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Texas Instruments LM5574MTX/NOPB
- Part No.:
- LM5574MTX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5574MTX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:8,474
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Product details
Overview
LM5574MTX/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, adjustable 50–500kHz switching frequency, and 1.225V feedback reference. It delivers robust DC/DC conversion for industrial power bus applications requiring wide VIN range and cycle-by-cycle current limiting.
For engineers reviewing the LM5574MTX/NOPB datasheet, LM5574MTX/NOPB pinout, LM5574MTX/NOPB application, or LM5574MTX/NOPB equivalent, key selection considerations include its 6–75V input range, TSSOP-16 package thermal performance (RθJA = 95°C/W), soft-start programmability, and SYNC pin for multi-regulator synchronization - all critical for high-reliability industrial power design.
Technical Context
The LM5574MTX/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 supplies ~7V bias from inputs up to 75V while limiting current to 25mA.
Protection includes cycle-by-cycle current limit (0.7A typ), thermal shutdown at 165°C, remote shutdown via SD pin (0.7V threshold), and forced 500ns off-time to ensure bootstrap capacitor recharge and diode current sampling. The SYNC pin supports master-slave synchronization across multiple LM5574 devices without external logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 75V - enables direct regulation from industrial 24V/48V/72V buses without pre-regulation. |
| Output Current | 0.5A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in distributed systems. |
| Feedback Reference | 1.225V ±1.5% - sets precise output voltage down to 1.225V with minimal external resistor tolerance impact. |
| Switching Frequency | 50kHz to 500kHz (resistor-programmable) - allows trade-off between inductor size (higher fSW) and efficiency (lower fSW). |
| Integrated MOSFET Rds(on) | 750mΩ max - reduces conduction loss and simplifies layout vs. external-FET controllers. |
| Thermal Resistance | RθJA = 95°C/W (TSSOP-16) - defines junction-to-ambient rise under PCB copper constraints typical in industrial enclosures. |
| Current Limit Threshold | 0.7A typ - provides overcurrent protection aligned with 0.5A rated output, including propagation-delay compensation. |
Pinout & Package
LM5574MTX/NOPB is housed in a 16-pin TSSOP package (5mm × 6.4mm, 0.65mm pitch) with exposed thermal pad (PGND-connected) for enhanced heat dissipation in industrial ambient conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Accepts 6–75V unregulated supply; feeds internal start-up regulator and buck switch drain. |
| VCC | Bias supply output | Provides ~7V regulated bias (≤25mA) for control circuitry; can accept auxiliary 7.5–14V supply to reduce IC dissipation. |
| SW | Switching node | Source of internal N-MOSFET; connects to inductor and Schottky diode cathode - critical for EMI layout. |
| BST | Bootstrap capacitor connection | Connects to SW via 0.022µF ceramic capacitor to enable high-side gate drive for internal N-MOSFET. |
| FB | Feedback input | Senses output voltage divider; internal 1.225V reference sets regulation point - determines output accuracy. |
| COMP | Error amplifier output | Interface for type-II compensation network (R/C between COMP and FB) - stabilizes loop across load/line transients. |
| RT | Oscillator frequency set | Resistor to AGND programs switching frequency from 50kHz to 500kHz - directly impacts inductor size and efficiency. |
| SYNC | Oscillator sync I/O | Allows multiple LM5574MTX/NOPB units to synchronize; eliminates beat frequencies and eases EMI filtering. |
| SD | Shutdown/UVLO input | 0.7V threshold enables line undervoltage lockout or remote enable/disable - supports system-level power sequencing. |
| SS | Soft-start control | 10µA current source charges external capacitor to ramp reference voltage - prevents inrush current during startup. |
| RAMP | Emulated current ramp | External capacitor sets slope of reconstructed current signal - enables stable current-mode control without sensing noise. |
| IS | Diode current sense | Connects to Schottky diode anode to sample recirculating current - provides DC level for emulated ramp reconstruction. |
| PRE | Pre-charge assist | Open-drain output pulsed 250ns before switch-on to charge BST capacitor when SW remains high - improves light-load reliability. |
| AGND | Analog ground reference | Reference for FB, COMP, RT, RAMP, SS - must be separated from PGND to avoid noise coupling into error amplifier. |
