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Texas Instruments LM2831XMF
- Part No.:
- LM2831XMF
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2831XMF.pdf
- Description:
- IC REG BUCK ADJ 1.5A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,627
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Product details
Overview
LM2831XMF from Texas Instruments is a monolithic, high-frequency PWM step-down DC-DC regulator in SOT23-5 package, delivering 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 operates from 3.0 V to 5.5 V input and regulates down to 0.6 V output, targeting space-constrained local power conversion in USB-powered devices and HDD core supplies.
For engineers reviewing the LM2831XMF datasheet, LM2831XMF pinout, LM2831XMF application, or LM2831XMF equivalent, key selection considerations include its 1.6 MHz fixed-frequency operation, SOT23-5 thermal performance (θJA = 118 °C/W), 30 nA shutdown current, current-mode control architecture, and compatibility with ceramic output capacitors for fast transient response.
Technical Context
The LM2831XMF employs current-mode PWM control with internal compensation, enabling stable regulation across wide load and line variations without external loop components. Its 30 ns minimum on-time supports high duty-cycle operation at low output voltages (e.g., 0.6 V from 3.3 V input) while maintaining 1.6 MHz switching.
It integrates thermal shutdown (165 °C trip), cycle-by-cycle current limiting (1.8 A min / 2.5 A typ), undervoltage lockout (2.73 V rising threshold), and output overvoltage protection (15% above VFB). The internal 0.6 V reference feeds a high-impedance FB pin (100 nA bias), enabling precise resistor-divider-based output programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | Fixed 1.6 MHz - enables use of sub-4 µH inductors and compact 22 µF ceramic output capacitors. |
| Output Current | 1.5 A continuous - supported by internal 130 mΩ PMOS switch in SOT23-5 package. |
| Input Voltage Range | 3.0 V to 5.5 V - matches USB 5 V and single-cell Li-ion (fully charged) supply rails. |
| Output Voltage Range | 0.6 V to 4.5 V - set via external resistor divider; 0.6 V minimum enables modern low-Vcore ICs. |
| Feedback Reference | 0.600 V ±2% - high-accuracy internal bandgap reference with 0.02 %/V line regulation. |
| Shutdown Current | 30 nA - ultra-low quiescent draw enables battery-backed always-on systems. |
| Thermal Shutdown | 165 °C with 15 °C hysteresis - protects against sustained overload or poor PCB heatsinking. |
Pinout & Package
SOT23-5 package (NSC drawing MF05A, top mark SKYB), thermally optimized with exposed pad not present - PCB layout must prioritize short, low-inductance VIN–SW–GND paths and place feedback resistors adjacent to GND pin.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SW | Switch node | Connects to inductor and catch diode anode; carries high di/dt AC current - requires minimal trace length and solid ground return. |
| 2 - GND | Signal & power ground | Reference for FB and EN; bottom resistor of feedback divider must connect here directly to minimize noise coupling. |
| 3 - FB | Feedback input | High-impedance (≤100 nA bias) node sensing output voltage divider - sensitive to noise; trace must be short and routed away from SW/VIN. |
| 4 - EN | Enable control | Logic-high active (≥1.8 V) input; floating or >VIN+0.3 V prohibited - requires pull-up or controlled GPIO. |
| 5 - VIN | Power input | Supplies internal circuitry and PMOS switch; requires local 22 µF ceramic capacitor with low ESL placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Internal PMOS switch | 130 mΩ RDS(ON) in SOT23-5 - reduces conduction loss and eliminates external high-side FET. |
| Current-mode control | Single-loop stability with no external compensation - simplifies design and improves load transient response. |
| Internal soft-start | ~600 µs VOUT ramp - limits inrush current into bulk capacitance during power-up. |
| Overvoltage protection | Triggers at FB ≥ 1.15 × VFB (≈0.69 V) - disables switch to prevent damage during feedback fault or startup overshoot. |
| Undervoltage lockout | 2.73 V (rising) with 430 mV hysteresis - prevents erratic operation during brown-out or weak input sources. |
Applications
| USB-Powered Devices | HDD Core Power |
|---|---|
Use Scenario: Portable SSDs or USB hubs requiring regulated 1.2 V or 1.8 V from 5 V bus power. IC Role / Device Role / Timing Role: Primary step-down regulator converting 5 V USB input to low-voltage core rail. Use Value: 1.6 MHz operation allows tiny 3.3 µH inductor and avoids audible noise; 30 nA shutdown extends battery runtime. |
Use Scenario: 2.5-inch hard disk drive logic board supplying 1.2 V to controller ASIC. IC Role / Device Role / Timing Role: Local point-of-load converter delivering stable 1.5 A at <100 mV ripple. Use Value: Internal current-mode control maintains regulation under rapid spindle motor load transients; thermal shutdown prevents failure during enclosure overheating. |
| Set-Top Boxes | DSL Modems |
Use Scenario: Low-cost STB mainboard generating 3.3 V for SoC I/O and memory interface. IC Role / Device Role / Timing Role: High-efficiency buck regulator operating from 5 V standby or main rail. Use Value: 93% peak efficiency at 1 A reduces heat buildup in sealed plastic enclosures; SOT23-5 footprint saves PCB area. |
