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Texas Instruments LM5574MT
- Part No.:
- LM5574MT
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5574MT.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,609
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Product details
Overview
LM5574MT from Texas Instruments is a 75V-input, 0.5A synchronous step-down switching regulator with integrated 750mΩ N-channel MOSFET, emulated current-mode control, adjustable 50–500kHz switching frequency, and 1.225V feedback reference. It delivers robust industrial power conversion in telecom and factory automation systems where wide input range and thermal resilience are critical.
For engineers reviewing the LM5574MT datasheet, LM5574MT pinout, LM5574MT application, or LM5574MT equivalent, key selection criteria include its 6–75V input range, cycle-by-cycle current limiting, soft-start programmability, SYNC capability for multi-regulator EMI reduction, and TSSOP-16 thermal performance (RθJA = 95°C/W).
Technical Context
The LM5574MT implements emulated current-mode control using a reconstructed ramp signal-generated via internal voltage-controlled current source (IRAMP = (10µA × (VIN – VOUT)) + 50µA) and external RAMP capacitor-to avoid noise-sensitive switch-current sensing. This architecture enables stable operation at very low duty cycles (<10%) required for high VIN/VOUT ratios.
Its dual-mode VCC regulator operates in LDO mode below 9V VIN (VCC ≈ VIN) and switches to regulated 7V output above 9V, enabling seamless operation across 6–75V input. Protection includes cycle-by-cycle current limit (0.7A typ), thermal shutdown (165°C), remote shutdown (SD pin thresholds: 0.7V off / 1.225V on), and forced 500ns off-time for bootstrap recharge and diode current sampling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 75V - supports unregulated industrial bus rails and telecom -48V/-60V systems with margin. |
| Output Current | 0.5A continuous - sufficient for powering FPGA I/O banks, PLC sensor interfaces, and isolated gate drivers. |
| Feedback Reference | 1.225V ±1.5% - enables precise output regulation down to 1.225V with external resistor divider. |
| Switching Frequency | 50kHz to 500kHz - set by single RT resistor; allows trade-off between inductor size (higher f) and conduction loss (lower f). |
| Integrated MOSFET RDS(on) | 750mΩ max - reduces external component count and simplifies layout vs. controller-only solutions. |
| Thermal Resistance | RθJA = 95°C/W - defines junction-to-ambient rise under standard PCB layout; requires thermal pad grounding for full rating. |
| Soft-Start Current | 10µA typ - sets rise time of SS capacitor voltage; enables controlled inrush current during power-up. |
Pinout & Package
The LM5574MT is housed in a 16-pin TSSOP package (5mm × 6.4mm) with exposed thermal pad (PGND-connected) for enhanced heat dissipation in industrial environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply | Accepts 6–75V; powers internal bias regulator and buck switch; requires local 10µF ceramic bypass. |
| VCC | Bias regulator output | Provides 7V (≥9V VIN) or tracks VIN (<9V); supplies internal logic and gate driver; needs 0.1–1µF decoupling. |
| SW | Switch node | Connects to inductor and Schottky diode anode; carries high dv/dt; must be minimized in loop area. |
| BST | Bootstrap supply | Connects via 0.022µF ceramic to SW; charges internal high-side gate driver during off-time. |
| FB | Feedback input | Inverting input of error amp; referenced to 1.225V; sets output voltage via resistor divider to OUT. |
| COMP | Error amplifier output | Connects to FB via type-II compensation network (R/C) to stabilize loop response. |
| RT | Oscillator programming | Resistor to AGND sets frequency (50–500kHz); placement critical for noise immunity. |
| SYNC | Frequency synchronization | Allows master-slave sync of multiple LM5574MTs or external clock injection; reduces EMI peaks. |
| SD | Shutdown control | 0.7V threshold disables regulator; 1.225V enables; open-circuit defaults to active via 5µA pullup. |
| SS | Soft-start timing | 10µA current source charges external capacitor; controls output voltage ramp rate at startup. |
| RAMP | Emulated current ramp | External capacitor (50–2000pF) sets slope; determines current-loop gain and stability. |
| IS | Diode current sense | Connects to Schottky diode anode; samples recirculating current for DC level reconstruction. |
| PRE | Pre-charge assist | Open-drain output pulsed 250ns before switch-on; aids BST charging when SW doesn't go low. |
| AGND | Analog ground | Reference for FB, COMP, RAMP, RT; separate from PGND to minimize noise coupling. |
| PGND | Power ground | Low-side return for IS sense resistor and PRE switch; connects to thermal pad for heat sinking. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode control | Eliminates leading-edge spike filtering and enables reliable sub-10% duty cycle operation for high VIN/VOUT ratios. |
| Programmable oscillator (50–500kHz) | Single RT resistor allows optimization of magnetic size vs. efficiency without changing IC or layout. |
| Integrated 75V/750mΩ N-MOSFET | Reduces BOM count by 1 active device and simplifies PCB routing vs. external switch solutions. |
| SYNC pin for multi-device synchronization | Enables deterministic phase alignment of multiple LM5574MTs to suppress beat frequencies and narrow EMI peaks. |
| 1.5% feedback reference accuracy | Ensures tight output regulation across temperature and line/load variations without trimming. |
Applications
| Industrial Power Supplies | Telecom Line Cards |
|---|---|
Use Scenario: Converting 48V telecom bus to 3.3V/5V for DSPs, FPGAs, and interface ICs in base station line cards. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated low-voltage rails with high PSRR and fast load transient response. Use Value: 75V absolute max rating accommodates 48V transients; SYNC capability aligns switching with other rails to reduce conducted EMI. | Use Scenario: Providing 12V auxiliary power from 72V industrial battery or rectified AC in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: High-input-voltage DC-DC converter supplying isolated DC/DC modules and analog sensor front-ends. Use Value: 6–75V input range covers brownout and surge conditions; thermal shutdown (165°C) ensures reliability in enclosed cabinets. |
| Factory Automation Sensors | Energy Metering Systems |
