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Analog Devices Inc. LT3972HMSE#PBF
- Part No.:
- LT3972HMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3972HMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,177
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Product details
Overview
LT3972HMSE#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode synchronous step-down DC/DC regulator IC with integrated 95mΩ NPN switch and boost Schottky diode. It operates from 3.6V to 33V input, delivers up to 3.5A output, supports adjustable switching frequency from 200kHz to 2.4MHz, and achieves 75μA quiescent current in Burst Mode for automotive battery regulation and industrial power supplies.
For engineers reviewing the LT3972HMSE#PBF datasheet, LT3972HMSE#PBF pinout, LT3972HMSE#PBF application, or LT3972HMSE#PBF equivalent, key selection criteria include its –40°C to 150°C guaranteed junction temperature range, integrated bias-sourcing capability from VOUT > 3V, power good flag with 91% threshold, thermal shutdown, and soft-start via RUN/SS pin ramping.
Technical Context
The LT3972HMSE#PBF implements constant-frequency current-mode control with internal error amplifier, slope compensation, and VC-pin-based peak-current limiting. Its oscillator is resistor-programmable (RT pin) and supports external synchronization (SYNC pin) from 250kHz to 2MHz.
It features dual bias paths: internal regulator draws from VIN by default but switches to BD pin when externally supplied ≥3V - enabling higher light-load efficiency. Overvoltage lockout triggers at 33V (min), disabling switching while sustaining 62V transients; power good (PG) asserts open-collector low until FB reaches 91% of 0.79V reference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 33V continuous; withstands 62V non-repetitive transients - enables direct connection to 24V/36V automotive or industrial rails. |
| Max Output Current | 3.5A typical - sufficient for powering FPGAs, microcontrollers, and sensor subsystems without external current boosting. |
| Quiescent Current | 75μA at 12VIN → 3.3VOUT in Burst Mode - extends battery life in always-on systems like telematics or remote sensors. |
| Switch On-Resistance | 95mΩ - reduces conduction loss and thermal stress under full load, supporting compact thermal design in MSOP package. |
| Feedback Reference | 0.79V ±10mV - allows precise output programming from 0.79V to 30V using standard resistor dividers. |
| Operating Temp Range | –40°C to +150°C (H-grade) - qualified for under-hood automotive and high-ambient industrial environments. |
| Switching Frequency | 200kHz to 2.4MHz (adjustable via RT resistor) - balances inductor size, EMI, and minimum on/off time constraints across wide VIN/VOUT ratios. |
Pinout & Package
LT3972HMSE#PBF is housed in a thermally enhanced 10-lead MSOP package with exposed pad (Pin 11 = GND), offering θJA = 45°C/W and θJC = 10°C/W for high-power density applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (1) | Boost Diode Anode Input | Supplies bias current to internal regulator; enables efficiency boost when connected to VOUT ≥3V. |
| BOOST (2) | Bootstrap Drive Voltage | Provides >VIN voltage to fully saturate internal NPN switch; requires external capacitor/diode network. |
| SW (3) | Switch Node | Connects to inductor, catch diode cathode, and boost capacitor - carries high di/dt switching current. |
| VIN (4) | Main Power Input | Supplies internal regulator and switch driver; must be locally bypassed with ≥10μF ceramic capacitor. |
| RUN/SS (5) | Enable & Soft-Start Control | Pull ≥2.5V for operation; tie RC network to generate controlled VOUT ramp; <0.2V disables IC with <1μA IQ. |
| SYNC (6) | External Clock Input | Accepts TTL/CMOS clock (250kHz–2MHz); grounds for Burst Mode; edges must have <1μs rise/fall time. |
| PG (7) | Power Good Flag | Open-collector output; pulls low when VOUT reaches 91% of programmed value - used for system sequencing. |
| FB (8) | Feedback Input | Regulated to 0.79V; connects to resistor divider tap - sets output voltage with ±1.3% accuracy over temp. |
