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Texas Instruments LM2731YMFX
- Part No.:
- LM2731YMFX
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2731YMFX.pdf
- Description:
- IC REG BOOST ADJ 1.8A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,993
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Product details
Overview
LM2731YMFX from Texas Instruments is a 0.6-MHz fixed-frequency current-mode boost converter IC with integrated 22-V, 1.8-A DMOS FET switch in a 5-pin SOT-23 package. It operates from 2.7 V to 14 V input, delivers up to 20 V output, and features cycle-by-cycle current limiting and thermal shutdown - ideal for space-constrained portable power rails in digital cameras and PDAs.
For engineers reviewing the LM2731YMFX datasheet, LM2731YMFX pinout, LM2731YMFX application, or LM2731YMFX equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternatives, and supply-chain support for production deployment.
Technical Context
The LM2731YMFX uses peak-current-mode control with an internal ramp generator and PWM comparator, where the FB voltage (1.23 V nominal) sets output via external resistor divider. Its 0.6-MHz switching frequency enables compact magnetics while maintaining >78% efficiency at 300 mA load across 2.7–5 V input to 12 V output.
Protection includes per-cycle current limiting triggered by the internal 33-mΩ sense path and thermal shutdown activating at ~160°C junction temperature. The SHDN pin is active-low with <1 µA shutdown current and requires tie-to-VIN if unused.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 0.6 MHz (Y option) - enables use of ≤10 µH inductors and 2.2–4.7 µF ceramic capacitors for minimal board area. |
| Input Voltage Range | 2.7 V to 14 V - supports single-cell Li-ion (3.0–4.2 V), dual-cell alkaline (2.7–3.6 V), and 5 V/12 V system rails. |
| Internal Switch Rating | 22 V VDS, 1.8 A peak - allows regulated outputs up to 20 V with margin; RDS(ON) = 300–450 mΩ ensures low conduction loss at light-to-moderate loads. |
| Feedback Reference | 1.230 V ±25 mV (–40°C to 125°C) - defines output voltage accuracy; used with external resistive divider to set VOUT = 1.23 × (1 + R1/R2). |
| Shutdown Current | <1 µA - extends battery life in standby mode; SHDN pin must be tied to VIN if unused to prevent floating. |
| Thermal Protection | Activates at ~160°C junction temperature; resumes operation at ~150°C - prevents permanent damage during overload or poor PCB thermal design. |
| Package | SOT-23 (DBV), 1.60 mm × 2.90 mm - surface-mount, thermally enhanced for high-power-density designs with RθJA = 209.9°C/W. |
Pinout & Package
LM2731YMFX is housed in a 5-pin SOT-23 (DBV) package with exposed pad not electrically connected. Thermal performance relies on copper pour under the GND pin and SW pin routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch Drain | Connects to inductor and Schottky diode anode; carries high dv/dt switching node - requires short, low-inductance layout. |
| GND (Pin 2) | Analog & Power Ground | Reference for FB, SHDN, and internal circuits; must be low-impedance connection to minimize noise coupling into feedback path. |
| FB (Pin 3) | Feedback Input | High-impedance node sensing output via resistor divider; bias current ≤500 nA - minimizes divider current error and power loss. |
| SHDN (Pin 4) | Shutdown Control | Active-low logic input; threshold 0.5 V (OFF) / 1.5 V (ON); must not float - tie to VIN if unused or use 50–100 kΩ pull-up. |
| VIN (Pin 5) | Power Input | Supplies internal circuitry and switch driver; requires local 2.2 µF ceramic capacitor placed within 3 mm of pin to suppress input ripple. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated control loop | Eliminates need for external compensation components except feedforward capacitor (CF ≈ 220 pF), reducing BOM count and layout sensitivity. |
| Low RDS(ON) DMOS FET | 300–450 mΩ typical at 25°C - reduces conduction loss and thermal rise, enabling >85% efficiency at 100 mA load with 3.3 V → 5 V boost. |
| Cycle-by-cycle current limiting | Protects internal switch during overloads and startup surges; limit threshold varies with duty cycle (e.g., ~1.5 A at 50% DC, ~1.1 A at 80% DC). |
| Logic-level shutdown | Compatible with 1.8 V/3.3 V/5 V microcontrollers; draws <2 µA when asserted, enabling deep-sleep modes without external enable circuitry. |
| Wide input range (2.7–14 V) | Supports direct connection to unregulated battery sources - no pre-regulator needed for single- or dual-cell systems. |
Applications
| Digital Camera Power Supply | PDA Local Boost Rail |
|---|---|
|
Use Scenario: Boosting 3.3 V main rail to 5 V for CCD sensor bias and 12 V for flash LED driver in compact handheld camera modules. IC Role / Device Role / Timing Role: Primary DC-DC boost regulator providing regulated, low-noise output with fast transient response to handle burst-mode flash current demands. Use Value: Enables use of tiny 10 µH inductor and 4.7 µF ceramic output cap - saves >30% board area vs. lower-frequency solutions. |
Use Scenario: Generating stable 5 V from 3.0–3.6 V alkaline battery stack to power USB transceivers and SD card interfaces in palm-sized PDAs. IC Role / Device Role / Timing Role: High-efficiency, low-quiescent-current boost controller ensuring >100 hours of standby runtime and clean power during data transfer bursts. Use Value: Shutdown current <1 µA extends battery life; 0.6-MHz operation avoids audible noise in audio-sensitive environments. |
| Portable Phone Display Backlight | White LED Current Source |
|
Use Scenario: Driving 4-series white LEDs (16–18 V forward) from 3.7 V Li-ion battery in feature phones with OLED/LCD displays. IC Role / Device Role / Timing Role: Constant-voltage boost stage feeding external constant-current LED driver IC or linear current sink. Use Value: 22-V internal switch supports full LED string voltage with margin; thermal shutdown prevents overheating during display-on peaks. |
