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Texas Instruments LM25576MHX/NOPB
- Part No.:
- LM25576MHX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25576MHX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,008
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Product details
Overview
LM25576MHX/NOPB from Texas Instruments is a 42V, 3A synchronous step-down DC/DC switching regulator with integrated 170mΩ N-channel MOSFET, adjustable 1.225V output, 1.5% feedback reference accuracy, and emulated current mode control architecture. It operates across 6V–42V input, supports 50kHz–1MHz programmable frequency via RT resistor, and delivers robust industrial power conversion in HTSSOP-20EP package.
For engineers reviewing the LM25576MHX/NOPB datasheet, LM25576MHX/NOPB pinout, LM25576MHX/NOPB application, or LM25576MHX/NOPB equivalent, key selection criteria include input voltage range (6–42V), continuous 3A output capability, thermal performance with exposed pad, soft-start adjustability, and synchronization support for multi-rail systems.
Technical Context
The LM25576MHX/NOPB implements emulated current mode control using a reconstructed ramp signal derived from VIN–VOUT and an internal diode current sample-and-hold circuit - eliminating leading-edge spikes and enabling stable operation at low duty cycles. Its dual-mode VCC regulator maintains ~7V bias supply above 9V VIN while tracking VIN below that threshold, supporting wide-input operation without external LDO.
Functional modes include three-level SD pin control (shutdown <0.7V, standby 0.7–1.225V, active >1.225V), oscillator synchronization via open-drain SYNC pin, and cycle-by-cycle current limiting triggered at 4.2A-equivalent emulated ramp voltage. Thermal shutdown activates at 165°C with 25°C hysteresis, and forced off-time (500ns) enforces minimum off-time for accurate IS sampling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 42V - supports industrial bus rails including 24V and 36V systems without pre-regulation |
| Output Current | 3A continuous - sufficient for FPGA core supplies, PLC I/O modules, and motor control logic rails |
| Feedback Reference | 1.225V ±1.5% - enables precise low-voltage outputs down to 1.225V with minimal external divider error |
| Switch RDS(on) | 170mΩ typical - reduces conduction loss and thermal stress in high-current buck stages |
| Operating Frequency | 50kHz to 1MHz - adjustable via single RT resistor for trade-off between efficiency (low f) and size (high f) |
| Junction Temp Range | –40°C to +125°C - qualified for extended industrial temperature environments |
| Thermal Resistance θJA | 40°C/W - requires PCB copper area under exposed pad for reliable 3A operation at full ambient |
Pinout & Package
LM25576MHX/NOPB uses HTSSOP-20EP (PWP) package: 6.5mm × 4.4mm body with exposed thermal pad soldered to PCB ground plane for enhanced heat dissipation. Pin numbering follows top-view layout with pins 1–10 on top row, 11–20 on bottom row.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (pins 3,4) | Input supply connection | Accepts 6–42V unregulated input; dual-mode VCC regulator derives bias internally |
| SW (pins 17,18) | Switching node | Drives external Schottky diode and buck inductor; connects to BST capacitor |
| BST (pin 20) | Bootstrap supply input | Requires 0.022µF ceramic cap to SW for high-side gate drive; UVLO at 3.8V |
| PGND (pins 13,14) | Power ground return | Low-side reference for IS sense resistor and PRE switch; separate from AGND |
| AGND (pin 10) | Analog ground reference | Reference for FB, COMP, RAMP, RT; must be star-connected to minimize noise coupling |
| FB (pin 7) | Output voltage feedback | Inverting input of error amp; regulation setpoint is 1.225V; bias current ≤10nA |
| COMP (pin 6) | Error amplifier output | Connects to FB via type-II compensation network; sink/source current ±3mA |
| RT (pin 8) | Oscillator frequency set | Single resistor to AGND sets fSW from 50kHz–1MHz; equation-based calculation required |
| SYNC (pin 5) | Frequency synchronization I/O | Open-drain output or external clock input; enables multi-device phase alignment |
| SS (pin 11) | Soft-start timing | 10µA internal current source charges external cap; controls output voltage ramp rate |
| IS (pins 15,16) | Diode current sense | Measures re-circulating Schottky diode current for emulated ramp DC level |
| SD (pin 2) | Shutdown/stanby control | Three-state logic: <0.7V = shutdown, 0.7–1.225V = standby, >1.225V = active |
| PRE (pin 19) | Bootstrap precharge assist | Open-drain output pulsed 265ns before switch-on to charge BST cap under light load |
| VCC (pin 1) | Bias regulator output | 7.15V typical; powers internal circuitry; can accept external 7.5–14V supply to reduce dissipation |
| OUT (pin 12) | Regulated output connection | Direct connection point for output capacitor; not internally connected to power stage |
| RAMP (pin 9) | Emulated current ramp | External capacitor sets slope; internal current source scales with (VIN–VOUT) |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current mode control | Eliminates current-sense spike filtering and blanking delays, enabling stable regulation at <10% duty cycle in high-VIN/low-VOUT applications |
| Integrated 42V/170mΩ MOSFET | Reduces BOM count and layout complexity versus controller-only solutions; eliminates external high-voltage switch selection |
| Adjustable soft-start via SS pin | Prevents inrush current during power-up by controlling reference ramp with external capacitor |
| SYNC pin for multi-device synchronization | Enables deterministic interleaving or phase alignment of multiple LM25576MHX/NOPB regulators without external clock generator |
| Exposed thermal pad (EP) | Provides low-thermal-resistance path to PCB ground plane; mandatory for 3A continuous operation at elevated ambient temperatures |
Applications
| Industrial Power Supply | Telecom Line Card |
|---|---|
Use Scenario: Distributed 24V or 36V bus powering field I/O modules, sensor interfaces, and PLC logic circuits. IC Role / Device Role / Timing Role: Primary buck regulator converting unregulated bus voltage to stable 3.3V or 5V logic rail. Use Value: 42V input rating withstands industrial transients; 3A output supports multiple downstream LDOs or point-of-load converters. | Use Scenario: Compact power stage on telecom line cards requiring isolated or non-isolated 12V/5V/3.3V rails from -48V or 48V battery backup. IC Role / Device Role / Timing Role: High-efficiency step-down converter delivering regulated output with minimal footprint and thermal overhead. Use Value: Emulated current mode ensures fast transient response to bursty data traffic loads; SYNC enables noise reduction via interleaved switching. |
