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Analog Devices Inc. LT3972EDD#TRPBF
- Part No.:
- LT3972EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3972EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:6,565
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Product details
Overview
LT3972EDD#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic 33V-input, 3.5A synchronous step-down DC/DC regulator with adjustable 200kHz–2.4MHz switching frequency, 75μA quiescent current in Burst Mode®, and integrated boost Schottky diode. It delivers regulated 0.79V–30V output in automotive battery regulation and industrial distributed supplies.
For engineers reviewing the LT3972EDD#TRPBF datasheet, LT3972EDD#TRPBF pinout, LT3972EDD#TRPBF application, or LT3972EDD#TRPBF equivalent, key selection criteria include input voltage range (3.6V–33V), thermal performance in 3mm×3mm DFN, soft-start control via RUN/SS, power good flag timing, and synchronization capability across 250kHz–2MHz.
Technical Context
The LT3972EDD#TRPBF employs current-mode control with internal 95mΩ NPN switch and integrated boost diode driver for high-efficiency saturation. Its oscillator supports programmable frequency via RT resistor and includes frequency foldback during startup/overload to limit peak inductor current.
It features active VC clamp for current limiting, RUN/SS-controlled soft-start ramp, and open-collector PG flag triggered at 91% of FB-set output voltage. Bias current sourcing from VOUT (>3V) reduces quiescent consumption, while overvoltage lockout disables switching above 33V (62V transient tolerant).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 33V continuous; withstands 62V transients - enables direct connection to 24V/36V automotive or industrial rails without pre-regulation. |
| Max Output Current | 3.5A - supports mid-power applications like FPGA core rails or sensor subsystems without external current boosting. |
| Quiescent Current | 75μA at 12VIN→3.3VOUT in Burst Mode® - extends battery life in always-on monitoring systems. |
| Switching Frequency | 200kHz to 2.4MHz (RT-programmable) - allows trade-off between small magnetics (high-f) and efficiency/dropout (low-f). |
| Feedback Voltage | 790mV ±10mV - sets precise output regulation point; enables accurate 1.2V, 1.8V, 3.3V, or 5V outputs with standard resistor ratios. |
| Power Good Threshold | 91% of programmed VOUT - provides reliable system sequencing signal with 65mV offset and 10mV hysteresis. |
| Thermal Range | –40°C to +125°C junction - qualified for under-hood automotive and industrial control cabinet deployment. |
| Package | 10-lead 3mm × 3mm DFN with exposed pad - achieves θJA = 45°C/W for compact, thermally robust PCB layouts. |
Pinout & Package
The LT3972EDD#TRPBF is housed in a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed pad (Pin 11) soldered to PCB ground for low thermal resistance (θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost diode anode connection | Supplies bias current to internal regulator; connects to external Schottky anode for bootstrapped gate drive. |
| BOOST (Pin 2) | Bootstrap capacitor drive node | Provides >VIN voltage to fully saturate internal NPN switch; requires external capacitor and diode. |
| SW (Pin 3) | Switch node | Connects to inductor, catch diode cathode, and boost capacitor; carries high di/dt switching current. |
| VIN (Pin 4) | Main input supply | Feeds internal regulator and switch; must be locally bypassed with ≥10μF X7R ceramic capacitor. |
| RUN/SS (Pin 5) | Enable & soft-start control | Pull ≥2.5V for operation; tie RC network to generate controlled VOUT ramp; <0.2V forces shutdown (<1μA IQ). |
| SYNC (Pin 6) | External clock input | Accepts 250kHz–2MHz square wave for EMI reduction; tie to GND for Burst Mode® operation. |
| PG (Pin 7) | Power good open-collector output | Sinks current when VOUT < 91% of target; requires external pull-up for system reset/sequencing logic. |
| FB (Pin 8) | Feedback input | Regulated to 790mV; connects to resistor divider tap for output voltage programming. |
| VC (Pin 9) | Error amplifier output | Controls peak switch current; connect RC compensation network to ground for loop stability. |
| RT (Pin 10) | Oscillator frequency set | Resistor to GND programs switching frequency (200kHz–2.4MHz); values from 9.09kΩ to 215kΩ per datasheet table. |
Key Features
| Feature | Design Value |
|---|---|
| Low-ripple Burst Mode® operation | Maintains <15mVP-P output ripple at light loads while achieving 75μA IQ, critical for noise-sensitive analog or RF subsystems. |
| Integrated boost Schottky diode driver | Eliminates need for external bootstrap diode; simplifies layout and improves reliability in space-constrained designs. |
| Synchronizable switching frequency | Enables EMI compliance by locking to system clock or spreading spectrum across 250kHz–2MHz band. |
| Thermal shutdown protection | Halts switching if junction temperature exceeds safe limit; auto-recovery on cooldown prevents latch-up in overload conditions. |
| Overvoltage lockout (OVL) | Disables switching above 33V (min), protecting downstream circuitry during load dump or surge events up to 62V. |
| Output voltage programmability | 0.79V to 30V via FB resistor divider - supports wide range of logic, analog, and interface rail requirements. |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to stable 3.3V or 5V for ADAS camera modules or infotainment processors. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, ripple-controlled power with OVL protection against 62V load-dump transients. Use Value: Enables direct battery connection without front-end TVS or pre-regulator, reducing BOM count and board area by 30% versus discrete solutions. | Use Scenario: Powering remote I/O nodes or fieldbus interfaces in factory automation systems with 24V DC distribution rails. IC Role / Device Role / Timing Role: Local point-of-load regulator delivering 3.5A at 5V with soft-start sequencing and PG confirmation for PLC backplane communication. Use Value: Ensures clean startup and fault signaling across long cable runs, preventing brown-out resets during hot-plug insertion. |
