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Texas Instruments LM25576QMH/NOPB
- Part No.:
- LM25576QMH/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25576QMH/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:978
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Product details
Overview
LM25576QMH/NOPB from Texas Instruments is a 42V, 3A synchronous step-down DC/DC switching regulator with integrated 170mΩ N-channel MOSFET, emulated current-mode control, adjustable 50kHz–1MHz switching frequency, and 1.225V feedback reference. It delivers robust industrial power conversion in HTSSOP-20EP packaging with thermal enhancement via exposed pad.
For engineers reviewing the LM25576QMH/NOPB datasheet, LM25576QMH/NOPB pinout, LM25576QMH/NOPB application, or LM25576QMH/NOPB equivalent, key selection criteria include input voltage range (6–42V), output current capability (3A continuous), soft-start adjustability, SYNC pin for multi-device synchronization, and thermal shutdown at 165°C.
Technical Context
The LM25576QMH/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 <0.7V, standby 0.7–1.225V, active >1.225V), programmable oscillator via RT resistor, and SYNC-driven synchronization across multiple devices. Protection includes cycle-by-cycle current limit (4.2A threshold), thermal shutdown (165°C), and UVLO on VCC (5.35V turn-on).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 42V - supports wide industrial bus voltages including 24V and 36V rails without external pre-regulation. |
| Output Current | 3A continuous - sufficient for powering FPGA I/O banks, industrial PLC modules, or sensor signal chains. |
| Feedback Reference | 1.225V ±1.5% - enables precise output regulation down to 1.225V with minimal external resistor tolerance impact. |
| Switching Frequency | 50kHz to 1MHz - adjustable via single RT resistor to optimize size (higher f = smaller L/C) vs. efficiency (lower f = lower switching loss). |
| Junction Temp Range | –40°C to +125°C - qualified for extended industrial temperature operation in enclosed enclosures or high-ambient environments. |
| Thermal Resistance | RθJA = 40°C/W - requires PCB copper pour under exposed pad to meet thermal limits at full load. |
| Current Limit Threshold | 4.2A cycle-by-cycle - protects against short-circuit and overload while allowing transient peaks during startup or load steps. |
Pinout & Package
LM25576QMH/NOPB uses the HTSSOP-20EP (PWP) package: 6.5mm × 4.4mm body with 0.65mm pitch and exposed thermal pad (EP) soldered to PCB ground plane for enhanced heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (pins 3,4) | Main power input | Accepts 6–42V unregulated supply; connects directly to bulk capacitor and must be decoupled near device. |
| SW (pins 17,18) | Switch node | Drives external Schottky diode and buck inductor; high dv/dt node requiring tight layout and guard ring. |
| PGND (pins 13,14) | Power ground return | Low-impedance return path for diode current and switch conduction; separate from AGND to minimize noise coupling. |
| AGND (pin 10) | Analog reference ground | Reference for FB, COMP, RAMP, and error amplifier; must connect to PGND at single point near IC. |
| FB (pin 7) | Feedback input | Connects to resistor divider from VOUT; regulates output by comparing to internal 1.225V reference. |
| COMP (pin 6) | Error amplifier output | Interface for type-II compensation network (R+C+R) between COMP and FB to stabilize loop response. |
| RT (pin 8) | Oscillator set input | Single resistor to AGND sets switching frequency; value calculated per TI equation for target fSW. |
| SYNC (pin 5) | Frequency sync I/O | Allows daisy-chaining multiple LM25576QMH/NOPB units or locking to external clock to reduce EMI peaks. |
| SS (pin 11) | Soft-start control | External capacitor sets rise time of internal reference; prevents inrush current during power-up. |
| SD (pin 2) | Shutdown enable | Three-state logic: <0.7V = shutdown, 0.7–1.225V = standby, >1.225V = active; internal 5µA pullup if floating. |
| BST (pin 20) | Bootstrap supply | Connects 0.022µF ceramic cap to SW; provides gate drive voltage for internal high-side MOSFET. |
| IS (pins 15,16) | Diode current sense | Connects to Schottky anode; samples recirculating current to reconstruct DC level of emulated ramp. |
| RAMP (pin 9) | Emulated ramp control | External capacitor to AGND sets slope; value selected per LOUT to match 0.5V/A scaling of current sense. |
| PRE (pin 19) | Bootstrap precharge | Open-drain assist for BST capacitor charging during light-load or precharged-output conditions. |
