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Texas Instruments LM26420YSQ/NOPB
- Part No.:
- LM26420YSQ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
LM26420YSQ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A DL 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,770
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Product details
Overview
LM26420YSQ/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 0.55 MHz switching frequency and integrated 75-mΩ PMOS / 50-mΩ NMOS power switches - used for core and I/O voltage regulation in FPGAs and USB-powered embedded systems.
For engineers reviewing the LM26420YSQ/NOPB datasheet, LM26420YSQ/NOPB pinout, LM26420YSQ/NOPB application, or LM26420YSQ/NOPB equivalent, key selection criteria include independent enable/power-good signaling, 180° phase-shifted operation for reduced input ripple, thermal shutdown at 165°C, and compatibility with compact 4.0 mm × 4.0 mm WQFN-16 packaging.
Technical Context
The LM26420YSQ/NOPB implements current-mode PWM control with internal compensation, enabling stable regulation across 0.8 V–4.5 V output range using only external resistive feedback. Its 0.55 MHz fixed-frequency operation supports small external magnetics while maintaining high efficiency (up to 93%) and low output voltage ripple.
Each channel features independent precision enable (1.04 V threshold, 150 mV hysteresis) and open-drain power-good indicators, plus cycle-by-cycle current limiting (3.3 A typical), overvoltage protection (15% above VREF), and soft-start ramping of the 0.8 V reference over ~600 µs - all coordinated without external timing components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 5.5 V - supports direct regulation from USB 5 V or single-cell Li-ion battery rails. |
| Output Voltage Range | 0.8 V to 4.5 V - configurable via external resistor divider for FPGA core (1.2 V) and I/O (2.5 V) rails. |
| Max Output Current | 2 A per channel - sufficient for powering CPU cores, ASICs, and high-speed interface I/O domains. |
| Switching Frequency | 0.55 MHz - enables use of compact 1–2.2 µH inductors and low-ESR ceramic capacitors. |
| Feedback Reference | 0.8 V ±1.5% - high-accuracy internal reference ensures tight output regulation under load transients. |
| Thermal Shutdown | 165°C junction - protects device during overload or poor PCB thermal design; resumes at ~150°C. |
| Phase Relationship | 180° out-of-phase switching - reduces input capacitor RMS current and eases EMI filtering. |
Pinout & Package
LM26420YSQ/NOPB uses a 16-pin WQFN package (4.0 mm × 4.0 mm, 0.65 mm pitch) with exposed die attach pad (DAP) connected to system ground for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIND1, VIND2 | Power input supply for Buck 1 and Buck 2 | Separate input pins allow independent input sourcing or local decoupling per channel. |
| SW1, SW2 | Switch node outputs | Connect directly to respective inductors; require low-inductance layout to minimize switching losses. |
| FB1, FB2 | Feedback inputs | High-impedance nodes (≤100 nA bias) for precision resistor-divider-based output voltage setting. |
| PG1, PG2 | Open-drain Power Good indicators | Signal valid output within ±4% of target; require external pull-up resistor (10–100 kΩ) to enable sequencing. |
| EN1, EN2 | Independent enable inputs | Logic-high active (≥1.04 V); 150 mV hysteresis prevents chatter during slow-rising control signals. |
| AGND | Signal ground reference | Must be tied to local ground plane near FB resistors to avoid noise coupling into feedback path. |
| DAP | Die attach pad | Primary thermal and electrical ground connection - must be soldered to large copper pour for <36.2°C/W θJA. |
Key Features
| Feature | Design Value |
|---|---|
| Independent power-good signaling | Enables safe sequencing of downstream logic or memory rails before enabling next-stage loads. |
| 180° phase-shifted operation | Halves input capacitor RMS current versus in-phase dual buck, reducing required capacitance by ~30%. |
| Start-up into prebiased outputs | Prevents reverse current flow when powering up into partially charged rails - critical for hot-swap applications. |
| Internal soft start | Ramps 0.8 V reference over ~600 µs to limit inrush current and eliminate output overshoot. |
| CISPR25 Class 5 compliance | Meets automotive conducted emissions requirements without additional shielding or filtering components. |
Applications
| FPGA Core & I/O Power | HDD/SSD Controller Supply |
|---|---|
Use Scenario: Providing separate 1.2 V core and 2.5 V I/O rails to Xilinx Artix-7 FPGA on compact industrial controller board. IC Role / Device Role / Timing Role: Dual synchronous buck regulator supplying regulated DC power with independent sequencing and fault reporting. Use Value: Eliminates need for two discrete converters; 180° phase shift reduces input ripple, easing compliance with strict EMI limits in enclosed enclosures. | Use Scenario: Powering 3.3 V SATA controller and 1.8 V NAND flash interface in portable SSD enclosure. IC Role / Device Role / Timing Role: Dual-output DC/DC converter generating tightly regulated voltages from shared 5 V USB-C input rail. Use Value: Independent EN/PG pins enable staggered startup to avoid inrush current exceeding USB 5 V port limits (900 mA). |
| USB-Powered Embedded System | CPU/ASIC Core + I/O Regulation |
Use Scenario: Regulating 1.2 V processor core and 3.3 V peripheral bus from 5 V USB power in medical sensor hub. IC Role / Device Role / Timing Role: High-efficiency dual buck IC managing power delivery with thermal monitoring and fault signaling. Use Value: 93% peak efficiency minimizes self-heating in sealed plastic housing; thermal shutdown prevents unsafe temperature rise. | Use Scenario: Generating 1.0 V core and 1.8 V I/O supplies for ARM Cortex-A53 SoC in edge AI gateway. IC Role / Device Role / Timing Role: Monolithic dual buck converter supporting dynamic voltage scaling and independent rail control. Use Value: Precision enable thresholds allow coordination with SoC power management unit for controlled sleep/wake transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS65261RHBR | Fixed 1.2 V / 3.3 V outputs; no adjustable FB; 2.2 MHz switching; 3 A per channel | Less flexible for custom voltage combinations but simplifies BOM with no external resistors needed | Choose when standard voltages suffice and higher current headroom is required |
| RTQ2132BGQW | 0.6 V–5.5 V adjustable outputs; 1.5 MHz; 2.5 A per channel; integrated MOSFETs; smaller 3 mm × 3 mm QFN | Higher switching frequency allows even smaller passives; lower RDS(on) improves light-load efficiency | Prefer for space-constrained designs needing tighter output tolerance (±1%) and faster transient response |
Compared with TPS65261RHBR and RTQ2132BGQW, the LM26420YSQ/NOPB offers superior flexibility in output voltage configuration (0.8–4.5 V), proven CISPR25 Class 5 compliance for automotive-adjacent applications, and robust 180° phase-shifted operation - making it ideal where custom rail generation, EMI control, and thermal resilience are prioritized over minimal footprint or fixed-voltage simplicity.
