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Texas Instruments LM25576MH/NOPB
- Part No.:
- LM25576MH/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25576MH/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,225
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Product details
Overview
LM25576MH/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 power conversion in industrial bus supplies.
For engineers reviewing the LM25576MH/NOPB datasheet, LM25576MH/NOPB pinout, LM25576MH/NOPB application, or LM25576MH/NOPB equivalent, key selection considerations include its HTSSOP-20EP package with exposed thermal pad, cycle-by-cycle current limiting, thermal shutdown, remote shutdown capability, and synchronization support for multi-rail systems.
Technical Context
The LM25576MH/NOPB implements emulated current mode control using a reconstructed ramp signal derived from VIN–VOUT and diode current sampling-eliminating leading-edge spikes and enabling stable operation at low duty cycles. Its dual-mode VCC regulator maintains 7V bias up to 42V input while limiting internal dissipation.
Functional modes include three-level SD pin control (shutdown, standby, active), oscillator synchronization via open-drain SYNC pin, and adjustable soft-start via external capacitor on SS pin. Protection includes cycle-by-cycle current limit (4.2A threshold), thermal shutdown at 165°C, and UVLO on VCC and BST pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 42V - supports wide industrial and telecom bus rails without pre-regulation |
| Output Current | 3A continuous - sufficient for FPGA core, DSP, or PLC I/O power rails |
| Feedback Reference | 1.225V ±1.5% - enables precise low-voltage regulation down to 1.225V with minimal external components |
| Switch RDS(on) | 170mΩ typical - reduces conduction loss and improves efficiency at high load |
| Switching Frequency | 50kHz to 1MHz - selectable via RT resistor to balance size, efficiency, and EMI |
| Thermal Shutdown | 165°C with 25°C hysteresis - ensures safe operation under sustained overload or poor heatsinking |
| Junction Temp Range | –40°C to +125°C - qualified for extended industrial temperature environments |
Pinout & Package
LM25576MH/NOPB uses the HTSSOP-20EP (PWP) package: 6.5mm × 4.4mm body with 20 leads and an exposed thermal pad (EP) soldered to PCB ground plane for enhanced thermal performance (RθJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (pins 3,4) | Main input supply | Accepts 6V–42V; powers internal bias regulator and high-side switch |
| SW (pins 17,18) | Switch node | Connects to buck inductor and external Schottky diode anode; carries full switching current |
| PGND (pins 13,14) | Power ground | Low-side return for IS sense resistor and PRE switch; must be low-inductance path |
| AGND (pin 10) | Analog ground | Reference for FB, COMP, RAMP, RT; isolated from PGND to minimize noise coupling |
| FB (pin 7) | Feedback input | Monitors output voltage divider; triggers regulation when voltage equals 1.225V reference |
| COMP (pin 6) | Error amplifier output | Connects to type-II compensation network between COMP and FB for loop stability |
| RT (pin 8) | Oscillator set | Resistor-to-AGND sets switching frequency; value determines timing accuracy and EMI profile |
| SYNC (pin 5) | Frequency sync I/O | Open-drain pin enabling master-slave synchronization of multiple LM25576 devices |
| SD (pin 2) | Shutdown control | Three-state logic: <0.7V = shutdown, 0.7–1.225V = standby, >1.225V = active |
| BST (pin 20) | Bootstrap supply | Connects to SW via 0.022µF ceramic capacitor to drive high-side gate during on-time |
| IS (pins 15,16) | Diode current sense | Measures re-circulating diode current for accurate DC level reconstruction in emulated ramp |
| RAMP (pin 9) | Emulated ramp source | External capacitor sets slope; internal current source scales with (VIN–VOUT) for duty-cycle stability |
| SS (pin 11) | Soft-start control | 10µA current source charges external capacitor to ramp reference voltage and prevent inrush |
| PRE (pin 19) | Bootstrap precharge | Open-drain output pulsed before each on-time to assist BST capacitor charging at light loads |
| VCC (pin 1) | Bias supply output | 7V regulated output (up to 25mA); tracks VIN below 9V, regulates above 9V to reduce dissipation |
| OUT (pin 12) | Regulated output | Direct connection to output capacitor; senses output voltage through FB divider |
| EP | Exposed thermal pad | Must be soldered to solid copper ground plane for thermal management and EMI reduction |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current mode control | Eliminates current-sense spike filtering delays and enables stable sub-10% duty cycles in high-VIN/low-VOUT applications |
| Integrated 42V/170mΩ MOSFET | Reduces BOM count and layout complexity while maintaining 3A output capability without external switch |
| Programmable 50kHz–1MHz frequency | Allows optimization of inductor size, efficiency, and conducted EMI across diverse industrial designs |
| Multi-device synchronization | Enables phase-aligned switching of multiple LM25576MH/NOPB regulators to reduce input ripple and simplify filtering |
| Three-level shutdown control | Supports sequenced power-up, brown-out hold-off, and graceful system-level disable via single SD pin |
| Exposed thermal pad (HTSSOP-20EP) | Provides 6.9°C/W junction-to-board thermal resistance-critical for sustained 3A operation in compact enclosures |
Applications
| Industrial PLC Power Supply | Telecom Line Card DC/DC |
|---|---|
Use Scenario: Providing isolated 3.3V/2.5V rails from 24V or 48V backplane in programmable logic controllers. IC Role / Device Role / Timing Role: Primary buck controller delivering regulated core and I/O voltages with fast transient response to varying load steps. Use Value: Emulated current mode ensures tight load regulation and immunity to input rail noise common in factory-floor environments. | Use Scenario: Generating 12V and 5V outputs from -48V telecom battery backup systems with reverse-polarity protection. IC Role / Device Role / Timing Role: High-input-voltage buck converter operating from rectified -48V (positive 48V referenced to chassis ground). Use Value: 42V absolute max rating and 6V–42V operating range enable direct use without front-end pre-regulator, reducing cost and footprint. |
