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Texas Instruments LM26420XSQ/NOPB
- Part No.:
- LM26420XSQ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
LM26420XSQ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A DL 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,212
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Product details
Overview
LM26420XSQ/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 internal 0.8 V reference (±1.5%). It integrates 75-mΩ PMOS and 50-mΩ NMOS power switches in a thermally enhanced HTSSOP-20 package for FPGA core/I/O power delivery.
For engineers reviewing the LM26420XSQ/NOPB datasheet, LM26420XSQ/NOPB pinout, LM26420XSQ/NOPB application, or LM26420XSQ/NOPB equivalent, key selection criteria include dual independent enable/power-good signaling, 180° phase-shifted operation for reduced input ripple, CISPR25 Class 5 EMI compliance, thermal shutdown at 165°C, and support for prebiased start-up - all critical for compact, high-density power designs in USB-powered and embedded systems.
Technical Context
The LM26420XSQ/NOPB implements current-mode PWM control with internal compensation, enabling stable regulation across 3–5.5 V input and 0.8–4.5 V output ranges. Its 2.2 MHz switching frequency (X-version) supports ultra-small external magnetics and capacitors while maintaining up to 93% peak efficiency.
Each buck channel features independent precision enable (1.04 V threshold, 150 mV hysteresis), open-drain power-good indicators, and cycle-by-cycle current limiting (3.3 A typical). Regulators operate 180° out of phase to minimize input capacitor RMS current and reduce conducted EMI - validated per CISPR25 Class 5 standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 5.5 V - supports single-cell Li-ion, USB 5 V, and industrial 3.3 V/5 V rails without external LDO pre-regulation. |
| Output Voltage Accuracy | ±1.5% over line/load/temperature - ensures tight Vcore and I/O voltage tolerance for FPGAs and ASICs. |
| Switching Frequency | 2.2 MHz (typical) - enables use of ≤1 µH inductors and 10–22 µF ceramic output capacitors for space-constrained layouts. |
| Max Output Current | 2 A per channel - sufficient for powering CPU cores, DDR memory I/O, and SoC subsystems simultaneously. |
| Internal Reference | 0.8 V ±1.5% - sets baseline for precise feedback divider design; supports 0.8–4.5 V programmable outputs. |
| Thermal Shutdown | 165°C junction - protects against sustained overload or poor PCB thermal design; auto-recovery at ~150°C. |
| EMI Compliance | CISPR25 Class 5 conducted emissions - meets automotive infotainment and industrial EMC requirements without added filtering. |
Pinout & Package
LM26420XSQ/NOPB uses the HTSSOP-20 (PWP) package (6.50 mm × 4.40 mm), featuring exposed die attach pad (DAP) connected to system ground for low thermal impedance (RθJA = 38.5°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VINC | Control circuit supply | Provides 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 respective buck; 150 mV hysteresis prevents chatter during ramp-up. |
| VIND1 / VIND2 | Power input for Buck 1/2 | Separate high-current VIN paths reduce crosstalk; each connects directly to input bulk capacitor. |
| SW1 / SW2 | Switch node outputs | Drive external inductors; require low-inductance layout and Kelvin connections to minimize ringing. |
| PGND1 / PGND2 | Power ground returns | Dedicated low-impedance paths for each buck's bottom switch; must connect to DAP and input cap ground. |
| FB1 / FB2 | Feedback inputs | Connect to resistor dividers setting VOUT; high-impedance (≤100 nA bias) enables precision resistor selection. |
| PG1 / PG2 | Open-drain power-good | Assert low when respective VOUT is within ±4% of target; requires external pull-up (10–100 kΩ) to sequencing logic. |
| AGND | Analog ground reference | Reference point for FB pins and internal error amp; must tie to PGND near DAP with short trace. |
Key Features
| Feature | Design Value |
|---|---|
| 180° phase-shifted operation | Reduces input capacitor RMS current by ~30%, lowering required capacitance and board area. |
| Prebiased output start-up | Enables safe turn-on into powered-down downstream circuits without reverse current or latch-up risk. |
| Internal soft-start (600 µs) | Controls output ramp rate to limit inrush current and prevent overshoot on both channels simultaneously. |
| Overvoltage protection (OVP) | Shuts off top switch if FB exceeds 15% above 0.8 V reference, protecting load ICs from transient overvoltage. |
| Undervoltage lockout (UVLO) | Disables operation below 2.63 V (rising) with 330 mV hysteresis, ensuring clean startup and preventing brownout oscillation. |
Applications
| FPGA Core & I/O Power | HDD/SSD Controller Supply |
|---|---|
Use Scenario: Powering Xilinx Artix-7 FPGA requiring 1.2 V core and 2.5 V I/O banks from a shared 5 V bus. IC Role / Device Role / Timing Role: Dual-buck regulator providing tightly regulated, sequenced, and monitored voltages with independent PG signals for configuration safety. Use Value: Eliminates need for two discrete converters; 2.2 MHz operation allows <10 mm² total solution size including passives. | Use Scenario: Generating 1.2 V and 2.5 V rails for SATA controller and NAND flash interface in portable SSD enclosures. IC Role / Device Role / Timing Role: High-efficiency dual regulator supporting burst-mode operation and fast load transient response for intermittent data transfers. Use Value: Achieves >90% efficiency at 500 mA load, extending battery life; CISPR25 compliance avoids EMI filtering overhead. |
| USB-Powered Embedded Systems | ASIC Core & Auxiliary Rail |