Use Scenario: Powering 24V fieldbus nodes (e.g., Profibus, CAN) from variable 24–60V DC distribution lines. IC Role / Device Role / Timing Role: Input-stage regulator feeding downstream LDOs or isolated DC-DC converters for sensor signal chains. Use Value: Adjustable soft-start prevents inrush into long cable runs; 1.225V reference enables accurate 2.5V/3.3V sensor rail generation. | Use Scenario: Generating 3.3V microcontroller supply from 100V+ metering bus in smart electricity meters with surge protection. IC Role / Device Role / Timing Role: Primary step-down regulator surviving lightning-induced surges up to 75V with minimal external components. Use Value: Integrated 75V MOSFET eliminates need for external HV transistor; cycle-by-cycle current limit protects against shorted secondary windings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5575MT | Higher 1.5A output current; identical pinout and feature set; shares same TSSOP-16 package. | Used where higher load current is required (e.g., multi-rail systems), but increases conduction loss at light loads. | Select LM5575MT only if >0.5A continuous output is needed; otherwise LM5574MT offers better light-load efficiency. |
| TPS54360DGQ | 65V max input; 3.5A output; integrated high-side MOSFET; different pinout and compensation scheme. | Suitable for higher-current industrial SMPS, but requires redesign of compensation and layout due to non-pin-compatible footprint. | Choose TPS54360DGQ when scaling output current beyond 0.5A and accepting layout revision; not drop-in compatible. |
Compared with LM5575MT and TPS54360DGQ, the LM5574MT provides optimal balance of 75V input tolerance, 0.5A capability, and minimal external components for space-constrained industrial converters-making it preferred for cost-sensitive, thermally demanding 12–24V output designs.
Availability
LM5574MT is available at Aetrix Electronics and suitable for industrial power supplies, telecom line cards, factory automation sensors, and energy metering systems requiring stable component supply and long-term manufacturability.
Supply support for LM5574MT 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 over 50 years of innovation in high-reliability power conversion.
The LM5574MT belongs to TI's high-voltage buck regulator product line, designed specifically for industrial and telecom applications demanding wide input range, integrated FETs, and robust fault protection without external complexity.
FAQ
What is the maximum input voltage rating for the LM5574MT?
The LM5574MT has an absolute maximum input voltage rating of 76V on the VIN pin. Its recommended operating range is 6V to 75V, making it suitable for industrial 48V and telecom -48V/-60V systems with transient margin. Exceeding 76V risks permanent damage, especially during line transients or ringing-so proper input filtering and layout are essential. The LM5574MT's dual-mode VCC regulator ensures stable internal biasing across this full range.
How does the LM5574MT achieve current-mode control without a sense resistor?
The LM5574MT uses emulated current-mode control: it reconstructs the inductor current ramp using an internal voltage-controlled current source (IRAMP = (10µA × (VIN – VOUT)) + 50µA) and an external RAMP capacitor, while sampling diode current at the IS pin to establish the DC level. This avoids noise-prone shunt resistors and enables stable operation at very low duty cycles. The LM5574MT's architecture eliminates leading-edge spikes and propagation delays inherent in direct current sensing.
Can the LM5574MT synchronize its switching frequency with other regulators?
Yes, the LM5574MT features a dedicated SYNC pin that supports both master and slave operation. Multiple LM5574MT devices can be synchronized by connecting their SYNC pins together-the highest-frequency unit acts as master. It also accepts external clock signals (≥15ns pulse width, higher than free-running frequency) for system-level EMI reduction. This capability is confirmed in the LM5574MT datasheet Section 6.3.2 and Figure 6-2 through 6-4.
What thermal considerations apply to the LM5574MT in a 16-pin TSSOP package?
The LM5574MT in TSSOP-16 has RθJA = 95°C/W (JEDEC standard board). To maintain safe junction temperature (<125°C), thermal design must include a properly soldered exposed thermal pad tied to PGND and a minimum 1-inch² copper pour. Derating is required above 70°C ambient; at 0.5A load and 48V input, typical efficiency is ~85%, resulting in ~0.4W dissipation. The LM5574MT integrates thermal shutdown at 165°C with 25°C hysteresis for fail-safe operation.
Is the LM5574MT pin-compatible with other members of the LM557x family?
Yes, the LM5574MT is pin-compatible with the LM5575MT (1.5A version) in the same TSSOP-16 package-sharing identical pin functions, layout, and compensation requirements. However, it is not pin-compatible with LM5576 (adjustable current limit) or earlier LM557x variants with different pinouts. Always verify package markings and consult TI's official LM5574MT datasheet SNVS478G for mechanical and electrical compatibility before substitution.
LM5574MT 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):
- 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 FAQ
1.How can I place an order for LM5574MT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5574MT 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 reliable?
The price and inventory of LM5574MT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5574MT is usually 5 days.
3.What payment methods are accepted for LM5574MT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5574MT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5574MT?
LM5574MT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5574MT 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?
For technical support, including LM5574MT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5574MT requirements.
6.How does Aetrix verify that LM5574MT is sourced from the original manufacturer or authorized distributors?
All LM5574MT 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 meets industry standards.
7.What is the process for return or replacement of LM5574MT?
All LM5574MT units undergo pre-shipment inspection (PSI). If there is an issue with LM5574MT, 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 part is unused and in its original packaging.
Return procedure for LM5574MT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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