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Texas Instruments LM25574MT
- Part No.:
- LM25574MT
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25574MT.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,627
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Product details
Overview
LM25574MT from Texas Instruments is a 42-V, 0.5-A step-down switching regulator with integrated 750-mΩ N-channel MOSFET, emulated current mode control, and adjustable 50 kHz–1 MHz switching frequency. It delivers stable output down to 1.225 V from 6–42 V input and supports industrial power rails in telecom and automotive bus applications.
For engineers reviewing the LM25574MT datasheet, LM25574MT pinout, LM25574MT application, or LM25574MT equivalent, key selection factors include its TSSOP-16 package, cycle-by-cycle current limiting, soft-start programmability via external capacitor, and master/slave synchronization capability for multi-rail systems.
Technical Context
The LM25574MT implements emulated current mode control using a reconstructed ramp signal-generated by an internal voltage-controlled current source (IRAMP = (10 µA × (VIN − VOUT)) + 50 µA) and an external RAMP-to-AGND capacitor-eliminating leading-edge spikes and enabling reliable low-duty-cycle operation at high VIN/VOUT ratios. Its error amplifier features 70 dB DC gain and 3 MHz unity-gain bandwidth for robust loop compensation.
It integrates dual-mode VCC regulation (direct VIN coupling below 9 V; regulated 7 V above), thermal shutdown at 165°C with 25°C hysteresis, and a dedicated IS pin for diode current sensing with sample-and-hold circuitry. The SYNC pin supports both external clock synchronization and self-synchronization across multiple devices via open-drain pull-down architecture.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 42 V - supports wide industrial and automotive bus voltages without pre-regulation |
| Output Current | 0.5 A continuous - sufficient for point-of-load conversion in mid-power subsystems |
| Feedback Reference | 1.225 V ±1.5% - enables precise output setting down to 1.225 V with minimal external resistor tolerance impact |
| Switching Frequency | 50 kHz to 1 MHz - adjustable via single RT-to-AGND resistor for size/efficiency trade-off optimization |
| Integrated MOSFET Rds(on) | 750 mΩ max - reduces conduction loss and external component count in compact designs |
| Soft-Start Control | Adjustable via external SS capacitor - prevents inrush current and ensures controlled power-up sequencing |
| Synchronization | Master/slave capable via SYNC pin - eliminates beat frequencies in multi-phase or multi-rail systems |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm), thermally enhanced with separate AGND and PGND pins for analog/digital isolation and improved EMI performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply connection | Accepts 6–42 V; powers internal bias regulator and buck switch; absolute max 45 V |
| VCC | Bias regulator output | Dual-mode: tracks VIN ≤9 V; regulated 7 V ≥9 V; requires 0.1–1 µF ceramic decoupling |
| SW | Switching node | Source of internal N-MOSFET; connects to inductor and external Schottky diode anode |
| BST | Bootstrap capacitor input | Connects to SW via 0.022 µF ceramic capacitor to drive high-side gate during on-time |
| PGND | Power ground return | Low-side reference for IS sense resistor and PRE switch; must be routed separately from AGND |
| AGND | Analog ground reference | Reference for FB, COMP, RAMP, RT, SS; ties to system ground but isolated from PGND for noise immunity |
| FB | Feedback input | Connects to resistor divider from OUT; internal 1.225 V reference sets output voltage |
| COMP | Error amplifier output | Interface for type-II compensation network between COMP and FB to stabilize control loop |
| RAMP | Emulated current ramp node | External capacitor to AGND sets slope; current source scales with (VIN − VOUT) for accurate duty-cycle tracking |
| RT | Oscillator frequency set | Single resistor to AGND programs switching frequency from 50 kHz to 1 MHz |
| SS | Soft-start timing | Internal 10 µA current source charges external capacitor to control output voltage ramp rate |
| SD | Shutdown/standby control | Three-state: <0.7 V = shutdown; 0.7–1.225 V = standby; >1.225 V = active; 5 µA internal pull-up |
| SYNC | Oscillator sync I/O | Open-drain output/input; synchronizes multiple LM25574MTs or accepts external clock ≥ free-run frequency |
| IS | Diode current sense | Connects to Schottky diode anode; internal 250 mΩ sense resistor enables DC-level reconstruction of inductor current |
| PRE | Bootstrap pre-charge assist | Open-drain output pulsed 250 ns before on-time to charge BST capacitor under light/no-load conditions |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current mode control | Eliminates current-sense spike filtering delays and enables stable operation at very low duty cycles (e.g., 12 V → 3.3 V @ 1 MHz) |
| Integrated 42-V, 750-mΩ N-MOSFET | Reduces BOM count and PCB area; eliminates external high-voltage switch selection and layout complexity |
| Adjustable soft-start via SS pin | Prevents input inrush and output overshoot by controlling reference ramp rate with external capacitor value |
| Master/slave synchronization | Enables phase-aligned switching across multiple LM25574MTs to reduce input ripple and EMI in multi-output systems |
| Dual-mode VCC regulator | Minimizes internal power dissipation at high VIN by regulating VCC to 7 V while maintaining full functionality |
| Cycle-by-cycle current limit | Provides immediate overcurrent protection at 0.7 A typical; avoids thermal runaway during short-circuit or overload events |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Converting 24 V battery or 36 V industrial bus to 5 V/3.3 V for PLC I/O, sensors, and microcontrollers. IC Role / Device Role / Timing Role: Primary buck regulator delivering 0.5 A with input transient tolerance up to 42 V and thermal shutdown at 165°C. Use Value: Eliminates need for external high-voltage MOSFET and gate driver; simplifies design for EN 50155-compliant rail systems. |
Use Scenario: Powering infotainment sub-systems and lighting controllers from 12 V vehicle battery with load dump immunity. IC Role / Device Role / Timing Role: Step-down converter operating from 6–42 V input range, supporting cold-crank (6 V) and load-dump (42 V) conditions. Use Value: Built-in UVLO hysteresis and shutdown thresholds enable robust start-up and fault recovery without external supervision. |
