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Texas Instruments SM72485X/NOPB
- Part No.:
- SM72485X/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
SM72485X/NOPB.pdf
- Description:
- IC REG BUCK ADJ 150MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,730
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Product details
Overview
SM72485X/NOPB from Texas Instruments is a 100-V, 150-mA constant on-time buck switching regulator with integrated 100-V N-channel buck switch, internal start-up regulator, and no loop compensation required. It operates from 6 V to 95 V input, delivers adjustable output down to 2.5 V, and targets high-voltage bias regulation in photovoltaic junction boxes and 42-V automotive systems.
For engineers reviewing the SM72485X/NOPB datasheet, SM72485X/NOPB pinout, SM72485X/NOPB application, or SM72485X/NOPB equivalent, key selection criteria include its VIN range (6–95 V), constant-frequency operation across line/load, intelligent current limit with RCL-programmable off-time, thermal shutdown at 165°C, and dual-package availability (VSSOP-8 and WSON-8).
Technical Context
The SM72485X/NOPB implements a constant on-time control architecture where tON ∝ 1/VIN, enabling stable switching frequency (50 kHz–1.1 MHz) without external compensation. Its regulation relies on a precision 2.5-V internal reference compared against FB voltage, with overvoltage protection at 2.875 V.
Current limiting uses a forced off-time generator whose duration is inversely proportional to VOUT and set by RCL; minimum off-time is fixed at 300 ns for bootstrap capacitor recharge. The integrated N-channel switch features 2.2 Ω typical RDS(ON), driven via a floating gate driver with BST-SW bootstrap capacitor and precharge switch active during light-load off-times.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 95 V - supports direct connection to PV strings, telecom -48 V, and 42-V automotive buses without pre-regulation. |
| Output Current | 150 mA max - sufficient for biasing gate drivers, sensors, and microcontrollers in high-voltage subsystems. |
| Feedback Reference | 2.5 V ±20 mV - enables precise output programming using standard resistor dividers (e.g., 1 kΩ + 3.01 kΩ for 10 V). |
| On-Time Range | 400 ns to 3.5 µs - programmable via RT resistor; ensures stable operation even at 95 V input with ≥400 ns minimum. |
| Current Limit Threshold | 0.3 A typical - provides short-circuit protection while allowing peak inrush during startup. |
| Thermal Shutdown | 165°C with 25°C hysteresis - prevents catastrophic failure under sustained overload or poor PCB thermal design. |
| Package Options | VSSOP-8 (3 mm × 3 mm) and WSON-8 (4 mm × 4 mm) - thermally enhanced layouts support >125°C junction operation in compact spaces. |
Pinout & Package
SM72485X/NOPB is available in two thermally optimized packages: 8-pin VSSOP (3.00 mm × 3.00 mm) and 8-pin WSON (4.00 mm × 4.00 mm), both featuring an exposed thermal pad connected to GND for improved heat dissipation.
| 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. |
| VIN | Main Input Supply | Accepts 6–95 V DC; powers internal bias regulator and supplies energy to buck stage. |
| RT/SD | On-Time Programming / Shutdown | Resistor-to-VIN sets tON; pulled low disables regulator and shuts off VCC bypass switch. |
| FB | Feedback Input | Inverting input of regulation comparator; referenced to 2.5 V; bias current ≤100 nA enables high-impedance divider networks. |
| RCL | Current Limit Off-Time Control | Resistor-to-RTN sets off-time duration during current limit events; 35 µs max when FB = 0 V (short-circuit condition). |
| BST | Bootstrap Supply | Connects to SW via 0.01-µF ceramic capacitor; supplies floating gate drive voltage for N-channel switch. |
| VCC | Internal Bias Rail | Regulated 7 V output (or VIN-tracked below 8.5 V); requires 0.47-µF local decoupling; current-limited to 9.2 mA. |
| RTN | Signal Ground | Ground reference for FB, RCL, and RT/SD; must be low-impedance return path separate from power ground loops. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time control eliminates need for external compensation network, reducing BOM count and layout sensitivity. |
| Ultra-fast transient response | On-time adjustment per cycle enables immediate reaction to load steps without phase-margin trade-offs. |
| Intelligent current limit | Off-time scales with output voltage - longer off-time during shorts (35 µs), shorter during mild overloads - minimizing foldback and improving recovery. |
| Integrated start-up regulator | VIN-connected bias circuit delivers regulated VCC from 6 V up to 95 V, eliminating need for auxiliary supply or LDO pre-bias. |
| Precharge switch | 150-ns active discharge of SW node during minimum off-time ensures reliable bootstrap capacitor recharge under light loads or precharged outputs. |
Applications
| PV Panel Smart Junction Boxes | Nonisolated Telecommunication Buck Regulator |
|---|---|
Use Scenario: Regulating raw PV string voltage (e.g., 60–90 V) down to 12 V or 5 V for monitoring ICs, communication modules, and MOSFET gate drivers inside junction boxes. IC Role / Device Role / Timing Role: Primary high-voltage buck controller providing isolated bias rails without transformer or optocoupler. Use Value: Enables direct integration into module-level electronics with no external pre-regulator, leveraging 95-V input rating and thermal shutdown for outdoor reliability. | Use Scenario: Generating 3.3 V or 5 V from -48 V telecom bus for baseband processors, PHYs, and clock buffers in remote radio units and access switches. IC Role / Device Role / Timing Role: Nonisolated step-down converter delivering stable low-voltage rails from negative high-voltage supply using inverted topology. Use Value: Eliminates need for isolated DC/DC or charge-pump solutions; supports wide input transients common in telecom environments. |
| Secondary High Voltage Post Regulator | 42-V Automotive Systems |