Use Scenario: Directly regulating current to 3-white-LED strings (12 V total) in portable media players using FB pin feedback with current-sense resistor. IC Role / Device Role / Timing Role: Configured as constant-current source via feedback network - eliminates need for separate LED driver IC. Use Value: 1.23 V reference enables precise current setting (e.g., 20 mA with 61.5 Ω sense resistor); internal current limit protects against open-circuit LED failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2731XMF/NOPB | 1.6-MHz switching frequency; higher RDS(ON) (typ. 400 mΩ); identical pinout and FB reference. | Better suited for ultra-compact layouts needing smallest inductors; trades ~3–5% efficiency for size reduction. | Select LM2731XMF/NOPB only when board space is critical and efficiency >80% at 500 mA is acceptable. |
| TPS61040DRVR | Fixed 600-kHz frequency like LM2731YMFX but adds integrated soft-start, adjustable current limit (0.4–1.2 A), and higher max VOUT (28 V). | Preferred for designs requiring programmable current protection or higher output voltage headroom beyond 20 V. | Choose TPS61040DRVR when soft-start control or wider output voltage range (up to 28 V) is required - not pin-compatible. |
Compared with LM2731YMFX, LM2731XMF/NOPB offers smaller passive components at the cost of reduced efficiency, while TPS61040DRVR adds configurability and voltage headroom but requires layout changes and different feedback design.
Availability
LM2731YMFX is available at Aetrix Electronics and suitable for portable electronics, battery-powered imaging systems, and embedded display power supplies requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LM2731YMFX 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 technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2731 family was designed specifically for portable and space-constrained applications requiring high-efficiency, low-component-count boost conversion - targeting PDA, digital camera, and handheld communication devices.
FAQ
What is the maximum output voltage achievable with the LM2731YMFX?
The LM2731YMFX supports output voltages up to 20 V, limited by its 22-V internal DMOS FET's breakdown rating and safe operating area. This is confirmed in the Absolute Maximum Ratings table (SW pin voltage: –0.4 V to 22 V) and the Applications section, which explicitly lists "boosting to voltages up to 20 V" as a primary use case. Exceeding 20 V risks FET avalanche and thermal failure.
Does the LM2731YMFX require external compensation components?
The LM2731YMFX is internally compensated, eliminating the need for traditional Type-II or Type-III compensation networks. However, a feedforward capacitor (CF = 220 pF typical) is mandatory for stability, as specified in Section 8.2.2.4 of the datasheet. Omitting CF causes oscillation and regulation failure - it is not optional despite internal compensation.
Can the LM2731YMFX drive white LEDs directly as a constant-current source?
Yes - the LM2731YMFX can be configured as a constant-current source by connecting the LED string between VOUT and ground, and feeding the LED current through a sense resistor to the FB pin. With its precise 1.23 V reference and low FB bias current (≤500 nA), it achieves accurate current regulation (e.g., 20 mA with 61.5 Ω). This is validated in the Applications section under "White LED Current Sources."
What is the recommended external diode for the LM2731YMFX?
Texas Instruments recommends the MBR0520 Schottky diode (20 V, 0.5 A average) for the LM2731YMFX, as stated in Section 8.2.2.5. Its low forward voltage (~0.35 V at 300 mA) minimizes conduction loss and improves efficiency, while its fast recovery prevents reverse recovery spikes that could destabilize the regulator. For >0.5 A loads, the Microsemi UPS5817 is cited as an alternative.
How does the LM2731YMFX behave during thermal shutdown?
When the LM2731YMFX junction temperature exceeds ~160°C, thermal shutdown disables the internal FET switch until the die cools to ~150°C. During shutdown, the device draws <1 µA quiescent current and holds FB and SHDN pins in high-impedance state. Recovery is automatic and does not require cycling SHDN - this behavior is documented in Section 7.4.2 and confirmed in the Thermal Information table.
LM2731YMFX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- 22V (Switch)
- Current - Output:
- 1.8A (Switch)
- Frequency - Switching:
- 600kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2731YMFX FAQ
1.How can I place an order for LM2731YMFX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2731YMFX 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 LM2731YMFX reliable?
The price and inventory of LM2731YMFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2731YMFX is usually 5 days.
3.What payment methods are accepted for LM2731YMFX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2731YMFX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2731YMFX?
LM2731YMFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2731YMFX 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 LM2731YMFX?
For technical support, including LM2731YMFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2731YMFX requirements.
6.How does Aetrix verify that LM2731YMFX is sourced from the original manufacturer or authorized distributors?
All LM2731YMFX 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 LM2731YMFX meets industry standards.
7.What is the process for return or replacement of LM2731YMFX?
All LM2731YMFX units undergo pre-shipment inspection (PSI). If there is an issue with LM2731YMFX, 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 LM2731YMFX part is unused and in its original packaging.
Return procedure for LM2731YMFX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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