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Texas Instruments LM25574Q0MT/NOPB
- Part No.:
- LM25574Q0MT/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25574Q0MT/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,741
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Product details
Overview
LM25574Q0MT/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 telecom and automotive bus applications where input voltage ranges from 6 V to 42 V.
For engineers reviewing the LM25574Q0MT/NOPB datasheet, LM25574Q0MT/NOPB pinout, LM25574Q0MT/NOPB application, or LM25574Q0MT/NOPB equivalent, this page provides verified functional context, TSSOP-16 package mapping, soft-start and synchronization behavior, thermal shutdown thresholds, and real-world design implications of its emulated ramp architecture and diode-sense current measurement.
Technical Context
The LM25574Q0MT/NOPB implements emulated current-mode control using a sample-and-hold DC level derived from IS-pin diode current sensing and an externally capacitor-set ramp slope (RAMP-to-AGND), eliminating leading-edge spikes and enabling stable operation at low duty cycles. Its dual-mode VCC regulator tracks VIN below 9 V and regulates to 7 V above 9 V, supporting 6–42 V input while limiting internal dissipation.
Frequency is set via RT-to-AGND resistor (50–1000 kHz range); SYNC pin enables master/slave synchronization across multiple devices. Protection includes cycle-by-cycle current limit (0.6–0.8 A), thermal shutdown at 165°C, remote shutdown via SD pin (0.7 V shutdown / 1.225 V enable), and forced 500 ns off-time limiting maximum duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 42 V - supports wide industrial and automotive bus rails without external pre-regulation. |
| Output Current | 0.5 A continuous - defined by integrated 750-mΩ N-MOSFET RDS(on) and thermal limits in TSSOP-16 package. |
| Feedback Reference | 1.225 V ±1.5% - sets output voltage accuracy; used with external resistor divider for adjustable VOUT. |
| Switching Frequency | 50 kHz to 1 MHz - programmable via single RT resistor; higher frequencies reduce inductor size but increase switching loss. |
| Current Limit Threshold | 0.6–0.8 A - cycle-by-cycle protection triggered by emulated ramp exceeding 1.4 V; prevents MOSFET overstress. |
| Thermal Shutdown | 165°C with 25°C hysteresis - halts switching until junction cools; ensures reliability under sustained overload or poor airflow. |
| Soft-Start Current | 7–14 µA - charges external SS capacitor linearly; controls output voltage ramp rate to limit inrush current. |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm body), 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; powers internal bias regulator and high-side switch; requires local ceramic bypass. |
| VCC | Bias regulator output | Provides ~7 V (regulated) or tracks VIN (≤9 V); powers control circuitry; needs 0.1–1 µF decoupling. |
| SW | Switching node | Drives external Schottky diode and buck inductor; connects internally to N-MOSFET source. |
| BST | Bootstrap capacitor input | Charges external 0.022 µF BST–SW capacitor during off-time to drive high-side gate. |
| PRE | Pre-charge assist output | Open-drain pulse (250 ns/cycle) aids BST capacitor charging under light load or pre-biased output. |
| PGND | Power ground return | Low-side reference for SW, IS, and external diode; must be low-inductance path to minimize noise. |
| AGND | Analog ground reference | Reference for FB, COMP, RAMP, RT; separate from PGND to avoid switching noise coupling into control loop. |
| FB | Feedback input | Connects to resistor divider from VOUT; internal error amp compares to 1.225 V reference. |
| COMP | Error amplifier output | Interface for type-II compensation network (R/C between COMP and FB) to stabilize voltage loop. |
| RAMP | Emulated current ramp node | External capacitor (50–2000 pF) sets slope; current source scales with (VIN – VOUT) for accurate emulation. |
| RT | Oscillator frequency set | Resistor to AGND programs frequency (F = 1/(135×10⁻¹²·RRT + 580×10⁻⁹)); precision resistor recommended. |
| SYNC | Frequency synchronization I/O | Can accept external clock or drive other LM25574 devices; internal weak pull-up/strong pull-down enables daisy-chain sync. |
