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Texas Instruments LM5574MT/NOPB
- Part No.:
- LM5574MT/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5574MT/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,689
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Product details
Overview
LM5574MT/NOPB from Texas Instruments is a 75V-input, 0.5A synchronous step-down switching regulator with integrated 750mΩ N-channel MOSFET, emulated current-mode control, and adjustable 50–500kHz switching frequency. It delivers stable output down to 1.225V and supports industrial power bus applications requiring wide VIN range and robust fault protection.
For engineers reviewing the LM5574MT/NOPB datasheet, LM5574MT/NOPB pinout, LM5574MT/NOPB application, or LM5574MT/NOPB equivalent, key selection considerations include its 6–75V input range, cycle-by-cycle current limiting, thermal shutdown, soft-start programmability, and SYNC capability for multi-regulator EMI reduction.
Technical Context
The LM5574MT/NOPB implements emulated current-mode control using a reconstructed ramp signal-derived from VIN–VOUT and an IS-pin diode current sample-to avoid noise-sensitive current sensing while enabling stable operation at very low duty cycles. Its dual-mode VCC regulator autonomously supplies 7V bias from inputs up to 75V, eliminating external bias rails.
It features a programmable oscillator (RT-resistor set), SYNC pin for master-slave synchronization across multiple units, and integrated protections including thermal shutdown (165°C), cycle-by-cycle current limit (0.7A typ), and remote shutdown via SD pin with hysteresis. The 16-pin TSSOP package supports compact high-voltage buck designs with minimal external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 75V - enables direct regulation from telecom (-48V), industrial 24/48V, and unregulated HV bus without pre-regulator. |
| Output Current | 0.5A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in distributed power systems. |
| Feedback Reference | 1.225V ±1.5% - sets precise output voltage with external resistor divider; enables outputs as low as 1.225V. |
| Switching Frequency | 50kHz to 500kHz - adjustable via RT resistor; balances inductor size, efficiency, and EMI performance. |
| Integrated MOSFET Rds(on) | 750mΩ (max 1500mΩ) - reduces external component count and conduction loss in medium-power buck stages. |
| Thermal Shutdown | 165°C with 25°C hysteresis - protects against sustained overload or poor heatsinking in enclosed industrial environments. |
| Soft-Start Current | 10µA (typ) - controls ramp rate of output voltage via external SS capacitor; prevents inrush into downstream capacitance. |
Pinout & Package
LM5574MT/NOPB is housed in a 16-pin TSSOP (PW) package measuring 5mm × 6.4mm, optimized for thermal performance (RθJA = 95°C/W) and high-voltage layout separation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply | Accepts 6–75V; powers internal bias regulator and buck switch; requires local ceramic bypass. |
| VCC | Bias regulator output | Provides 7V (±3%) internal supply; can be externally powered (7.5–14V) to reduce dissipation. |
| SW | Switch node | Connects to inductor and Schottky diode anode; carries high dv/dt switching waveform. |
| BST | Bootstrap capacitor connection | Requires 0.022µF ceramic cap to SW; enables high-side gate drive for integrated N-MOSFET. |
| FB | Feedback input | Compares output voltage (via resistor divider) to 1.225V reference; sets regulated output level. |
| COMP | Error amplifier output | Interface for type-II compensation network between COMP and FB to stabilize loop response. |
| RT | Oscillator frequency set | Resistor to AGND programs switching frequency from 50kHz to 500kHz per TI equation. |
| SYNC | Oscillator sync I/O | Allows multiple LM5574MT/NOPB units to synchronize or lock to external clock > free-run frequency. |
| SD | Shutdown control | Logic-level input: <0.7V = shutdown, >1.225V = active; supports undervoltage lockout via divider. |
| SS | Soft-start timing | 10µA current source charges external capacitor to ramp reference voltage and control startup slew. |
| RAMP | Emulated current ramp | External capacitor sets slope; reconstructs inductor current to enable noise-immune current-mode control. |
| IS | Diode current sense | Connects to Schottky anode; samples recirculating current for DC level of emulated ramp. |
| PRE | Pre-charge assist | Open-drain output tied to SW; aids BST capacitor charging during light-load or pre-biased conditions. |
| AGND / PGND | Analog & power ground | Separate ground pins minimize noise coupling: AGND for references, PGND for high-current return paths. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode architecture | Eliminates leading-edge spike filtering and enables stable sub-10% duty cycle operation at high VIN/VOUT ratios. |
| Integrated 75V/750mΩ N-MOSFET | Reduces BOM count and PCB area; eliminates need for external high-voltage switch and driver. |
| Programmable soft-start | 10µA current source + external capacitor allows precise control of output voltage rise time and inrush current. |
| Multi-device synchronization | SYNC pin enables deterministic phase alignment of multiple LM5574MT/NOPB regulators to suppress beat frequencies and EMI peaks. |
| Dual-mode VCC regulator | Auto-switches between LDO (VIN <9V) and regulated 7V (VIN >9V), supporting full 6–75V input without auxiliary supply. |
| Comprehensive fault protection | Includes cycle-by-cycle current limit (0.7A), thermal shutdown (165°C), and remote shutdown with hysteresis. |
Applications
| Industrial Power Supply | Telecom Line Card |
|---|---|
|
Use Scenario: Regulating 48V or 72V backplane voltage to 3.3V/5V for FPGA, MCU, and PHY ICs on DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Primary non-isolated buck converter delivering 0.5A with high line regulation and transient immunity. Use Value: Eliminates need for pre-regulator stage; withstands 75V transients common in factory automation wiring. |
