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Texas Instruments LM25574QMTX/NOPB
- Part No.:
- LM25574QMTX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25574QMTX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,073
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Product details
Overview
LM25574QMTX/NOPB from Texas Instruments is a 42-V, 0.5-A synchronous step-down DC/DC switching regulator with integrated 750-mΩ N-channel MOSFET, emulated current-mode control, adjustable 50 kHz–1 MHz switching frequency, and 1.225 V feedback reference. It delivers robust industrial power conversion in TSSOP-16 for input rails up to 42 V.
For engineers reviewing the LM25574QMTX/NOPB datasheet, LM25574QMTX/NOPB pinout, LM25574QMTX/NOPB application, or LM25574QMTX/NOPB equivalent, key selection considerations include input voltage range (6–42 V), output current capability (0.5 A), soft-start adjustability, SYNC pin for multi-device synchronization, and thermal shutdown at 165°C.
Technical Context
The LM25574QMTX/NOPB implements emulated current-mode control using a reconstructed ramp signal derived from VIN–VOUT and an internal sample-and-hold of diode current via the IS pin. This architecture eliminates leading-edge spikes, enables stable operation at low duty cycles, and provides inherent line feed-forward without external compensation complexity.
Its dual-mode VCC regulator tracks VIN below 9 V and regulates to 7 V above 9 V, supporting wide-input operation while minimizing internal dissipation. The device features cycle-by-cycle current limiting (0.7 A typ), 500 ns forced off-time, and master/slave synchronization via the open-drain SYNC pin with 11 kΩ source impedance and 110 Ω sink impedance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 42 V - supports industrial bus, telecom, and automotive battery-supplied systems without pre-regulation. |
| Output Current | 0.5 A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in space-constrained designs. |
| Feedback Reference | 1.225 V ±1.5% - enables precise output regulation down to 1.225 V with external resistor divider scaling. |
| Switching Frequency | 50 kHz to 1 MHz (set by RT resistor) - allows trade-off between inductor size, efficiency, and EMI performance. |
| Current Limit Threshold | 0.7 A typical - provides cycle-by-cycle overcurrent protection compatible with Schottky diode-based buck topology. |
| Thermal Shutdown | 165°C with 25°C hysteresis - ensures safe operation under overload or poor heatsinking conditions. |
| Soft-Start Current | 10 µA typical - sets rise time of internal reference via external SS capacitor for controlled output voltage ramp-up. |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm), thermally enhanced with exposed PGND pad; RoHS-compliant, lead-free (NOPB suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply connection | Accepts 6–42 V unregulated input; absolute max 45 V - requires local ceramic bypassing near pin. |
| VCC | Bias regulator output | Dual-mode supply: tracks VIN ≤9 V, regulated to 7 V >9 V; powers internal circuitry and bootstrap driver. |
| SW | Switching node | Drain of internal N-MOSFET; connects to inductor and external Schottky diode cathode. |
| BST | Bootstrap capacitor input | Connects to SW via 0.022 µF ceramic capacitor to enable high-side gate drive for internal MOSFET. |
| PGND | Power ground return | Low-side reference for switch and IS sense path; must be separated from AGND for noise immunity. |
| AGND | Analog ground reference | Reference for FB, COMP, RAMP, RT, SS; requires star grounding to minimize control loop noise. |
| FB | Feedback input | Inverting input of error amplifier; 1.225 V threshold - sets output voltage via resistive divider from OUT. |
| COMP | Error amplifier output | Connects to FB via type-II compensation network (R/C) to stabilize voltage loop dynamics. |
| RT | Oscillator frequency set | Resistor-to-AGND sets switching frequency (50 kHz–1 MHz); layout-critical - place close to IC. |
| RAMP | Emulated current ramp input | External capacitor-to-AGND sets ramp slope; value depends on L and VIN–VOUT per design equation. |
| SS | Soft-start timing | 10 µA internal current source charges external capacitor to control output voltage rise time. |
| IS | Diode current sense | Measures re-circulating diode anode current to reconstruct DC level of inductor current for control. |
| SD | Shutdown/stanby control | Three-state logic: <0.7 V = shutdown, 0.7–1.225 V = standby, >1.225 V = active; includes 5 µA pull-up. |
| SYNC | Oscillator sync I/O | Open-drain output / input; synchronizes multiple LM25574 devices or accepts external clock ≥ free-run freq. |
| PRE | Bootstrap pre-charge assist | Open-drain output pulsed 250 ns before switch-on to aid BST capacitor charging under light load/pre-bias. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 42-V, 750-mΩ N-MOSFET | Enables single-chip 0.5-A buck solution without external high-voltage switch or driver complexity. |
| Emulated current-mode architecture | Eliminates current-sense noise and propagation delay, enabling stable regulation at very low duty cycles. |
| Adjustable soft-start (SS pin) | Prevents inrush current and output overshoot via user-selected capacitor; holds low during fault conditions. |
| Master/slave synchronization (SYNC pin) | Reduces system-level EMI by aligning switching edges across multiple regulators without external clock generator. |
| Wide-bandwidth error amplifier (3 MHz GBW) | Supports fast transient response and flexible compensation - achieves stability with standard type-II networks. |
| Built-in protections | Cycle-by-cycle current limit, thermal shutdown (165°C), UVLO on VCC and SD pins, and short-circuit robustness. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Powers microcontroller, CAN transceiver, and sensor interfaces from 24-V vehicle battery or 24-V industrial bus with transient tolerance. IC Role / Device Role / Timing Role: Primary buck regulator delivering 3.3 V or 5 V at 0.5 A with input rejection up to 42 V and thermal resilience. Use Value: Eliminates need for external HV MOSFET and gate driver; withstands load dump (ISO 7637-2 Pulse 5a) when combined with input TVS. |
Use Scenario: Generates stable 5-V rail for body electronics (door modules, lighting controllers) in 12-V automotive systems. IC Role / Device Role / Timing Role: Step-down regulator operating from cold-crank (6 V) to load-dump (42 V) input conditions with soft-start sequencing. Use Value: Maintains regulation during cranking; SD pin enables controlled wake-up/sleep via MCU GPIO; SYNC supports multi-rail coordination. |
