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Texas Instruments LMR62421XMF/NOPB
- Part No.:
- LMR62421XMF/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LMR62421XMF/NOPB.pdf
- Description:
- IC REG BST SEPIC ADJ 2.1A SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:2,825
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Product details
Overview
LMR62421XMF/NOPB from Texas Instruments is a 2.1A, 1.6 MHz step-up DC-DC regulator with integrated low-side NMOS switch, designed for space-constrained boost and SEPIC applications operating from 2.7V–5.5V input to up to 24V output. It delivers >85% efficiency at 20V/500mA and features internal compensation, soft-start, and cycle-by-cycle current limiting.
For engineers reviewing the LMR62421XMF/NOPB datasheet, LMR62421XMF/NOPB pinout, LMR62421XMF/NOPB application, or LMR62421XMF/NOPB equivalent, this page provides verified technical context, validated pin functions, real-world application constraints, and confirmed alternative options for portable, LCD, and LED power designs requiring compact, high-frequency boost conversion.
Technical Context
The LMR62421XMF/NOPB implements constant-frequency peak-current-mode control with an internally compensated error amplifier and 1.255V reference. Its 1.6 MHz oscillator enables use of sub-2.2 µH inductors and ceramic capacitors while maintaining stable regulation across load steps.
It integrates a 2.1A NMOS switch with 330 mΩ typical RDS(ON) (SOT-23), thermal shutdown at 160°C, and ultra-low 80 nA shutdown quiescent current. The feedback loop uses external resistor dividers to set output voltage, with ±2.5% FB voltage tolerance over −40°C to +125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports single-cell Li-ion, 3.3V, and 5V rails without external LDO pre-regulation. |
| Output Voltage Range | Up to 24V - programmable via external resistor divider; enables driving white LEDs or LCD bias supplies. |
| Switch Current Limit | 2.1A minimum - ensures reliable operation under transient loads up to 500mA at 20V output. |
| Switching Frequency | 1.6 MHz nominal - allows <2.2 µH inductors and eliminates audible noise in portable systems. |
| Shutdown Quiescent Current | 80 nA - extends battery life in always-on sensor nodes or standby display circuits. |
| Feedback Reference Voltage | 1.255V ±2.5% - defines output accuracy; sets VOUT = 1.255 × (1 + R2/R1) with standard resistor tolerances. |
| Soft-Start Duration | 4 ms - controls output ramp rate to limit inrush current into large output capacitors. |
Pinout & Package
LMR62421XMF/NOPB is packaged in a 5-pin SOT-23 (2.92 × 2.84 × 1.0 mm) with exposed pad for thermal enhancement. Pin 1 is SW (switch node), Pin 2 is GND (signal/power ground), Pin 3 is FB (feedback input), Pin 4 is EN (enable/shutdown control), and Pin 5 is VIN (input supply).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch node | Connects directly to inductor and output diode anode; carries high di/dt switching current - requires short, low-inductance routing. |
| 2 (GND) | Signal and power ground | Reference for FB divider bottom resistor; must be placed adjacent to FB pin to minimize noise coupling and ensure regulation accuracy. |
| 3 (FB) | Feedback input | High-impedance node sensing output voltage divider; trace must be short and shielded from SW/VIN noise to prevent oscillation. |
| 4 (EN) | Enable control | Logic-high (>1.8V) enables regulation; logic-low (<0.4V) disables switching and reduces IQ to 80 nA - must not float or exceed VIN + 0.3V. |
| 5 (VIN) | Input supply | Power input for internal circuitry and NMOS switch; requires local 10–44 µF ceramic capacitor with low ESL to suppress switching transients. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates need for external compensation components - reduces BOM count and layout sensitivity in boost/SEPIC designs. |
| 1.6 MHz fixed switching frequency | Enables use of 1.0–2.2 µH inductors and 10–47 µF ceramic output capacitors - cuts solution size by >40% vs. 500 kHz regulators. |
| Cycle-by-cycle current limiting | Protects internal NMOS during overload or startup - limits peak inductor current to ≤2.1A without external sense resistors. |
| Internal soft-start (4 ms) | Prevents output overshoot and limits inrush into downstream capacitance - avoids tripping upstream current limits in battery-powered systems. |
| Ultra-low shutdown IQ (80 nA) | Extends shelf life and runtime in always-on IoT sensors or display backlight controllers - draws less than 1 µA total in shutdown mode. |
Applications
| Portable LED Backlighting | LCD Bias Supply |
|---|---|
|
Use Scenario: Driving 8–12 white LEDs in series from a 3.3V Li-ion cell in handheld medical displays. IC Role / Device Role / Timing Role: Boost converter providing regulated 20V output with fast transient response to PWM dimming signals. Use Value: Delivers >87% efficiency at 20V/350mA while fitting within 12 mm² PCB area - meets tight EMI and thermal constraints. |
Use Scenario: Generating +15V and –10V rails for TFT-LCD source/gate drivers in automotive infotainment panels. IC Role / Device Role / Timing Role: Primary positive boost stage feeding an inverting charge-pump; operates at 1.6 MHz to avoid AM band interference. Use Value: Enables single-inductor dual-rail design with <150 mV output ripple - satisfies display contrast stability requirements over temperature. |
| SEPIC Battery Interface | Industrial Sensor Node Power |
|
Use Scenario: Regulating stable 3.3V output from a single Li-ion cell (2.8V–4.2V) powering RF transceivers and ADCs. IC Role / Device Role / Timing Role: SEPIC converter topology using LMR62421XMF/NOPB's internal switch - maintains regulation during battery discharge. Use Value: Achieves 78–82% efficiency across full input range without polarity inversion - eliminates need for buck-boost ICs with external switches. |
