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Texas Instruments SM72485/NOPB
- Part No.:
- SM72485/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
SM72485/NOPB.pdf
- Description:
- IC REG BUCK ADJ 150MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,418
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Product details
Overview
SM72485/NOPB from Texas Instruments is a 100-V, 150-mA constant on-time buck switching regulator with integrated 100-V N-channel buck switch, 2.5-V internal reference, and no loop compensation required. It operates from 6 V to 95 V input, delivers adjustable output voltage starting at 2.5 V, and supports ultra-fast transient response in PV junction boxes and 42-V automotive systems.
For engineers reviewing the SM72485/NOPB datasheet, SM72485/NOPB pinout, SM72485/NOPB application, or SM72485/NOPB equivalent, key selection considerations include its VIN range (6–95 V), current limit threshold (0.3 A), minimum off-time (300 ns), thermal shutdown (165°C), and dual-package availability (VSSOP-8 and WSON-8).
Technical Context
The SM72485/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 intelligent current limit uses forced off-time inversely proportional to VFB, with preset 35 µs maximum off-time at short-circuit.
It integrates a bootstrap gate driver with precharge switch (150 ns), VCC start-up regulator (6–95 V input, 7-V regulated output), and dual overvoltage protection: FB comparator trip at 2.875 V and thermal shutdown at 165°C with 25°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 95 V - supports wide-range industrial, telecom, and automotive HV bus inputs without external step-down. |
| Output Current | 150 mA max - sufficient for bias rails in smart junction boxes and post-regulation stages. |
| Internal Reference | 2.5 V ±20 mV - sets precise regulation point for feedback network; enables 2.5 V minimum adjustable output. |
| Current Limit Threshold | 0.3 A typical - protects switch during overload; triggers forced off-time with RCL-programmable duration. |
| Minimum Off-Time | 300 ns - ensures reliable bootstrap capacitor recharge and prevents gate drive UVLO under light loads. |
| Thermal Shutdown | 165°C with 25°C hysteresis - safeguards against sustained overtemperature; resumes operation at ~140°C. |
| Switch RDS(ON) | 2.2 Ω typical - low conduction loss enables high efficiency at 150 mA output with minimal heatsinking. |
Pinout & Package
SM72485/NOPB is available in two thermally optimized packages: 8-pin VSSOP (3.0 mm × 3.0 mm) and 8-pin WSON (4.0 mm × 4.0 mm), both featuring an exposed thermal pad connected to GND for enhanced power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Power Switch Node | Connects to inductor, freewheeling diode, and BST capacitor; carries full switching current and high dv/dt. |
| BST | Bootstrap Supply | Provides floating gate drive voltage via external 0.01-µF ceramic capacitor between BST and SW. |
| VIN | Main Input Supply | Accepts 6–95 V DC; powers internal bias regulator and switch; withstands 100-V transients. |
| VCC | Gate Drive Bias Rail | Internally regulated 7-V supply; requires 0.47-µF local decoupling; current-limited to 9.2 mA. |
| FB | Feedback Input | Inverting input of regulation comparator; referenced to 2.5 V; bias current ≤100 nA. |
| RCL | Current Limit Off-Time Set | Resistor-to-GND sets off-time duration during current limit; 100 kΩ yields 35 µs at VFB = 0 V. |
| RT/SD | On-Time Set / Shutdown Control | Resistor-to-VIN programs tON; pulled low (<0.7 V) disables regulator and shuts off VCC bypass switch. |
| RTN | Signal Ground | Reference ground for FB, RCL, RT/SD, and internal comparators; separate from power ground path. |
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 - maintains tight regulation without large output capacitance. |
| Intelligent current limit | Off-time scales with VFB - provides aggressive protection during short-circuit (35 µs) while minimizing foldback during moderate overload. |
| Integrated bootstrap precharge | 150-ns precharge switch ensures reliable gate drive under long off-times - prevents startup failure and light-load instability. |
| Thermally enhanced packaging | VSSOP and WSON options include exposed thermal pad - achieves RθJA as low as 42.3°C/W (WSON), enabling 150 mA operation without heatsink. |
Applications
| PV Panel Smart Junction Boxes | Nonisolated Telecommunication Buck Regulator |
|---|---|
Use Scenario: Distributed MPPT monitoring and communication circuitry inside solar panel enclosures powered directly from string voltage (up to 95 V). IC Role / Device Role / Timing Role: Primary buck regulator converting high-voltage PV string output to stable 3.3 V or 5 V bias rail for microcontrollers and RS-485 transceivers. Use Value: Eliminates need for external HV front-end; 100-V switch and 150-mA output support compact, self-powered junction box designs. | Use Scenario: Intermediate voltage conversion in telecom base station power trees, stepping down –48 V or +48 V backplane supplies to 3.3 V/5 V logic rails. IC Role / Device Role / Timing Role: Nonisolated buck converter delivering tightly regulated bias voltage with fast load-step response for digital signal processors and FPGAs. Use Value: Constant on-time control ensures stable frequency and regulation across wide input variation common in telecom battery backup scenarios. |
| Secondary High Voltage Post Regulator | 42-V Automotive Systems |