| PGND | Power ground return | Low-side return for IS sense resistor and PRE switch - carries high di/dt currents; requires solid copper pour under device. |
| OUT | Regulated output | Direct connection to output capacitor - serves as power rail for downstream loads; voltage set by FB divider ratio. |
Key Features
| Feature | Design Value |
|---|---|
| Emulated current-mode architecture | Eliminates current-sense noise and propagation delay issues, enabling stable regulation at <10% duty cycle in high-VIN/low-VOUT applications. |
| Adjustable soft-start | 10µA internal current source + external capacitor allows precise control of output voltage ramp rate - prevents overshoot and stress on downstream components. |
| Controller synchronization (SYNC) | Enables deterministic phase alignment of multiple LM5574MTX/NOPB regulators - reduces input ripple current and simplifies EMI filter design. |
| Dual-mode VCC regulator | Auto-switches between LDO mode (<9V VIN) and regulated 7V mode (>9V VIN) - maintains consistent bias supply across full 6–75V input range. |
| Integrated protection suite | Cycle-by-cycle current limit, thermal shutdown (165°C), and remote shutdown via SD pin - ensures safe operation under fault conditions without external circuitry. |
Applications
| Industrial Power Bus Converter | Telecom Remote Radio Unit (RRU) Supply |
|---|---|
|
Use Scenario: Converting 48V telecom or 72V industrial bus to 3.3V/5V for FPGA, MCU, and ADC power rails in harsh environments. IC Role / Device Role / Timing Role: Primary buck controller providing isolated, regulated low-voltage rails with high input transient immunity. Use Value: 75V absolute maximum rating and 6–75V operating range eliminate need for front-end pre-regulators; TSSOP thermal performance sustains 0.5A output at 85°C ambient. |
Use Scenario: Powering RF front-end modules in outdoor base stations where input voltage varies widely due to cable drop and battery backup. IC Role / Device Role / Timing Role: High-voltage buck regulator delivering stable 12V or 15V bias to GaN amplifiers and analog front-ends. Use Value: Adjustable frequency (50–500kHz) allows optimization for efficiency at partial load; SYNC pin enables synchronized switching across multiple RF sections to suppress intermodulation. |
| Programmable Logic Controller (PLC) I/O Module | Factory Automation Sensor Hub |
|
Use Scenario: Generating isolated 5V and 3.3V supplies for digital I/O, analog input conditioning, and CAN transceivers inside DIN-rail mounted PLC modules. IC Role / Device Role / Timing Role: Central DC/DC converter managing multiple downstream LDOs and isolated DC/DCs in compact, convection-cooled enclosures. Use Value: Soft-start and remote shutdown (SD pin) support hot-swap capability and system-level power sequencing; 1.5% reference accuracy ensures sensor measurement integrity. |
Use Scenario: Powering arrays of temperature, pressure, and vibration sensors deployed on rotating machinery or robotic arms with variable input sources. IC Role / Device Role / Timing Role: Robust point-of-load regulator converting 24V field bus to clean 3.3V for low-power IoT sensor nodes and wireless transceivers. Use Value: Wide input range accommodates brownouts and surges common in factory floors; emulated current mode ensures fast transient response to burst-mode sensor sampling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5575MTX/NOPB | Higher 1.5A output current, same 6–75V input, identical pinout and features - differs only in MOSFET Rds(on) (330mΩ vs 750mΩ) and thermal design. | Required when >0.5A load current or lower conduction loss is needed; otherwise functionally interchangeable in existing layouts. | Select LM5575MTX/NOPB if peak load exceeds 0.5A or board thermal margin is constrained; LM5574MTX/NOPB remains optimal for cost-sensitive ≤0.5A designs. |
| TPS54360DGQR | 6–60V input, 3.5A output, integrated FET, but lacks SYNC pin and uses traditional current-sense architecture - no RAMP/IS pins. | Not suitable for >60V inputs or multi-regulator synchronization; better for higher-current, lower-input-voltage applications with less stringent EMI requirements. | Choose TPS54360DGQR only for 24–60V systems needing >0.5A; LM5574MTX/NOPB is irreplaceable for 72V bus or synchronized multi-rail designs. |
Compared with LM5575MTX/NOPB, LM5574MTX/NOPB offers lower BOM cost and adequate current for many industrial sensors and controllers, while TPS54360DGQR trades input voltage headroom and synchronization capability for higher output current - making LM5574MTX/NOPB the sole choice for 72V+ synchronized buck conversion.