| VC (9) | Error Amplifier Output | Controls peak switch current; external RC compensation network stabilizes loop and sets bandwidth. |
| RT (10) | Oscillator Frequency Set | Resistor-to-GND sets fSW from 200kHz to 2.4MHz per published RT vs. fSW table. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | Maintains <15mVP-P output ripple at light loads while achieving 75μA IQ - eliminates need for external LDO post-regulation in battery-powered systems. |
| Integrated Boost Diode | On-die Schottky eliminates external diode, reducing BOM count and PCB area - simplifies layout and improves reliability in space-constrained modules. |
| Thermal Protection | Internal shutdown activates above 165°C junction temperature - prevents permanent damage during overload or poor heatsinking conditions. |
| Saturating Switch Design | 95mΩ on-resistance with bipolar NPN architecture ensures low conduction loss even at high duty cycles - critical for high-VIN, low-VOUT conversion. |
| Output Voltage Range | Programmable from 0.79V to 30V - supports single IC across multiple rail requirements (e.g., 1.2V core, 3.3V I/O, 5V USB, 12V analog). |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery (with 62V load dump transients) to stable 3.3V or 5V for infotainment ECUs and ADAS sensors. IC Role / Device Role / Timing Role: Primary buck controller with OVP, PG flag, and thermal protection - ensures safe, sequenced power delivery in harsh automotive environments. Use Value: Eliminates need for external TVS and discrete switch driver; H-grade rating guarantees operation at 150°C junction temperature under hood. | Use Scenario: Providing isolated, efficient point-of-load (POL) regulation in factory automation PLCs with wide-input 24V/48V bus. IC Role / Device Role / Timing Role: High-efficiency step-down regulator delivering 3.5A at 5V/12V from noisy industrial supply - handles brownouts and surges without dropout. Use Value: 75μA Burst Mode IQ extends runtime during standby; SYNC pin enables EMI reduction via spread-spectrum clock alignment across multiple rails. |
| Industrial Supplies | Wall Transformer Regulation |
Use Scenario: Converting unregulated 24V–36V DC from DIN-rail power supplies into clean 3.3V/5V for programmable logic controllers and I/O modules. IC Role / Device Role / Timing Role: Main DC/DC converter with soft-start, power good signaling, and robust transient response - meets IEC 61000-4-5 surge immunity requirements. Use Value: Exposed-pad MSOP package enables direct thermal coupling to heatsink; 33V OVL protects against field-wiring errors and backfeed events. | Use Scenario: Replacing linear regulators in AC/DC wall adapters to achieve >90% efficiency at 3.5A output for networking equipment and PoE injectors. IC Role / Device Role / Timing Role: High-frequency buck controller (up to 2.4MHz) enabling ultra-small magnetics and minimal output capacitance. Use Value: Adjustable fSW allows optimization for size (2.4MHz) or efficiency (200kHz); integrated BD diode reduces component count and cost versus discrete solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | Lower max input (15V), lower IQ (12μA), no integrated boost diode, smaller 10-MSOP package | Better suited for low-voltage, ultra-low-power applications (e.g., IoT sensors); lacks 62V transient tolerance | Select LTC3631EMSE#PBF only if input never exceeds 15V and sub-20μA IQ is mandatory - not drop-in for LT3972HMSE#PBF's high-voltage use cases. |
| MPQ4333GQ-AEC1-P | Automotive-grade (AEC-Q200), 36V max input, 3.5A, 75μA IQ, integrated MOSFETs (no external diode needed), but no BD bias-sourcing or SYNC | Designed for automotive qualification; lacks programmable fSW and external sync - limits EMI control flexibility | Choose MPQ4333GQ-AEC1-P when AEC-Q200 compliance is required and fixed 2.2MHz operation suffices; otherwise LT3972HMSE#PBF offers broader design adaptability. |
Compared with LTC3631EMSE#PBF and MPQ4333GQ-AEC1-P, the LT3972HMSE#PBF uniquely combines 62V transient survivability, BD-bias efficiency enhancement, and 200kHz–2.4MHz programmability - making it optimal for ruggedized industrial and non-AEC automotive designs requiring field-serviceable flexibility.