| Telecom Remote Radio Unit | Factory Automation Sensor Hub |
|
Use Scenario: Generating stable 3.3 V supply for FPGAs and ADCs in outdoor base station equipment powered from -48 V DC via intermediate 12 V rail. IC Role / Device Role / Timing Role: Secondary buck stage with synchronized switching to minimize conducted EMI in dense RF environments. Use Value: SYNC pin allows alignment with system clock or other converters, reducing spectral peaks and easing EMC certification. |
Use Scenario: Distributed 5 V power for IO-Link masters, fieldbus interfaces, and isolated sensor conditioners in modular control cabinets. IC Role / Device Role / Timing Role: Compact, thermally efficient buck regulator in TSSOP-16 package with PGND/AGND separation for noise-sensitive analog sections. Use Value: Separate power and analog grounds plus wide bandwidth error amplifier ensure clean supply for precision analog front-ends. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM25011MH/NOPB | Higher 60 V input rating, 1.5 A output, SO-PowerPAD-8 package; no RAMP or IS pins; uses traditional current sense | Better suited for higher-current, higher-input-voltage applications where board space permits larger thermal pad | Select when >0.5 A output or >42 V transients are required; not pin-compatible; requires different compensation and layout |
| TPS54340DDAR | 42 V input, 3.5 A output, SOIC-8; integrated current sense, no RAMP/IS pins; fixed 2.5 V ref; no SYNC | Targeted at cost-sensitive, higher-current applications where synchronization and ultra-low duty cycle are not needed | Choose for simpler, higher-current designs without need for emulated current mode or multi-device sync; different footprint and feedback scheme |
Compared with LM25574MT, LM25011MH offers higher voltage/current headroom but lacks emulated current mode and synchronization; TPS54340DDAR provides greater output current in smaller SOIC-8 but sacrifices design flexibility in ramp control, soft-start tuning, and multi-IC coordination.
Availability
LM25574MT is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and telecom remote radio units requiring stable component supply and long-term production continuity.
Supply support for LM25574MT 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 LM25574MT belongs to TI's high-voltage buck regulator product line, designed specifically for robust, easy-to-use DC/DC conversion in harsh industrial and automotive environments where wide input range and built-in protection are critical.
FAQ
What is the maximum input voltage the LM25574MT can safely handle?
The LM25574MT has an absolute maximum VIN rating of 45 V, with recommended operation from 6 V to 42 V. Exceeding 45 V-even transiently-can cause permanent damage. Layout best practices (e.g., low-inductance VIN bypassing near the IC) are essential to suppress ringing during load or line transients. The device includes internal protection, but sustained overvoltage beyond 45 V voids reliability guarantees.
How does the LM25574MT achieve stable operation at very low duty cycles?
The LM25574MT uses emulated current mode control, generating a clean ramp signal via an internal current source (IRAMP = (10 µA × (VIN − VOUT)) + 50 µA) and external RAMP capacitor-avoiding noisy switch-node current sensing. This eliminates leading-edge blanking delays and enables stable regulation down to ~3% duty cycle (e.g., 36 V → 1.225 V @ 1 MHz), unlike traditional current-mode controllers limited by measurement delay.
Can the LM25574MT synchronize to an external clock, and what are the requirements?
Yes, the LM25574MT SYNC pin accepts external clocks with frequency higher than its free-running oscillator (set by RT). The external source must have open-drain output, minimum pulse width of 15 ns, and logic-low threshold ≤1.3 V. Pull-down impedance must be ≤110 Ω; pull-up impedance should be ≥11 kΩ. Synchronization ensures deterministic phase alignment across multiple regulators to reduce input ripple and EMI.
What is the role of the IS pin on the LM25574MT, and how must it be connected?
The IS pin connects to the anode of the external Schottky freewheeling diode and senses re-circulating diode current through an internal 250 mΩ resistor. This sampled current establishes the DC level of the emulated ramp, ensuring accurate average-current reconstruction. Incorrect IS connection (e.g., to cathode or ground) disables current limit and causes regulation failure. A short, low-inductance trace is mandatory.
Does the LM25574MT require external components for soft-start, and how is it configured?
Yes-the LM25574MT uses an external capacitor on the SS pin to set soft-start duration. An internal 10 µA current source charges the capacitor, ramping the error amplifier reference from 0 V to 1.225 V. For example, a 100 nF capacitor yields ~12 ms ramp time. Leaving SS open disables soft-start; connecting SS to GND forces immediate startup. This external control allows precise sequencing in multi-rail systems.
LM25574MT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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 FAQ
1.How can I place an order for LM25574MT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25574MT 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 reliable?
The price and inventory of LM25574MT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25574MT is usually 5 days.
3.What payment methods are accepted for LM25574MT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25574MT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25574MT?
LM25574MT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25574MT 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?
For technical support, including LM25574MT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25574MT requirements.
6.How does Aetrix verify that LM25574MT is sourced from the original manufacturer or authorized distributors?
All LM25574MT 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 meets industry standards.
7.What is the process for return or replacement of LM25574MT?
All LM25574MT units undergo pre-shipment inspection (PSI). If there is an issue with LM25574MT, 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 part is unused and in its original packaging.
Return procedure for LM25574MT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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