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Texas Instruments LM2831ZMFX
- Part No.:
- LM2831ZMFX
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2831ZMFX.pdf
- Description:
- IC REG BUCK ADJ 1.5A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,896
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Product details
Overview
LM2831ZMFX 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 3.0 MHz switching frequency, and 0.6V ±2% feedback reference voltage. It operates from 3.0V to 5.5V input and regulates down to 0.6V output, targeting space-constrained local power conversion in USB-powered devices and set-top boxes.
For engineers reviewing the LM2831ZMFX datasheet, LM2831ZMFX pinout, LM2831ZMFX application, or LM2831ZMFX equivalent, key selection criteria include its 3.0 MHz fixed-frequency operation enabling ultra-small external inductors, 30 nA shutdown current for battery-sensitive designs, current-mode control with internal compensation, thermal shutdown at 165°C, and output overvoltage protection triggered at +15% of VFB.
Technical Context
The LM2831ZMFX employs constant-frequency current-mode PWM control with an internally compensated error amplifier and a 0.6V precision bandgap reference. Its 3.0 MHz oscillator supports minimum on-times as low as 30 ns, enabling stable regulation down to 0.6V output across the full 3V–5.5V input range.
It integrates pulse-by-pulse current limiting (typ. 2.5A), soft-start (≈600 µs ramp), undervoltage lockout (2.73V rising threshold, 430 mV hysteresis), and thermal shutdown with 15°C hysteresis. The SOT-23-5 package uses a single ground pin shared for signal and power return, requiring careful PCB layout for optimal EMI and thermal performance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | Fixed 3.0 MHz - enables use of ≤2.2 µH inductors and compact ceramic capacitors, minimizing board area. |
| Output Current | 1.5 A continuous - supported by internal 130 mΩ PMOS switch in SOT-23-5 package, with cycle-by-cycle current limit (min 1.8 A). |
| Input Voltage Range | 3.0 V to 5.5 V - matches standard USB 5V and Li-ion single-cell systems; UVLO prevents startup below 2.73 V. |
| Output Voltage Range | 0.6 V to 4.5 V - set via external resistor divider; 0.6 V reference has ±2% tolerance over −40°C to +125°C. |
| Quiescent Current | 4.3–6.5 mA (active), 30 nA (shutdown) - enables >1-year battery life in always-on standby applications. |
| Thermal Protection | Junction shutdown at 165°C with 15°C hysteresis - prevents permanent damage during overload or poor heatsinking. |
| Efficiency | Up to 93% - achieved using low-RDS(ON) PMOS switch and optimized gate drive, verified at 5VIN/3.3VOUT/1.25A. |
Pinout & Package
LM2831ZMFX is housed in a RoHS-compliant 5-pin SOT-23 package (NSC drawing MF05A, top mark SLAB), with exposed pad omitted - thermal path relies on PCB copper area under pins 2 (GND) and 4 (VIN). Pin 1 (SW) carries high di/dt switching node; pin 3 (FB) is high-impedance and must be routed short and away from noise sources.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | SW (Switch Node) | Drain of internal PMOS switch; connects to inductor and catch diode anode - high dv/dt node requiring minimal trace length and loop area. |
| 2 | GND (Ground) | Common signal and power return; bottom resistor of feedback divider must connect here directly to minimize noise coupling. |
| 3 | FB (Feedback) | High-impedance input to error amplifier; voltage divider sets output - sensitive to noise; route short and shield from SW/VIN traces. |
| 4 | EN (Enable) | Logic-level control: ≥1.8 V enables regulation; ≤0.4 V disables with 30 nA shutdown current - tie high via resistor if always-on. |
| 5 | VIN (Input Supply) | Main power input (3.0–5.5 V); requires local 22 µF ceramic capacitor with low ESL placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| 3.0 MHz Fixed Switching Frequency | Enables use of 1.6 µH inductors (e.g., TDK VLCF4018T-1R6N) and eliminates need for external frequency programming components. |
| Internal 130 mΩ PMOS Switch | Reduces conduction loss at 1.5A load; delivers >90% efficiency at 5VIN/3.3VOUT without external MOSFET or driver. |
| 0.6 V ±2% Internal Reference | Supports accurate low-VOUT regulation (e.g., 1.2 V, 0.9 V) with standard 1% resistors; stable over −40°C to +125°C. |
| Integrated Soft-Start (600 µs) | Controls output ramp rate to limit inrush current into bulk capacitance - avoids tripping upstream current limits or brownouts. |
| Output Overvoltage Protection | Shuts off PMOS switch when FB exceeds 15% above 0.6 V - protects downstream logic from catastrophic overvoltage events. |
Applications
| USB-Powered Portable Devices | Set-Top Box Core Supplies |
|---|---|
|
Use Scenario: Powering ARM-based SoCs and DDR memory in battery-backed or bus-powered media players. IC Role / Device Role / Timing Role: Primary 5V-to-1.2V/1.8V step-down regulator supplying processor core and I/O rails. Use Value: 3.0 MHz operation allows <2.2 µH inductors and eliminates audible coil whine; 30 nA shutdown extends battery runtime. |
Use Scenario: Generating clean 3.3V and 1.2V rails for demodulator ICs and video processors in cable/satellite receivers. IC Role / Device Role / Timing Role: Local point-of-load converter replacing linear regulators to improve thermal management and efficiency. Use Value: 93% peak efficiency reduces heat buildup in sealed enclosures; internal compensation simplifies BOM and layout validation. |
| HDD Preamp & Servo Supplies | DSL Modem Line Card Power |
|