Availability
LM26420YSQ/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, USB-powered embedded systems, and industrial CPU/ASIC core regulation requiring stable component supply and long-term production continuity.
Supply support for LM26420YSQ/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-reliability DC/DC conversion.
The LM26420 product line delivers dual synchronous buck regulation for space-constrained, thermally demanding applications - designed specifically for FPGA, CPU, and storage subsystems requiring precise, sequenced, and efficient multi-rail power.
FAQ
What is the switching frequency of the LM26420YSQ/NOPB?
The LM26420YSQ/NOPB operates at a fixed 0.55 MHz switching frequency, optimized for compact external components and low EMI. This frequency is inherent to the Y-version variant and cannot be adjusted externally. The LM26420YSQ/NOPB achieves up to 93% peak efficiency at this frequency while maintaining excellent transient response and thermal performance in its 4.0 mm × 4.0 mm WQFN package.
Does the LM26420YSQ/NOPB support start-up into a prebiased output?
Yes, the LM26420YSQ/NOPB supports start-up into prebiased output loads - a critical feature for hot-swap and redundant power systems. During such start-up, the feedback reference ramps from the existing output voltage level rather than from 0 V, preventing reverse current flow through the bottom FET. This behavior is confirmed in the official TI datasheet (SNVS579L, Section 7.3.1) and applies specifically to the LM26420YSQ/NOPB variant.
What are the thermal characteristics of the LM26420YSQ/NOPB in its WQFN package?
The LM26420YSQ/NOPB in the 16-pin WQFN package has a junction-to-ambient thermal resistance (θJA) of 36.2°C/W and junction-to-board (θJB) of 14.1°C/W when mounted on a standard 2-layer PCB with adequate copper pour. Its thermal shutdown activates at 165°C junction temperature and releases at ~150°C. Proper DAP soldering to a large ground plane is essential to achieve these ratings and sustain 2 A continuous output per channel.
Can the two outputs of the LM26420YSQ/NOPB be configured to different voltages?
Yes, the LM26420YSQ/NOPB supports independent output voltage configuration via separate FB1 and FB2 pins. Each output is set using a resistor divider referenced to the internal 0.8 V bandgap - for example, 2.5 V on VOUT1 and 1.2 V on VOUT2. The datasheet confirms full adjustability from 0.8 V to 4.5 V per channel, with no coupling between channels beyond shared input and ground connections.
What is the purpose of the VINC pin on the LM26420YSQ/NOPB?
The VINC pin on the LM26420YSQ/NOPB supplies power to the internal control circuitry, including the error amplifier, PWM comparator, and logic blocks. It must be decoupled with an RC filter (e.g., 1–10 Ω + 0.22–1 µF) to suppress high-frequency noise from the main input rail. Unlike VIND1/VIND2, VINC does not source power-switch current - its quiescent current is 3.3–5 mA (non-switching) and drops to 0.05 µA in shutdown, ensuring low standby power consumption.
LM26420YSQ/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:
- 550kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (4x4)
LM26420YSQ/NOPB FAQ
1.How can I place an order for LM26420YSQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM26420YSQ/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 LM26420YSQ/NOPB reliable?
The price and inventory of LM26420YSQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM26420YSQ/NOPB is usually 5 days.
3.What payment methods are accepted for LM26420YSQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM26420YSQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM26420YSQ/NOPB?
LM26420YSQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM26420YSQ/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 LM26420YSQ/NOPB?
For technical support, including LM26420YSQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM26420YSQ/NOPB requirements.
6.How does Aetrix verify that LM26420YSQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM26420YSQ/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 LM26420YSQ/NOPB meets industry standards.
7.What is the process for return or replacement of LM26420YSQ/NOPB?
All LM26420YSQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM26420YSQ/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 LM26420YSQ/NOPB part is unused and in its original packaging.
Return procedure for LM26420YSQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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