| VCC (pin 1) | Bias supply output | 7V regulated output (for VIN >9V) or VIN-tracked (for VIN <9V); powers internal circuitry and gate driver. |
| OUT (pin 12) | Regulated output | Direct connection to output capacitor; not a power terminal but voltage sense reference point. |
| EP | Exposed thermal pad | Mandatory solder connection to PCB ground plane; primary thermal path for junction-to-board conduction (RθJB = 6.9°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode architecture | Eliminates current-sense spike filtering delays and enables stable regulation at sub-10% duty cycles in high-VIN/low-VOUT applications. |
| Integrated 42V/170mΩ N-channel MOSFET | Reduces BOM count and layout complexity versus controller-only solutions; eliminates external high-voltage switch selection. |
| Adjustable soft-start via external capacitor | Prevents output overshoot and inrush into large capacitive loads; timing controlled by internal 10µA current source. |
| SYNC pin for multi-device synchronization | Enables deterministic interleaving or common-frequency operation across multiple converters to suppress beat frequencies and narrow EMI peaks. |
| Wide bandwidth error amplifier (3MHz GBW) | Supports fast transient response to load steps typical in industrial I/O or motor control subsystems without complex compensation. |
| Thermal shutdown with 25°C hysteresis | Protects against sustained overloads or poor heatsinking; automatic recovery after cooldown avoids latch-up behavior. |
Applications
| Industrial Power Supply | Telecom Line Card |
|---|---|
Use Scenario: Converting 24V or 48V backplane voltage to 3.3V/5V for PLC I/O modules, HMIs, or fieldbus interfaces. IC Role / Device Role / Timing Role: Primary buck regulator delivering 3A continuous output with line/load regulation <±1% and transient response <50µs. Use Value: Enables compact, thermally efficient design meeting IEC 61000-4-2/3 immunity requirements due to low EMI from synchronized switching. | Use Scenario: Generating isolated 12V bias for optical transceivers or PoE-powered Ethernet switches operating from -48V telecom supply. IC Role / Device Role / Timing Role: Non-isolated intermediate stage stepping -48V to 12V before downstream isolation; operates in constant-frequency mode for predictable noise spectrum. Use Value: Supports hot-swap sequencing via SD pin control and withstands 42V transients on input rail per GR-1089-CORE. |
| Automotive Body Control Module | Test & Measurement Equipment |
Use Scenario: Powering microcontroller, CAN transceiver, and sensor interface in 12V/24V vehicle subsystems with cold-crank (6V) and load-dump (42V) tolerance. IC Role / Device Role / Timing Role: Input-stage regulator handling wide VIN range; integrates protection features eliminating need for external TVS or reset ICs. Use Value: Meets AEC-Q100 Grade 2 (–40°C to +105°C) when used with automotive-grade passives; reduces system-level validation effort. | Use Scenario: Providing stable 5V/3.3V rails for ADC front-ends, FPGA configuration, and analog signal conditioning in portable bench instruments. IC Role / Device Role / Timing Role: Low-noise, low-ripple power source with adjustable frequency to avoid interference with sensitive measurement bands (e.g., 100kHz–1MHz). Use Value: Emulated current mode ensures consistent loop stability across varying input/output ratios, critical for calibration accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QWRNTRQ1 | 42V, 1A rated; uses constant-on-time control instead of emulated current mode; smaller 10-pin WSON package. | Lower output current; better suited for space-constrained, lower-power nodes like sensor hubs or auxiliary rails. | Select when 1A output suffices and board area is premium; not suitable for 3A loads without parallel configuration. |
| TPS54340QDDARQ1 | 42V, 3.5A; current-mode control with external sense resistor; no integrated MOSFET (external FET required). | Higher peak current; requires external high-side FET and current-sense resistor; greater design flexibility but higher BOM count. | Select when higher efficiency at light load or custom FET selection is needed; adds complexity versus integrated solution. |
Compared with LM5164QWRNTRQ1 and TPS54340QDDARQ1, the LM25576QMH/NOPB offers integrated 3A capability in a thermally enhanced 20-pin package with emulated current-mode control optimized for wide-VIN industrial systems-balancing integration, thermal performance, and ease of loop compensation without external FETs or sense resistors.
