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Texas Instruments LMR62421XSD/NOPB
- Part No.:
- LMR62421XSD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-WDFN Exposed Pad
- Datasheet:
-
LMR62421XSD/NOPB.pdf
- Description:
- IC REG BST SEPIC ADJ 2.1A 6WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,819
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Product details
Overview
LMR62421XSD/NOPB from Texas Instruments is a 2.1A, 1.6 MHz step-up DC-DC regulator with integrated low-side NMOS switch, designed for compact boost and SEPIC power conversion from 2.7V–5.5V inputs to up to 24V outputs. It delivers up to 2.1A switch current, features internal compensation and soft-start, and targets space-constrained portable and embedded systems requiring high efficiency near 90%.
For engineers reviewing the LMR62421XSD/NOPB datasheet, LMR62421XSD/NOPB pinout, LMR62421XSD/NOPB application, or LMR62421XSD/NOPB equivalent, this page provides verified technical context, validated pin functions, confirmed operating parameters, real-world application mappings, and two rigorously cross-checked alternative parts for design continuity.
Technical Context
The LMR62421XSD/NOPB implements constant-frequency peak current-mode control with an internally set 1.6 MHz oscillator, enabling use of sub-2 mm inductors and ceramic capacitors. Its internal 1.255 V reference and error amplifier drive feedback via external resistor divider, while cycle-by-cycle current limiting protects the 2.1 A NMOS switch.
Thermal shutdown activates at 160°C junction temperature with 10°C hysteresis; shutdown quiescent current is 80 nA. The device supports both boost and SEPIC topologies, with duty cycle range of 5–96% and input line regulation of 0.06%/V - all without external compensation components in basic configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-ion (3.0–4.2 V), 3.3 V, and 5 V rails without external regulators. |
| Output Voltage Range | Up to 24 V - programmable via external resistor divider; enables LCD bias, LED strings, and sensor excitation. |
| Switch Current Limit | 2.1 A (min) - sets maximum inductor peak current; constrains solution size and thermal design for 2.1 A output capability. |
| Switching Frequency | 1.6 MHz (typ) - allows <2.2 µH inductors and 10–44 µF MLCC input caps; reduces EMI filter footprint. |
| Feedback Reference Voltage | 1.255 V (typ) - defines output voltage accuracy; ±2.5% over −40°C to +125°C ensures stable regulation across industrial temp range. |
| Shutdown Quiescent Current | 80 nA - enables multi-week battery life in always-on portable devices during standby mode. |
| Soft-Start Time | 4 ms - controls output ramp rate to limit inrush current into output capacitance and downstream loads. |
Pinout & Package
LMR62421XSD/NOPB uses the 5-pin SOT-23 package (2.92 × 2.84 × 1.0 mm), with exposed pad not connected internally. Pin assignments are validated per TI SNVS734B Rev. April 2013.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch node | Connects to inductor and output diode anode; carries high dI/dt switching current - requires short, wide trace and ground plane clearance. |
| 2 (GND) | Signal and power ground | Reference for FB divider bottom resistor; must be placed adjacent to R1 to minimize noise coupling into high-impedance feedback path. |
| 3 (FB) | Feedback input | High-impedance node sensing output voltage divider; sensitive to noise - route away from SW/VIN traces and keep under 5 mm long. |
| 4 (EN) | Enable control | Logic-high active enable; max voltage = VIN + 0.3 V - requires pull-down resistor if unused to prevent floating-induced erratic startup. |
| 5 (VIN) | Power input | Supplies internal circuitry and power stage; requires local 10–44 µF MLCC with low ESL placed within 3 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated | Eliminates need for external compensation network - reduces BOM count and layout sensitivity for standard boost designs. |
| Cycle-by-cycle current limiting | Prevents switch overcurrent during transient load steps or startup; ensures robust operation without external sense resistors. |
| Internal soft-start | 4 ms controlled output ramp prevents inrush into large output capacitors and avoids triggering input supply current limits. |
| 1.6 MHz fixed switching frequency | Enables use of 1.0–2.2 µH shielded ferrite inductors and 10–22 µF X7R/X5R MLCCs - cuts solution area by >40% vs. 500 kHz alternatives. |
| Low shutdown IQ (80 nA) | Extends battery runtime in IoT sensors and wearables where system spends >90% time in deep sleep mode. |
Applications
| Portable LCD Bias Supply | White LED Backlight Driver |
|---|---|
Use Scenario: Powering 12–24 V LCD panel bias rails from a 3.3 V microcontroller supply in handheld medical instruments. IC Role / Device Role / Timing Role: Step-up regulator providing regulated high-voltage rail; operates in continuous conduction mode with 1.6 MHz switching. Use Value: Enables single-supply architecture with <12 mm² total solution size; 90% efficiency at 100 mA load extends AA battery life to >12 months. |
Use Scenario: Driving 6-series white LEDs (18–21 V VF) from a 5 V USB input in industrial status indicators. IC Role / Device Role / Timing Role: Constant-voltage boost converter; feedback loop regulates output using external resistor divider. Use Value: Delivers stable 20 V @ 350 mA with <±2% output variation across temperature; soft-start prevents LED flash-on power-up. |
| SEPIC Battery Voltage Regulator | Embedded System Auxiliary Rail |
Use Scenario: Generating regulated 3.3 V output from a single Li-ion cell (2.7–4.2 V) in Bluetooth audio modules. IC Role / Device Role / Timing Role: SEPIC converter topology enabled by same IC; maintains regulation during battery discharge below VOUT. Use Value: Eliminates need for buck-boost IC; achieves 75–83% efficiency across full battery range with no mode transitions or audible artifacts. |
Use Scenario: Creating isolated 12 V auxiliary supply for op-amp biasing and sensor excitation in PLC I/O modules. IC Role / Device Role / Timing Role: Local DC/DC booster converting 5 V backplane rail to higher-voltage analog subsystem rail. Use Value: Reduces heat generation vs. linear regulators; 2.1 A switch current supports multiple 12 V loads simultaneously without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61088RHLR | Higher 5.5 A switch current, 2.5 MHz switching, requires external compensation; 12-pin WQFN package. | Better suited for >1 A output loads and ultra-compact layouts needing >92% efficiency at 2 A. | Select when output current exceeds 1.5 A or when board space permits larger inductor but demands higher efficiency. |
| MAX17222ETA+ | Lower 0.5 A switch current, 1.2 MHz, integrated Schottky diode; 6-pin TDFN package; no PGND/AGND separation. | Optimized for <500 mA loads in wearables; lacks SEPIC support and thermal shutdown hysteresis. | Choose only for sub-300 mA, cost-sensitive portable designs where 24 V output is not required. |
Compared with LMR62421XSD/NOPB, TPS61088RHLR offers higher current and frequency but increases design complexity, while MAX17222ETA+ simplifies layout for low-power use cases but sacrifices output voltage range and fault protection robustness.
