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Texas Instruments LM2831XSD
- Part No.:
- LM2831XSD
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LM2831XSD.pdf
- Description:
- IC REG BUCK ADJ 1.5A 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
LM2831XSD from Texas Instruments is a monolithic, high-frequency PWM step-down DC-DC regulator in a 6-pin LLP package, delivering up to 1.5A output current with internal 150 mΩ PMOS switch, fixed 1.6 MHz switching frequency, and 0.6 V ±2% feedback reference voltage. It operates from 3.0 V to 5.5 V input and supports output voltages from 0.6 V to 4.5 V, targeting compact local power conversion in space-constrained USB-powered devices and HDD core supplies.
For engineers reviewing the LM2831XSD datasheet, LM2831XSD pinout, LM2831XSD application, or LM2831XSD equivalent, key selection criteria include its 1.6 MHz fixed-frequency operation, thermal shutdown at 165°C, 30 nA shutdown current, current-mode control architecture, and compatibility with ceramic output capacitors for fast transient response in embedded power rails.
Technical Context
The LM2831XSD employs current-mode PWM control with internal compensation, enabling stable regulation across wide load and line variations without external loop components. Its 1.6 MHz oscillator supports ultra-small inductors (e.g., 2.7 µH–3.3 µH) and chip-scale ceramic capacitors while maintaining <600 µs soft-start and cycle-by-cycle current limiting at 2.5 A (typ).
It integrates undervoltage lockout (UVLO rising threshold 2.90 V), overvoltage protection (15% above VFB), and thermal shutdown with 15°C hysteresis. The 6-pin LLP package features separate VIND and VINA pins for optimized power/ground separation, and a thermally enhanced DAP connected to system ground.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | Fixed 1.6 MHz - enables use of sub-3.3 µH inductors and eliminates need for bulk electrolytic output capacitance. |
| Output Current | 1.5 A continuous - sufficient for CPU core, FPGA I/O, or ASIC logic rail in portable electronics. |
| Input Voltage Range | 3.0 V to 5.5 V - matches single-cell Li-ion, USB 5V, or regulated 3.3V/5V system rails. |
| Feedback Reference | 0.600 V ±2% - sets precise output voltage via external resistor divider; supports down to 0.6 V output. |
| PMOS RDS(ON) | 150 mΩ (LLP-6 package) - determines conduction loss at full load; lower than SOT23-5 variant's 130 mΩ due to thermal trade-off. |
| Shutdown Current | 30 nA - enables battery-backed systems to maintain >1-year shelf life without significant drain. |
| Thermal Shutdown | 165°C junction temperature - protects against sustained overload or poor PCB thermal design; resumes at ~150°C. |
Pinout & Package
The LM2831XSD is housed in a thermally enhanced 6-pin LLP (Leadless Leadframe Package) with exposed die attach pad (DAP), optimized for low θJA (80°C/W) and θJC (18°C/W) when soldered to a 4-layer PCB with ≥4 thermal vias under the DAP.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (FB) | Feedback input | High-impedance node sensing output voltage via resistor divider; requires short trace routing to minimize noise coupling. |
| 2 (GND) | Signal and power ground | Reference for FB, EN, and internal circuitry; must be tied to low-impedance ground plane near input/output capacitor grounds. |
| 3 (SW) | Switch node | Connects to inductor and catch diode anode; carries high di/dt; requires minimal loop area to reduce EMI. |
| 4 (VIND) | Main power input | Supplies energy to internal PMOS switch; routed with wide, low-inductance trace adjacent to input capacitor. |
| 5 (VINA) | Control circuit supply | Provides bias for internal logic and error amplifier; must be connected directly to VIND on PCB to avoid instability. |
| 6 (EN) | Enable control | Logic-high active enable; threshold 1.8 V; must not float or exceed VINA + 0.3 V to prevent damage. |
| DAP | Die attach pad | Thermal path only - must be soldered to solid ground plane with ≥4 thermal vias; not electrically functional as GND. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables fast transient response (<10 µs recovery) and inherent cycle-by-cycle current limiting without external sense resistor. |
| Internal soft-start | Ramps VFB reference from 0 V to 0.6 V over ~600 µs, limiting inrush current into output capacitors during power-up. |
| Output overvoltage protection | Shuts off PMOS switch if FB exceeds 0.69 V (15% above 0.6 V), preventing damage to downstream 1.2 V or 1.8 V logic. |
| Separate VIND/VINA pins | Isolates high-current power path from sensitive control circuitry, improving PSRR and reducing noise-induced regulation error. |
| Thermally robust LLP-6 package | Exposes silicon die underside via DAP, achieving 18°C/W junction-to-case thermal resistance with proper PCB layout. |
Applications
| USB-Powered Devices | HDD Core Power |
|---|---|
|
Use Scenario: Portable SSDs and USB hubs requiring efficient 5 V-to-1.2 V/1.8 V conversion from limited bus power. IC Role / Device Role / Timing Role: Primary buck regulator supplying processor and NAND flash VCCQ/VCCIO rails. Use Value: 1.6 MHz operation allows 3.3 µH inductor and 2×22 µF X5R MLCCs, fitting within tight 12 mm × 12 mm board area. |
Use Scenario: 2.5-inch hard disk drives needing stable 1.2 V core voltage from 5 V SATA bus with minimal heat rise. IC Role / Device Role / Timing Role: Local point-of-load regulator for HDD controller ASIC, operating continuously under bursty write loads. Use Value: 150 mΩ RDS(ON) and 93% peak efficiency at 1.5 A reduce thermal load on small metal enclosure, avoiding fan requirement. |
| Set-Top Boxes | DSL Modems |
|