Availability
LM25576QMH/NOPB is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, and automotive body electronics requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM25576QMH/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 broad industrial and automotive qualification expertise.
The LM25576QMH/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for robust, easy-to-implement DC/DC conversion in harsh industrial environments where input transients, wide voltage ranges, and thermal reliability are critical.
FAQ
What is the maximum output current supported by the LM25576QMH/NOPB?
The LM25576QMH/NOPB delivers 3A of continuous output current under recommended operating conditions (TJ ≤ 125°C, proper PCB thermal design). Peak current capability reaches 4.2A before cycle-by-cycle limiting engages. Actual achievable current depends on ambient temperature, airflow, and copper area under the exposed pad-TI's WEBENCH® tool models thermal derating based on layout parameters for the LM25576QMH/NOPB.
How does the LM25576QMH/NOPB achieve stable operation at very low duty cycles?
The LM25576QMH/NOPB uses emulated current-mode control, reconstructing the inductor current ramp without sensing the noisy switch-node current. This eliminates blanking delays and leading-edge spikes, enabling reliable PWM at sub-10% duty cycles-critical for high-input/low-output applications like 42V-to-3.3V conversion. The RAMP pin capacitor and IS pin diode current sampling jointly define the accurate current representation used by the LM25576QMH/NOPB's PWM comparator.
Can the LM25576QMH/NOPB synchronize its switching frequency with other converters?
Yes-the LM25576QMH/NOPB includes a dedicated SYNC pin that supports both master and slave operation. Multiple LM25576QMH/NOPB units can be daisy-chained to self-synchronize, or it can lock to an external clock source (e.g., MCU timer or dedicated oscillator). The internal oscillator is disabled when SYNC is driven low, ensuring deterministic phase alignment and reduced EMI in multi-rail systems using the LM25576QMH/NOPB.
What thermal management practices are required for the LM25576QMH/NOPB at full 3A load?
At full 3A load and 42V input, the LM25576QMH/NOPB dissipates ~2.5W. To maintain TJ ≤ 125°C, TI specifies RθJA = 40°C/W-requiring ≥4 cm² of 2-oz copper connected to the exposed pad (EP) and vias to inner ground planes. Thermal simulation in WEBENCH® confirms optimal copper area and via count for the LM25576QMH/NOPB based on your specific board stack-up and airflow conditions.
Does the LM25576QMH/NOPB support remote shutdown and undervoltage lockout?
Yes-the LM25576QMH/NOPB implements a three-threshold SD pin: <0.7V = shutdown (IQ ≈ 85µA), 0.7–1.225V = standby (VCC active, output disabled), >1.225V = normal operation. An external resistor divider from VIN to GND sets the undervoltage lockout point, with hysteresis of 0.1V. The internal 5µA pullup allows default-enable operation if the SD pin is left floating-simplifying designs where remote control isn't required for the LM25576QMH/NOPB.
LM25576QMH/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:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HTSSOP
LM25576QMH/NOPB FAQ
1.How can I place an order for LM25576QMH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25576QMH/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 LM25576QMH/NOPB reliable?
The price and inventory of LM25576QMH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25576QMH/NOPB is usually 5 days.
3.What payment methods are accepted for LM25576QMH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25576QMH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25576QMH/NOPB?
LM25576QMH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25576QMH/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 LM25576QMH/NOPB?
For technical support, including LM25576QMH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25576QMH/NOPB requirements.
6.How does Aetrix verify that LM25576QMH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25576QMH/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 LM25576QMH/NOPB meets industry standards.
7.What is the process for return or replacement of LM25576QMH/NOPB?
All LM25576QMH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25576QMH/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 LM25576QMH/NOPB part is unused and in its original packaging.
Return procedure for LM25576QMH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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