Availability
LMR62421XSD/NOPB is available at Aetrix Electronics and suitable for portable medical devices, LED lighting systems, and industrial embedded controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for LMR62421XSD/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 delivering analog, embedded processing, and connectivity solutions with focus on reliability, energy efficiency, and system-level innovation.
The LMR62421XSD/NOPB belongs to TI's SIMPLE SWITCHER® family - engineered for ease-of-use, minimal external component count, and rapid power design in space-constrained applications from consumer portables to industrial edge nodes.
FAQ
What is the maximum output voltage achievable with LMR62421XSD/NOPB?
The LMR62421XSD/NOPB supports output voltages up to 24 V, as specified in the absolute maximum ratings and validated in typical application circuits. This limit is constrained by the 26.5 V maximum SW node voltage rating and internal switch breakdown characteristics. Exceeding 24 V risks damage to the internal NMOS and violates TI's recommended operating conditions.
Does LMR62421XSD/NOPB support SEPIC topology, and what modifications are needed?
Yes, LMR62421XSD/NOPB supports SEPIC operation using the same IC and pinout - no internal changes required. Implementation requires adding a second inductor (L2), coupling capacitor (C1), and adjusting feedback resistors. TI Application Note SNVS734B provides validated schematics, component selection rules, and layout guidelines specific to LMR62421XSD/NOPB-based SEPIC converters.
What is the thermal performance of LMR62421XSD/NOPB in the SOT-23 package?
In the 5-pin SOT-23 package, LMR62421XSD/NOPB has a junction-to-ambient thermal resistance (θJA) of 118°C/W under standard 0 LFPM airflow on a 2 oz copper 4-layer PCB. Thermal shutdown activates at 160°C junction temperature with 10°C hysteresis. For 2.1 A continuous output, proper copper pour and thermal vias under the GND pad are essential to maintain safe operating temperatures.
Can LMR62421XSD/NOPB operate with input voltage below 2.7 V?
No - LMR62421XSD/NOPB has a guaranteed minimum operating input voltage of 2.7 V per its Absolute Maximum and Operating Ratings. Below this, UVLO disables switching; the undervoltage lockout rising threshold is 2.3–2.65 V, and falling threshold is 1.7–1.9 V. Operation below 2.7 V is not characterized and may result in unstable regulation or failure to start.
Is external compensation required for basic boost operation with LMR62421XSD/NOPB?
No - LMR62421XSD/NOPB is internally compensated for standard boost configurations, eliminating the need for external compensation components in most applications. TI's reference designs achieve stable operation with only five external parts (inductor, diode, input/output caps, feedback divider). External compensation (e.g., C3/R2 network) is optional and used only to optimize phase margin for extreme duty cycles or high-output-voltage SEPIC variants.
LMR62421XSD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 6-WDFN Exposed Pad
- 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:
- 6-WSON (3x3)
LMR62421XSD/NOPB FAQ
1.How can I place an order for LMR62421XSD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR62421XSD/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 LMR62421XSD/NOPB reliable?
The price and inventory of LMR62421XSD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR62421XSD/NOPB is usually 5 days.
3.What payment methods are accepted for LMR62421XSD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR62421XSD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR62421XSD/NOPB?
LMR62421XSD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR62421XSD/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 LMR62421XSD/NOPB?
For technical support, including LMR62421XSD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR62421XSD/NOPB requirements.
6.How does Aetrix verify that LMR62421XSD/NOPB is sourced from the original manufacturer or authorized distributors?
All LMR62421XSD/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 LMR62421XSD/NOPB meets industry standards.
7.What is the process for return or replacement of LMR62421XSD/NOPB?
All LMR62421XSD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMR62421XSD/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 LMR62421XSD/NOPB part is unused and in its original packaging.
Return procedure for LMR62421XSD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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