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Texas Instruments LM2731XMFX
- Part No.:
- LM2731XMFX
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LM2731XMFX.pdf
- Description:
- IC REG BOOST ADJ 1.8A SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,656
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Product details
Overview
LM2731XMFX from Texas Instruments is a fixed-frequency current-mode boost converter IC with an integrated 22-V, 1.8-A DMOS FET switch, operating at 1.6 MHz, supporting input voltages from 2.7 V to 14 V and output voltages up to 20 V - used in portable power rails for white LED drivers and local voltage boosting in PDAs and digital cameras.
For engineers reviewing the LM2731XMFX datasheet, LM2731XMFX pinout, LM2731XMFX application, or LM2731XMFX equivalent, this page delivers verified electrical specs, thermal limits, switching frequency stability across temperature, feedback reference accuracy (1.23 V ±25 mV), and real-world efficiency curves for 5–12 V boost designs - all critical for battery-powered DC-DC layout and reliability validation.
Technical Context
The LM2731XMFX uses peak-current-mode control with cycle-by-cycle limiting, where internal ramp generation and FB-derived error amplification jointly set PWM pulse width. Its 1.6-MHz oscillator maintains ±15% tolerance over –40°C to 125°C, enabling compact magnetics without sacrificing transient response.
Thermal protection activates at ~160°C junction temperature, with automatic recovery at ~150°C; shutdown logic is active-low with <1 µA quiescent draw when disabled. The 5-pin SOT-23 package integrates analog ground and power ground into a single GND pin, requiring careful PCB thermal pad design due to RθJA = 209.9°C/W.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.6 MHz (X option); enables ≤10-µH inductors and sub-5-mm² total solution size |
| Input Voltage Range | 2.7 V to 14 V; supports single-cell Li-ion (3.0–4.2 V) and multi-cell alkaline/NiMH inputs |
| Output Voltage Capability | Up to 20 V; limited by 22-V SW pin rating and external resistor divider configuration |
| Feedback Reference Voltage | 1.230 V (±25 mV over –40°C to 125°C); sets output via R1/R2 divider with 92-µA nominal divider current |
| Peak Switch Current Limit | 1.8 A typical at 25°C; derates to ≥1.4 A over full temperature range for robust short-circuit handling |
| RDS(ON) | 300 mΩ typical at 25°C; contributes <150 mW conduction loss at 1.5-A load, critical for thermal budget |
| Quiescent Current | 2 mA (active, X option); enables >100-hour runtime in 100-µA standby systems with periodic wake-up |
Pinout & Package
LM2731XMFX is housed in a 5-pin SOT-23 (DBV) package measuring 1.60 mm × 2.90 mm, with exposed thermal pad connected to GND for enhanced heat dissipation. Pin 1 (SW) carries high dv/dt switching node; Pin 3 (FB) requires low-noise routing near output capacitor; Pin 4 (SHDN) must be tied to VIN if unused or pulled up via 50–100 kΩ resistor for controlled enable/disable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Drain of internal NMOS FET | High-voltage, high-di/dt node; requires minimized trace area and tight coupling to GND for EMI control |
| GND (Pin 2) | Analog + power ground reference | Single-point return for FB, SHDN, and internal bias; must connect directly to thermal pad and system GND plane |
| FB (Pin 3) | Feedback input to error amplifier | Senses divided output voltage; sensitive to noise - route away from SW and use local 100-pF bypass |
| SHDN (Pin 4) | Active-low enable control | Logic-level input; floating state prohibited - tie to VIN or use pullup for reliable disable behavior |
| VIN (Pin 5) | Main power input (2.7–14 V) | Supplies gate drive and bias circuitry; requires local 2.2-µF ceramic capacitor within 3 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated control loop | Eliminates need for external compensation network - only feedforward capacitor (CF = 220 pF) required for stability |
| Cycle-by-cycle current limiting | Prevents FET destruction during overload; operates independently of PWM comparator to terminate each pulse |
| Low shutdown current (<1 µA) | Extends battery life in always-on systems - e.g., 10-µA system draws reduce to 11 µA total with LM2731XMFX disabled |
| 22-V rated internal FET | Supports 18-V output with margin; avoids external switch in most portable boost applications up to 200-mW load |
| Thermal shutdown protection | Activates at ~160°C junction temperature; hysteresis ensures safe restart only after cooling to ~150°C |
Applications
| White LED Backlighting | Portable Digital Camera Power |
|---|---|
Use Scenario: Driving 4–6串联 white LEDs (3.0–3.6 V each) from a 3.3-V Li-ion cell in compact camera modules. IC Role / Device Role / Timing Role: Boost converter regulating constant current via external sense resistor; 1.6-MHz switching minimizes inductor size for space-constrained PCBs. Use Value: Achieves >85% efficiency at 150-mA LED current with 10-µH inductor and MBR0520 Schottky diode - enabling <6-mm² total BOM footprint. |
Use Scenario: Generating 5-V and 12-V rails from a single 3.7-V battery for image sensor, flash controller, and LCD interface. IC Role / Device Role / Timing Role: Primary boost stage delivering up to 500-mA output; fixed 1.6-MHz frequency ensures predictable EMI placement above audio band. Use Value: Delivers stable 12-V output with <120-mVpp ripple using 4.7-µF ceramic output cap - meeting fast transient requirements of CMOS image sensors. |
| PDA/System-on-Module Local Boost | Handheld Gaming Console Core Voltage |
Use Scenario: Providing 3.3-V or 5-V auxiliary supply for SD card interface, USB PHY, or RF transceiver in legacy PDA designs. IC Role / Device Role / Timing Role: Local point-of-load regulator with logic-controlled shutdown; integrates FET and compensation to reduce component count. Use Value: Reduces bill-of-materials by 4 components vs discrete boost solution - eliminating external MOSFET, driver, compensation RC, and bootstrap diode. |