Availability
LT3972HMSE#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, distributed supply regulation, and industrial power supplies requiring stable component supply with guaranteed long-term availability and extended temperature support.
Supply support for LT3972HMSE#PBF 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
Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3972 product line was designed by Linear Technology specifically for high-input-voltage, high-reliability DC/DC conversion in automotive, industrial, and avionics applications - emphasizing thermal robustness, transient immunity, and integration of bias and protection functions.
FAQ
What is the maximum input voltage rating for LT3972HMSE#PBF, and how does overvoltage protection work?
The LT3972HMSE#PBF has an absolute maximum VIN rating of 62V for non-repetitive 1-minute transients, with guaranteed operation up to 33V. Its overvoltage lockout circuit disables switching when VIN exceeds 33V (min), preventing damage while allowing safe clamping of load-dump events common in automotive systems. The LT3972HMSE#PBF remains functional and resumes regulation once VIN drops below the hysteresis threshold.
Does LT3972HMSE#PBF require an external Schottky diode, and what is the role of the BD pin?
No, the LT3972HMSE#PBF integrates a boost Schottky diode - eliminating the need for an external diode. The BD pin connects to the anode of this internal diode and also supplies bias current to the internal regulator. When BD is connected to an output voltage ≥3V, the LT3972HMSE#PBF draws bias from VOUT instead of VIN, improving light-load efficiency - a key advantage over conventional buck controllers.
What thermal specifications apply to LT3972HMSE#PBF, and how is thermal performance enabled in the MSOP package?
The LT3972HMSE#PBF is rated for –40°C to +150°C junction temperature (H-grade), with guaranteed specifications across that range. Its 10-lead MSOP package features an exposed thermal pad (Pin 11 = GND) that must be soldered to a PCB copper plane. This achieves θJC = 10°C/W and θJA = 45°C/W, enabling reliable 3.5A operation without forced airflow - critical for sealed industrial enclosures and under-hood automotive modules.
How does the LT3972HMSE#PBF implement soft-start, and what external components are required?
The LT3972HMSE#PBF implements soft-start via the RUN/SS pin: applying a controlled voltage ramp to this pin controls the rate at which the output voltage rises. An external resistor and capacitor from RUN/SS to GND generate the ramp - for example, a 100kΩ resistor and 100nF capacitor yields ~10ms startup time. This prevents inrush current and ensures orderly system power-up, and the same pin doubles as shutdown control (<0.2V disables the LT3972HMSE#PBF).
Can LT3972HMSE#PBF synchronize to an external clock, and what are the timing requirements?
Yes, the LT3972HMSE#PBF supports external clock synchronization via the SYNC pin, accepting frequencies from 250kHz to 2MHz. Clock edges must have rise and fall times faster than 1μs to ensure reliable locking. When not used, SYNC must be grounded to enable low-ripple Burst Mode operation. This feature allows EMI reduction through frequency alignment across multiple converters in dense PCB layouts.
LT3972HMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 33V
- Voltage - Output (Min/Fixed):
- 0.79V
- Voltage - Output (Max):
- 30V
- Current - Output:
- 3.5A
- Frequency - Switching:
- 230kHz ~ 2.45MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3972HMSE#PBF FAQ
1.How can I place an order for LT3972HMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3972HMSE#PBF 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 LT3972HMSE#PBF reliable?
The price and inventory of LT3972HMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3972HMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3972HMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3972HMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3972HMSE#PBF?
LT3972HMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3972HMSE#PBF 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 LT3972HMSE#PBF?
For technical support, including LT3972HMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3972HMSE#PBF requirements.
6.How does Aetrix verify that LT3972HMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3972HMSE#PBF 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 LT3972HMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3972HMSE#PBF?
All LT3972HMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3972HMSE#PBF, 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 LT3972HMSE#PBF part is unused and in its original packaging.
Return procedure for LT3972HMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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