Use Scenario: Providing regulated 2.5V/3.3V to HDD read/write channel ICs and voice coil motor drivers. IC Role / Device Role / Timing Role: High-transient-response buck regulator handling rapid load steps during seek operations. Use Value: Current-mode control ensures stable regulation under 10 A/µs load transients; thermal shutdown prevents damage during stall conditions. |
Use Scenario: Converting 5V USB or wall-adapter input to 3.3V for ADSL PHY and microcontroller subsystems. IC Role / Device Role / Timing Role: Compact, low-noise DC-DC stage meeting ETSI Class B conducted emissions requirements. Use Value: Small SOT-23 footprint fits tight spacing near RJ-11 connectors; 3.0 MHz switching moves noise spectrum above sensitive analog bands. |
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 | 3.0 MHz, 3A output, 2.7–6V input, 0.6V ref, but uses external compensation and requires separate soft-start capacitor. | Higher current capability suits dual-rail SoC designs; less integrated than LM2831ZMFX for simple 1.5A use cases. | Select when >1.5A load or tighter output accuracy (<±1%) is required; accept added BOM complexity. |
| MP2108DQ-LF-Z | 2.0 MHz, 1.5A, 2.5–5.5V input, 0.6V ref, no OVP, 100 nA shutdown current, SOT563 package. | Lacks output overvoltage protection and thermal shutdown hysteresis; smaller package increases thermal resistance. | Choose only for cost-sensitive, non-safety-critical applications where OVP and precise thermal behavior are not mandated. |
Compared with TPS62130ARGTR and MP2108DQ-LF-Z, the LM2831ZMFX provides superior integration (internal soft-start, OVP, thermal hysteresis) and lower shutdown current (30 nA vs. 100 nA), making it optimal for space- and battery-constrained USB peripherals where reliability and simplicity are prioritized over raw current headroom.
Availability
LM2831ZMFX is available at Aetrix Electronics and suitable for USB-powered portable devices, set-top box core supplies, HDD preamp circuits, and DSL modem line cards requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2831ZMFX 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 high-reliability power management solutions, with decades of expertise in DC-DC conversion architecture and automotive-grade qualification.
The LM2831 family was designed specifically for compact, high-frequency point-of-load regulation in consumer and networking equipment, emphasizing minimal external component count, robust protection features, and ease of layout in dense PCB environments.
FAQ
What is the switching frequency of the LM2831ZMFX?
The LM2831ZMFX has a fixed internal switching frequency of 3.0 MHz, with typical variation of ±25% (2.25–3.75 MHz) over temperature and input voltage. This high frequency enables use of sub-2 µH inductors and small ceramic capacitors, reducing solution size significantly compared to lower-frequency alternatives like the LM2831Y (550 kHz).
Does the LM2831ZMFX require external compensation components?
No, the LM2831ZMFX uses internal compensation and requires no external RC network. Its current-mode control architecture and factory-tuned loop response eliminate the need for compensation pins or external components - simplifying design and improving consistency across manufacturing lots.
What is the maximum output current capability of the LM2831ZMFX?
The LM2831ZMFX delivers up to 1.5 A continuous output current under typical conditions (TA = 25°C, 5VIN/3.3VOUT, 2-layer PCB with 1 oz copper). Derating applies at higher ambient temperatures or with limited airflow; thermal shutdown activates at 165°C junction temperature to protect the device.
How does the enable (EN) pin function on the LM2831ZMFX?
The EN pin on the LM2831ZMFX is a logic-compatible input: applying ≥1.8 V enables regulation, while ≤0.4 V places the device in ultra-low-power shutdown mode (30 nA quiescent current). The pin must never float or exceed VIN + 0.3 V; a pull-up resistor to VIN is recommended for default-on operation.
Is the LM2831ZMFX pin-compatible with other variants in the LM2831 family?
Yes, all LM2831 variants (X/Y/Z) in the SOT-23-5 package share identical pinout, footprint, and electrical interface - including LM2831ZMFX, LM2831XMFX, and LM2831YMFX. Only the internal oscillator frequency differs; no PCB changes are needed when substituting between them for frequency-tuning purposes.
LM2831ZMFX 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:
- 3MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2831ZMFX FAQ
1.How can I place an order for LM2831ZMFX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2831ZMFX 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 LM2831ZMFX reliable?
The price and inventory of LM2831ZMFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2831ZMFX is usually 5 days.
3.What payment methods are accepted for LM2831ZMFX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2831ZMFX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2831ZMFX?
LM2831ZMFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2831ZMFX 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 LM2831ZMFX?
For technical support, including LM2831ZMFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2831ZMFX requirements.
6.How does Aetrix verify that LM2831ZMFX is sourced from the original manufacturer or authorized distributors?
All LM2831ZMFX 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 LM2831ZMFX meets industry standards.
7.What is the process for return or replacement of LM2831ZMFX?
All LM2831ZMFX units undergo pre-shipment inspection (PSI). If there is an issue with LM2831ZMFX, 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 LM2831ZMFX part is unused and in its original packaging.
Return procedure for LM2831ZMFX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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