| Industrial Supplies | Wall Transformer Regulation |
Use Scenario: Generating 12V/15V auxiliary supplies for motor drives or programmable logic controllers operating in harsh ambient temperatures. IC Role / Device Role / Timing Role: High-input-voltage buck regulator with –40°C to +125°C operation and thermal shutdown for uncooled enclosures. Use Value: Delivers full 3.5A output without derating at 85°C ambient, eliminating need for heatsinks or forced air cooling. | Use Scenario: Replacing linear regulators in AC/DC wall adapters to improve efficiency and reduce heat in compact consumer electronics enclosures. IC Role / Device Role / Timing Role: Efficient 33V-input buck converter stepping down rectified AC to 5V/3.3V USB or microcontroller rails. Use Value: Achieves >90% efficiency at 1A load, cutting adapter surface temperature by 25°C versus 78L05-based designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8640SEDD#TRPBF | Higher 42V max input, 4A output, Silent Switcher® architecture; 2.5μA IQ in Sleep Mode vs 75μA Burst Mode® | Better EMI performance and lower quiescent current; requires different compensation and layout due to dual-switch topology | Preferred for ultra-low-noise or battery-critical applications where EMI filtering or <5μA sleep current is mandatory. |
| MPQ4470AGRE-AEC1-Z | Automotive-grade (AEC-Q100), 36V input, 3.5A output, but no integrated boost diode; requires external bootstrap diode | Lacks integrated BD driver and PG flag; supports SYNC but no frequency foldback or VC clamp | Suitable for cost-sensitive automotive modules where external diode placement is acceptable and PG signaling is handled externally. |
Compared with LT3972EDD#TRPBF, LT8640SEDD#TRPBF offers superior EMI suppression and deeper sleep current but demands more complex layout and higher BOM cost; MPQ4470AGRE-AEC1-Z provides AEC-Q100 qualification at lower price but sacrifices integration (no BD driver, no PG) and advanced protection features.
Availability
LT3972EDD#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supplies, and wall transformer regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3972EDD#TRPBF 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 digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LT3972EDD#TRPBF belongs to ADI's Power by Linear™ family of monolithic DC/DC regulators, designed specifically for high-input-voltage, high-reliability applications in automotive and industrial environments where wide VIN range, low quiescent current, and robust protection are essential.
FAQ
What is the maximum input voltage rating for LT3972EDD#TRPBF in continuous operation?
The LT3972EDD#TRPBF supports continuous operation up to 33V input. It tolerates non-repetitive 62V transients for up to one minute, with overvoltage lockout disabling switching above 33V (minimum) to protect downstream circuitry. For sustained 36V+ inputs, external clamping or pre-regulation is required before the LT3972EDD#TRPBF input.
Does LT3972EDD#TRPBF require an external bootstrap diode?
No - the LT3972EDD#TRPBF integrates a boost Schottky diode driver (BD pin) and does not require an external bootstrap diode. The BD pin connects directly to the anode of an external Schottky diode whose cathode ties to BOOST, enabling self-powered gate drive for the internal NPN switch without additional diodes.
How is soft-start implemented on LT3972EDD#TRPBF?
Soft-start on LT3972EDD#TRPBF is implemented via the RUN/SS pin: an external RC network (e.g., 100kΩ + 100nF) generates a controlled voltage ramp at RUN/SS, which internally clamps the VC pin voltage to limit inrush current and ensure monotonic VOUT rise. The LT3972EDD#TRPBF begins switching only after RUN/SS exceeds 2.5V.
What is the function of the PG (power good) pin on LT3972EDD#TRPBF?
The PG pin on LT3972EDD#TRPBF is an open-collector output that signals when the regulated output reaches 91% of its programmed value. It sinks current until VFB stabilizes within tolerance, enabling system-level power sequencing. PG is valid only when VIN > 3.6V and RUN/SS is high - the LT3972EDD#TRPBF must be enabled and powered for PG assertion.
Can LT3972EDD#TRPBF synchronize to an external clock?
Yes - the LT3972EDD#TRPBF supports external clock synchronization via the SYNC pin, accepting square-wave inputs from 250kHz to 2MHz. This feature enables EMI reduction through frequency alignment or spread-spectrum operation. When unused, SYNC must be tied to ground to retain Burst Mode® operation at light loads.
LT3972EDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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):
- 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3972EDD#TRPBF FAQ
1.How can I place an order for LT3972EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3972EDD#TRPBF 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 LT3972EDD#TRPBF reliable?
The price and inventory of LT3972EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3972EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3972EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3972EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3972EDD#TRPBF?
LT3972EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3972EDD#TRPBF 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 LT3972EDD#TRPBF?
For technical support, including LT3972EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3972EDD#TRPBF requirements.
6.How does Aetrix verify that LT3972EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3972EDD#TRPBF 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 LT3972EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3972EDD#TRPBF?
All LT3972EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3972EDD#TRPBF, 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 LT3972EDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3972EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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