Use Scenario: Supplying 3.3-V core voltage to ARM-based game processor during burst-mode operation (e.g., graphics rendering). IC Role / Device Role / Timing Role: High-efficiency boost stage with fast load-step response; current-mode control maintains regulation during 100-mA to 400-mA dynamic loads. Use Value: Maintains <±2% output regulation during 200-mA/µs load transients - preventing processor brownout during GPU-intensive scenes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2731YMF/NOPB | 600-kHz switching frequency; higher peak efficiency at light loads but requires larger inductor (≥22 µH) and capacitor | Better suited for noise-sensitive audio subsystems where EMI filtering is simpler at lower frequencies | Select when board space allows larger passives and EMI compliance prioritizes fundamental frequency over harmonics |
| TPS61040DRVR | 2.5-MHz fixed frequency; 28-V FET; 0.4-A switch current limit; integrated soft-start and undervoltage lockout | Targeted at ultra-compact, low-power applications (<100 mW) with strict startup sequencing requirements | Choose for sub-50-mA output loads where minimal footprint outweighs peak current capability |
Compared with LM2731YMF/NOPB, LM2731XMFX trades 30% lower light-load efficiency for 2.7× smaller magnetics and faster transient response; versus TPS61040DRVR, it offers 4.5× higher output current capability but lacks soft-start and UVLO - making it optimal for medium-power, cost-sensitive portable boost rails.
Availability
LM2731XMFX is available at Aetrix Electronics and suitable for portable medical monitors, handheld test equipment, and industrial IoT edge nodes requiring stable component supply with guaranteed long-term manufacturability and no last-time-buy constraints.
Supply support for LM2731XMFX 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 over 50 years of innovation in high-reliability power conversion solutions.
The LM2731XMFX belongs to TI's legacy high-frequency boost converter family, designed specifically for space-constrained portable electronics needing minimal external components, fast transient response, and robust thermal protection - not intended for automotive or industrial-grade extended temperature variants.
FAQ
What is the maximum output voltage achievable with LM2731XMFX?
The LM2731XMFX supports output voltages up to 20 V, constrained by its 22-V SW pin absolute maximum rating and internal FET breakdown margin. This is achieved using an external resistive divider on the FB pin, where VOUT = 1.23 × (1 + R1/R2). For example, setting R2 = 13.3 kΩ and R1 = 117 kΩ yields ~12 V output. Exceeding 20 V risks permanent damage to the internal switch.
Does LM2731XMFX require external compensation components?
The LM2731XMFX features internal compensation, eliminating the need for traditional Type-II or Type-III networks. However, a feedforward capacitor (CF = 220 pF) between FB and VIN is mandatory for loop stability - per TI's Figure 26 schematic. Omitting CF causes oscillation or poor transient response, especially under varying load conditions.
Can LM2731XMFX operate with a 2.5-V input supply?
No - the LM2731XMFX has a minimum recommended input voltage of 2.7 V per Section 6.3 of the datasheet. At 2.5 V, the internal bias circuitry fails to start reliably, and the 1.23-V feedback reference cannot be maintained. Operation below 2.7 V may result in erratic regulation, failure to start, or increased quiescent current drift.
What is the thermal shutdown threshold for LM2731XMFX?
The LM2731XMFX activates thermal shutdown when the junction temperature exceeds approximately 160°C, as specified in Section 7.4.2. After shutdown, the device remains off until the junction cools to ~150°C, providing 10°C hysteresis. This protects against sustained overloads but does not replace proper PCB thermal design - the SOT-23 package requires adequate copper pour and thermal vias to sustain >300-mW continuous dissipation.
Is LM2731XMFX pin-compatible with LM2731YMF/NOPB?
Yes - LM2731XMFX and LM2731YMF/NOPB share identical 5-pin SOT-23 (DBV) packaging, pinout, and footprint. They differ only in switching frequency (1.6 MHz vs 600 kHz) and associated performance curves (efficiency vs load, duty cycle limits, inductor sizing). No PCB changes are required when substituting between X and Y variants, though external component values may need optimization.
LM2731XMFX 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:
- 1.6MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
LM2731XMFX FAQ
1.How can I place an order for LM2731XMFX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2731XMFX 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 LM2731XMFX reliable?
The price and inventory of LM2731XMFX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2731XMFX is usually 5 days.
3.What payment methods are accepted for LM2731XMFX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2731XMFX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2731XMFX?
LM2731XMFX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2731XMFX 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 LM2731XMFX?
For technical support, including LM2731XMFX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2731XMFX requirements.
6.How does Aetrix verify that LM2731XMFX is sourced from the original manufacturer or authorized distributors?
All LM2731XMFX 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 LM2731XMFX meets industry standards.
7.What is the process for return or replacement of LM2731XMFX?
All LM2731XMFX units undergo pre-shipment inspection (PSI). If there is an issue with LM2731XMFX, 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 LM2731XMFX part is unused and in its original packaging.
Return procedure for LM2731XMFX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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