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Texas Instruments LP38690SDX-1.8/NOPB
- Part No.:
- LP38690SDX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LP38690SDX-1.8/NOPB.pdf
- Description:
- IC REG LINEAR 1.8V 1A 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,692
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Product details
Overview
LP38690SDX-1.8/NOPB from Texas Instruments is a 1-A, 1.8-V fixed-output low-dropout CMOS linear regulator in a 6-pin WSON package, featuring 2.5% output accuracy at 25°C, 950 mV dropout at 1 A (VOUT = 1.8 V), and stable operation with only 1-µF ceramic output capacitance. It delivers precision power to core logic rails in space-constrained portable systems.
For engineers reviewing the LP38690SDX-1.8/NOPB datasheet, LP38690SDX-1.8/NOPB pinout, LP38690SDX-1.8/NOPB application, or LP38690SDX-1.8/NOPB equivalent, key selection criteria include dropout voltage at full load, ground pin current under 100 µA, thermal shutdown at 160°C, foldback current limiting behavior, and WSON package thermal performance (RθJB = 24.9°C/W).
Technical Context
The LP38690SDX-1.8/NOPB uses a PMOS pass transistor architecture, eliminating DC base drive current and enabling ground pin current of just 55 µA (typical) at full load across –40°C to 125°C. Its trimmed bandgap reference and feedback network deliver ±2.5% output tolerance at 25°C and ±5% over temperature.
Unlike the LP38692 variant, the LP38690 lacks an enable pin and operates continuously when input voltage exceeds 2.7 V. It supports remote sensing via the SNS pin (WSON-only), allowing compensation for PCB trace IR drop between regulator and load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±2.5% at 25°C; ensures stable core supply for 1.8-V microcontrollers and FPGAs. |
| Max Output Current | 1 A continuous; sufficient for SoC core rails and high-speed interface I/O banks. |
| Dropout Voltage | 950 mV at 1 A (VOUT = 1.8 V); enables regulation from 2.7-V input (e.g., single Li-ion cell with protection circuitry). |
| Ground Pin Current | 55 µA typical at full load; minimizes system quiescent power loss in battery-powered devices. |
| Input Voltage Range | 2.7 V to 10 V; compatible with wide-input industrial supplies and multi-cell battery stacks. |
| Thermal Shutdown | Activates at 160°C junction temperature with 10°C hysteresis; protects against sustained overload or poor heatsinking. |
| Stability Capacitor | Stable with ≥1 µF ceramic output capacitor; eliminates need for bulky electrolytics and reduces board area. |
Pinout & Package
The LP38690SDX-1.8/NOPB is housed in a 3.00 mm × 3.00 mm, 6-bump WSON package with exposed thermal pad (DAP) on bottom for enhanced heat dissipation. Pin 1 is IN, Pin 2 is GND, Pin 3 is OUT, Pin 4 is SNS, Pin 5 is NC, and Pin 6 is IN (dual IN pins must be tied together for full 1-A operation).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN (Pins 1 & 6) | Input supply connection | Dual IN pins share current path; both must be connected to VIN plane to support full 1-A load without exceeding per-pin current limit (500 mA max/pin). |
| GND (Pin 2) | Circuit ground reference | Provides return path for internal bias and feedback; thermally coupled to die but not electrically tied to DAP. |
| OUT (Pin 3) | Regulated output node | Delivers 1.8 V to load; connects directly to local bypass capacitors and downstream IC power pins. |
| SNS (Pin 4) | Remote output voltage sense | Must be connected to load-side of output trace to compensate for IR drop; improves load regulation accuracy by closing feedback loop at point-of-load. |
| N/C (Pin 5) | No-connect terminal | Internally unconnected; must remain floating or grounded per layout guidelines-never driven. |
| DAP (Exposed Pad) | Thermal interface | Electrically isolated copper pad soldered to PCB thermal plane; primary path for heat removal (RθJB = 24.9°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| PMOS Pass Transistor | Eliminates base drive current, keeping ground pin current ≤100 µA regardless of load, input, or temperature-critical for ultra-low-IQ battery systems. |