Use Scenario: Converting 5 V USB power to 1.2 V processor core and 2.5 V peripheral interface in IoT edge nodes. IC Role / Device Role / Timing Role: Compact dual-buck converter with independent enable control for dynamic power gating of subsystems. Use Value: Enables deep-sleep modes with <0.1 µA shutdown current; 180° phasing minimizes USB port voltage droop. | Use Scenario: Supplying 1.2 V digital core and 2.5 V analog/IO domains for custom ASIC in industrial PLC modules. IC Role / Device Role / Timing Role: Precision dual-regulator with ±1.5% output accuracy and thermal monitoring for mission-critical operation. Use Value: Maintains timing margin under full load at 85°C ambient; PG signals feed FPGA configuration state machine for fault recovery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54290RGER | Fixed 500 kHz frequency; lower max output current (1.5 A/channel); no integrated OVP. | Suitable for cost-sensitive, non-automotive applications where EMI filtering is less constrained. | Select when lower BOM cost and simpler layout outweigh need for 2.2 MHz switching and CISPR25 compliance. |
| RTQ2134BGQW | 4-MHz switching; higher quiescent current (12 µA vs. 0.05 µA shutdown); different enable threshold (1.2 V). | Better suited for ultra-low-power always-on subsystems requiring faster transient response. | Choose when 4-MHz operation enables smaller passives and faster load step recovery is prioritized over EMI certification. |
Compared with TPS54290RGER and RTQ2134BGQW, the LM26420XSQ/NOPB uniquely combines CISPR25 Class 5 compliance, 180° phase shift, and prebiased start-up in a single 20-pin HTSSOP package - making it optimal for space-limited, noise-sensitive, and safety-aware dual-rail applications where reliability and regulatory readiness are non-negotiable.
Availability
LM26420XSQ/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, USB-powered embedded systems, and industrial ASIC core/I/O supply requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LM26420XSQ/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 designing analog, embedded processing, and power management ICs for industrial, automotive, and communications markets.
The LM26420XSQ/NOPB belongs to TI's high-density DC/DC converter product line, engineered specifically for compact, high-efficiency dual-rail power solutions in FPGA, ASIC, and portable electronics applications.
FAQ
What is the switching frequency of the LM26420XSQ/NOPB?
The LM26420XSQ/NOPB operates at a fixed 2.2 MHz switching frequency, as designated by the "X" suffix in its part number. This high-frequency capability enables the use of miniature inductors (≤1 µH) and low-ESR ceramic capacitors, reducing overall solution footprint. The frequency remains stable across input voltage (3–5.5 V), load (0–2 A), and temperature (–40°C to 125°C) ranges, with typical variation of ±15%.
Does the LM26420XSQ/NOPB support powering prebiased outputs?
Yes, the LM26420XSQ/NOPB supports start-up into prebiased output loads - a critical feature for hot-swap and multi-rail sequencing applications. During prebias start-up, the internal soft-start circuit ramps the feedback reference from the existing output voltage level (not from 0 V) at the same controlled rate (~600 µs), preventing reverse current flow and avoiding potential damage to downstream components.
How does the LM26420XSQ/NOPB achieve CISPR25 Class 5 EMI compliance?
The LM26420XSQ/NOPB achieves CISPR25 Class 5 conducted emissions compliance through a combination of 180° phase-shifted switching, optimized internal gate drive timing, and integrated EMI-reduction circuitry. Its 2.2 MHz fundamental frequency places noise energy above sensitive AM radio bands, and the interleaved operation reduces input ripple amplitude - minimizing the need for external common-mode chokes or Y-capacitors in automotive and industrial designs.
What is the purpose of the VINC pin on the LM26420XSQ/NOPB?
The VINC pin on the LM26420XSQ/NOPB supplies bias voltage to the internal control circuitry, including the error amplifier, PWM comparator, and logic blocks. Unlike VIND pins, VINC is not a high-current path; it draws only ~5 mA in active mode. To ensure stability, TI specifies an RC filter (1–10 Ω series resistor + 0.22–1 µF X7R capacitor to AGND) between VINC and AGND to attenuate high-frequency noise from the main input rail.
Can the LM26420XSQ/NOPB be used with different output voltages than 2.5 V and 1.2 V?
Yes, the LM26420XSQ/NOPB supports programmable output voltages from 0.8 V to 4.5 V per channel using external resistor dividers on FB1 and FB2. The internal 0.8 V reference (±1.5%) serves as the feedback setpoint; for example, a 2.5 V output requires R1/R2 ≈ 2.125:1 (e.g., 21.25 kΩ/10 kΩ). The device maintains ±1.5% accuracy over line, load, and temperature - confirmed in TI's SNVS579L datasheet Section 6.5.
LM26420XSQ/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)
LM26420XSQ/NOPB FAQ
1.How can I place an order for LM26420XSQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM26420XSQ/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 LM26420XSQ/NOPB reliable?
The price and inventory of LM26420XSQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM26420XSQ/NOPB is usually 5 days.
3.What payment methods are accepted for LM26420XSQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM26420XSQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM26420XSQ/NOPB?
LM26420XSQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM26420XSQ/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 LM26420XSQ/NOPB?
For technical support, including LM26420XSQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM26420XSQ/NOPB requirements.
6.How does Aetrix verify that LM26420XSQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM26420XSQ/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 LM26420XSQ/NOPB meets industry standards.
7.What is the process for return or replacement of LM26420XSQ/NOPB?
All LM26420XSQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM26420XSQ/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 LM26420XSQ/NOPB part is unused and in its original packaging.
Return procedure for LM26420XSQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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