Use Scenario: DSL modem PCB powering PHY and DSP subsystems from 5 V adapter input. IC Role / Device Role / Timing Role: Compact DC-DC solution for isolated 1.8 V or 2.5 V digital rails. Use Value: Fixed 1.6 MHz frequency avoids EMI interference with DSL upstream bands; 0.6 V reference enables precise low-voltage generation. |
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, 1.5 A, 0.6 V ref, but uses synchronous rectification (no external diode needed); 12 µA quiescent current in PWM mode. | Enables higher efficiency (>95%) at light loads due to synchronous operation; requires different inductor saturation rating. | Select when lowest possible no-load power or elimination of catch diode is critical; verify PCB layout accommodates different pinout. |
| RT8059GJ6 | 1.5 MHz, 1.5 A, 0.6 V ref, integrated MOSFETs (synchronous), but rated for 2.5 V–5.5 V input only - no 3.0 V start-up support. | Lacks UVLO below 2.5 V; unsuitable for 3.3 V-only systems or brown-out resilience requirements. | Prefer for 5 V-input-only designs where synchronous efficiency outweighs input range limitation; confirm system never operates near 2.5 V. |
Compared with LM2831XMF, TPS62231DRVR offers superior light-load efficiency via synchronous rectification but requires redesign of diode-related layout; RT8059GJ6 provides integrated sync-FETs yet sacrifices 3.0 V operational capability, limiting use in dual-rail or battery-backed systems.
Availability
LM2831XMF is available at Aetrix Electronics and suitable for USB-powered devices, HDD core supplies, and set-top box power management requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for LM2831XMF 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 broad portfolio coverage from power management to signal chain solutions.
The LM2831 family was designed specifically for high-density, cost-sensitive point-of-load DC-DC conversion in consumer and computing applications where small size, fixed-frequency operation, and minimal external components are essential.
FAQ
What is the maximum output current capability of the LM2831XMF?
The LM2831XMF delivers up to 1.5 A continuous output current under typical conditions (TA ≤ 85 °C, proper PCB thermal design). Its internal 130 mΩ PMOS switch and current-limit threshold of 1.8 A (min) define this capability. Actual achievable current depends on ambient temperature, PCB copper area, and airflow - derating is required above 85 °C ambient per θJA = 118 °C/W.
Does the LM2831XMF require an external catch diode?
Yes, the LM2831XMF 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 and relies on external freewheeling conduction during the off-time. Diode selection must meet reverse voltage ≥ VIN(max) + margin and forward current ≥ IOUT × (1 − D).
Can the LM2831XMF operate from a 3.0 V input supply?
Yes, the LM2831XMF is fully specified to operate from 3.0 V to 5.5 V input. Its undervoltage lockout activates at 2.73 V (rising), ensuring reliable startup from nominal 3.0 V sources. At 3.0 V input, it can regulate down to 0.6 V output with appropriate duty cycle (D ≈ 20%), enabled by its 30 ns minimum on-time and current-mode control.
What is the purpose of the EN pin on the LM2831XMF?
EN is the enable control input for the LM2831XMF. A logic-high signal (≥1.8 V) enables switching operation; a logic-low or open state places the device in ultra-low-power shutdown (IQ = 30 nA). The pin must never float or exceed VIN + 0.3 V. A pull-up resistor to VIN or microcontroller GPIO is recommended for controlled sequencing.
How is output voltage programmed on the LM2831XMF?
Output voltage is set using a resistor divider from VOUT to GND, with the midpoint connected to the FB pin. The internal 0.600 V reference determines regulation point: VOUT = 0.6 V × (1 + R1/R2). For example, R2 = 10 kΩ and R1 = 45.3 kΩ yields 3.3 V. R2 should be ≤100 kΩ to limit FB bias current error; both resistors must be placed close to the IC with GND connection tied directly to Pin 2.
LM2831XMF 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
LM2831XMF FAQ
1.How can I place an order for LM2831XMF through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2831XMF 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 LM2831XMF reliable?
The price and inventory of LM2831XMF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2831XMF is usually 5 days.
3.What payment methods are accepted for LM2831XMF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2831XMF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2831XMF?
LM2831XMF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2831XMF 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 LM2831XMF?
For technical support, including LM2831XMF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2831XMF requirements.
6.How does Aetrix verify that LM2831XMF is sourced from the original manufacturer or authorized distributors?
All LM2831XMF 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 LM2831XMF meets industry standards.
7.What is the process for return or replacement of LM2831XMF?
All LM2831XMF units undergo pre-shipment inspection (PSI). If there is an issue with LM2831XMF, 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 LM2831XMF part is unused and in its original packaging.
Return procedure for LM2831XMF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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