Use Scenario: Low-cost STB mainboard converting 5 V standby to 3.3 V for SoC I/O and memory interface. IC Role / Device Role / Timing Role: Secondary buck converter supporting always-on HDMI CEC and IR receiver functions. Use Value: 30 nA shutdown current ensures <1 µA system standby draw, meeting Energy Star Level 6 requirements. |
Use Scenario: DSL gateway powering PHY and DSP cores from 5 V wall adapter with strict EMI limits. IC Role / Device Role / Timing Role: High-frequency buck regulator feeding ADSL2+ line driver and analog front-end. Use Value: Fixed 1.6 MHz frequency places switching harmonics outside DSL band (0–2.2 MHz), simplifying EMI filter design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2831YSD | Fixed 550 kHz switching frequency; 130 mΩ RDS(ON) in same LLP-6 package; higher quiescent current (4.5 mA vs 5 mA in active mode). | Better efficiency at light loads due to lower RDS(ON), but requires larger 4.7 µH inductor and more board area. | Select LM2831YSD when board space permits larger magnetics and thermal budget allows higher junction temperature rise. |
| TPS62231DRVR | 1.6 MHz synchronous buck; 0.6 V reference; 1.8 A output; integrated MOSFETs; 17 µA quiescent current in PFM mode. | Higher integration eliminates external catch diode; supports automatic PFM/PWM mode transition for wider load efficiency optimization. | Choose TPS62231DRVR when minimizing BOM count and extending battery runtime in portable designs outweighs cost sensitivity. |
Compared with LM2831YSD, the LM2831XSD trades slightly higher conduction loss for smaller passive size; versus TPS62231DRVR, it offers lower system cost with discrete diode flexibility but requires external diode placement and layout care.
Availability
LM2831XSD is available at Aetrix Electronics and suitable for USB-powered devices, HDD core supplies, set-top boxes, and DSL modems requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2831XSD 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 belongs to TI's high-frequency buck regulator product line, designed specifically for space-constrained, battery-sensitive applications where small inductors, low quiescent current, and thermal robustness are critical.
FAQ
What is the maximum output current capability of the LM2831XSD?
The LM2831XSD delivers up to 1.5 A continuous output current under typical thermal conditions (TA = 25°C, 4-layer PCB with thermal vias). Its current limit is guaranteed at 1.8 A minimum and typically 2.5 A, allowing brief peak loads beyond 1.5 A without shutdown-provided junction temperature remains below 165°C. Derating is required above 85°C ambient.
Does the LM2831XSD require an external catch diode, and what specifications are critical?
Yes, the LM2831XSD requires an external Schottky catch diode. Critical specs include forward voltage ≤0.45 V at 1.5 A (to maximize efficiency), reverse voltage rating ≥6 V (for 5.5 V input margin), and average current rating ≥1.5 A. Recommended parts include Toshiba CRS08 or Diodes Inc. AP1510SG, both validated in TI's LM2831X design examples.
How does the LM2831XSD handle input undervoltage conditions?
The LM2831XSD incorporates undervoltage lockout (UVLO) with a rising threshold of 2.90 V (typ) and hysteresis of 0.43 V. When VIN drops below 2.3 V (typ), the device disables the PMOS switch and enters ultra-low-power shutdown (30 nA). This prevents erratic operation during brown-out and ensures clean restart once VIN exceeds 2.90 V.
Can the LM2831XSD be used with ceramic output capacitors exclusively?
Yes, the LM2831XSD is fully compatible with multilayer ceramic capacitors (MLCCs) for both input and output filtering. Its internal compensation and current-mode control ensure stability with ≥22 µF total X5R/X7R ceramic output capacitance. Low-ESR MLCCs improve transient response and eliminate need for tantalum or electrolytic alternatives.
What is the purpose of the separate VIND and VINA pins on the LM2831XSD?
VIND supplies power to the internal PMOS switch, while VINA powers the control circuitry (error amplifier, oscillator, logic). Connecting them externally on the PCB isolates high-current switching noise from sensitive analog blocks, improving regulation accuracy and PSRR-especially critical in noise-sensitive applications like audio or RF subsystems powered from the same 5 V rail.
LM2831XSD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-WDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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 FAQ
1.How can I place an order for LM2831XSD through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2831XSD 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 reliable?
The price and inventory of LM2831XSD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2831XSD is usually 5 days.
3.What payment methods are accepted for LM2831XSD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2831XSD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2831XSD?
LM2831XSD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2831XSD 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?
For technical support, including LM2831XSD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2831XSD requirements.
6.How does Aetrix verify that LM2831XSD is sourced from the original manufacturer or authorized distributors?
All LM2831XSD 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 meets industry standards.
7.What is the process for return or replacement of LM2831XSD?
All LM2831XSD units undergo pre-shipment inspection (PSI). If there is an issue with LM2831XSD, 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 part is unused and in its original packaging.
Return procedure for LM2831XSD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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