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Texas Instruments LM25574MTX/NOPB
- Part No.:
- LM25574MTX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM25574MTX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,143
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Product details
Overview
LM25574MTX/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 from 6 V to 42 V input to stable low-voltage rails in space-constrained systems.
For engineers reviewing the LM25574MTX/NOPB datasheet, LM25574MTX/NOPB pinout, LM25574MTX/NOPB application, or LM25574MTX/NOPB equivalent, key selection considerations include input voltage range (6–42 V), output current capability (0.5 A), TSSOP-16 thermal performance (RθJA = 90 °C/W), soft-start adjustability, and SYNC-capable multi-device synchronization.
Technical Context
The LM25574MTX/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 very low duty cycles. Its dual-mode VCC regulator maintains ~7 V bias for VIN > 9 V and tracks VIN directly below 9 V, supporting wide-input operation without external LDO.
Functional modes include three-level SD pin control (shutdown < 0.7 V, standby 0.7–1.225 V, active > 1.225 V), master/slave synchronization via open-drain SYNC pin, and cycle-by-cycle current limiting with 0.7 A typical trip threshold. Protection includes thermal shutdown (165 °C), short-circuit response, and forced 500 ns off-time to ensure reliable IS pin sampling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 42 V - supports direct connection to industrial 24 V, automotive 36 V, and telecom 48 V bus rails without pre-regulation. |
| 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; tight tolerance reduces output drift across temperature. |
| Switching Frequency | 50 kHz to 1 MHz (resistor-programmable) - allows trade-off between inductor size (higher fSW) and efficiency (lower fSW). |
| Integrated MOSFET RDS(on) | 750 mΩ (typical) - reduces conduction loss and simplifies BOM by eliminating external high-side switch. |
| Thermal Resistance | RθJA = 90 °C/W (TSSOP-16) - defines junction-to-ambient rise under natural convection; requires minimal copper area for 0.5 A operation at 125 °C max TJ. |
| Soft-Start Current | 10 µA (typical) - sets rise time of internal reference via external capacitor; prevents inrush current during power-up. |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm body size) with exposed thermal pad; RoHS-compliant, lead-free (NOPB suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply | Accepts 6–42 V unregulated input; absolute max 45 V; requires local 10 µF ceramic bypass. |
| VCC | Bias regulator output | Dual-mode: tracks VIN ≤9 V, regulated to ~7 V above 9 V; powers internal logic and gate driver. |
| 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 capacitor from VCC during off-time to drive high-side gate. |
| PRE | Pre-charge assist | Open-drain output pulsed 250 ns/cycle to aid BST capacitor charging under light load or pre-biased output. |
| PGND | Power ground | Low-side return for SW, IS, and output inductor; separate from AGND to minimize noise coupling. |
| AGND | Analog ground | Reference for FB, COMP, RT, RAMP, SS; must be star-connected to PGND at single point near IC. |
| FB | Feedback input | Inverting input of error amplifier; connected to resistor divider from OUT; 1.225 V threshold sets VOUT. |
| COMP | Error amplifier output | Connects external Type II compensation network (R/C) between COMP and FB for loop stability. |
| RT | Oscillator frequency set | Resistor to AGND programs fSW; e.g., 32.4 kΩ yields ~200 kHz; layout critical-place close to pin. |
| RAMP | Emulated current ramp | External capacitor to AGND sets ramp slope; value depends on L and VIN–VOUT per IRAMP = (10 µA/V)(VIN–VOUT)+50 µA. |
| SS | Soft-start control | 10 µA current source charges external capacitor; controls reference ramp rate and inrush limiting. |
| SD | Shutdown/stanby enable | Three-state: <0.7 V = shutdown (70 µA IQ), 0.7–1.225 V = standby (VCC active, SW disabled), >1.225 V = active. |
| SYNC | Frequency synchronization | Open-drain input/output; synchronizes multiple LM25574s or accepts external clock > fSW (min 15 ns pulse). |