| SD | Shutdown/standby control | 0.7 V = shutdown, 1.225 V = active; internal 5 µA pull-up allows open-circuit enable; supports UVLO threshold setting. |
| SS | Soft-start timing | Internal 10 µA current source charges external capacitor; holds COMP reference low until SS voltage rises. |
| IS | Diode current sense | Measures re-circulating Schottky diode current; internal 250 mΩ sense resistor feeds sample-and-hold for DC ramp level. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode control | Eliminates need for current-sense resistor and RC filtering; enables stable regulation at <10% duty cycle in high-VIN/low-VOUT designs. |
| Integrated 42-V, 750-mΩ N-MOSFET | Reduces BOM count and layout area; eliminates external high-voltage switch selection and gate-drive complexity. |
| Adjustable soft-start (SS pin) | External capacitor sets rise time of error amplifier reference; prevents output overshoot and inrush into large capacitive loads. |
| Master/slave synchronization (SYNC) | Enables phase-aligned multi-rail supplies; avoids beat-frequency EMI and reduces input ripple current in parallel configurations. |
| Dual-mode VCC regulator | Tracks VIN ≤9 V (reducing dropout), regulates to 7 V >9 V (limiting internal power dissipation); supports auxiliary VCC injection. |
| Diode-current-based current sensing (IS pin) | Uses internal 250 mΩ sense resistor on recirculating path; avoids high-side MOSFET current sensing errors and propagation delays. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Converts 24 V vehicle battery or 24/48 V industrial rail to 3.3 V or 5 V for microcontrollers and I/O drivers. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 0.5 A output; handles line transients up to 42 V and cold-crank dips down to 6 V. Use Value: Emulated current mode ensures stable regulation during rapid load steps (e.g., solenoid activation), while SYNC enables coordinated multi-rail sequencing. |
Use Scenario: Powers CAN transceivers, sensor interfaces, and MCU subsystems in automotive body electronics. IC Role / Device Role / Timing Role: High-input-voltage DC/DC converter operating from 9–16 V nominal battery with load dump tolerance up to 42 V. Use Value: Thermal shutdown (165°C) and cycle-by-cycle current limit protect against shorted outputs in harsh under-hood environments. |
| Telecom Remote Radio Unit | Factory Automation Sensor Hub |
|
Use Scenario: Steps down -48 V telecom bus (via inverted buck-boost front-end) or 36–60 V PoE++ derived rail to 12 V intermediate bus. IC Role / Device Role / Timing Role: Secondary buck stage providing isolated, low-noise 12 V for RF amplifiers and ADCs; operates at 500 kHz for compact magnetics. Use Value: Adjustable frequency avoids sensitive RF bands; RAMP capacitor tuning optimizes transient response for burst-mode digital loads. |
Use Scenario: Powers mixed-signal sensor nodes (temperature, pressure, vibration) in distributed IIoT edge controllers. IC Role / Device Role / Timing Role: Centralized 5 V/3.3 V supply with remote shutdown (SD pin) for firmware-controlled power gating of peripheral clusters. Use Value: 1.225 V reference accuracy ensures precise ADC reference stability; TSSOP-16 package supports automated SMT assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM25011Q0MK/NOPB | Higher 60 V input rating, 1.5 A output, but larger SO-PowerPAD-8 package; no RAMP or IS pins - uses traditional current-sense resistor. | Preferred for >42 V transients or >0.5 A loads; lacks emulated ramp benefits for ultra-low-duty-cycle operation. | Select when input voltage exceeds 42 V or output current demand exceeds 0.5 A; accept added board area and external sense resistor. |
| TPS54340QDGQRQ1 | 42 V input, 3.5 A output, integrated high-side FET; uses current-sense resistor and fixed 2.5 V reference; AEC-Q100 qualified. | Targeted at automotive powertrain; supports wider temperature range (–40°C to 150°C) and stricter qualification requirements. | Choose for ASIL-B systems requiring automotive qualification; trade off higher cost and larger QFN-10 package for proven automotive reliability. |
Compared with LM25574Q0MT/NOPB, LM25011Q0MK/NOPB extends input voltage and output current but sacrifices emulated ramp advantages and increases component count, while TPS54340QDGQRQ1 offers higher current and AEC-Q100 compliance at the expense of design flexibility and non-standard reference voltage.
