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Texas Instruments LM26420XMH/NOPB
- Part No.:
- LM26420XMH/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM26420XMH/NOPB.pdf
- Description:
- IC REG BUCK ADJ 2A DL 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:338
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Product details
Overview
LM26420XMH/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, internal 0.8 V reference (±1.5%), and independent enable/power-good signals - used in FPGA core power and CPU I/O voltage regulation.
For engineers reviewing the LM26420XMH/NOPB datasheet, LM26420XMH/NOPB pinout, LM26420XMH/NOPB application, or LM26420XMH/NOPB equivalent, key selection criteria include dual-output sequencing capability, 2.2 MHz high-frequency operation enabling compact passive sizing, thermal shutdown at 165°C, ±1.5% feedback reference accuracy, and independent precision enable thresholds (1.04 V typical).
Technical Context
The LM26420XMH/NOPB implements current-mode PWM control with internal compensation, supporting 180° out-of-phase switching between channels to reduce input ripple. Its BICMOS process integrates 75 mΩ PMOS top switches and 50 mΩ NMOS bottom switches per channel, enabling ≥93% peak efficiency across 3–5.5 V input range.
It features cycle-by-cycle current limiting (3.3 A typical), overvoltage protection triggered at +15% of VREF, undervoltage lockout with 330 mV hysteresis (2.628 V rising threshold), and soft-start with 600 µs reference ramp - all implemented without external compensation components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 5.5 V - supports USB-powered and single-cell Li-ion systems without pre-regulation. |
| Switching Frequency | 2.2 MHz (±16%) - enables use of ≤1 µH inductors and 10–22 µF ceramic output capacitors for space-constrained designs. |
| Output Current per Channel | 2 A continuous - sufficient for FPGA core rails and ASIC I/O supplies with margin. |
| Feedback Reference Voltage | 0.8 V ±1.5% - sets output accuracy baseline; combined with 1% resistors yields ≤3.5% total VOUT tolerance. |
| Top Switch RDS(on) | 75 mΩ (typical, HTSSOP) - limits conduction loss at 2 A to ~300 mW per channel under worst-case conditions. |
| Thermal Shutdown Threshold | 165°C junction - protects against sustained overload or poor PCB thermal design; auto-recovery at ~150°C. |
| Enable Threshold Voltage | 1.04 V (typical) with 150 mV hysteresis - ensures clean startup sequencing and immunity to noise on EN pins. |
Pinout & Package
LM26420XMH/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) connected to system ground for low thermal impedance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VINC | Control circuit supply | Provides bias for internal LDO and logic; requires RC filter (1–10 Ω + 0.22–1 µF) to suppress VIN noise. |
| EN1 / EN2 | Independent enable inputs | Logic-high active (≥1.04 V); each controls its respective buck channel; hysteresis prevents chatter during slow-rising signals. |
| VIND1 / VIND2 | Power input for Buck 1/2 | Separate input pins allow independent input sourcing or local decoupling per channel. |
| SW1 / SW2 | Switch node outputs | Connect directly to inductor; require low-ESR ceramic caps and tight layout to minimize EMI and ringing. |
| PGND1 / PGND2 | Power ground returns | Dedicated ground paths per channel reduce cross-talk and improve current-sense accuracy. |
| FB1 / FB2 | Feedback inputs | High-impedance (≤100 nA bias) nodes; connect to resistor dividers setting VOUT = 0.8 V × (1 + R1/R2). |
| PG1 / PG2 | Open-drain power-good indicators | Assert low when corresponding VOUT is within ±7.5% of target; require external pull-up (10–100 kΩ) to sequence downstream rails. |
| AGND | Signal ground reference | Reference point for FB, EN, and internal error amplifier; must be tied to PGND near device DAP with short trace. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase switching | Reduces input capacitor RMS current by ~30%, allowing smaller bulk capacitance and lower EMI. |
| Internal soft start (600 µs) | Prevents inrush current and output overshoot; enables ratiometric startup when both EN pins are asserted simultaneously. |
| Start-up into prebiased outputs | Supports hot-swap and partial-power-down scenarios without damaging downstream loads or causing latch-up. |
| CISPR25 Class 5 compliance | Meets automotive conducted emissions requirements without external filters - validated in TI reference layouts. |
| Independent precision enable & PG | Enables flexible power sequencing (e.g., VCCIO before VCCINT in FPGAs) and fault reporting without external supervisors. |
Applications
| Local 5 V to FPGA Core Power | USB-Powered Device Rail Generation |
|---|---|
Use Scenario: Converting 5 V USB input to 1.2 V core and 2.5 V I/O rails for Xilinx Artix-7 FPGA in portable test equipment. IC Role / Device Role / Timing Role: Dual synchronous buck regulator providing tightly regulated, sequenced, low-noise power with independent PG signaling for FPGA configuration handshake. Use Value: Eliminates need for discrete supervisors and external sequencing ICs; 2.2 MHz operation allows <3 mm² total inductor+capacitor area per rail. | Use Scenario: Powering ARM Cortex-M7 microcontroller and 3.3 V sensor interface from single 5 V USB port in IoT edge node. IC Role / Device Role / Timing Role: Primary DC/DC converter generating two independent, enable-controlled rails with fast transient response for mixed-signal SoC operation. Use Value: Internal 0.8 V reference and 1.5% tolerance ensure stable ADC reference and PLL supply; PG signals confirm rail readiness before firmware initialization. |
| HDD Preamp & Servo Drive Power | Set-Top Box CPU Core/I/O Supply |
