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Texas Instruments LM26420YMHX/NOPB
- Part No.:
- LM26420YMHX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM26420YMHX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A DL 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,228
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Product details
Overview
LM26420YMHX/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 output, operating from 3 V to 5.5 V input with 0.55 MHz fixed switching frequency and integrated 75-mΩ PMOS / 50-mΩ NMOS power switches - used for core/I/O voltage regulation in FPGAs, CPUs, and USB-powered embedded systems.
For engineers reviewing the LM26420YMHX/NOPB datasheet, LM26420YMHX/NOPB pinout, LM26420YMHX/NOPB application, or LM26420YMHX/NOPB equivalent, key selection considerations include its dual independent enable/power-good controls, 180° out-of-phase operation for reduced input ripple, internal 0.8 V ±1.5% reference, thermal shutdown at 165°C, and compliance with CISPR25 Class 5 conducted emissions.
Technical Context
The LM26420YMHX/NOPB implements current-mode PWM control with internal compensation, enabling stable regulation across 0.8 V–4.5 V output range and supporting startup into prebiased loads. Its 0.55 MHz switching frequency (Y-version) balances efficiency and component size, while 180° phase shift between SW1 and SW2 minimizes input capacitor RMS current.
Each channel features independent precision enable (1.04 V threshold, 150 mV hysteresis), open-drain power good (±40 mV hysteresis), and cycle-by-cycle current limiting (3.3 A typical). Overvoltage protection triggers at ~15% above VREF, and undervoltage lockout activates below 2.628 V with 330 mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 5.5 V - supports single-cell Li-ion, USB 3.0, and 5 V rail inputs without external LDO pre-regulation. |
| Output Voltage Accuracy | 0.8 V ±1.5% - enables precise core voltage setting with minimal feedback resistor tolerance impact. |
| Switching Frequency | 0.55 MHz - allows use of compact 1–2.2 µH inductors and reduces EMI filtering burden vs lower-frequency alternatives. |
| Max Output Current | 2 A per channel - sufficient for FPGA I/O banks or CPU subsystems without external current boosting. |
| Efficiency | Up to 93% - minimizes thermal load in space-constrained industrial and portable designs. |
| Thermal Shutdown | 165°C junction - protects against sustained overload or poor PCB thermal design without requiring external thermal monitoring. |
| Phase Relationship | 180° out-of-phase - cuts input capacitor RMS current by ~70% versus in-phase operation, extending capacitor life. |
Pinout & Package
LM26420YMHX/NOPB is packaged in HTSSOP-20 (6.50 mm × 4.40 mm) with exposed die attach pad (DAP) for enhanced thermal dissipation. Pin functions are validated per TI SNVS579L Rev L datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VINC | Control circuit 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 respective buck; hysteresis prevents chatter during slow-rising control signals. |
| VIND1 / VIND2 | Power input for Buck 1/2 | Separate high-current paths reduce crosstalk; each must be decoupled near package with ≥10 µF ceramic. |
| SW1 / SW2 | Switch node outputs | Connect directly to inductor; require low-inductance layout to minimize switching losses and EMI. |
| FB1 / FB2 | Feedback inputs | High-impedance (≤100 nA bias) nodes; bottom resistor must tie to AGND, not PGND, for accuracy. |
| PG1 / PG2 | Open-drain Power Good | Assert low when respective output deviates >±40 mV from target; requires external pull-up (10–100 kΩ). |
| PGND1 / PGND2 | Power ground returns | Separate low-impedance paths for each buck's return current; must connect to DAP and system GND at single point. |
| AGND | Signal ground reference | Reference for FB, EN, PG; must be isolated from noisy PGND until joined at DAP or star ground. |
| DAP | Exposed thermal pad | Primary thermal path and electrical GND; must be soldered to ≥2 cm² copper pour with ≥4 thermal vias to inner layers. |
Key Features
| Feature | Design Value |
|---|---|
| CISPR25 Class 5 compliance | Meets automotive EMC requirements without additional shielding or ferrite beads in standard layout. |
| Internal soft-start (600 µs) | Prevents inrush current and output overshoot; supports ratiometric startup when EN1/EN2 tied. |
| Start-up into prebiased outputs | Enables hot-swap or partial-power-down sequencing without damaging downstream loads. |
| Independent power-good indicators | Allows safe sequencing of FPGA configuration, memory initialization, or multi-rail SoC boot. |
| Overvoltage protection (OVP) | Clamps output at ~0.92 V (15% above 0.8 V reference) to protect sensitive 1.2 V/2.5 V loads. |
Applications
| FPGA Core & I/O Power | HDD/SSD Controller Supply |
|---|---|
Use Scenario: Powering Xilinx Artix-7 FPGA with 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 rails with independent enable timing. Use Value: Eliminates need for discrete sequencing ICs; 180° phase shift reduces input capacitance by 40% vs in-phase dual converters. | Use Scenario: Generating 1.2 V for SATA controller and 2.5 V for flash interface in portable SSD enclosures. IC Role / Device Role / Timing Role: High-efficiency dual DC/DC converter with thermal shutdown protecting against enclosure overheating. Use Value: 93% peak efficiency extends battery runtime; PG1/PG2 signals coordinate firmware-initiated safe shutdown. |
| USB-Powered Industrial Sensor Hub | CPU Subsystem for Set-Top Box |