Availability
LM25574Q0MT/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 and voltage ranges.
Supply support for LM25574Q0MT/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 LM25574Q0MT/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for robust, low-component-count DC/DC conversion in industrial, telecom, and automotive applications where input voltage exceeds 24 V.
FAQ
What is the maximum input voltage the LM25574Q0MT/NOPB can safely handle?
The LM25574Q0MT/NOPB has an absolute maximum VIN rating of 45 V, with recommended operation from 6 V to 42 V. Exceeding 45 V risks permanent damage. During transients (e.g., load dump), ensure proper input clamping and local ceramic bypassing near VIN and GND pins to suppress ringing above this limit. The device's internal protection does not cover overvoltage beyond absolute maximum ratings.
How does the LM25574Q0MT/NOPB achieve current sensing without an external sense resistor?
The LM25574Q0MT/NOPB uses internal diode-current sensing via the IS pin: an internal 250 mΩ resistor between IS and PGND measures re-circulating Schottky diode current, and a sample-and-hold circuit captures its DC level just before each switch-on event. This DC level combines with an emulated ramp (set by RAMP capacitor and VIN–VOUT-dependent current source) to reconstruct inductor current - eliminating external sense resistors and associated noise/filtering challenges.
Can the LM25574Q0MT/NOPB synchronize to an external clock, and what are the timing requirements?
Yes - the LM25574Q0MT/NOPB SYNC pin accepts external clocks with frequency higher than its free-running oscillator (set by RT). The external signal must have ≥15 ns pulse width and use open-drain interface with pull-up. Internal SYNC driver features strong pull-down/weak pull-up, enabling daisy-chained synchronization of up to five devices, where the highest-frequency unit acts as master. No external level-shifting is required for 3.3 V or 5 V logic clocks.
What is the purpose of the PRE pin on the LM25574Q0MT/NOPB, and when should it be used?
The PRE (pre-charge) pin is an open-drain output that pulses low for 250 ns each switching cycle to assist bootstrap capacitor (BST–SW) charging under light-load conditions or when the output is pre-biased before startup. It is especially useful in applications with high output capacitance or where the output voltage may be present prior to EN/SD assertion - preventing bootstrapping failure and ensuring reliable high-side gate drive during initial soft-start.
Does the LM25574Q0MT/NOPB require special layout considerations for the RAMP and COMP pins?
Yes - the RAMP pin is highly sensitive to noise and parasitic capacitance. Its external capacitor must be placed within 2 mm of the RAMP and AGND pins using short, direct traces; ceramic dielectric (X7R/C0G) is mandatory. Similarly, the COMP pin carries the error amplifier output; its compensation network (typically type-II: series RC from COMP to FB, plus parallel C to AGND) must be routed away from noisy nodes (SW, PGND, VIN) and use ground guard rings to prevent instability caused by coupling or leakage.
LM25574Q0MT/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:
- 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:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM25574Q0MT/NOPB FAQ
1.How can I place an order for LM25574Q0MT/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25574Q0MT/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 LM25574Q0MT/NOPB reliable?
The price and inventory of LM25574Q0MT/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25574Q0MT/NOPB is usually 5 days.
3.What payment methods are accepted for LM25574Q0MT/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25574Q0MT/NOPB transactions.
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4.How is shipping managed for LM25574Q0MT/NOPB?
LM25574Q0MT/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25574Q0MT/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 LM25574Q0MT/NOPB?
For technical support, including LM25574Q0MT/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25574Q0MT/NOPB requirements.
6.How does Aetrix verify that LM25574Q0MT/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25574Q0MT/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 LM25574Q0MT/NOPB meets industry standards.
7.What is the process for return or replacement of LM25574Q0MT/NOPB?
All LM25574Q0MT/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25574Q0MT/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 LM25574Q0MT/NOPB part is unused and in its original packaging.
Return procedure for LM25574Q0MT/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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