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Texas Instruments SM72485SD/NOPB
- Part No.:
- SM72485SD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
SM72485SD/NOPB.pdf
- Description:
- IC REG BUCK ADJ 150MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
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Product details
Overview
SM72485SD/NOPB from Texas Instruments is a 100-V, 150-mA constant on-time buck switching regulator with integrated 100-V N-channel buck switch, 6 V to 95 V input range, and adjustable 2.5 V reference-based output voltage - used in PV junction boxes and 42-V automotive post-regulation.
For engineers reviewing the SM72485SD/NOPB datasheet, SM72485SD/NOPB pinout, SM72485SD/NOPB application, or SM72485SD/NOPB equivalent, key selection criteria include input voltage tolerance (95 V max), no-loop-compensation operation, intelligent current limit with RCL-programmable off-time, thermal shutdown at 165°C, and dual-package availability (VSSOP/WSON).
Technical Context
The SM72485SD/NOPB implements a constant on-time control architecture where tON ∝ 1/VIN, enabling stable operating frequency across line and load variations without external compensation. Its internal 2.5 V reference regulates output via FB pin feedback, while overvoltage protection triggers at 2.875 V.
Current limiting uses a forced off-time generator whose duration is inversely proportional to VFB and set by RCL; minimum off-time is fixed at 300 ns to ensure bootstrap capacitor recharge. The integrated start-up regulator delivers regulated 7 V to VCC from 6–95 V input, with bypass mode below 8.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 95 V - supports wide-range industrial, telecom, and automotive bus inputs without external pre-regulator |
| Output Current | 150 mA max - sufficient for bias rails in high-voltage subsystems like smart PV junction boxes |
| Switch Rating | 100-V N-channel integrated buck switch - eliminates external MOSFET and gate driver in compact designs |
| Reference Voltage | 2.5 V ±20 mV - enables precise output programming with standard resistor dividers (e.g., 1 kΩ/3.01 kΩ for 10 V) |
| Thermal Shutdown | 165°C with 25°C hysteresis - protects against sustained overload or poor PCB thermal design |
| On-Time Min | 400 ns at 95 V - sets maximum practical switching frequency and ensures reliable current limit response |
| VCC Regulator | 7 V output, 9.2 mA current limit - powers internal gate driver and logic; bypassed below 8.5 V to reduce dissipation |
Pinout & Package
SM72485SD/NOPB is available in thermally enhanced 8-pin WSON (4 mm × 4 mm) package with exposed thermal pad (to be connected to ground plane). Pin functions are validated per TI SNVS697E datasheet Rev E (Dec 2016).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Power Switch Node | Connects to inductor, freewheeling diode, and bootstrap capacitor - carries full switching current and high dv/dt |
| BST | Bootstrap Supply | Drives high-side gate via external 0.01-µF ceramic cap; charged from VCC during SW low phase |
| FB | Feedback Input | Inverting input of regulation comparator; 2.5 V threshold sets output voltage via resistor divider |
| RCL | Current Limit Off-Time Set | Resistor-to-ground programs off-time duration after current limit trip - shorter off-time for partial overloads |
| RT/SD | On-Time Set / Shutdown | Resistor-to-VIN sets tON; pulled low disables regulator - no external pull-up required |
| VIN | Main Power Input | Accepts 6–95 V DC; internal 100-V rating allows transient margin up to 100 V |
| VCC | Internal Bias Supply | Regulated 7 V output; requires 0.47-µF local decoupling; UVLO at 5.3 V prevents erratic startup |
| RTN | Signal Ground | Ground reference for FB, RCL, RT/SD - must be low-impedance path to minimize noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time architecture eliminates need for external compensation network - reduces BOM count and layout sensitivity |
| Ultra-fast transient response | On-time adjustment per cycle enables immediate reaction to load steps - critical for PV panel MPPT auxiliary supplies |
| Intelligent current limit | Off-time scales with FB voltage - 35 µs for short-circuit, sub-µs for mild overload - minimizes foldback and improves recovery |
| Integrated start-up regulator | Self-powered from VIN; bypass mode below 8.5 V reduces quiescent loss - enables direct connection to 12–90 V inputs |
| Precharge switch | 150 ns pulse during minimum off-time ensures BST capacitor retains sufficient charge - prevents gate drive dropout at light loads |
Applications
| PV Panel Smart Junction Box | 42-V Automotive Post-Regulator |
|---|---|
Use Scenario: Regulating power for monitoring ICs, communication modules, and bypass switches inside photovoltaic panel enclosures exposed to 60–90 V DC bus voltages. IC Role / Device Role / Timing Role: Primary buck bias regulator converting unregulated PV string voltage to stable 3.3 V or 5 V for microcontrollers and sensors. Use Value: Integrated 100-V switch and no-compensation design enable compact, robust, and cost-effective enclosure integration without external FET or compensation components. | Use Scenario: Generating stable 5 V or 3.3 V from 42-V battery rail for infotainment, ADAS camera modules, or body control units in next-gen vehicles. IC Role / Device Role / Timing Role: High-input-voltage step-down converter providing isolated bias supply with fast transient immunity during load dump events. Use Value: 95 V input rating and thermal shutdown protect against 120 V load dump transients; constant frequency simplifies EMI filtering in safety-critical domains. |
| Nonisolated Telecom Buck Regulator | Secondary High-Voltage Post Regulator |
