling or ESD paths. |
| ADJ (Pin 4) | Feedback reference node | Sets output voltage via external R1/R2 divider; 100-nA max leakage ensures minimal divider current error and noise susceptibility. |
| OUT (Pin 5) | Regulated output | Delivers precise, low-noise DC output; requires local 1-µF ceramic capacitor with ESR 0–100 mΩ for stability. |
| DAP (Exposed pad) | Thermal and electrical ground | Must be soldered to PCB ground plane with ≥4 thermal vias - reduces junction-to-board thermal resistance to 24.9°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| PMOS pass transistor | Eliminates DC base-drive current, keeping ground pin current ≤55 µA regardless of load - extends battery life in always-on portable devices. |
| Ceramic-capacitor stability | Stable with 1-µF ceramic output capacitors (0–100 mΩ ESR) - removes need for bulkier, higher-ESR tantalum or aluminum electrolytic capacitors. |
| Wide input range | Operates from 2.7 V to 10 V - supports single-cell Li-ion, multi-cell alkaline, and fixed industrial rails without redesign. |
| High-temp guaranteed specs | Full electrical specifications ensured from –40°C to +125°C - qualified for automotive under-hood and industrial control environments. |
| Foldback current limit | Self-protecting behavior: limits to 450 mA when VIN–VOUT > 5 V, rising to 1500 mA when differential drops below 4 V - prevents thermal runaway during short-circuit events. |
Applications
| Hard Disk Drive Power Rail | Notebook Computer Core Voltage |
|---|---|
Use Scenario: Supplies regulated 3.3-V or 5-V rail to HDD spindle motor driver ICs and interface logic during spin-up and data transfer. IC Role / Device Role / Timing Role: Low-noise, high-current LDO delivering stable voltage despite rapid load transients and varying input from buck converter. Use Value: 0.7 µV/√Hz output noise prevents bit errors; 450-mV dropout enables operation from 5.45-V input as battery discharges. | Use Scenario: Powers CPU I/O or chipset auxiliary rails requiring precise, low-ripple voltage in space-constrained laptop motherboards. IC Role / Device Role / Timing Role: Adjustable-output LDO generating custom voltages (e.g., 1.8 V, 2.5 V) from shared 5-V or 3.3-V intermediate bus. Use Value: WSON-6 footprint (3×3 mm) saves board area; 50.6°C/W RθJA allows full 1-A load without heatsink in thin-profile designs. |
| Battery-Powered Portable Instrumentation | Industrial Sensor Signal Conditioning |
Use Scenario: Powers precision ADCs, op-amps, and microcontrollers in handheld multimeters or gas analyzers operating from 2xAA or Li-ion cells. IC Role / Device Role / Timing Role: Primary voltage regulator maintaining accuracy and low quiescent current across wide battery voltage range (2.7–4.2 V). Use Value: 55-µA ground current minimizes standby drain; ±2.5% VADJ accuracy ensures stable reference for 16-bit measurement systems. | Use Scenario: Provides clean, stable 5-V or 3.3-V supply to analog front-end circuits in factory-floor pressure/temperature transmitters. IC Role / Device Role / Timing Role: Isolation-stage LDO decoupling sensor signal chain from noisy digital or motor-control domains. Use Value: 55-dB PSRR at 120 Hz rejects ripple from nearby SMPS; –40°C to +125°C guaranteed operation supports uncooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable-output LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPL7407LPGEDR | 7-channel high-side driver with integrated 500-mA LDO; fixed 3.3-V output; no ADJ pin; larger 16-pin HTSSOP package. | Designed for LED/motor driving with auxiliary bias rail - not a standalone adjustable LDO. | Select only if system requires integrated driver + fixed LDO; not suitable for programmable voltage or space-constrained layouts. |
| TPS7A4701RGWR | 1-A ultra-low-noise (4-µVRMS) LDO with 20-µA IQ; adjustable output; WQFN-20 package; higher cost and larger footprint. | Targeted at ultra-high-precision analog (audio, medical) - over-specified for general-purpose portable power. | Choose only when sub-1-µV/√Hz noise or <20-µA quiescent current is mandatory; otherwise LP38690SDX-ADJ/NOPB offers better cost/performance balance. |
Compared with TPL7407LPGEDR and TPS7A4701RGWR, LP38690SDX-ADJ/NOPB delivers optimal trade-off of adjustability, WSON-6 compactness, 1-A capability, and ceramic-capacitor compatibility - making it the preferred choice for cost-sensitive, space-constrained battery-powered systems requiring 1.25–9-V outputs.