Use Scenario: Tight-regulation post-converter after a main 400-V–60-V DC/DC stage, powering ADAS sensors, camera ISPs, or infotainment SoCs requiring <1% output tolerance. IC Role / Device Role / Timing Role: Precision secondary regulator with 2.5-V reference and low FB bias current ensuring minimal divider error. Use Value: Delivers high PSRR and fast load-step response without compensation tuning - critical for noise-sensitive imaging and radar subsystems. | Use Scenario: Powering body control modules, lighting controllers, and HVAC actuators directly from next-generation 42-V battery architecture. IC Role / Device Role / Timing Role: Robust primary DC/DC converter tolerant of load dump (100-V transient) and cold-crank (6-V minimum). Use Value: Meets automotive-grade thermal performance (125°C TJ) and includes VCC UVLO, gate drive UVLO, and thermal shutdown for functional safety compliance. |
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 | Wider input range (8–100 V), lower IQ (100 µA), but requires external compensation and lacks RCL-programmable current limit. | Preferred for ultra-low standby power designs; less suitable for space-constrained layouts needing no compensation. | Select LM5017MH/NOPB when minimizing quiescent current is critical and board area allows compensation components. |
| TPS54160DGQ | Lower input range (3.5–60 V), integrated soft-start, but no BST pin or precharge switch - limits high-VIN bootstrap reliability. | Better for 24-V industrial systems; not rated for 95-V continuous operation or PV string inputs. | Choose TPS54160DGQ for cost-sensitive 24-V applications where input never exceeds 60 V and soft-start is mandatory. |
Compared with LM5017MH/NOPB and TPS54160DGQ, SM72485X/NOPB uniquely combines 95-V input capability, no-loop-compensation simplicity, and intelligent current limiting in dual thermally enhanced packages - making it optimal for high-reliability, high-input-voltage bias regulation where layout area and transient robustness are prioritized over ultra-low IQ.
Availability
SM72485X/NOPB is available at Aetrix Electronics and suitable for photovoltaic junction box designs, 42-V automotive ECUs, telecom -48 V bias rails, and industrial high-voltage sensor interfaces requiring stable component supply across extended temperature and voltage ranges.
Supply support for SM72485X/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 SM72485X/NOPB belongs to TI's high-voltage buck regulator product line, designed specifically for efficient, compact, and robust DC/DC conversion in photovoltaic, automotive, and telecommunications infrastructure where input voltages exceed 60 V.
FAQ
What is the maximum input voltage rating for SM72485X/NOPB?
The SM72485X/NOPB has an absolute maximum input voltage rating of 100 V and a recommended operating range of 6 V to 95 V. This allows direct connection to photovoltaic strings, 48-V telecom buses, and 42-V automotive systems without external pre-regulation. Operation beyond 95 V is limited to transient conditions only, as specified in the Absolute Maximum Ratings table.
Does SM72485X/NOPB require external loop compensation components?
No, SM72485X/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 simplifies design, reduces BOM count, and improves immunity to component tolerances and layout parasitics.
How is the output voltage programmed on SM72485X/NOPB?
The output voltage of SM72485X/NOPB is programmed using a resistive divider from VOUT to GND, connected to the FB pin. With a precise 2.5-V internal reference, VOUT = 2.5 × (RFB1 + RFB2) / RFB1. For example, using RFB1 = 1.0 kΩ and RFB2 = 3.01 kΩ yields a nominal 10-V output. FB bias current is only 100 nA, minimizing divider error.
What package options are available for SM72485X/NOPB?
SM72485X/NOPB is offered in two surface-mount packages: 8-pin VSSOP (3.00 mm × 3.00 mm) and 8-pin WSON (4.00 mm × 4.00 mm). Both include an exposed thermal pad that must be soldered to a GND plane for optimal thermal performance. The WSON variant offers lower thermal resistance (RθJA = 42.3°C/W) and is preferred for higher ambient temperature or higher load current applications.
Can SM72485X/NOPB be used in automotive applications?
Yes, SM72485X/NOPB is suitable for 42-V automotive systems. It operates across –40°C to +125°C junction temperature, includes thermal shutdown at 165°C, VCC and gate-drive undervoltage lockouts, and withstands 100-V transients - meeting key requirements for body electronics, lighting, and ADAS subsystems. Its 6–95 V input range covers cold-crank and load-dump conditions.
SM72485X/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)
SM72485X/NOPB FAQ
1.How can I place an order for SM72485X/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for SM72485X/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 SM72485X/NOPB reliable?
The price and inventory of SM72485X/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM72485X/NOPB is usually 5 days.
3.What payment methods are accepted for SM72485X/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM72485X/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM72485X/NOPB?
SM72485X/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM72485X/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 SM72485X/NOPB?
For technical support, including SM72485X/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM72485X/NOPB requirements.
6.How does Aetrix verify that SM72485X/NOPB is sourced from the original manufacturer or authorized distributors?
All SM72485X/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 SM72485X/NOPB meets industry standards.
7.What is the process for return or replacement of SM72485X/NOPB?
All SM72485X/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with SM72485X/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 SM72485X/NOPB part is unused and in its original packaging.
Return procedure for SM72485X/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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