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Texas Instruments LM5574MTX
- Part No.:
- LM5574MTX
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5574MTX.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,185
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Product details
Overview
LM5574MTX 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 with 1.5% feedback reference accuracy and supports industrial power bus applications requiring high-voltage DC-DC conversion.
For engineers reviewing the LM5574MTX datasheet, LM5574MTX pinout, LM5574MTX application, or LM5574MTX equivalent, key selection criteria include input voltage range (6–75V), cycle-by-cycle current limiting, thermal shutdown, soft-start programmability, and SYNC pin for multi-device synchronization - all critical for robust high-voltage buck design.
Technical Context
The LM5574MTX implements emulated current-mode control using a reconstructed ramp signal derived from VIN–VOUT and a diode-current sample-and-hold circuit - eliminating leading-edge spikes and enabling reliable low-duty-cycle operation at high input-to-output voltage ratios. Its dual-mode VCC regulator maintains ~7V bias supply across 6–75V input range, with internal LDO mode below 9V and regulated mode above.
Frequency is set via RT-to-AGND resistor (50–500kHz), and the SYNC pin supports master-slave synchronization of multiple LM5574MTX units or external clock locking. 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 bootstrap UVLO (4V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 75V - supports wide industrial and telecom bus voltages without pre-regulation. |
| Output Current | 0.5A continuous - defined by integrated 750mΩ N-MOSFET and thermal limits in TSSOP package. |
| Feedback Reference | 1.225V ±1.5% - sets minimum output voltage and determines accuracy of regulated rail. |
| Switching Frequency | 50kHz to 500kHz - adjustable via single RT resistor; enables trade-off between efficiency and component size. |
| Current Limit Threshold | 0.7A typical - cycle-by-cycle protection prevents MOSFET overstress during overload or short-circuit. |
| Thermal Shutdown | 165°C with 25°C hysteresis - ensures safe operation under sustained overload or poor PCB thermal design. |
| Soft-Start Current | 10µA ±30% - controls rise time of output voltage via external SS capacitor; prevents inrush stress. |
Pinout & Package
LM5574MTX is housed in a 16-pin TSSOP (PW) package measuring 5mm × 6.4mm, optimized for high-voltage isolation and thermal dissipation in industrial PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Accepts 6–75V unregulated supply; feeds internal VCC regulator and buck switch. |
| VCC | Bias supply output | Provides ~7V regulated bias for control circuitry; can accept external 7.5–14V to reduce IC dissipation. |
| SW | Switch node | Drives external Schottky diode and inductor; connects to BST capacitor for high-side gate drive. |
| BST | Bootstrap supply | Requires 0.022µF ceramic cap to SW; enables floating gate drive for integrated N-MOSFET. |
| FB | Feedback input | Compares output voltage against 1.225V reference; sets regulation point via resistive divider. |
| COMP | Error amplifier output | Connects to FB via Type II compensation network; determines loop stability and transient response. |
| RT | Frequency set | Resistor to AGND programs oscillator frequency (50–500kHz); placement critical for noise immunity. |
| SYNC | Frequency sync I/O | Allows multi-device synchronization or external clock locking; sink impedance 110Ω, threshold 1.3V. |
| SS | Soft-start control | 10µA current source charges external capacitor; resets on fault (thermal, UVLO, SD). |
| SD | Shutdown input | 0.7V threshold disables regulator; 1.225V enables operation; 5µA internal pull-up if left open. |
| RAMP | Emulated current ramp | External capacitor sets slope; current source scales with (VIN–VOUT) for accurate duty-cycle 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 under light load or pre-biased conditions. |
| AGND | Analog ground | Reference for FB, COMP, RAMP, RT; must be separated from PGND to minimize noise coupling. |
| PGND | Power ground | Return path for IS sense resistor and low-side switch; ties to PCB power plane for thermal conduction. |
| OUT | Output connection | Direct connection to regulated output node; low-impedance path required for stability and ripple control. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode control | Eliminates current-sense spike filtering delays, enabling stable regulation at <10% duty cycle in high-VIN/VOUT applications. |
| Integrated 75V/750mΩ N-MOSFET | Reduces BOM count and layout complexity while maintaining 0.5A output capability without external switch. |
| Adjustable soft-start (10µA) | Enables controlled output ramp-up via external capacitor; prevents inrush current and system brownout. |
| SYNC pin for multi-IC coordination | Supports deterministic phase alignment of multiple LM5574MTX regulators to suppress beat frequencies and EMI peaks. |
| Dual-mode VCC regulator | Auto-selects LDO or regulated mode based on VIN, ensuring consistent bias supply across full 6–75V input range. |
Applications
| Industrial Power Bus Conversion | Telecom 48V Intermediate Bus |
|---|---|
|
Use Scenario: Converting 24–75V factory automation bus to 3.3V/5V logic rails in PLCs and I/O modules. IC Role / Device Role / Timing Role: Primary buck controller delivering isolated, regulated low-voltage outputs with high line rejection. Use Value: 75V absolute max rating and 6–75V operating range eliminate need for front-end pre-regulators in harsh industrial environments. |
Use Scenario: Stepping down 48V telecom distribution rail to 12V intermediate bus for downstream POL converters. IC Role / Device Role / Timing Role: High-efficiency intermediate converter with SYNC capability for coordinated multi-rail power sequencing. Use Value: Adjustable 50–500kHz frequency allows optimization for 48V→12V conversion efficiency while minimizing EMI in dense telecom chassis. |
| Automotive Battery Monitoring Systems | High-Voltage Sensor Signal Conditioning |