Use Scenario: Deriving 1.2 V and 2.5 V rails from USB 3.0 5 V input for ARM Cortex-M7 + analog front-end. IC Role / Device Role / Timing Role: Compact dual buck managing power integrity under dynamic sensor sampling loads. Use Value: 0.55 MHz switching enables <3 mm² total inductor footprint; CISPR25 compliance avoids USB-IF radiated emission failures. | Use Scenario: Supplying 1.2 V CPU core and 2.5 V video decoder I/O in thermally constrained STB chassis. IC Role / Device Role / Timing Role: Dual synchronous buck with independent enable for staggered boot and thermal-aware throttling. Use Value: Thermal shutdown at 165°C prevents thermal runaway; HTSSOP-20 package fits 8 mm height envelope. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54290RTER | Fixed 2.2 MHz switching (X-version), higher RDS(on) (110 mΩ top), no OVP, 0.8 V reference ±2%. | Lacks overvoltage protection and tighter reference; better suited for ultra-compact layouts where 2.2 MHz enables smaller passives. | Select when board area is critical and OVP is handled externally; verify thermal performance at 2 A continuous. |
| RTQ2132BGQW | 0.65 MHz switching, 1.5% VREF, integrated MOSFETs, but only one PG pin and no independent EN control. | Single power-good signal limits sequencing flexibility; suitable for cost-sensitive consumer apps with simpler rail sequencing. | Choose when dual independent enables are unnecessary and BOM count reduction outweighs sequencing granularity. |
Compared with TPS54290RTER and RTQ2132BGQW, LM26420YMHX/NOPB provides superior sequencing control via dual EN/PG pins, built-in OVP, and tighter reference accuracy - making it preferred for industrial and FPGA applications demanding robust fault handling and rail coordination.
Availability
LM26420YMHX/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, HDD controller supplies, and USB-powered sensor hubs requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM26420YMHX/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, noise-sensitive applications including automotive infotainment, industrial PLCs, and portable computing - emphasizing EMI control, thermal resilience, and seamless power sequencing.
FAQ
What is the switching frequency of LM26420YMHX/NOPB and how does it affect design?
The LM26420YMHX/NOPB operates at a fixed 0.55 MHz switching frequency. This enables use of small, low-profile inductors (1–2.2 µH) and ceramic output capacitors while maintaining high efficiency (up to 93%). The frequency is optimized to balance EMI performance, thermal behavior, and passive component size - unlike the 2.2 MHz LM26420X variant, the Y-version prioritizes lower switching losses in thermally constrained applications.
Does LM26420YMHX/NOPB support startup into a prebiased output?
Yes, LM26420YMHX/NOPB supports startup into prebiased output loads. During such conditions, the internal soft-start ramp begins from the existing output voltage rather than 0 V, preventing reverse current flow and potential damage to downstream components. This capability is confirmed in the TI SNVS579L datasheet Section 7.3.1 and is critical for hot-swap and partial-power-down system architectures.
How are the power-good signals (PG1/PG2) configured on LM26420YMHX/NOPB?
PG1 and PG2 are open-drain outputs requiring external pull-up resistors (typically 10–100 kΩ) to a valid logic supply. Each asserts low when its respective output voltage deviates more than ±40 mV from the target (e.g., 1.2 V or 2.5 V), with hysteresis ensuring noise immunity. These signals can drive FPGA DONE pins, microcontroller interrupts, or enable cascaded regulators - all independently configurable per channel in LM26420YMHX/NOPB.
What thermal management features does LM26420YMHX/NOPB include?
LM26420YMHX/NOPB integrates thermal shutdown at 165°C junction temperature, automatically disabling both buck channels until the die cools to ~150°C. Its HTSSOP-20 package includes an exposed DAP connected to internal GND, requiring soldering to ≥2 cm² PCB copper with ≥4 thermal vias for effective heat transfer. The datasheet specifies RθJA = 38.5°C/W, confirming suitability for industrial ambient temperatures up to 85°C with proper layout.
Can LM26420YMHX/NOPB be used in automotive applications?
LM26420YMHX/NOPB is not qualified for automotive AEC-Q100 applications. While it meets CISPR25 Class 5 conducted emissions - a common automotive EMC requirement - it lacks automotive-grade qualification, extended temperature range (−40°C to +125°C is supported, but not validated per AEC), and automotive-specific reliability testing. For automotive use, TI recommends the pin-compatible LM26420-Q1 variant, which carries full AEC-Q100 Grade 1 certification and automotive PPAP support.
LM26420YMHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- 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:
- 20-HTSSOP
LM26420YMHX/NOPB FAQ
1.How can I place an order for LM26420YMHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM26420YMHX/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 LM26420YMHX/NOPB reliable?
The price and inventory of LM26420YMHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM26420YMHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM26420YMHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM26420YMHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM26420YMHX/NOPB?
LM26420YMHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM26420YMHX/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 LM26420YMHX/NOPB?
For technical support, including LM26420YMHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM26420YMHX/NOPB requirements.
6.How does Aetrix verify that LM26420YMHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM26420YMHX/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 LM26420YMHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM26420YMHX/NOPB?
All LM26420YMHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM26420YMHX/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 LM26420YMHX/NOPB part is unused and in its original packaging.
Return procedure for LM26420YMHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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