| IS | Diode current sense | Measures re-circulating Schottky diode current; internal 250 mΩ sense resistor feeds sample-and-hold for DC level. |
| OUT | Regulated output | High-current output node; connect directly to output capacitor and load; low-ESR ceramic recommended. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode architecture | Eliminates current-sense noise and propagation delay, enabling stable regulation at <10% duty cycle in high-VIN/low-VOUT applications. |
| Integrated 42-V, 750-mΩ N-MOSFET | Reduces component count and PCB footprint; eliminates gate driver design while maintaining 0.5 A output capability. |
| Adjustable soft-start (SS pin) | External capacitor sets controlled output voltage ramp, preventing input inrush and downstream supply sequencing issues. |
| Master/slave SYNC capability | Enables EMI reduction via synchronized switching of multiple converters; no external clock generator required for multi-rail systems. |
| Wide 6–42 V input range | Supports direct connection to industrial 24 V, automotive battery (cold-crank tolerant), and telecom -48 V phantom power rails. |
| Built-in protection suite | Includes cycle-by-cycle current limit (0.7 A typ), thermal shutdown (165 °C), UVLO on VCC and SD pins, and forced 500 ns off-time. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
|
Use Scenario: Powering isolated analog sensor interfaces and digital I/O drivers in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary 3.3 V or 5 V buck converter supplying MCU core, ADC reference, and optocoupler drivers from 24 V DC bus. Use Value: 42 V input rating withstands 40 V transients per IEC 61000-4-4; TSSOP-16 thermal performance sustains 0.5 A at 70 °C ambient without heatsink. |
Use Scenario: Generating 5 V rail for microcontroller, CAN transceiver, and LED drivers in vehicle door modules and seat controllers. IC Role / Device Role / Timing Role: High-reliability step-down regulator operating from 9–16 V battery with cold-crank support down to 6 V. Use Value: Emulated current mode ensures stable regulation during engine start (6 V dips); SD pin enables wake-on-CAN functionality. |
| Telecom Remote Radio Unit | Factory Automation Sensor Node |
|
Use Scenario: Converting -48 V phantom power to +5 V or +3.3 V for RF front-end ICs and FPGAs in outdoor base station radios. IC Role / Device Role / Timing Role: Input-stage buck converter accepting reverse-polarity protected -48 V input (via external diode) to generate intermediate rail. Use Value: 42 V absolute max rating accommodates clamped -48 V inputs; SYNC pin enables phase-shifted parallel operation to reduce input ripple. |
Use Scenario: Powering low-power wireless sensor transceivers (Zigbee, LoRa) and MEMS accelerometers in predictive maintenance nodes. IC Role / Device Role / Timing Role: Efficient 12 V to 3.3 V conversion with adjustable frequency to avoid RF interference bands. Use Value: 50 kHz–1 MHz programmability allows selecting 800 kHz to clear 2.4 GHz ISM band harmonics; 70 µA shutdown current extends battery life. |
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 75-V input rating, 1.5-A output, HTSSOP-16 package; no SYNC or PRE pins; uses traditional current-sense resistor. | Better suited for 48 V industrial bus or PoE++ applications requiring >0.5 A; lacks multi-device synchronization. | Select LM25011MH/NOPB when input exceeds 42 V or output current >0.5 A is needed; LM25574MTX/NOPB preferred for EMI-sensitive, multi-rail sync designs. |
| TPS54340DDAR | 42-V input, 3.5-A output, SOIC-8; current-mode (not emulated); fixed 500-kHz fSW; no RAMP or PRE pins. | Higher current density for compact 3.3 V/5 V rails; lacks adjustable frequency and soft-start flexibility. | Choose TPS54340DDAR for cost-sensitive, high-current single-rail applications; LM25574MTX/NOPB offers superior transient response and design flexibility in noise-critical systems. |
Compared with LM25011MH/NOPB and TPS54340DDAR, the LM25574MTX/NOPB uniquely combines wide-input operation, precise 0.5 A capability, emulated current-mode stability, and multi-device synchronization in a thermally optimized TSSOP-16 package-making it optimal for industrial and automotive subsystems demanding reliability, low EMI, and design scalability.
