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Texas Instruments SM72485SDE/NOPB
- Part No.:
- SM72485SDE/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WDFN Exposed Pad
- Datasheet:
-
SM72485SDE/NOPB.pdf
- Description:
- IC REG BUCK ADJ 150MA 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,072
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Product details
Overview
SM72485SDE/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 down to 2.5 V, and targets high-voltage DC-DC bias conversion in photovoltaic junction boxes and 42-V automotive systems.
For engineers reviewing the SM72485SDE/NOPB datasheet, SM72485SDE/NOPB pinout, SM72485SDE/NOPB application, or SM72485SDE/NOPB equivalent, key selection criteria include input voltage range (6–95 V), constant-frequency operation via VIN-inversely-proportional on-time, 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 SM72485SDE/NOPB implements a constant-frequency buck topology using an on-time inversely proportional to VIN - enabling stable switching frequency across line and load variations without external compensation. Its control loop compares FB voltage against a precision 2.5-V reference and triggers fixed-duration on-pulses determined by RT and VIN.
Current limiting uses forced off-time inversely proportional to VOUT and set by RCL, delivering 0.3-A threshold with 350-ns response time and short-circuit protection. Integrated features include VCC start-up regulator (6–95 V input), bootstrap gate drive with precharge switch, gate-drive UVLO (2.8–4.8 V), and thermal shutdown with 25°C hysteresis.
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 controllers, sensors, and gate drivers in high-voltage auxiliary rails. |
| Internal Reference | 2.5 V ±20 mV - enables precise output voltage setting via resistor divider; FB bias current is only 100 nA. |
| Switch RDS(ON) | 2.2 Ω typ - low conduction loss for 100-V N-channel integrated switch, reducing external component count. |
| Thermal Shutdown | 165°C activation - protects against sustained overload or poor PCB thermal design; resumes at 140°C. |
| Minimum On-Time | 400 ns at 95 V - ensures reliable current-limit operation and sets maximum practical switching frequency. |
| Startup VCC Regulator | 7 V regulated output - powers internal circuitry directly from VIN; bypass mode below 8.5 V reduces dropout loss. |
Pinout & Package
SM72485SDE/NOPB is available in thermally enhanced WSON-8 (4 mm × 4 mm) package with exposed thermal pad (to be connected to GND). Pin functions are electrically identical between WSON and VSSOP variants.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST | Bootstrap supply node | Connects to SW via 0.01-µF ceramic capacitor; supplies floating gate drive voltage during on-time. |
| FB | Feedback input | Inverting input of regulation comparator; referenced to 2.5 V; 100-nA bias current enables high-resistor-divider designs. |
| RCL | Current-limit off-time programming | Resistor to RTN sets forced off-time duration (35 µs at FB = 0 V); enables adaptive short-circuit recovery. |
| RT/SD | On-time programming / shutdown control | Resistor to VIN sets on-time inversely proportional to VIN; pulled low to disable regulator with <1.05-V threshold. |
| RTN | Analog ground reference | Common return for FB, RCL, and internal regulation circuits; must be low-impedance path to system GND. |
| SW | Power switch node | Drives external inductor and freewheeling diode; connects to BST capacitor; handles full switching current. |
| VCC | Internal bias supply | Regulated 7-V output; requires 0.47-µF local decoupling; current-limited to 9.2 mA; powers gate driver and logic. |
| VIN | Main power input | Accepts 6–95 V DC; powers VCC regulator and switch; withstands 100-V transients; absolute max 100 V. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Constant on-time architecture eliminates need for external compensation network - simplifies layout and reduces BOM count. |
| Ultra-fast transient response | On-time adjustment per cycle enables immediate reaction to load steps without phase-margin constraints of voltage-mode control. |
| Intelligent current limit | Off-time scales with VOUT and RCL - provides aggressive protection during short-circuit while minimizing foldback under mild overload. |
| Integrated start-up regulator | VCC derived directly from VIN across full 6–95 V range - eliminates need for external bias supply or LDO. |
| Precharge switch for BST | 150-ns active precharge during minimum off-time prevents bootstrap capacitor discharge during light-load or startup conditions. |
Applications
| PV Panel Smart Junction Boxes | Nonisolated Telecommunication Buck Regulator |
|---|---|
|
Use Scenario: Step-down conversion from 60–90 V PV string voltage to 12 V or 5 V for monitoring ICs and wireless transceivers inside junction box enclosures. IC Role / Device Role / Timing Role: Primary DC-DC bias regulator providing isolated auxiliary rail; operates continuously under partial shading and wide temperature range. Use Value: High input voltage tolerance (95 V) and 125°C junction rating enable direct integration into harsh outdoor environments without derating. |
Use Scenario: Generating -12 V or +5 V bias rails from -48 V telecom distribution bus for interface ICs, op-amps, and clock buffers. IC Role / Device Role / Timing Role: Nonisolated buck converter replacing discrete FET+controller solutions; delivers stable output despite bus ripple and load transients. Use Value: No loop compensation and ultra-fast transient response maintain tight regulation during burst-mode data transmission events. |
| Secondary High Voltage Post Regulator | 42-V Automotive Systems |
|
Use Scenario: Final-stage regulation after front-end HV-to-HV conversion (e.g., 400 V → 48 V → 3.3 V) in battery management or ADAS domain controllers. IC Role / Device Role / Timing Role: Secondary-side point-of-load regulator; accepts up to 95 V input from intermediate bus; immune to upstream switching noise. Use Value: 100-V integrated switch and 165°C thermal shutdown ensure robustness against voltage spikes from adjacent high-power converters. |
Use Scenario: Powering infotainment head units, body control modules, or lighting drivers from next-generation 42-V vehicle electrical architecture. IC Role / Device Role / Timing Role: Main 5-V or 3.3-V supply for microcontrollers and communication interfaces; must survive cold-crank (6 V) and load-dump (95 V) events. Use Value: Wide 6–95 V input range covers full automotive operating envelope; VCC bypass mode below 8.5 V maintains regulation during cranking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDDARQ1 | 4.5–65 V input, 3.5-A output, current-mode control with external compensation; requires loop tuning. | Higher current capability but narrower input range; suited for higher-power loads where dynamic performance must be optimized. | Choose LM5164QDDARQ1 when >150 mA output or automotive AEC-Q100 qualification is mandatory; not drop-in due to different control scheme and pinout. |
| TPS54160DGQR | 3.5–60 V input, 1.5-A output, integrated 120-mΩ FET; requires external compensation; lower max input voltage. | Lower cost and higher current, but lacks 95-V rating and intelligent current limit; less suitable for PV or 42-V automotive. | Choose TPS54160DGQR for industrial 24/48-V systems where input transients are controlled and cost sensitivity outweighs HV robustness. |
Compared with LM5164QDDARQ1 and TPS54160DGQR, the SM72485SDE/NOPB uniquely combines 95-V input tolerance, no-compensation constant on-time control, and programmable intelligent current limiting - making it optimal for unregulated high-voltage bias rails where simplicity, reliability, and transient immunity are prioritized over peak current delivery.
