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Texas Instruments LM2831XMFX
- Part No.:
- LM2831XMFX
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2831XMFX.pdf
- Description:
- IC REG BUCK ADJ 1.5A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,684
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Product details
Overview
LM2831XMFX from Texas Instruments is a monolithic, high-frequency PWM step-down DC-DC regulator in a 5-pin SOT-23 package, delivering up to 1.5A output current with internal 130 mΩ PMOS switch, fixed 1.6 MHz switching frequency, and 0.6 V ±2% internal reference voltage. It serves as a compact local voltage converter for space-constrained applications such as USB-powered devices and set-top boxes.
For engineers reviewing the LM2831XMFX datasheet, LM2831XMFX pinout, LM2831XMFX application, or LM2831XMFX equivalent, key selection criteria include input voltage range (3.0–5.5 V), output voltage adjustability (0.6–4.5 V), thermal shutdown (165°C), ultra-low shutdown current (30 nA), and current-mode control with internal compensation.
Technical Context
The LM2831XMFX implements constant-frequency current-mode PWM control with an internally compensated error amplifier and a 1.6 MHz oscillator. Its architecture supports fast transient response and stable regulation across load and line variations without external compensation components.
It integrates pulse-by-pulse current limiting (typ. 2.5 A), soft-start (≈600 µs ramp), output overvoltage protection (15% above VFB), and undervoltage lockout (2.73 V rising threshold, 430 mV hysteresis). The 130 mΩ PMOS switch enables high power density while maintaining up to 93% efficiency at full load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.6 MHz - enables use of sub-4 µH inductors and small ceramic capacitors, minimizing PCB area. |
| Input Voltage Range | 3.0 V to 5.5 V - compatible with single-cell Li-ion, USB 5 V, and 3.3 V/5 V system rails. |
| Output Voltage Range | 0.6 V to 4.5 V - adjustable via external resistor divider; supports core voltages down to Vcore levels. |
| Max Output Current | 1.5 A - sustained delivery enabled by low RDS(ON) (130 mΩ) PMOS switch and thermal shutdown (165°C). |
| Feedback Reference | 0.600 V ±2% - precise internal reference enabling ±1% output accuracy with proper resistor tolerance. |
| Quiescent Current | 5 mA (active), 30 nA (shutdown) - ensures minimal battery drain in portable systems during standby. |
| Duty Cycle Range | 5% to 94% - supports wide VIN-to-VOUT ratios, including 5 V → 0.6 V conversion at D ≈ 12%. |
Pinout & Package
LM2831XMFX uses the 5-pin SOT-23-5 package (NSC drawing MF05A, top mark SKYB), with exposed pad not present. Thermal performance: θJA = 118°C/W (still air, 2 oz copper, 4-layer board).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch node | Connects to inductor and catch diode cathode; carries high di/dt switching current - requires short, low-inductance routing. |
| 2 (GND) | Signal and power ground | Reference for feedback network and internal circuitry; bottom resistor of FB divider must be placed adjacent to this pin. |
| 3 (FB) | Feedback input | High-impedance node sensing output voltage via resistor divider; sensitive to noise - trace must be short and shielded from SW/VIN. |
| 4 (EN) | Enable control | Logic-high active enable; floating or >VIN+0.3 V violates absolute max rating - requires pull-up or controlled logic drive. |
| 5 (VIN) | Power input | Supplies both control circuitry and PMOS switch; requires local 22 µF ceramic input capacitor with low ESL. |
Key Features
| Feature | Design Value |
|---|---|
| Internal soft-start | Ramps VFB reference from 0 V to 0.6 V over ~600 µs, limiting inrush current into output capacitance. |
| Current-mode PWM control | Enables inherent cycle-by-cycle current limiting and stable operation without external compensation components. |
| Output overvoltage protection | Disables switch when FB exceeds 15% above 0.6 V, preventing damage to downstream loads during feedback fault. |
| Thermal shutdown | Halts switching at 165°C junction temperature and resumes only after cooling to ~150°C, protecting against sustained overload. |
| Ultra-low shutdown current | 30 nA enables multi-year battery life in always-on, intermittently powered applications like IoT sensors. |
Applications
| Local 5V to Vcore Conversion | USB-Powered Devices |
|---|---|
Use Scenario: Regulating 5 V USB supply down to 1.2 V or 0.9 V for microcontroller core logic in portable instrumentation. IC Role / Device Role / Timing Role: Primary step-down regulator providing tightly regulated, low-noise Vcore with fast load transient response. Use Value: Enables direct USB bus powering without external LDO post-regulation, reducing BOM count and board area. |
Use Scenario: Powering FPGA I/O banks or USB PHY circuitry from a 5 V USB port in consumer accessories. IC Role / Device Role / Timing Role: Efficient buck converter supplying 3.3 V rail with <5 mV load regulation and <10 µs recovery from 1 A step load. Use Value: Maintains stable operation under dynamic USB host negotiation and enumeration events without brownout. |
| HDD Core Power | Set-Top Box SoC Supply |
Use Scenario: Delivering 1.1 V @ 1.5 A to HDD controller ASIC during spin-up and read/write bursts. IC Role / Device Role / Timing Role: High-current, high-frequency DC-DC stage handling peak currents exceeding 1.2 A with <100 µs transient response. Use Value: Prevents voltage droop-induced command timeout errors during mechanical actuator activation. |