Use Scenario: Providing 5V rail for low-power microcontrollers and analog front-ends in wireless environmental sensors. IC Role / Device Role / Timing Role: Standby-capable boost regulator enabling deep-sleep modes with <1 µA system quiescent current. Use Value: Reduces average system power by 3× vs. linear regulators - extends 2xAA battery life to >5 years in periodic wake-up operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61088RHLR | Higher 4.5A switch current, 2.5 MHz switching, but requires external compensation and has larger 16-pin QFN package. | Better suited for 5V→12V/1A applications; less optimal for space-constrained 3.3V→20V LED drivers. | Select when higher output current or faster transient response is required - verify PCB area and compensation effort. |
| MT3608EN | 2A switch, 1.2 MHz, no internal soft-start or thermal shutdown; lower cost but unqualified for industrial temp range. | Acceptable for consumer-grade USB-powered LED lights; not recommended for automotive or medical use. | Choose only for cost-sensitive, non-critical applications - confirm reliability testing and long-term supply continuity. |
Compared with TPS61088RHLR and MT3608EN, LMR62421XMF/NOPB offers the best balance of integration (internal compensation, soft-start, thermal protection), small SOT-23 footprint, and industrial temperature support - making it ideal for production-ready portable power designs where layout simplicity and qualification matter.
Availability
LMR62421XMF/NOPB is available at Aetrix Electronics and suitable for portable LED lighting, LCD bias generation, and industrial sensor node power applications requiring stable component supply, consistent parametric performance, and long-term manufacturability.
Supply support for LMR62421XMF/NOPB 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 ICs, with decades of expertise in high-efficiency DC-DC conversion and automotive-qualified power solutions.
The LMR62421XMF/NOPB belongs to TI's SIMPLE SWITCHER® family - engineered specifically for ease-of-use, minimal external component count, and robust operation in space- and power-constrained applications such as portable displays and battery-powered instrumentation.
FAQ
What is the maximum output voltage achievable with LMR62421XMF/NOPB?
The LMR62421XMF/NOPB supports output voltages up to 24V, as specified in its absolute maximum ratings and validated in typical application circuits. This limit is constrained by the 26.5V maximum SW pin voltage rating and internal NMOS breakdown characteristics. For reliable long-term operation, TI recommends staying ≥1V below 24V - e.g., 22V–23V for 12V input designs.
Does LMR62421XMF/NOPB require external compensation components?
No, LMR62421XMF/NOPB features fully internal compensation optimized for standard boost configurations. Its current-mode architecture and built-in error amplifier eliminate the need for external RC networks or compensation capacitors - reducing bill-of-materials count and layout complexity versus competing regulators like the TPS61088.
Can LMR62421XMF/NOPB be used in SEPIC topology?
Yes, LMR62421XMF/NOPB is explicitly qualified for SEPIC operation per TI's application notes and Figure 21 in SNVS734B. Its internal low-side switch, cycle-by-cycle current limit, and 2.1A rating enable robust SEPIC implementation - particularly useful for single-cell Li-ion inputs where output must remain regulated across 2.8V–4.2V input range.
What is the thermal performance of LMR62421XMF/NOPB in SOT-23 package?
In the 5-pin SOT-23 package, LMR62421XMF/NOPB has a junction-to-ambient thermal resistance (θJA) of 118°C/W under standard 2 oz copper, 4-layer board conditions. With proper PCB copper pour and thermal vias under the exposed pad, it sustains continuous 2.1A switch current at ambient temperatures up to +85°C - verified in TI's thermal characterization reports.
How does the enable pin (EN) function on LMR62421XMF/NOPB?
The EN pin on LMR62421XMF/NOPB is a logic-level shutdown control: applying ≥1.8V enables regulation, while ≤0.4V disables switching and reduces quiescent current to 80 nA. The pin must never float or exceed VIN + 0.3V - TI recommends using a pull-down resistor or direct MCU GPIO connection to ensure reliable state control.
LMR62421XMF/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- 24V
- Current - Output:
- 2.1A (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
LMR62421XMF/NOPB FAQ
1.How can I place an order for LMR62421XMF/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR62421XMF/NOPB 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 LMR62421XMF/NOPB reliable?
The price and inventory of LMR62421XMF/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR62421XMF/NOPB is usually 5 days.
3.What payment methods are accepted for LMR62421XMF/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR62421XMF/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR62421XMF/NOPB?
LMR62421XMF/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR62421XMF/NOPB 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 LMR62421XMF/NOPB?
For technical support, including LMR62421XMF/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR62421XMF/NOPB requirements.
6.How does Aetrix verify that LMR62421XMF/NOPB is sourced from the original manufacturer or authorized distributors?
All LMR62421XMF/NOPB 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 LMR62421XMF/NOPB meets industry standards.
7.What is the process for return or replacement of LMR62421XMF/NOPB?
All LMR62421XMF/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMR62421XMF/NOPB, 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 LMR62421XMF/NOPB part is unused and in its original packaging.
Return procedure for LMR62421XMF/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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