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Texas Instruments LM26420XSQX/NOPB
- Part No.:
- LM26420XSQX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
LM26420XSQX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A DL 16WQFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM26420XSQX/NOPB from Texas Instruments is a dual-channel synchronous buck DC/DC converter delivering 2 A per channel at 2.5 V and 1.2 V outputs, operating from 3 V to 5.5 V input, with 2.2 MHz fixed switching frequency and integrated 75-mΩ PMOS / 50-mΩ NMOS power switches. It serves as core and I/O voltage regulator for FPGAs and ASICs in space-constrained USB-powered and embedded systems.
For engineers reviewing the LM26420XSQX/NOPB datasheet, LM26420XSQX/NOPB pinout, LM26420XSQX/NOPB application, or LM26420XSQX/NOPB equivalent, key selection considerations include its 2.2 MHz operation enabling compact 1-µH inductors, independent precision enable (1.04 V threshold) and open-drain power-good signals per channel, internal 0.8 V reference (±1.5%), and thermal shutdown at 165°C.
Technical Context
The LM26420XSQX/NOPB implements current-mode PWM control with internal compensation, supporting minimum on-times down to 30 ns to sustain regulation at 0.8 V output across its full 3–5.5 V input range. Its two regulators operate 180° out of phase to reduce input ripple current and improve EMI performance.
It integrates independent UVLO (2.628 V rising, 330 mV hysteresis), overvoltage protection (15% above VREF), cycle-by-cycle current limiting (3.3 A typical), and soft-start (600 µs ramp). The device uses separate VIND1/VIND2 power inputs and shares AGND/PGND pins optimized for high-frequency layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 5.5 V - supports direct USB 5 V, single-cell Li-ion, or regulated 3.3 V rails without pre-regulation. |
| Switching Frequency | 2.2 MHz (typical) - enables use of 1–2.2 µH inductors and 10–22 µF ceramic output capacitors for ultra-compact layouts. |
| Output Current | 2 A per channel - sufficient for FPGA core (VCCINT) and I/O (VCCIO) or CPU core/I/O pair in portable devices. |
| Feedback Reference | 0.8 V ±1.5% - sets output accuracy; used with external resistor divider to configure 0.8–4.5 V outputs (e.g., 2.5 V/1.2 V shown). |
| Power Switch RDS(on) | 75 mΩ (top), 50 mΩ (bottom) - delivers >93% peak efficiency at 2 A, minimizing thermal load in HTSSOP-20 package. |
| Enable Threshold | 1.04 V with 150 mV hysteresis - allows precise sequencing using resistor dividers off upstream supplies or microcontroller GPIO. |
| Thermal Shutdown | 165°C junction - protects against sustained overload or poor PCB thermal design; auto-recovery at ~150°C. |
Pinout & Package
LM26420XSQX/NOPB is packaged in a thermally enhanced 20-pin HTSSOP (PWP) with 6.50 mm × 4.40 mm body size and exposed die attach pad (DAP) for low-thermal-impedance grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VINC | Control IC supply | Provides clean bias for internal logic and error amplifier; requires RC filter (1–10 Ω + 0.22–1 µF) to reject VIN noise. |
| EN1, EN2 | Independent enable inputs | Logic-high (>1.04 V) activates each buck channel; hysteresis prevents chatter during slow-rising control signals. |
| VIND1, VIND2 | Power input for Buck 1/2 | Separate high-current inputs allow independent input sourcing or local decoupling per channel. |
| SW1, SW2 | Switch node outputs | Connect directly to inductor; swing between VIN and GND; require tight loop layout with low-ESR input caps. |
| FB1, FB2 | Feedback inputs | Monitor output via resistor divider; high-impedance (≤100 nA bias) enables use of high-value resistors for low quiescent current. |
| PG1, PG2 | Open-drain Power Good | Assert low when respective output is within ±7.5% of target; requires external pull-up (10–100 kΩ) for sequencing or fault indication. |
| PGND1, PGND2, AGND | Ground terminals | PGND pins carry high di/dt switch currents; AGND is signal reference - must be joined at single point near DAP. |
| DAP | Exposed thermal pad | Must be soldered to large PCB copper area for thermal conduction; primary GND connection path for heat dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| 180° phase-shifted dual outputs | Reduces RMS input capacitor ripple current by ~30%, allowing smaller bulk capacitance and lower EMI. |
| CISPR25 Class 5 compliance | Validated conducted emissions performance - simplifies automotive and industrial EMC certification. |
| Start-up into prebiased outputs | Enables safe hot-plug operation without reverse current flow or output overshoot when VOUT is already charged. |
| Internal soft-start (600 µs) | Controls output ramp rate to limit inrush current and prevent undershoot on downstream LDOs or processors. |
| Independent UVLO and OVP per channel | Allows robust fault isolation: one channel can shut down due to overvoltage while the other remains operational. |
Applications
| FPGA Core & I/O Power | HDD/SSD Controller Supply |
|---|---|
Use Scenario: Powering Xilinx Artix-7 or Intel Cyclone V FPGA requiring 1.2 V core (2 A) and 2.5 V I/O bank (2 A) from a shared 5 V USB source. IC Role / Device Role / Timing Role: Dual synchronous buck regulator providing tightly regulated, sequenced, and monitored VCCINT and VCCIO rails. Use Value: Eliminates need for two discrete converters; 2.2 MHz operation reduces total BOM area by >40% vs. 500 kHz alternatives. | Use Scenario: Generating 1.2 V and 2.5 V supplies for SATA controller and NAND flash interface in portable SSD enclosures. IC Role / Device Role / Timing Role: High-efficiency dual DC/DC converter delivering stable, low-noise power under dynamic load transients. Use Value: Achieves >92% efficiency at 1.5 A per rail, extending battery life; phase interleaving lowers input ripple for cleaner 5 V bus sharing. |
| USB-Powered Embedded Systems | ASIC Core & Memory Interface |
