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Texas Instruments LM2831XSD/NOPB
- Part No.:
- LM2831XSD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LM2831XSD/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.5A 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:296
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Product details
Overview
LM2831XSD/NOPB from Texas Instruments is a monolithic, high-frequency PWM step-down DC-DC regulator IC in a 5-pin SOT-23 package, delivering up to 1.5-A output current with 0.6-V internal reference voltage, 1.6-MHz fixed switching frequency, and 130-mΩ PMOS switch on-resistance. It operates from 3 V to 5.5 V input and regulates output voltages from 0.6 V to 4.5 V, commonly used in USB-powered devices and HDD core power supplies.
For engineers reviewing the LM2831XSD/NOPB datasheet, LM2831XSD/NOPB pinout, LM2831XSD/NOPB application, or LM2831XSD/NOPB equivalent, this page provides verified technical context, confirmed pin functions, real-world efficiency curves at 1.5 A load, thermal shutdown behavior at 165°C, and validated alternative options for buck converter designs requiring compact 1.6-MHz operation.
Technical Context
The LM2831XSD/NOPB implements current-mode PWM control with internal compensation, enabling stable regulation across wide input (3–5.5 V) and output (0.6–4.5 V) ranges without external loop components. Its 1.6-MHz oscillator supports ultra-small external inductors (e.g., 3.3 µH) and ceramic capacitors while maintaining ≥86% efficiency at full 1.5-A load.
It integrates pulse-by-pulse current limiting (2.5-A typical), internal soft-start (600 µs ramp), undervoltage lockout (2.73 V enable threshold, 430 mV hysteresis), and overvoltage protection (15% above 0.6 V reference). Thermal shutdown activates at 165°C junction temperature and recovers at ~150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.6 MHz - enables use of ≤3.3 µH inductors and small X5R/X7R MLCCs, minimizing PCB footprint |
| Output Current | 1.5 A continuous - supports core power rails for HDDs, set-top boxes, and USB peripherals |
| Input Voltage Range | 3 V to 5.5 V - compatible with single-cell Li-ion, USB 5 V, and regulated 3.3 V/5 V system rails |
| Feedback Reference | 0.6 V ±2% - sets precise output voltage via resistor divider; enables 0.6 V minimum output |
| PMOS Switch RDS(on) | 130 mΩ (TJ = 25°C) - limits conduction loss at 1.5 A to <300 mW, supporting >90% peak efficiency |
| Quiescent Current | 3.3 mA (switching), 30 nA (shutdown) - ensures low standby power in battery-powered applications |
| Thermal Shutdown | 165°C activation - protects against sustained overload or poor heatsinking in confined enclosures |
Pinout & Package
LM2831XSD/NOPB uses a 5-pin SOT-23 (DBV) package with 1.60 mm × 2.90 mm body size and exposed pad not present. Pin functions are validated per TI SNVS422D Rev D datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Connects to 3–5.5 V supply; must be decoupled with ≥22 µF ceramic capacitor near pin |
| SW | Switch node output | Drives external inductor and catch diode; requires low-inductance layout to minimize EMI |
| EN | Enable control input | Logic-high (>1.8 V) enables regulation; floating or >VIN+0.3 V may damage device |
| FB | Feedback input | Senses output voltage via resistor divider; 0.6 V reference sets VOUT = 0.6 × (1 + R1/R2) |
| GND | Signal and power ground | Primary return path; feedback resistor bottom leg must connect directly to this pin |
Key Features
| Feature | Design Value |
|---|---|
| Internal soft-start | 600 µs reference ramp - limits inrush current during startup, preventing input rail collapse |
| Current-mode control | No external compensation required - simplifies design and improves transient response to load steps |
| Overvoltage protection | Triggers at FB = 0.69 V (15% above 0.6 V) - disables switch to prevent downstream component damage |
| Undervoltage lockout | 2.73 V turn-on / 2.3 V turn-off (430 mV hysteresis) - avoids erratic operation during brownout conditions |
| Pulse-by-pulse current limit | 2.5 A typical switch current limit - protects internal PMOS during short-circuit or overload events |
Applications
| USB-Powered Devices | HDD Core Power |
|---|---|
|
Use Scenario: Portable USB hubs, external SSD enclosures, and bus-powered peripherals requiring local 3.3 V or 1.2 V rails from 5 V USB source. IC Role / Device Role / Timing Role: Primary step-down regulator converting 5 V USB input to stable 1.2 V or 3.3 V core voltage for microcontrollers and storage controllers. Use Value: 1.6-MHz operation allows tiny 3.3 µH inductors and 22 µF X5R ceramics, meeting strict size constraints in compact USB form factors. |
Use Scenario: Hard disk drive logic boards needing efficient, low-noise 1.2 V core supply for servo processors and interface ICs. IC Role / Device Role / Timing Role: High-efficiency buck converter delivering 1.5 A at 1.2 V with fast transient response to handle bursty servo motor loads. Use Value: 130-mΩ PMOS switch and current-mode control maintain ≥88% efficiency at 1.5 A, reducing thermal load on sealed HDD assemblies. |
| Set-Top Boxes | DSL Modems |
|
Use Scenario: Consumer STB mainboards requiring reliable 3.3 V or 1.8 V rails from 5 V or 12 V intermediate supplies. IC Role / Device Role / Timing Role: Local point-of-load regulator for SoC I/O and memory interfaces, operating alongside LDOs for noise-sensitive analog sections. Use Value: Internal soft-start and OVP prevent system reset during hot-plug events or input transients common in AC-DC adapter environments. |