Availability
SM72485SDE/NOPB is available at Aetrix Electronics and suitable for photovoltaic junction boxes, 42-V automotive ECUs, telecom secondary regulators, and industrial high-voltage auxiliary power supplies requiring stable component supply across extended product lifecycles.
Supply support for SM72485SDE/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 SM72485SDE/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 telecom infrastructure applications where wide input range and fault resilience are critical.
FAQ
What is the maximum input voltage rating for the SM72485SDE/NOPB?
The SM72485SDE/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 while surviving transient overvoltages up to 100 V. The device incorporates internal protection to prevent damage during such events, and its 100-V N-channel buck switch is rated accordingly. Always observe derating guidelines for long-term reliability at elevated temperatures.
Does the SM72485SDE/NOPB require external compensation components?
No, the SM72485SDE/NOPB does not require external compensation components. Its constant on-time control architecture - where on-time varies inversely with VIN - inherently provides stable regulation without feedback loop compensation. This eliminates the need for external capacitors or resistors in the compensation network, simplifying design, reducing BOM count, and improving layout robustness. The internal 2.5-V reference and fast comparator-based regulation enable this self-stabilizing behavior across line and load variations.
How is output voltage programmed on the SM72485SDE/NOPB?
Output voltage on the SM72485SDE/NOPB is programmed using two external resistors (RFB1 and RFB2) forming a voltage divider from VOUT to GND, with the FB pin connected to their junction. The regulation equation is VOUT = 2.5 V × (RFB1 + RFB2) / RFB1. For example, selecting RFB1 = 1 kΩ and RFB2 = 3.01 kΩ yields a nominal 10-V output. The FB pin draws only 100 nA, enabling use of high-value resistors to minimize quiescent current without compromising accuracy.
What is the purpose of the RCL pin on the SM72485SDE/NOPB?
The RCL pin on the SM72485SDE/NOPB programs the forced off-time duration during current-limit events. A resistor connected between RCL and RTN sets the off-time inversely proportional to VOUT - longer off-times (e.g., 35 µs) occur during short-circuit conditions (FB ≈ 0 V), while shorter durations apply under moderate overload. This intelligent current limiting minimizes foldback, improves recovery time, and enhances safety at high input voltages. The SM72485SDE/NOPB datasheet provides Equation 4 to calculate exact off-time based on RCL and FB voltage.
Can the SM72485SDE/NOPB be used in automotive applications?
Yes, the SM72485SDE/NOPB is suitable for 42-V automotive systems, including body control modules and lighting drivers. It operates across the full automotive voltage range - from cold-crank (6 V) to load-dump transients (up to 95 V) - and features thermal shutdown at 165°C with 25°C hysteresis. While not AEC-Q100 qualified itself, its robust design, wide temperature range (–40°C to 125°C junction), and integrated protections make it widely deployed in automotive auxiliary rails where qualification is handled at the system level. Always verify compliance with specific OEM requirements.
SM72485SDE/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)
SM72485SDE/NOPB FAQ
1.How can I place an order for SM72485SDE/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for SM72485SDE/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 SM72485SDE/NOPB reliable?
The price and inventory of SM72485SDE/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM72485SDE/NOPB is usually 5 days.
3.What payment methods are accepted for SM72485SDE/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM72485SDE/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM72485SDE/NOPB?
SM72485SDE/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM72485SDE/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 SM72485SDE/NOPB?
For technical support, including SM72485SDE/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM72485SDE/NOPB requirements.
6.How does Aetrix verify that SM72485SDE/NOPB is sourced from the original manufacturer or authorized distributors?
All SM72485SDE/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 SM72485SDE/NOPB meets industry standards.
7.What is the process for return or replacement of SM72485SDE/NOPB?
All SM72485SDE/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with SM72485SDE/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 SM72485SDE/NOPB part is unused and in its original packaging.
Return procedure for SM72485SDE/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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