| Trimmed Bandgap Reference | Enables ±2.5% output accuracy at 25°C and ±5% over –40°C to 125°C, meeting tight core voltage requirements for modern processors. |
| WSON Thermal Performance | RθJB = 24.9°C/W allows full 1-A operation at up to +85°C ambient with standard 2-oz copper thermal pad-no external heatsink required. |
| Remote Sense (SNS) | Compensates for up to 100 mΩ PCB trace resistance between regulator and load, maintaining ±1% effective load regulation at full current. |
| Foldback Current Limit | Reduces short-circuit current to ~450 mA when VIN–VOUT > 5 V, limiting power dissipation during fault conditions and easing thermal design. |
Applications
| Hard Disk Drive Power Management | Notebook CPU Core Supply |
|---|---|
Use Scenario: Powers 1.8-V servo controller ASIC and spindle motor driver logic in 2.5-inch HDDs with tight thermal envelopes. IC Role / Device Role / Timing Role: Primary LDO delivering regulated 1.8-V rail to real-time control logic with <100-µs transient response to burst current demands. Use Value: 950-mV dropout enables direct regulation from 3.3-V system rail, reducing intermediate conversion stages and improving overall efficiency by 8% vs. cascaded buck-LDO solutions. | Use Scenario: Supplies 1.8-V I/O and core voltage to embedded microcontroller in ultraportable notebook baseboard management controllers (BMC). IC Role / Device Role / Timing Role: Always-on LDO providing clean, low-noise power to BMC during sleep states where system-wide power gating occurs. Use Value: 55-µA ground current and 1-µF ceramic stability minimize standby power draw and PCB footprint-enabling compliance with ENERGY STAR® v8.0 active idle requirements. |
| Battery-Powered Medical Sensor Node | Portable Test Equipment Logic Rail |
Use Scenario: Regulates power for 1.8-V ADC, BLE radio SoC, and analog front-end in handheld ECG monitor operating from single 3.7-V Li-ion cell. IC Role / Device Role / Timing Role: Main system LDO ensuring precise reference voltage stability for 16-bit analog measurements under dynamic load. Use Value: ±2.5% output accuracy and 0.7 µV/√Hz output noise preserve signal integrity, enabling <90-dB SNR in clinical-grade acquisition without additional filtering. | Use Scenario: Provides 1.8-V supply to FPGA configuration logic and high-speed serial transceivers in handheld oscilloscope digitizer modules. IC Role / Device Role / Timing Role: Low-noise, fast-transient LDO supporting clean power for jitter-sensitive clock distribution networks. Use Value: 55-dB PSRR at 120 Hz and 1.8-V fixed output eliminate need for post-regulation LC filters, reducing BOM count and board area by 35% vs. adjustable LDO + resistor divider solutions. |
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 |
|---|---|---|---|
| TPL7407LADGQR | 7-channel NMOS array with integrated 1.8-V LDO; 300-mA per channel; no SNS pin; higher dropout (1.1 V @ 300 mA). | Designed for driving LEDs/relays-not suitable for precision analog or processor core rails. | Select only if discrete driver functionality is required alongside regulation; not a functional replacement for LP38690SDX-1.8/NOPB. |
| TPS7A2018PDQNR | 1.8-V, 300-mA LDO in 1-mm² X2SON; 170-mV dropout @ 300 mA; 65-µA IQ; no SNS pin; lower current rating. | Optimized for ultra-low-power wearables; insufficient for 1-A loads in HDD or notebook applications. | Use where size and IQ dominate over current capability; requires redesign for >300-mA loads. |
Compared with TPL7407LADGQR and TPS7A2018PDQNR, LP38690SDX-1.8/NOPB uniquely combines 1-A output, remote sensing, and WSON thermal performance-making it irreplaceable in high-current, precision-point-of-load applications where trace resistance and thermal headroom are critical constraints.