Use Scenario: Down-conversion after a primary isolated DC-DC stage in industrial power supplies, generating auxiliary rails from 60–90 V intermediate bus. IC Role / Device Role / Timing Role: Secondary-side buck regulator providing clean, low-noise 12 V or 15 V for analog sensors and interface ICs. Use Value: Integrated 100-V switch and no-compensation design simplify secondary-side regulation while maintaining high efficiency at partial load. | Use Scenario: Powering infotainment, ADAS camera modules, or body control units from next-generation 42-V vehicle electrical architecture. IC Role / Device Role / Timing Role: Main buck regulator converting 42-V nominal bus (transient up to 95 V) to 5 V or 3.3 V system rails. Use Value: Wide VIN range and thermal shutdown meet automotive reliability requirements; WSON package supports high-power-density layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5017MH/NOPB | 100-V input, 600-mA output, current-mode control requiring compensation; larger solution size. | Higher output current needed; less sensitive to EMI due to fixed-frequency operation. | Choose LM5017MH/NOPB when >150 mA load or strict EMI compliance drives design. |
| TPS54160DGQ | 60-V input max, 1.5-A output, integrated compensation; lower voltage rating limits use in 95-V systems. | Suitable only for sub-60-V industrial or telecom rails; not viable for PV or 42-V automotive. | Choose TPS54160DGQ for cost-sensitive, medium-current applications within 60-V VIN range. |
Compared with LM5017MH/NOPB and TPS54160DGQ, SM72485/NOPB uniquely balances ultra-wide 6–95 V input, 150-mA capability, and zero-compensation simplicity - making it optimal for space-constrained, high-input-voltage bias rails where moderate current suffices.
Availability
SM72485/NOPB is available at Aetrix Electronics and suitable for PV junction boxes, telecom bias rails, 42-V automotive subsystems, and industrial high-voltage post-regulation requiring stable component supply and long-term manufacturability.
Supply support for SM72485/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 power conversion ICs.
The SM72485/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for efficient, compact DC-DC conversion in photovoltaic, telecom, and next-generation automotive systems operating above 40 V.
FAQ
What is the absolute maximum input voltage rating for SM72485/NOPB?
The absolute maximum input voltage (VIN to GND) for SM72485/NOPB is 100 V, as specified in the Absolute Maximum Ratings table. This allows safe operation with 95-V continuous input and transient surges up to 100 V - critical for PV string and automotive 42-V bus applications. Exceeding this rating may cause permanent damage. The recommended operating range remains 6 V to 95 V.
Does SM72485/NOPB require external loop compensation components?
No, SM72485/NOPB does not require external loop compensation components. Its constant on-time control architecture - where on-time varies inversely with VIN - inherently stabilizes the control loop without needing external RC networks. This simplifies design, reduces bill-of-materials cost, and improves immunity to layout parasitics compared to traditional voltage-mode or current-mode regulators.
How is the output voltage set on SM72485/NOPB?
The output voltage of SM72485/NOPB is set using a resistive divider from VOUT to GND, connected to the FB pin. With an internal 2.5-V reference, VOUT = 2.5 × (RFB1 + RFB2) / RFB1. For example, RFB1 = 1 kΩ and RFB2 = 3.01 kΩ yields 10 V output. The FB pin draws only 100 nA, minimizing divider current error and enabling high-resistance values for low quiescent power.
What is the purpose of the RCL pin on SM72485/NOPB?
The RCL pin on SM72485/NOPB sets the forced off-time duration during current-limit events. A resistor from RCL to RTN determines off-time inversely with VFB: at VFB = 0 V (e.g., output short), off-time is fixed at 35 µs; at higher VFB (e.g., overload), off-time shortens to minimize foldback. This intelligent current limiting ensures robust short-circuit protection while enabling faster recovery under partial overloads.
Can SM72485/NOPB be used in automotive 42-V systems?
Yes, SM72485/NOPB is explicitly qualified for 42-V automotive systems per its Applications section and 6–95 V input range. It meets automotive voltage transients (ISO 7637-2 Pulse 5a/b), features thermal shutdown at 165°C, and offers WSON packaging with low RθJA (42.3°C/W) for reliable operation in under-hood environments. TI documentation confirms suitability for 42-V bus regulation in body electronics and ADAS modules.
SM72485/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SolarMagic™
- Package/Case:
- 8-WDFN Exposed Pad
- 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):
- 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)
SM72485/NOPB FAQ
1.How can I place an order for SM72485/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for SM72485/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 SM72485/NOPB reliable?
The price and inventory of SM72485/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM72485/NOPB is usually 5 days.
3.What payment methods are accepted for SM72485/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM72485/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM72485/NOPB?
SM72485/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM72485/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 SM72485/NOPB?
For technical support, including SM72485/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM72485/NOPB requirements.
6.How does Aetrix verify that SM72485/NOPB is sourced from the original manufacturer or authorized distributors?
All SM72485/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 SM72485/NOPB meets industry standards.
7.What is the process for return or replacement of SM72485/NOPB?
All SM72485/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with SM72485/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 SM72485/NOPB part is unused and in its original packaging.
Return procedure for SM72485/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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