| Automotive Body Control Module | Test Equipment Auxiliary Rail |
Use Scenario: Powering microcontrollers and CAN transceivers in 12V/24V vehicle subsystems subject to load dump and cold crank. IC Role / Device Role / Timing Role: Input-filtered buck regulator with UVLO hysteresis and thermal shutdown for automotive-grade reliability. Use Value: 45V absolute maximum VIN rating withstands ISO 7637-2 load dump pulses up to 40V, minimizing need for TVS clamping. | Use Scenario: Generating precision ±15V analog rails from lab bench supply in automated test equipment requiring low-noise, stable outputs. IC Role / Device Role / Timing Role: Fixed-frequency buck stage feeding linear post-regulators; synchronized to system clock to suppress beat frequencies. Use Value: SYNC pin enables deterministic switching alignment with measurement sampling clocks, reducing spectral interference in sensitive analog paths. |
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, 100kHz–2.2MHz frequency range, smaller HTSSOP-14 package | Lower current capacity; better suited for space-constrained, lower-power industrial sensors | Select when board area is critical and load current ≤1A; not suitable for 3A applications |
| TPS54340DDAR | 42V input, 3.5A output, integrated FET, 100kHz–2.5MHz frequency, SOIC-8 package with thermal pad | Higher peak current, wider frequency range, but no SYNC or IS pin for diode current sensing | Choose for higher efficiency at light loads or when external synchronization is unnecessary |
Compared with LM5164MHX/NOPB and TPS54340DDAR, the LM25576MH/NOPB uniquely combines 3A output, emulated current mode for low-duty-cycle stability, and dedicated IS/SYNC/RAMP pins-making it optimal for multi-rail industrial systems requiring coordinated switching and robust transient response.
Availability
LM25576MH/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, telecom line cards, automotive body control modules, and test equipment auxiliary rails requiring stable component supply across extended temperature and voltage ranges.
Supply support for LM25576MH/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 LM25576 product line was designed specifically for rugged industrial and telecom applications demanding wide-input, high-current, and thermally efficient buck regulation without external MOSFETs or complex compensation.
FAQ
What is the maximum output current supported by the LM25576MH/NOPB?
The LM25576MH/NOPB delivers 3A of continuous output current under recommended operating conditions (TJ ≤ 125°C, proper PCB thermal design). Peak current capability reaches 4.2A due to cycle-by-cycle limiting, but sustained operation above 3A requires careful thermal management using the exposed pad and adequate copper area per TI's layout guidelines for the LM25576MH/NOPB.
Does the LM25576MH/NOPB require an external bootstrap capacitor?
Yes, the LM25576MH/NOPB requires a 0.022µF ceramic capacitor between BST and SW pins to charge the high-side gate driver. This capacitor must be placed adjacent to the device with short, low-inductance traces. The PRE pin provides optional precharge assistance during light-load or pre-biased start-up conditions to maintain reliable BST voltage for the LM25576MH/NOPB.
How does the LM25576MH/NOPB achieve stable operation at very low duty cycles?
The LM25576MH/NOPB uses emulated current mode control-reconstructing the inductor current ramp from VIN–VOUT and diode current sampling instead of measuring switch current directly. This eliminates leading-edge spikes and propagation delays, enabling stable regulation even below 10% duty cycle, which is essential for high-input/low-output applications like 42V-to-3.3V conversion in the LM25576MH/NOPB.
Can multiple LM25576MH/NOPB ICs be synchronized to reduce input ripple?
Yes, the LM25576MH/NOPB features an open-drain SYNC pin that allows multiple devices to self-synchronize or lock to an external clock. When SYNC pins are tied together, the highest-frequency device acts as master, aligning all switching edges. This reduces RMS input current ripple and simplifies bulk capacitor selection in multi-rail systems using the LM25576MH/NOPB.
What thermal performance can be expected from the LM25576MH/NOPB in a standard 4-layer PCB?
In a standard 4-layer PCB with 2oz copper, 1-in² thermal pad connected to internal ground planes, the LM25576MH/NOPB achieves approximately 6.9°C/W junction-to-board thermal resistance. At 3A output and 24V input, this yields ~45°C junction rise above ambient-well within the 125°C max rating. Full derating data is provided in the LM25576MH/NOPB thermal information table (RθJA = 40°C/W, RθJC = 33.6°C/W).
LM25576MH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- 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:
- 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
LM25576MH/NOPB FAQ
1.How can I place an order for LM25576MH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25576MH/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 LM25576MH/NOPB reliable?
The price and inventory of LM25576MH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25576MH/NOPB is usually 5 days.
3.What payment methods are accepted for LM25576MH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25576MH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25576MH/NOPB?
LM25576MH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25576MH/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 LM25576MH/NOPB?
For technical support, including LM25576MH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25576MH/NOPB requirements.
6.How does Aetrix verify that LM25576MH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25576MH/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 LM25576MH/NOPB meets industry standards.
7.What is the process for return or replacement of LM25576MH/NOPB?
All LM25576MH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25576MH/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 LM25576MH/NOPB part is unused and in its original packaging.
Return procedure for LM25576MH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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