Availability
LP38690SDX-ADJ/NOPB is available at Aetrix Electronics and suitable for hard disk drive power rails, notebook computer core voltage generation, and battery-powered portable instrumentation requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LP38690SDX-ADJ/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 specializing in analog, embedded processing, and power management ICs, with leadership in high-reliability, thermally optimized power solutions.
The LP38690SDX-ADJ/NOPB belongs to TI's LP3869x family of low-dropout linear regulators designed specifically for portable, battery-powered digital systems demanding fast start-up, ceramic-capacitor stability, and guaranteed operation across –40°C to +125°C.
FAQ
What is the maximum output current supported by LP38690SDX-ADJ/NOPB?
LP38690SDX-ADJ/NOPB supports up to 1 A of continuous output current. This rating assumes proper thermal management - specifically, use of the exposed thermal pad (DAP) soldered to a PCB ground plane with at least four thermal vias. At ambient temperatures above 85°C, derating per the 50.6°C/W junction-to-ambient thermal resistance is required to maintain safe junction temperature.
Does LP38690SDX-ADJ/NOPB include an enable (EN) pin?
No, LP38690SDX-ADJ/NOPB does not include an enable pin. It is always active when input voltage is applied within specification (2.7–10 V). The LP38692-ADJ variant provides an EN pin; LP38690SDX-ADJ/NOPB is functionally identical except for the absence of EN and presence of NC on Pin 3 - making it suitable for simpler, always-on applications.
What output capacitor value and type are required for stable operation of LP38690SDX-ADJ/NOPB?
LP38690SDX-ADJ/NOPB requires a minimum 1-µF ceramic output capacitor with ESR between 0 mΩ and 100 mΩ. X7R or X5R dielectric ceramics are strongly recommended for stable capacitance across temperature and voltage. Tantalum capacitors may be used but must meet the same ESR range and require careful derating due to ESR increase at low temperatures.
How is the output voltage set on LP38690SDX-ADJ/NOPB?
The output voltage of LP38690SDX-ADJ/NOPB is set using two external resistors (R1 and R2) connected to the ADJ pin, following the equation VOUT = VADJ × (1 + R1/R2), where VADJ = 1.25 V (±2.5%). TI recommends R2 ≤12 kΩ to ensure ≥100 µA minimum load current and R2 ≤100 kΩ to minimize noise susceptibility at the ADJ node.
What is the dropout voltage of LP38690SDX-ADJ/NOPB at 1 A and 3.3-V output?
At 1 A load and 3.3-V output, the dropout voltage of LP38690SDX-ADJ/NOPB is 650–1000 mV (typical 650 mV). This means the input voltage must be at least 3.95 V to maintain regulation. Dropout increases with higher output voltages and load currents - e.g., 800–1300 mV at 2.5-V output and 1 A.
LP38690SDX-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 10V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 9V
- 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:
- 6-WSON (3x3)
LP38690SDX-ADJ/NOPB FAQ
1.How can I place an order for LP38690SDX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38690SDX-ADJ/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 LP38690SDX-ADJ/NOPB reliable?
The price and inventory of LP38690SDX-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP38690SDX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LP38690SDX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38690SDX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38690SDX-ADJ/NOPB?
LP38690SDX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38690SDX-ADJ/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 LP38690SDX-ADJ/NOPB?
For technical support, including LP38690SDX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38690SDX-ADJ/NOPB requirements.
6.How does Aetrix verify that LP38690SDX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LP38690SDX-ADJ/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 LP38690SDX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LP38690SDX-ADJ/NOPB?
All LP38690SDX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP38690SDX-ADJ/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 LP38690SDX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LP38690SDX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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