Availability
LM5574MTX/NOPB is available at Aetrix Electronics and suitable for industrial power bus converters, telecom remote radio units, programmable logic controller I/O modules, and factory automation sensor hubs requiring stable component supply across extended product lifecycles.
Supply support for LM5574MTX/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 technologies, with decades of expertise in high-reliability industrial and automotive power solutions.
The LM5574MTX/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for industrial and telecom applications requiring wide-input-range, robust DC/DC conversion in space-constrained, thermally demanding environments.
FAQ
What is the maximum input voltage rating for LM5574MTX/NOPB?
The LM5574MTX/NOPB has an absolute maximum input voltage rating of 76V, with recommended operation from 6V to 75V. Exceeding 76V - even transiently - risks permanent damage. Layout best practices include placing high-quality input capacitors close to the VIN and PGND pins to suppress ringing during line transients. The device's dual-mode VCC regulator ensures reliable start-up across this full range.
Does LM5574MTX/NOPB require an external Schottky diode?
Yes, LM5574MTX/NOPB requires an external Schottky diode connected between the SW and OUT pins. Although it integrates a 750mΩ N-channel MOSFET as the high-side switch, it does not integrate a synchronous rectifier - the diode provides the low-side conduction path during the switch off-time. TI recommends CMSH2-100M or equivalent 100V/2A Schottky diodes for optimal efficiency and thermal performance.
How is the switching frequency set on LM5574MTX/NOPB?
The switching frequency of LM5574MTX/NOPB is set by a single resistor (RT) connected between the RT pin and AGND. Using Equation 1 from the datasheet (RT ≈ 1/(135×10⁻¹² × F) – 580×10⁻⁹), a 32.4kΩ resistor yields ~200kHz. Frequency ranges from 50kHz to 500kHz; values outside this range may cause instability or reduced efficiency. The RT resistor must be placed adjacent to the IC with short traces to minimize noise coupling.
Can LM5574MTX/NOPB operate without connecting the RAMP and IS pins?
No - both RAMP and IS pins are mandatory for proper operation. The IS pin senses recirculating diode current to establish the DC level of the emulated current ramp, and the RAMP pin hosts the external capacitor that sets the ramp slope. Omitting either disables the emulated current-mode control, causing loss of regulation, instability, or immediate current-limit shutdown. TI specifies 50–2000pF for CRAMP and requires direct routing to AGND.
What thermal derating applies to LM5574MTX/NOPB in a standard 2-layer PCB?
On a standard 2-layer PCB with 1oz copper and no thermal vias, LM5574MTX/NOPB's RθJA is 95°C/W. At 85°C ambient and 0.5A load (typical power dissipation ~0.5W), junction temperature rises ~48°C - well within the 125°C max operating limit. For sustained 0.5A operation above 85°C ambient, add thermal vias under the PGND pad and increase copper area to reduce RθJA toward the 55°C/W RθJB value cited in the datasheet.
LM5574MTX/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):
- 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/NOPB FAQ
1.How can I place an order for LM5574MTX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5574MTX/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 LM5574MTX/NOPB reliable?
The price and inventory of LM5574MTX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5574MTX/NOPB is usually 5 days.
3.What payment methods are accepted for LM5574MTX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5574MTX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5574MTX/NOPB?
LM5574MTX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5574MTX/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 LM5574MTX/NOPB?
For technical support, including LM5574MTX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5574MTX/NOPB requirements.
6.How does Aetrix verify that LM5574MTX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM5574MTX/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 LM5574MTX/NOPB meets industry standards.
7.What is the process for return or replacement of LM5574MTX/NOPB?
All LM5574MTX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM5574MTX/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 LM5574MTX/NOPB part is unused and in its original packaging.
Return procedure for LM5574MTX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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