| Telecom Remote Radio Unit | Factory Automation Sensor Hub |
|
Use Scenario: Converts -48-V telecom supply (via intermediate +12-V stage) to 3.3-V logic rail for FPGA and RF front-end ICs. IC Role / Device Role / Timing Role: Secondary-stage buck converter with tight output accuracy (1.225 V ref) and low-noise regulation for sensitive analog circuits. Use Value: Emulated current mode avoids noise coupling from high-dV/dt switching nodes into precision ADC references. |
Use Scenario: Powers isolated I/O modules, RS-485 transceivers, and temperature/humidity sensors from 24-V factory bus. IC Role / Device Role / Timing Role: High-reliability point-of-load regulator with thermal shutdown and remote disable (SD) for fail-safe system management. Use Value: TSSOP-16 package fits dense PCB layouts; built-in protections reduce need for external fault monitoring circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM25011QMYX/NOPB | Higher 60-V input rating, 1-A output, but larger SO-PowerPAD-8 package; no SYNC or PRE pins. | Preferred for higher-current or higher-input-voltage designs where synchronization is not required. | Select when >0.5 A output or >42 V input margin is needed; requires different layout and compensation. |
| TPS54340QDDARQ1 | 42-V, 3.5-A regulator with integrated FETs, spread-spectrum EMI reduction, and adjustable UVLO - uses SOIC-8 package. | Better suited for high-current automotive applications requiring AEC-Q100 qualification and lower EMI. | Choose for AEC-Q100-compliant designs needing >0.5 A; not pin-compatible - new schematic and layout required. |
Compared with LM25574QMTX/NOPB, LM25011QMYX/NOPB offers higher voltage/current headroom but lacks synchronization and soft-start flexibility, while TPS54340QDDARQ1 provides automotive-grade reliability and EMI features at significantly higher output capability - both require redesign, not drop-in replacement.
Availability
LM25574QMTX/NOPB is available at Aetrix Electronics and suitable for industrial PLC power supplies, automotive body control modules, telecom remote radio units, and factory automation sensor hubs requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM25574QMTX/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 power conversion ICs.
The LM25574 product line targets cost-sensitive, space-constrained industrial and automotive power applications requiring wide-input, medium-current DC/DC conversion with minimal external components and robust fault protection.
FAQ
What is the maximum input voltage rating for LM25574QMTX/NOPB?
The absolute maximum input voltage (VIN to GND) for LM25574QMTX/NOPB is 45 V, with recommended operating range from 6 V to 42 V. Exceeding 45 V risks permanent damage. During transients such as load dump, external clamping (e.g., TVS diode) is advised to keep VIN within spec. The device's internal protections do not cover overvoltage beyond absolute maximum ratings.
How does the LM25574QMTX/NOPB implement current sensing without a sense resistor?
LM25574QMTX/NOPB uses an emulated current-mode architecture: it samples diode current at the IS pin to establish the DC level of inductor current, then generates a voltage ramp proportional to (VIN – VOUT) via the RAMP pin and external capacitor. This eliminates the need for a discrete current-sense resistor while avoiding noise and delay issues associated with direct switch-current measurement.
Can LM25574QMTX/NOPB synchronize to an external clock, and what are the requirements?
Yes, LM25574QMTX/NOPB can synchronize to an external clock via the SYNC pin, which functions as an open-drain input/output. The external clock must exceed the free-running frequency set by the RT resistor, have pulse width ≥15 ns, and use an open-drain driver. Internal SYNC impedance is 11 kΩ (source) and 110 Ω (sink), with falling-edge threshold at 1.3 V.
What is the purpose of the PRE pin on LM25574QMTX/NOPB?
The PRE (pre-charge) pin on LM25574QMTX/NOPB is an open-drain output that pulses 250 ns before each switch-on event to assist charging of the BST–SW bootstrap capacitor. This ensures reliable high-side gate drive under light-load conditions or when the output is pre-biased before startup - critical for maintaining regulation during dynamic load transitions.
Does LM25574QMTX/NOPB support adjustable output voltage, and what is the minimum achievable value?
Yes, LM25574QMTX/NOPB supports fully adjustable output voltage using a resistor divider from OUT to FB. The internal feedback reference is precisely 1.225 V with ±1.5% accuracy over temperature, enabling stable regulation down to exactly 1.225 V - no external reference or additional circuitry is required to achieve this minimum output.
LM25574QMTX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-TSSOP (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:
- 500mA
- 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:
- 16-TSSOP
LM25574QMTX/NOPB FAQ
1.How can I place an order for LM25574QMTX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25574QMTX/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 LM25574QMTX/NOPB reliable?
The price and inventory of LM25574QMTX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25574QMTX/NOPB is usually 5 days.
3.What payment methods are accepted for LM25574QMTX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25574QMTX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25574QMTX/NOPB?
LM25574QMTX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25574QMTX/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 LM25574QMTX/NOPB?
For technical support, including LM25574QMTX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25574QMTX/NOPB requirements.
6.How does Aetrix verify that LM25574QMTX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25574QMTX/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 LM25574QMTX/NOPB meets industry standards.
7.What is the process for return or replacement of LM25574QMTX/NOPB?
All LM25574QMTX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25574QMTX/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 LM25574QMTX/NOPB part is unused and in its original packaging.
Return procedure for LM25574QMTX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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