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Texas Instruments LM25574MT/NOPB
- Part No.:
- LM25574MT/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25574MT/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:10,082
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Product details
Overview
LM25574MT/NOPB from Texas Instruments is a 42-V, 0.5-A synchronous step-down 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 LM25574MT/NOPB datasheet, LM25574MT/NOPB pinout, LM25574MT/NOPB application, or LM25574MT/NOPB equivalent, key selection criteria include input voltage range (6–42 V), output current capability (0.5 A), soft-start adjustability, SYNC capability for multi-regulator coordination, and thermal/overcurrent protection architecture.
Technical Context
The LM25574MT/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 ~7 V bias above 9 V VIN while tracking VIN below that threshold.
Frequency is set by a single RT-to-AGND resistor; SYNC pin supports master/slave synchronization across multiple LM2557x devices. Protection includes cycle-by-cycle current limiting (0.7 A typ), thermal shutdown (165 °C), and remote shutdown via SD pin with hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 42 V - supports wide industrial bus voltages including 12 V, 24 V, and 36 V nominal systems. |
| Output Current | 0.5 A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in distributed power architectures. |
| 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 - adjustable via RT resistor to optimize efficiency vs. size trade-offs in magnetics and capacitors. |
| MOSFET RDS(on) | 750 mΩ max - integrated high-voltage switch reduces BOM count and improves thermal performance in compact layouts. |
| Soft-Start Control | Adjustable via SS capacitor - prevents inrush current during power-up, critical for systems with large output capacitance. |
| Thermal Shutdown | 165 °C with 25 °C hysteresis - ensures safe operation under overload or poor heatsinking conditions without latch-up. |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm), thermally enhanced with exposed PGND pad; compatible with standard surface-mount assembly processes and reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Accepts 6–42 V unregulated supply; absolute max 45 V - requires local ceramic bypassing near pin. |
| VCC | Bias regulator output | Provides ~7 V internal supply; tracks VIN below 9 V; supports external auxiliary bias to reduce dissipation. |
| SW | Switch node | Drives external Schottky diode and buck inductor; connects to BST capacitor and PRE pin for bootstrap charging. |
| BST | Bootstrap supply | Charged via internal diode during SW off-time; requires 0.022 µF ceramic capacitor to SW for gate drive. |
| PGND | Power ground return | Low-side reference for IS sense resistor and PRE switch; must be routed separately from AGND for noise immunity. |
| AGND | Analog ground reference | Reference for FB, COMP, RAMP, RT, SS; requires star connection to PGND at single point to avoid coupling noise. |
| FB | Feedback input | Inverting input of error amplifier; regulated at 1.225 V - sets output voltage via external resistor divider. |
| COMP | Error amplifier output | Connects to FB via type-II compensation network; determines loop stability and transient response. |
| RT | Oscillator frequency set | Resistor to AGND programs switching frequency; value directly determines FSW per TI's published equation. |
| RAMP | Emulated current ramp | External capacitor to AGND sets ramp slope; value scaled to inductor L to match sample-and-hold gain (2 V/A). |
| IS | Diode current sense | Measures recirculating diode anode current; provides DC level for emulated ramp reconstruction. |
| SD | Shutdown control | Three-state logic: <0.7 V = shutdown, 0.7–1.225 V = standby, >1.225 V = active; internal 5 µA pull-up if open. |
| SYNC | Frequency synchronization | Open-drain input/output; allows multiple LM25574MT/NOPB units to lock to highest-frequency device or external clock. |
| SS | Soft-start timing | Internal 10 µA current source charges external capacitor; controls ramp rate of error amp reference during startup. |
| PRE | Bootstrap pre-charge | Open-drain assist for BST capacitor charging during light load or pre-biased output conditions; 250 ns pulse/cycle. |
| OUT | Regulated output | Direct connection to output capacitor; not internally connected - must be externally wired to filter components. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode control | Eliminates need for current-sense resistor and associated noise filtering; enables stable operation at sub-10% duty cycles in high-VIN/low-VOUT applications. |
| Integrated 42-V, 750-mΩ MOSFET | Reduces external component count and PCB area; eliminates gate driver design complexity while maintaining 0.5-A output capability. |
| Adjustable soft-start | Prevents output overshoot and input inrush by controlling reference ramp rate - critical for systems with >1000 µF output capacitance. |
| Master/slave SYNC capability | Enables phase-aligned switching across multiple regulators to minimize input ripple and EMI peaks in multi-rail power supplies. |
| Dual-mode VCC regulator | Tracks VIN below 9 V and regulates to 7 V above - optimizes internal power efficiency across full input range without external bias supply. |
| Robust protection suite | Includes cycle-by-cycle current limit (0.7 A), thermal shutdown (165 °C), UVLO on VCC and VIN, and remote shutdown via SD pin. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering isolated analog sensor interfaces and digital I/O drivers from 24 V rail in factory automation cabinets. IC Role / Device Role / Timing Role: Primary buck converter generating 3.3 V or 5 V for microcontroller, ADC, and CAN transceiver subsystems. Use Value: Wide 6–42 V input range accommodates brownouts and surges on industrial 24 V buses; SYNC enables coordinated switching with other rails to meet CISPR-25 conducted EMI limits. | Use Scenario: Supplying 5 V to body electronics such as door modules, lighting controllers, and LIN transceivers from vehicle battery (9–16 V nominal, up to 42 V load dump). IC Role / Device Role / Timing Role: High-reliability step-down regulator with thermal and overcurrent protection for automotive-grade power domains. Use Value: 165 °C thermal shutdown and 42 V absolute max rating meet AEC-Q100 stress requirements; adjustable soft-start prevents fuse blowing during cold-crank events. |