Use Scenario: Deriving 12 V or 15 V bias from -48 V or +48 V telecom distribution buses for optical transceivers, line cards, or fan controllers. IC Role / Device Role / Timing Role: Efficient nonisolated DC-DC stage delivering up to 150 mA with minimal external components and no optocoupler feedback loop. Use Value: Wide 6–95 V input accommodates both positive and negative telecom rails (with appropriate level-shifting); ultra-low FB bias current (100 nA) preserves accuracy with high-value dividers. | Use Scenario: Final-stage regulation after an isolated flyback or forward converter, stepping down 60–80 V intermediate bus to 3.3 V/5 V for sensitive digital loads. IC Role / Device Role / Timing Role: Secondary-side synchronous or diode-based buck controller ensuring tight output regulation despite primary-side transformer leakage and cross-regulation drift. Use Value: Precision 2.5 V reference and overvoltage comparator (2.875 V) provide accurate, fail-safe regulation - critical when upstream isolation adds uncertainty. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDDARQ1 | Automotive-grade (AEC-Q100), 100-V input, but requires external MOSFET and loop compensation; higher IQ (100 µA vs. 750 µA active) | Designed for ASIL-B systems; includes spread-spectrum and enhanced fault reporting not present in SM72485SD/NOPB | Choose LM5164QDDARQ1 when functional safety compliance and diagnostic coverage are mandatory |
| TPS54160DGQR | 60-V max input, external MOSFET, compensation required; lower cost but lacks intelligent current limit and bootstrap precharge | Suitable for ≤60 V industrial supplies where thermal stress and transient overload are less severe | Choose TPS54160DGQR only if input voltage stays below 60 V and design can accommodate compensation network and slower fault response |
Compared with LM5164QDDARQ1 and TPS54160DGQR, the SM72485SD/NOPB uniquely combines integrated 100-V switch, no-compensation operation, and programmable intelligent current limiting - making it optimal for space-constrained, high-input-voltage, non-safety-critical bias supplies where simplicity and reliability outweigh diagnostics or ultra-low quiescent current.
Availability
SM72485SD/NOPB is available at Aetrix Electronics and suitable for PV junction box power management, 42-V automotive subsystems, and telecom bias rail generation requiring stable component supply across long production lifecycles.
Supply support for SM72485SD/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 high-reliability power management solutions for industrial, automotive, and communications markets.
The SM72485 product line delivers high-voltage, low-component-count buck regulators targeting cost-sensitive, thermally constrained applications such as solar energy harvesting and next-generation vehicle electrical architectures.
FAQ
What is the maximum input voltage rating for the SM72485SD/NOPB?
The SM72485SD/NOPB has an absolute maximum input voltage rating of 100 V, with recommended continuous operation from 6 V to 95 V. This 95 V upper limit ensures safe operation under steady-state conditions including worst-case tolerances and ripple, while preserving margin against transients. The device's internal 100-V N-channel switch and gate driver are rated to withstand these levels without degradation.
Does the SM72485SD/NOPB require external loop compensation components?
No, the SM72485SD/NOPB does not require external loop compensation components. Its constant on-time control architecture - where on-time varies inversely with input voltage - inherently provides stable regulation without feedback compensation networks. This eliminates the need for external capacitors, resistors, or op-amps typically used in voltage-mode or current-mode controllers, reducing bill-of-materials count and layout complexity.
How is output voltage programmed on the SM72485SD/NOPB?
Output voltage on the SM72485SD/NOPB is programmed using a resistor divider connected between VOUT, FB, and RTN. The internal 2.5 V reference sets the regulation point: VOUT = 2.5 V × (RFB1 + RFB2) / RFB1. For example, using RFB1 = 1 kΩ and RFB2 = 3.01 kΩ yields a nominal 10 V output. FB bias current is only 100 nA, minimizing divider error and enabling use of high-value resistors to reduce quiescent current.
What is the purpose of the RCL pin on the SM72485SD/NOPB?
The RCL pin on the SM72485SD/NOPB sets the off-time duration following current limit detection. A resistor connected from RCL to RTN determines the forced off-time, which scales inversely with FB voltage: 35 µs at FB = 0 V (short-circuit condition), decreasing for partial overloads. This intelligent current limiting ensures robust short-circuit protection while minimizing foldback and enabling faster recovery than fixed off-time schemes.
Can the SM72485SD/NOPB operate with input voltages below 8.5 V?
Yes, the SM72485SD/NOPB operates down to 6 V input. Below 8.5 V, its internal VCC regulator enters bypass mode: VCC tracks VIN minus ~100 mV, powered directly through an internal ~100 Ω pass element. This avoids regulation losses and enables efficient low-input operation. VCC UVLO remains active at 5.3 V, ensuring reliable startup and shutdown behavior across the full 6–95 V range.
SM72485SD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SolarMagic™
- Package/Case:
- 8-WDFN Exposed Pad
- 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):
- 95V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 85V
- Current - Output:
- 150mA
- Frequency - Switching:
- 50kHz ~ 1.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (4x4)
SM72485SD/NOPB FAQ
1.How can I place an order for SM72485SD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for SM72485SD/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 SM72485SD/NOPB reliable?
The price and inventory of SM72485SD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM72485SD/NOPB is usually 5 days.
3.What payment methods are accepted for SM72485SD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM72485SD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM72485SD/NOPB?
SM72485SD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM72485SD/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 SM72485SD/NOPB?
For technical support, including SM72485SD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM72485SD/NOPB requirements.
6.How does Aetrix verify that SM72485SD/NOPB is sourced from the original manufacturer or authorized distributors?
All SM72485SD/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 SM72485SD/NOPB meets industry standards.
7.What is the process for return or replacement of SM72485SD/NOPB?
All SM72485SD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with SM72485SD/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 SM72485SD/NOPB part is unused and in its original packaging.
Return procedure for SM72485SD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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