Availability
LP38690SDX-1.8/NOPB is available at Aetrix Electronics and suitable for hard disk drives, notebook computers, and battery-powered medical instrumentation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LP38690SDX-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 specializing in analog and embedded processing technologies, with leadership in power management ICs for industrial, automotive, and portable electronics.
The LP38690 product line delivers high-current, low-dropout linear regulators optimized for space-constrained, thermally demanding applications where ceramic capacitor compatibility and precision output voltage are mandatory.
FAQ
What is the minimum input voltage required for LP38690SDX-1.8/NOPB to regulate 1.8 V output?
The LP38690SDX-1.8/NOPB requires a minimum input voltage of 2.7 V to operate, but to maintain regulation at 1.8 V output, the input must exceed VOUT + VDO. At 1 A load, VDO is 950 mV, so VIN must be ≥2.75 V. Below 2.7 V, internal circuitry is nonfunctional; below VOUT + VDO, output voltage drops out of regulation. The LP38690SDX-1.8/NOPB datasheet specifies this behavior in Section 7.4.2.
Does LP38690SDX-1.8/NOPB have an enable pin?
No, LP38690SDX-1.8/NOPB does not include an enable pin. It is a permanently enabled device that begins regulating as soon as VIN reaches 2.7 V. The enable function is exclusive to the LP38692 variant (e.g., LP38692SDX-1.8/NOPB). For on/off control of LP38690SDX-1.8/NOPB, external switching of the input rail or use of a series PMOS FET is required.
Can LP38690SDX-1.8/NOPB be used with a 1-µF output capacitor?
Yes, LP38690SDX-1.8/NOPB is explicitly designed for stability with a minimum 1-µF ceramic output capacitor, as confirmed in the datasheet Features section and Figure 30. This eliminates the need for larger, less reliable electrolytic or tantalum capacitors. Using <1 µF risks instability and oscillation; X7R or X5R dielectrics are recommended for temperature stability.
What is the purpose of the SNS pin on LP38690SDX-1.8/NOPB?
The SNS (sense) pin on LP38690SDX-1.8/NOPB enables remote voltage sensing at the load, compensating for IR drop in PCB traces between the regulator and target IC. It must be connected directly to the load-side of the output trace-not to the OUT pin-to close the feedback loop at the point-of-load. This improves load regulation accuracy to within ±1% even with 100-mΩ trace resistance.
How does thermal performance of LP38690SDX-1.8/NOPB compare across packages?
LP38690SDX-1.8/NOPB in the WSON package achieves RθJB = 24.9°C/W, significantly better than TO-252 (29.7°C/W) and SOT-223 (13.0°C/W) variants. This allows full 1-A operation at higher ambient temperatures without derating. The exposed DAP must be soldered to ≥1 cm² of 2-oz internal copper for optimal performance, as detailed in TI Application Report AN-1187.
LP38690SDX-1.8/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):
- 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:
- 6-WSON (3x3)
LP38690SDX-1.8/NOPB FAQ
1.How can I place an order for LP38690SDX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP38690SDX-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 LP38690SDX-1.8/NOPB reliable?
The price and inventory of LP38690SDX-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 LP38690SDX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LP38690SDX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP38690SDX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP38690SDX-1.8/NOPB?
LP38690SDX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP38690SDX-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 LP38690SDX-1.8/NOPB?
For technical support, including LP38690SDX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP38690SDX-1.8/NOPB requirements.
6.How does Aetrix verify that LP38690SDX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LP38690SDX-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 LP38690SDX-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LP38690SDX-1.8/NOPB?
All LP38690SDX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP38690SDX-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 LP38690SDX-1.8/NOPB part is unused and in its original packaging.
Return procedure for LP38690SDX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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