Availability
LM25574MTX/NOPB is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, telecom remote radio units, and factory automation sensor nodes requiring stable component supply across extended temperature and voltage ranges.
Supply support for LM25574MTX/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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The LM25574MTX/NOPB belongs to TI's high-voltage DC/DC regulator product line, engineered specifically for robust, low-component-count buck conversion in harsh environments-from factory floors to vehicle cabins.
FAQ
What is the maximum input voltage the LM25574MTX/NOPB can safely handle?
The LM25574MTX/NOPB has an absolute maximum VIN rating of 45 V. Continuous operation is specified from 6 V to 42 V. Exceeding 45 V-even transiently-risks permanent damage. Layout best practices (local 10 µF ceramic bypass, short VIN/GND traces) are essential to suppress ringing during load dumps or line transients. The LM25574MTX/NOPB is not rated for 48 V direct input without external clamping or pre-regulation.
How does the emulated current-mode control in the LM25574MTX/NOPB differ from traditional current-mode control?
Unlike traditional current-mode regulators that sense actual switch current (prone to noise and propagation delay), the LM25574MTX/NOPB reconstructs the current ramp using a diode-current sample-and-hold (DC level) plus a voltage-controlled current source (ramp slope). This eliminates leading-edge spikes and enables stable operation at very low duty cycles-critical for high-VIN/low-VOUT applications. The LM25574MTX/NOPB achieves this without external sense resistors or complex filtering.
Can the LM25574MTX/NOPB synchronize to an external clock, and what are the timing requirements?
Yes-the LM25574MTX/NOPB SYNC pin supports both master and slave operation. As a slave, it accepts an external open-drain clock signal with minimum pulse width of 15 ns and frequency higher than its free-running oscillator (set by RT). As a master, it drives SYNC low to synchronize other LM25574MTX/NOPB devices. Multiple units on a shared SYNC net self-organize with the highest-frequency unit acting as master-no external controller needed.
What thermal derating applies to the LM25574MTX/NOPB at 0.5 A output current?
With RθJA = 90 °C/W and max TJ = 125 °C, the LM25574MTX/NOPB dissipates ~0.19 W at 0.5 A (based on 750 mΩ RDS(on) and typical efficiency). This yields ~17 °C rise above ambient-well within limits for 2-layer PCBs with modest copper pour. No heatsink is required up to 70 °C ambient. For 85 °C ambient, reduce output current to ~0.4 A or add thermal vias under the exposed pad per TI SLMA011 guidelines.
Is the LM25574MTX/NOPB pin-compatible with other members of the LM2557x family?
No-LM25574MTX/NOPB is not pin-compatible with LM25575 or LM25576. While all share the TSSOP-16 package and similar functional blocks, pin assignments differ significantly (e.g., LM25575 lacks PRE and RAMP pins; LM25576 integrates BOOT diode). Substitution requires full schematic and layout review. The LM25574MTX/NOPB pinout is unique to its emulated current-mode architecture and must be implemented per the datasheet's Pin Configuration and Functions table.
LM25574MTX/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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM25574MTX/NOPB FAQ
1.How can I place an order for LM25574MTX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM25574MTX/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 LM25574MTX/NOPB reliable?
The price and inventory of LM25574MTX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM25574MTX/NOPB is usually 5 days.
3.What payment methods are accepted for LM25574MTX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM25574MTX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM25574MTX/NOPB?
LM25574MTX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM25574MTX/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 LM25574MTX/NOPB?
For technical support, including LM25574MTX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM25574MTX/NOPB requirements.
6.How does Aetrix verify that LM25574MTX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM25574MTX/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 LM25574MTX/NOPB meets industry standards.
7.What is the process for return or replacement of LM25574MTX/NOPB?
All LM25574MTX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM25574MTX/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 LM25574MTX/NOPB part is unused and in its original packaging.
Return procedure for LM25574MTX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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