Use Scenario: Delivering 1.2 V @ 2 A (core) and 2.5 V @ 2 A (preamp) from 5 V bus in 2.5-inch HDD actuator electronics. IC Role / Device Role / Timing Role: High-efficiency dual buck supplying noise-sensitive analog preamps and digital servo controllers with phase interleaving to minimize input ripple. Use Value: 93% peak efficiency reduces thermal load in sealed enclosure; 180° phase shift cuts input cap size by 40% vs. in-phase dual converters. | Use Scenario: Generating 1.1 V CPU core and 1.8 V memory I/O rails from 5 V main supply in consumer STB with thermal constraints. IC Role / Device Role / Timing Role: Compact dual buck regulator meeting tight board area targets while supporting dynamic voltage scaling via EN pin control. Use Value: HTSSOP package with DAP achieves 38.5°C/W θJA; thermal shutdown protects against fan failure without external monitoring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM26420YMH/NOPB | 0.55 MHz switching frequency; higher max duty cycle (98% vs. 91.5%); lower quiescent current in switching mode. | Better suited for high-VIN-to-low-VOUT conversion (e.g., 5 V → 1.0 V) where 2.2 MHz is unnecessary; larger inductors required. | Select LM26420YMH/NOPB when board area permits larger passives and efficiency at light load is prioritized over footprint. |
| TPS65270PWP | Same 20-pin HTSSOP package; 3 A per channel; integrated LDO for auxiliary rail; no phase interleaving. | Higher current capability and added LDO simplify multi-rail systems but increase cost and thermal density; lacks 180° phase shift. | Choose TPS65270PWP only if >2 A per rail or integrated LDO functionality is required; not drop-in compatible due to different pin functions. |
Compared with LM26420YMH/NOPB, the LM26420XMH/NOPB trades lower light-load efficiency for significantly smaller magnetics and reduced EMI filtering needs. Against TPS65270PWP, it offers tighter output tolerance (±1.5% vs. ±2%), proven CISPR25 Class 5 compliance, and true phase interleaving - critical for noise-sensitive applications.
Availability
LM26420XMH/NOPB is available at Aetrix Electronics and suitable for FPGA power delivery, USB-powered embedded systems, and HDD actuator electronics requiring stable component supply and long-term industrial availability.
Supply support for LM26420XMH/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 ICs, with decades of expertise in high-efficiency DC/DC conversion.
The LM26420 product line delivers dual synchronous buck regulators optimized for space-constrained, noise-sensitive applications like portable computing, storage, and consumer electronics - emphasizing integration, efficiency, and EMI performance.
FAQ
What is the maximum achievable efficiency of the LM26420XMH/NOPB?
The LM26420XMH/NOPB achieves up to 93% peak efficiency at 2 A load, 5 V input, and 1.2 V output, as measured per TI's SNVS579L datasheet Figure 1. Efficiency remains above 85% down to 100 mA load under same conditions, enabled by low RDS(on) switches and optimized gate drive.
Does the LM26420XMH/NOPB support powering up into a prebiased output?
Yes, the LM26420XMH/NOPB supports start-up into prebiased outputs - a key feature for hot-swap and partial-power-down systems. During such start-up, the feedback reference ramps from the existing output voltage level at the same 600 µs rate, preventing reverse current flow and output collapse.
What is the purpose of the separate VINC and VIND pins on the LM26420XMH/NOPB?
VINC powers the internal control circuitry (error amp, oscillator, logic), while VIND1/VIND2 supply the power switches. This separation isolates noise-sensitive analog blocks from high-current switching paths. VINC requires an RC filter (1–10 Ω + 0.22–1 µF) per datasheet Section 8.1.2 to maintain stability.
How does the LM26420XMH/NOPB implement power sequencing between its two outputs?
The LM26420XMH/NOPB enables precise sequencing via independent EN1/EN2 and PG1/PG2 pins. For example, asserting EN1 before EN2 starts Buck 1 first; connecting PG1 to EN2 creates a hardware interlock ensuring Buck 2 only enables after Buck 1 reaches regulation - all without external timing components.
Is the LM26420XMH/NOPB pin-compatible with other variants in the LM26420 family?
Yes, the LM26420XMH/NOPB shares identical 20-pin HTSSOP (PWP) pinout with LM26420YMH/NOPB and LM26420XMHX/NOPB (tape-and-reel). All variants use the same pin functions and package dimensions, enabling direct substitution where frequency and thermal requirements align.
LM26420XMH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- 20-HTSSOP
LM26420XMH/NOPB FAQ
1.How can I place an order for LM26420XMH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM26420XMH/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 LM26420XMH/NOPB reliable?
The price and inventory of LM26420XMH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM26420XMH/NOPB is usually 5 days.
3.What payment methods are accepted for LM26420XMH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM26420XMH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM26420XMH/NOPB?
LM26420XMH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM26420XMH/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 LM26420XMH/NOPB?
For technical support, including LM26420XMH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM26420XMH/NOPB requirements.
6.How does Aetrix verify that LM26420XMH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM26420XMH/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 LM26420XMH/NOPB meets industry standards.
7.What is the process for return or replacement of LM26420XMH/NOPB?
All LM26420XMH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM26420XMH/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 LM26420XMH/NOPB part is unused and in its original packaging.
Return procedure for LM26420XMH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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