| Telecom Remote Radio Unit | Test & Measurement Equipment |
Use Scenario: Generating 12 V intermediate rail from 48 V telecom backplane for RF amplifiers and DACs in outdoor base stations. IC Role / Device Role / Timing Role: Efficient, high-input-voltage buck stage operating at 500 kHz to minimize inductor size in space-constrained enclosures. Use Value: Emulated current mode enables stable regulation at 25% duty cycle (12 V out from 48 V in); RAMP capacitor tuning ensures optimal transient response under dynamic RF load steps. | Use Scenario: Providing clean, adjustable 3.3 V/5 V rails for FPGA configuration, ADC reference, and precision op-amps in benchtop analyzers. IC Role / Device Role / Timing Role: Low-noise, well-regulated supply with tight 1.225 V reference and high PSRR for sensitive analog front-ends. Use Value: 1.5% reference accuracy and wide bandwidth error amplifier (3 MHz GBW) support <10 mV output variation over line/load/temp; COMP pin enables custom loop shaping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM25011MH/NOPB | Higher 60 V input rating, 1.5 A output, but larger HTSSOP-16 package and no SYNC pin. | Used where higher input surge tolerance or output current is required; lacks multi-device synchronization. | Select when 60 V input headroom or >0.5 A load is needed; avoid if EMI-sensitive multi-rail sync is mandatory. |
| TPS54240DGQR | 42 V input, 2.5 A output, integrated high-side FET, but uses traditional current-sense resistor and no RAMP pin. | Preferred for higher-current industrial motor drives; lacks emulated ramp architecture and diode-current sensing. | Choose for cost-sensitive, higher-current designs where external sense resistor is acceptable; not drop-in for LM25574MT/NOPB layout. |
Compared with LM25574MT/NOPB, LM25011MH/NOPB trades SYNC capability and compact TSSOP-16 for higher voltage/current ratings, while TPS54240DGQR offers greater output current but requires additional current-sense components and lacks the noise-immune emulated ramp architecture.
Availability
LM25574MT/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, telecom remote radio units, and test & measurement equipment requiring stable component supply and long-term manufacturability.
Supply support for LM25574MT/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 LM25574MT/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for industrial, automotive, and telecom applications demanding wide input range, integrated FETs, and robust protection in compact packages.
FAQ
What is the maximum input voltage rating for the LM25574MT/NOPB?
The LM25574MT/NOPB has an absolute maximum input voltage (VIN to GND) rating of 45 V. Its recommended operating range is 6 V to 42 V. Exceeding 45 V risks permanent damage, especially during transients like load dump or inductive kickback - proper input clamping and layout practices are essential for reliability in 42 V systems.
How does the LM25574MT/NOPB achieve current-mode control without a sense resistor?
The LM25574MT/NOPB uses emulated current-mode control: it reconstructs the inductor current ramp using an internal voltage-controlled current source (IRAMP = 10 µA/V × (VIN – VOUT) + 50 µA) and a sample-and-hold circuit measuring diode anode current at the IS pin. This eliminates external sense resistors and associated noise, enabling stable operation at very low duty cycles.
Can the LM25574MT/NOPB synchronize to an external clock signal?
Yes, the LM25574MT/NOPB supports external clock synchronization via its SYNC pin. An open-drain clock source with pulse width ≥15 ns and frequency higher than the free-running oscillator (set by RT) can drive the SYNC pin. Multiple LM25574MT/NOPB units can also self-synchronize by connecting their SYNC pins together, with the highest-frequency unit acting as master.
What is the purpose of the PRE pin on the LM25574MT/NOPB?
The PRE pin on the LM25574MT/NOPB is an open-drain pre-charge assist for the bootstrap capacitor. It activates for 250 ns each switching cycle just before the high-side switch turns on, helping charge the BST capacitor during light-load conditions or when the output is pre-biased - ensuring reliable gate drive even with minimal output current.
Does the LM25574MT/NOPB require external compensation components?
Yes, the LM25574MT/NOPB requires external compensation components connected between the COMP and FB pins. A standard type-II network (resistor + capacitor + capacitor) is recommended to stabilize the control loop, set crossover frequency, and ensure adequate phase margin - TI provides design calculators and WEBENCH® Power Designer support for this task.
LM25574MT/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-TSSOP (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:
- 500mA
- Frequency - Switching:
- 50kHz ~ 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM25574MT/NOPB FAQ
1.How can I place an order for LM25574MT/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25574MT/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 LM25574MT/NOPB reliable?
The price and inventory of LM25574MT/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25574MT/NOPB is usually 5 days.
3.What payment methods are accepted for LM25574MT/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25574MT/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25574MT/NOPB?
LM25574MT/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25574MT/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 LM25574MT/NOPB?
For technical support, including LM25574MT/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25574MT/NOPB requirements.
6.How does Aetrix verify that LM25574MT/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25574MT/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 LM25574MT/NOPB meets industry standards.
7.What is the process for return or replacement of LM25574MT/NOPB?
All LM25574MT/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25574MT/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 LM25574MT/NOPB part is unused and in its original packaging.
Return procedure for LM25574MT/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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