Use Scenario: Generating 1.8 V for video decoder SoC in cable/satellite STB with ambient temperature up to 70°C. IC Role / Device Role / Timing Role: Thermally robust regulator operating continuously at 85% efficiency with junction temperature maintained below 125°C. Use Value: Eliminates need for heatsinking or airflow, supporting fanless enclosure design and long-term reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3 MHz fixed frequency, 2 A output, 2.5–6 V input, integrated synchronous rectification. | Higher efficiency (>95%) and lower output ripple due to synchronous topology; requires no external catch diode. | Select when higher current, tighter regulation, or reduced component count outweighs cost sensitivity. |
| MP2101DQ-LF-Z | 1.5 MHz frequency, 1.5 A output, 2.5–5.5 V input, 0.8 V reference, smaller 2 mm × 2 mm QFN-8 package. | Lower minimum input voltage supports single-cell LiFePO4 (2.8 V); QFN offers better thermal performance than SOT-23. | Select when board space is critical or input voltage may dip below 3.0 V during battery discharge. |
Compared with LM2831XMFX, TPS62130ARGTR delivers higher efficiency and integration but lacks UVLO hysteresis and has different enable logic; MP2101DQ-LF-Z offers wider input range and superior thermal resistance but requires external compensation for stability across all loads.
Availability
LM2831XMFX is available at Aetrix Electronics and suitable for USB-powered devices, set-top box SoC supplies, and HDD core power applications requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2831XMFX 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 and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.
The LM2831 series was developed specifically for high-density, high-efficiency point-of-load DC-DC conversion in portable and space-constrained electronics, emphasizing minimal external component count and robust protection features.
FAQ
What is the maximum output current capability of the LM2831XMFX?
The LM2831XMFX is rated for continuous 1.5 A output current under typical thermal conditions (θJA = 118°C/W, TA ≤ 85°C). Its internal 130 mΩ PMOS switch and thermal shutdown at 165°C enable reliable operation at full load; peak current limit is typically 2.5 A with pulse-by-pulse protection. Derating is required above 85°C ambient or with poor PCB thermal design.
Does the LM2831XMFX require external compensation components?
No, the LM2831XMFX uses internal compensation optimized for current-mode control, eliminating the need for external compensation networks. This simplifies design and reduces bill-of-materials count. Stability is guaranteed with standard 22 µF ceramic output capacitors and recommended inductor values (e.g., 3.3 µH for 1.2 V output at 1.6 MHz).
What is the purpose of the EN pin on the LM2831XMFX, and how should it be driven?
The EN pin on the LM2831XMFX is a logic-high active enable input. Driving it above 1.8 V (typical threshold) enables regulation; pulling it below 0.4 V disables the device, reducing quiescent current to 30 nA. It must never float or exceed VIN + 0.3 V. A pull-up resistor to VIN or microcontroller GPIO is recommended for controlled sequencing.
Can the LM2831XMFX operate with an input voltage lower than 3.0 V?
No - the LM2831XMFX has a specified minimum input voltage of 3.0 V and an undervoltage lockout (UVLO) rising threshold of 2.73 V. Operation below 3.0 V is outside guaranteed specifications; below 2.73 V, the device remains disabled. For sub-3 V inputs, consider alternatives like MP2101DQ-LF-Z (2.5 V min).
How does the LM2831XMFX achieve high efficiency despite its 1.6 MHz switching frequency?
The LM2831XMFX achieves up to 93% efficiency at 1.5 A through low conduction loss (130 mΩ PMOS RDS(ON)), optimized gate drive minimizing switching loss, and efficient current-mode control. Its 1.6 MHz frequency allows small inductors/capacitors without sacrificing efficiency - conduction losses dominate at high load, while switching losses remain low due to advanced BiCMOS process and fast 30 ns minimum on-time.
LM2831XMFX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- 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:
- SOT-23-5
LM2831XMFX FAQ
1.How can I place an order for LM2831XMFX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2831XMFX 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 LM2831XMFX reliable?
The price and inventory of LM2831XMFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2831XMFX is usually 5 days.
3.What payment methods are accepted for LM2831XMFX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2831XMFX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2831XMFX?
LM2831XMFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2831XMFX 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 LM2831XMFX?
For technical support, including LM2831XMFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2831XMFX requirements.
6.How does Aetrix verify that LM2831XMFX is sourced from the original manufacturer or authorized distributors?
All LM2831XMFX 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 LM2831XMFX meets industry standards.
7.What is the process for return or replacement of LM2831XMFX?
All LM2831XMFX units undergo pre-shipment inspection (PSI). If there is an issue with LM2831XMFX, 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 LM2831XMFX part is unused and in its original packaging.
Return procedure for LM2831XMFX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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