Use Scenario: Powering Ethernet PHYs and management processors on carrier-grade line cards fed from -48V DC plant. IC Role / Device Role / Timing Role: Point-of-load regulator converting -48V (absolute 48V) to 1.2V/1.8V/3.3V with tight output tolerance. Use Value: 1.225V reference accuracy ensures stable core voltage under varying load and temperature. |
| Railway Signaling System | Oil & Gas Sensor Transmitter |
|
Use Scenario: Converting 75V nominal traction battery or overhead catenary-derived supply to 5V for safety-critical signaling logic. IC Role / Device Role / Timing Role: High-reliability buck controller with thermal shutdown and current limiting for EN 5012x-compliant designs. Use Value: 165°C thermal shutdown and 75V absolute max rating meet harsh environment requirements. |
Use Scenario: Powering 4–20mA loop-powered transmitters in explosion-hazardous zones where input may vary from 12V to 42V. IC Role / Device Role / Timing Role: Wide-input buck regulator enabling single design across global loop voltage standards. Use Value: 6V minimum input supports brownout operation; adjustable frequency avoids sensitive RF bands in wireless sensor nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5576MT/NOPB | Higher 1.5A output current, same 75V input, identical pinout and feature set. | Used where higher load current or margin is required; shares layout and compensation network. | Select LM5576MT/NOPB when >0.5A continuous output is needed without redesigning feedback or compensation. |
| LM5164QPWPRQ1 | Automotive-grade (AEC-Q100), 100V input, 0.6A, integrated FET, but uses different control architecture (constant-on-time). | Targeted at automotive infotainment and ADAS; lacks SYNC and RAMP pins; no emulated current mode. | Choose LM5164QPWPRQ1 only for automotive-qualified designs requiring 100V rating and AEC-Q100 compliance. |
Compared with LM5574MT/NOPB, LM5576MT/NOPB offers higher current capacity in identical form factor, while LM5164QPWPRQ1 trades emulated current-mode control and SYNC capability for automotive qualification and extended input range-making it unsuitable as drop-in replacement but viable for new automotive designs.
Availability
LM5574MT/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, telecom line cards, railway signaling systems, and oil & gas sensor transmitters requiring stable component supply across long product lifecycles.
Supply support for LM5574MT/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 LM5574MT/NOPB belongs to TI's high-voltage buck regulator family designed specifically for industrial and telecom applications demanding wide input range, integrated FETs, and robust protection-enabling compact, efficient, and field-proven power stages.
FAQ
What is the maximum input voltage rating for LM5574MT/NOPB?
The LM5574MT/NOPB has an absolute maximum input voltage rating of 76V, with recommended operating range from 6V to 75V. Exceeding 76V-even momentarily during transients-can cause permanent damage. Layout best practices include placing high-quality ceramic input capacitors close to VIN and PGND pins to suppress ringing.
Does LM5574MT/NOPB require an external bootstrap capacitor?
Yes, LM5574MT/NOPB requires a 0.022µF ceramic capacitor between BST and SW pins to sustain gate drive for the internal high-side N-MOSFET. TI specifies this value for reliable operation across temperature and load; undersizing risks shoot-through or dropout during high-duty-cycle operation.
Can LM5574MT/NOPB synchronize to an external clock signal?
Yes, LM5574MT/NOPB supports external clock synchronization via its SYNC pin. An open-drain clock source with pulse width ≥15ns and frequency higher than the free-running oscillator (set by RT) can force alignment. Multiple LM5574MT/NOPB units can also self-synchronize by connecting their SYNC pins together.
What is the purpose of the IS pin on LM5574MT/NOPB?
The IS pin on LM5574MT/NOPB connects to the anode of the external Schottky diode to sample recirculating diode current. This measurement provides the DC offset for the emulated current ramp, enabling accurate current-mode control without direct high-side switch current sensing-reducing noise susceptibility and propagation delay.
How does the soft-start function work on LM5574MT/NOPB?
LM5574MT/NOPB implements soft-start via a 10µA internal current source charging an external capacitor on the SS pin. The rising SS voltage modulates the error amplifier reference, gradually increasing output voltage. During faults (thermal shutdown, UVLO, or SD assertion), the SS capacitor discharges to reset the sequence.
LM5574MT/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):
- 75V
- Voltage - Output (Min/Fixed):
- 1.225V
- Voltage - Output (Max):
- 70V
- Current - Output:
- 500mA
- Frequency - Switching:
- 50kHz ~ 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM5574MT/NOPB FAQ
1.How can I place an order for LM5574MT/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5574MT/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 LM5574MT/NOPB reliable?
The price and inventory of LM5574MT/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5574MT/NOPB is usually 5 days.
3.What payment methods are accepted for LM5574MT/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5574MT/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5574MT/NOPB?
LM5574MT/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5574MT/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 LM5574MT/NOPB?
For technical support, including LM5574MT/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5574MT/NOPB requirements.
6.How does Aetrix verify that LM5574MT/NOPB is sourced from the original manufacturer or authorized distributors?
All LM5574MT/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 LM5574MT/NOPB meets industry standards.
7.What is the process for return or replacement of LM5574MT/NOPB?
All LM5574MT/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM5574MT/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 LM5574MT/NOPB part is unused and in its original packaging.
Return procedure for LM5574MT/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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