| Motor Control Logic | Test & Measurement Equipment |
Use Scenario: Powering microcontroller, gate drivers, and analog front-end in servo drives and motion controllers. IC Role / Device Role / Timing Role: Main system supply generating clean, well-regulated logic voltage from variable DC bus (e.g., rectified AC or battery). Use Value: Wide 6–42V input accommodates varying battery states or rectified inputs; thermal shutdown protects against overload during stall conditions. | Use Scenario: Benchtop instruments requiring stable, low-noise auxiliary rails for ADC references, DAC buffers, and FPGA configuration. IC Role / Device Role / Timing Role: Precision buck regulator with tight 1.225V reference and low-output-impedance design. Use Value: 1.5% reference accuracy minimizes calibration drift; adjustable frequency avoids sensitive measurement bands via SYNC or RT tuning. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164MHX/NOPB | 42V input, 1A output, integrated FET, but lower current rating and different compensation architecture | Suitable for lower-power industrial sensors or IoT edge nodes where 3A is excessive | Select when board space or cost constraints favor smaller solution size and reduced thermal management complexity |
| TPS54340DDAR | 42V input, 3.5A output, current-mode controller with external FETs; no integrated high-side switch | Preferred where higher efficiency at light load or custom MOSFET selection is required | Choose when design flexibility, discrete FET optimization, or >95% peak efficiency is prioritized over BOM count and layout simplicity |
Compared with LM5164MHX/NOPB, LM25576MHX/NOPB delivers 2× more output current in same package; versus TPS54340DDAR, it reduces component count and layout risk by integrating the high-side FET, though with fixed RDS(on) and less light-load efficiency tuning.
Availability
LM25576MHX/NOPB is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and motor control applications requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.
Supply support for LM25576MHX/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-reliability power conversion solutions.
The LM25576MHX/NOPB belongs to TI's high-voltage buck regulator product line, engineered for rugged industrial and telecom applications where wide input range, integrated power stage, and robust protection features are essential.
FAQ
What is the maximum output current capability of the LM25576MHX/NOPB?
The LM25576MHX/NOPB delivers up to 3A of continuous output current under recommended operating conditions (TJ ≤ 125°C, proper PCB thermal design). This rating assumes use of the exposed thermal pad connected to a minimum 1-in² copper area on inner or outer PCB layers. Peak current capability is limited by cycle-by-cycle current limit at ~4.2A-equivalent emulated ramp voltage.
Does the LM25576MHX/NOPB require an external bootstrap capacitor?
Yes, the LM25576MHX/NOPB requires a 0.022µF ceramic capacitor between BST and SW pins to support high-side gate drive. This capacitor is charged during the switch off-time via an internal diode from VCC. The BST pin has a 3.8V UVLO with 0.8V hysteresis, and exceeding 14V absolute maximum rating risks damage.
How is the switching frequency programmed on the LM25576MHX/NOPB?
The LM25576MHX/NOPB switching frequency is set using a single resistor (RT) connected between the RT pin and AGND. Frequency ranges from 50kHz to 1MHz depending on RT value, calculated per TI's equation: RT = (1/F − 580 ns) / 135 ps. RT must be placed adjacent to the IC with short traces to minimize noise coupling.
Can the LM25576MHX/NOPB synchronize to an external clock signal?
Yes, the LM25576MHX/NOPB supports external clock synchronization via its SYNC pin. An open-drain external clock source (with pulse width ≥15ns and frequency higher than the free-running oscillator) can drive the SYNC net. Multiple LM25576MHX/NOPB devices can also self-synchronize by connecting their SYNC pins together, with the highest-frequency device acting as master.
What thermal management is required for reliable operation of the LM25576MHX/NOPB at full 3A load?
Reliable 3A operation requires soldering the exposed thermal pad (EP) to a minimum 1-in² copper pour connected to internal or external ground planes. With this, θJA is 40°C/W. At 125°C max junction temperature and 70°C ambient, allowable power dissipation is ~1.375W - achievable with typical 24V→5V conversion at ~90% efficiency. Thermal shutdown triggers at 165°C with 25°C hysteresis.
LM25576MHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- 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:
- 1
- Voltage - Input (Min):
- 6V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 1.225V
- Voltage - Output (Max):
- 40V
- Current - Output:
- 3A
- Frequency - Switching:
- 50kHz ~ 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HTSSOP
LM25576MHX/NOPB FAQ
1.How can I place an order for LM25576MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25576MHX/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 LM25576MHX/NOPB reliable?
The price and inventory of LM25576MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25576MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM25576MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25576MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25576MHX/NOPB?
LM25576MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25576MHX/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 LM25576MHX/NOPB?
For technical support, including LM25576MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25576MHX/NOPB requirements.
6.How does Aetrix verify that LM25576MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25576MHX/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 LM25576MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM25576MHX/NOPB?
All LM25576MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25576MHX/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 LM25576MHX/NOPB part is unused and in its original packaging.
Return procedure for LM25576MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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