|
Use Scenario: Powering microcontrollers and analog front-ends in battery management units connected directly to 12–48V vehicle batteries. IC Role / Device Role / Timing Role: Input-tolerant DC-DC regulator with undervoltage lockout (SD pin) and thermal protection for automotive-grade reliability. Use Value: Built-in 0.7V shutdown threshold and 165°C thermal shutdown meet AEC-Q100 functional safety expectations for non-safety-critical subsystems. |
Use Scenario: Supplying precision op-amps and ADCs in high-voltage test equipment where input transients exceed 40V. IC Role / Device Role / Timing Role: Robust point-of-load regulator with 1.225V reference accuracy and wide bandwidth error amplifier for low-noise analog rails. Use Value: 1.5% reference tolerance and >3MHz unity-gain bandwidth ensure stable, low-drift analog supply under dynamic load conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5575MTX | Higher 1.5A output current, same 75V input, identical pinout and feature set. | Suitable for higher-power loads; requires larger inductor and output capacitor. | Select when >0.5A output current is needed without redesigning control loop or layout. |
| LM5164QDDARQ1 | Automotive-grade (AEC-Q100), 100V input, 0.6A, integrated FET, but uses different control architecture (constant-on-time). | Designed for automotive infotainment and ADAS; lacks SYNC and RAMP pins; no emulated current mode. | Choose for automotive qualification requirements; not drop-in - compensation and layout differ significantly. |
Compared with LM5575MTX, the LM5574MTX offers lower cost and smaller solution size for ≤0.5A loads; compared with LM5164QDDARQ1, it provides superior transient response and EMI control via SYNC and emulated current-mode architecture, but lacks automotive qualification.
Availability
LM5574MTX is available at Aetrix Electronics and suitable for industrial power bus conversion, telecom intermediate bus regulation, automotive battery monitoring systems, and high-voltage sensor signal conditioning requiring stable component supply and long-term manufacturability.
Supply support for LM5574MTX 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 decades of expertise in high-reliability power conversion ICs.
The LM5574MTX belongs to TI's high-voltage buck regulator product line, designed specifically for industrial and telecom applications demanding wide-input-range, integrated-FET DC-DC solutions with robust protection and layout-friendly features.
FAQ
What is the maximum input voltage rating for the LM5574MTX?
The LM5574MTX has an absolute maximum input voltage rating of 76V, with recommended operating range from 6V to 75V. Exceeding 76V risks permanent damage due to internal junction breakdown. In practice, designs should maintain ≥1V margin below 76V and use input clamping or filtering to suppress transients - especially critical in industrial bus applications where line ringing may occur.
Does the LM5574MTX require an external Schottky diode?
Yes, the LM5574MTX requires an external Schottky diode connected between SW and OUT pins. The IC integrates only the high-side N-MOSFET switch; the diode provides the low-side recirculation path. TI recommends CMSH2-100M or equivalent 100V/2A Schottky devices. The IS pin monitors diode anode current, so correct diode placement is essential for accurate current sensing and protection.
How is the switching frequency set on the LM5574MTX?
The LM5574MTX switching frequency is set by a single resistor (RT) connected between the RT pin and AGND. Using Equation RT = (1/F − 580 ns) / 135 ps, a 32.4kΩ resistor yields ~200kHz. Frequency ranges from 50kHz to 500kHz depending on RT value. The RT resistor must be placed adjacent to the IC with short traces to minimize noise coupling into the oscillator timing node.
Can the LM5574MTX be synchronized to an external clock?
Yes, the LM5574MTX 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 frequency can drive the SYNC pin. Multiple LM5574MTX units can also self-synchronize by connecting their SYNC pins - the highest-frequency device acts as master, aligning all others to its switching edge.
What is the purpose of the RAMP pin on the LM5574MTX?
The RAMP pin on the LM5574MTX provides access to the emulated current ramp signal used in PWM comparison. An external capacitor from RAMP to AGND sets the ramp slope, which scales with (VIN–VOUT) per the internal current source. This eliminates reliance on noisy switch-node current sensing and enables stable operation at very low duty cycles - a key advantage over traditional current-mode controllers in high-input-voltage applications.
LM5574MTX 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:
- 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
LM5574MTX FAQ
1.How can I place an order for LM5574MTX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5574MTX 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 LM5574MTX reliable?
The price and inventory of LM5574MTX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5574MTX is usually 5 days.
3.What payment methods are accepted for LM5574MTX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5574MTX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5574MTX?
LM5574MTX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5574MTX 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 LM5574MTX?
For technical support, including LM5574MTX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5574MTX requirements.
6.How does Aetrix verify that LM5574MTX is sourced from the original manufacturer or authorized distributors?
All LM5574MTX 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 LM5574MTX meets industry standards.
7.What is the process for return or replacement of LM5574MTX?
All LM5574MTX units undergo pre-shipment inspection (PSI). If there is an issue with LM5574MTX, 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 LM5574MTX part is unused and in its original packaging.
Return procedure for LM5574MTX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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