Use Scenario: Powering ARM Cortex-M7 MCU, DDR3L memory, and sensor hub from a single 5 V USB Type-C port. IC Role / Device Role / Timing Role: Primary power management IC supplying processor core (1.2 V) and memory I/O (2.5 V) with independent enable/control. Use Value: Independent EN1/EN2 and PG1/PG2 support flexible power-up sequencing required by ARM boot ROM and DDR initialization. | Use Scenario: Providing 1.2 V core and 2.5 V SerDes/interface voltage for custom SoC in set-top box or gateway platform. IC Role / Device Role / Timing Role: Dual high-current buck regulator with precision enable and power-good signaling for system-level power sequencing. Use Value: Internal 0.8 V reference (±1.5%) and 1.04 V enable threshold enable accurate rail tracking and deterministic startup timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54290RTWR | 500 kHz max frequency; 3.5 V–20 V input; 2 A per channel; no integrated bottom FET (external sync rectifier required). | Targets higher-input industrial rails; lacks 2.2 MHz compactness and internal FET integration. | Choose when input exceeds 5.5 V or when external MOSFET control is preferred for thermal partitioning. |
| MP2491DS-LF-Z | 1.4 MHz switching; 4.5 V–18 V input; 2 A per channel; 0.8 V reference (±2%); no independent PG/EN per channel. | Designed for wider-input industrial/automotive; single enable and power-good pin limits sequencing flexibility. | Choose for cost-sensitive non-sequencing applications where input >5.5 V and board space is less constrained. |
Compared with TPS54290RTWR and MP2491DS-LF-Z, LM26420XSQX/NOPB uniquely combines 2.2 MHz operation, fully integrated dual FETs, independent per-channel enable/power-good, and sub-6 V input optimization - making it the only option that meets strict USB-powered, FPGA-centric, and ultra-compact design requirements without compromise.
Availability
LM26420XSQX/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, USB-powered embedded systems, and HDD/SSD controller designs requiring stable component supply, long-term production continuity, and TI-authorized traceability.
Supply support for LM26420XSQX/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 technologies, with decades of expertise in high-efficiency DC/DC conversion.
The LM26420 product line delivers dual synchronous buck regulators optimized for space-constrained, high-performance digital systems - specifically targeting FPGA, ASIC, and multi-rail processor applications demanding precision sequencing, low EMI, and minimal footprint.
FAQ
What input voltage range does the LM26420XSQX/NOPB support?
The LM26420XSQX/NOPB supports an input voltage range of 3 V to 5.5 V. This makes it ideal for direct connection to USB 5 V sources, single-cell Li-ion batteries (fully charged at ~4.2 V), or regulated 3.3 V intermediate rails. Operation below 3 V is prohibited by UVLO (2.628 V rising threshold), and absolute maximum input is 7 V per datasheet Absolute Maximum Ratings.
Does the LM26420XSQX/NOPB require external MOSFETs?
No, the LM26420XSQX/NOPB integrates both high-side (75-mΩ PMOS) and low-side (50-mΩ NMOS) power switches per channel. No external MOSFETs are needed - only external inductors, input/output capacitors, and feedback resistors are required to implement a complete dual-output power supply. This integration reduces solution size and simplifies layout versus controllers requiring external FETs.
How does the LM26420XSQX/NOPB handle power sequencing between its two outputs?
The LM26420XSQX/NOPB supports flexible sequencing via independent EN1 and EN2 pins and separate open-drain PG1 and PG2 signals. Each channel can be enabled at different times using resistor dividers or microcontroller GPIOs, and PG status can feed back to control logic or enable downstream regulators. When enabled simultaneously, outputs ramp ratiometrically due to shared soft-start circuitry - ensuring monotonic startup without cross-rail interaction.
What is the switching frequency of the LM26420XSQX/NOPB and why does it matter?
The LM26420XSQX/NOPB operates at a fixed 2.2 MHz switching frequency. This high frequency allows use of small 1–2.2 µH shielded inductors and low-ESR 10–22 µF ceramic output capacitors, significantly reducing total solution footprint and height. It also pushes switching noise beyond sensitive AM radio bands and enables faster transient response compared to lower-frequency alternatives like 500 kHz converters.
Can the LM26420XSQX/NOPB start up into a prebiased output?
Yes, the LM26420XSQX/NOPB supports start-up into prebiased outputs. Its current-mode architecture and controlled soft-start ramp (starting from the existing FB voltage rather than 0 V) prevent reverse current flow and output overshoot when powering loads already holding residual voltage - a critical capability for hot-swap, modular, or multi-source power systems where rail voltages may not fall to zero between cycles.
LM26420XSQX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-WQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 4.5V
- Current - Output:
- 2A
- Frequency - Switching:
- 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (4x4)
LM26420XSQX/NOPB FAQ
1.How can I place an order for LM26420XSQX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM26420XSQX/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 LM26420XSQX/NOPB reliable?
The price and inventory of LM26420XSQX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM26420XSQX/NOPB is usually 5 days.
3.What payment methods are accepted for LM26420XSQX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM26420XSQX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM26420XSQX/NOPB?
LM26420XSQX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM26420XSQX/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 LM26420XSQX/NOPB?
For technical support, including LM26420XSQX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM26420XSQX/NOPB requirements.
6.How does Aetrix verify that LM26420XSQX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM26420XSQX/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 LM26420XSQX/NOPB meets industry standards.
7.What is the process for return or replacement of LM26420XSQX/NOPB?
All LM26420XSQX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM26420XSQX/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 LM26420XSQX/NOPB part is unused and in its original packaging.
Return procedure for LM26420XSQX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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