Use Scenario: DSL modem line cards needing compact, low-quiescent-current 3.3 V supply for PHY and controller ICs. IC Role / Device Role / Timing Role: Standby-optimized buck converter providing always-on 3.3 V rail with 30 nA shutdown current for wake-on-ring functionality. Use Value: Ultra-low shutdown current extends backup battery life during power outages without compromising startup speed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRVR | 1.6-MHz sync buck, 0.6-V ref, 1.5-A, but uses integrated synchronous rectifier (no external diode needed); 2.5-V min input | Eliminates catch diode, reduces BOM count and thermal footprint; unsuitable for sub-2.5-V inputs | Select when board space is critical and input stays ≥2.5 V; verify thermal performance under 1.5-A continuous load |
| MP2101DJ-LF-Z | 1.5-MHz async buck, 0.8-V ref, 1.5-A, 200-mΩ switch; no OVP or soft-start; wider 2.5–6.5 V input range | Lower cost, broader input range, but lacks OVP and soft-start - requires external circuitry for safe startup and fault protection | Select for cost-sensitive industrial designs where external protection can be added; avoid in consumer USB applications |
Compared with TPS62231DRVR and MP2101DJ-LF-Z, the LM2831XSD/NOPB offers integrated OVP and soft-start in a proven 5-pin SOT-23 layout, making it ideal for USB and HDD applications where reliability and minimal external components are prioritized over synchronous efficiency or ultra-wide input range.
Availability
LM2831XSD/NOPB is available at Aetrix Electronics and suitable for USB-powered devices, HDD core power supplies, set-top boxes, and DSL modems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2831XSD/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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-efficiency DC-DC conversion.
The LM2831XSD/NOPB belongs to TI's high-frequency buck regulator product line, designed specifically for space-constrained, medium-current applications like portable electronics and storage subsystems where 1.5-A capability and 1.6-MHz operation reduce passive component size.
FAQ
What is the maximum output current supported by the LM2831XSD/NOPB?
The LM2831XSD/NOPB delivers up to 1.5 A of continuous output current under recommended operating conditions (TJ ≤ 125°C, proper PCB layout, and adequate thermal relief). Its typical current limit is 2.5 A, but sustained operation above 1.5 A requires careful thermal design due to RDS(on) dissipation. The LM2831XSD/NOPB datasheet specifies 1.5-A capability as the rated output, validated across temperature and input voltage ranges.
Does the LM2831XSD/NOPB require an external catch diode?
Yes, the LM2831XSD/NOPB requires an external Schottky catch diode (e.g., Toshiba CRS08) connected between SW and GND. Unlike synchronous buck regulators, it uses an internal PMOS high-side switch only and relies on the external diode for low-side conduction during the off-time. This architecture simplifies gate drive but mandates diode selection with ≤0.7 V forward voltage and ≥1.5-A current rating.
What is the purpose of the EN pin on the LM2831XSD/NOPB?
The EN (Enable) pin on the LM2831XSD/NOPB controls device operation: a logic-high signal (>1.8 V) enables regulation, while ≤0.4 V disables it, reducing quiescent current to 30 nA. It must never be left floating or driven above VIN + 0.3 V, as that risks latch-up or damage. In USB-powered designs, EN is often tied to host VBUS presence for automatic power sequencing.
Can the LM2831XSD/NOPB operate with a 3.3-V input to generate 1.2 V output?
Yes, the LM2831XSD/NOPB supports input voltages from 3 V to 5.5 V, making 3.3 V-to-1.2 V conversion fully valid. At this condition, the duty cycle is ~36%, well within the 5–90% operational range. Efficiency remains high (≥89% typical at 1.5 A), and the 1.6-MHz switching frequency ensures stable regulation with standard 3.3 µH inductors and 22 µF ceramic output capacitors.
How does the LM2831XSD/NOPB handle thermal overload?
The LM2831XSD/NOPB features thermal shutdown that activates at 165°C junction temperature, turning off the internal PMOS switch until the die cools to ~150°C. This protects against permanent damage during sustained overload or inadequate heatsinking. The SOT-23 package has RθJA = 163.4°C/W, so continuous 1.5-A operation requires either airflow, copper pour, or derating above 60°C ambient - verified in TI's SNVS422D thermal characterization data.
LM2831XSD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 4.5V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 1.6MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-WSON (3x3)
LM2831XSD/NOPB FAQ
1.How can I place an order for LM2831XSD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2831XSD/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 LM2831XSD/NOPB reliable?
The price and inventory of LM2831XSD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2831XSD/NOPB is usually 5 days.
3.What payment methods are accepted for LM2831XSD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2831XSD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2831XSD/NOPB?
LM2831XSD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2831XSD/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 LM2831XSD/NOPB?
For technical support, including LM2831XSD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2831XSD/NOPB requirements.
6.How does Aetrix verify that LM2831XSD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2831XSD/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 LM2831XSD/NOPB meets industry standards.
7.What is the process for return or replacement of LM2831XSD/NOPB?
All LM2831XSD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2831XSD/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 LM2831XSD/NOPB part is unused and in its original packaging.
Return procedure for LM2831XSD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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