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Analog Devices Inc. LT3972EDD#PBF
- Part No.:
- LT3972EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3972EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:908
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Product details
Overview
LT3972EDD#PBF from Analog Devices (formerly Linear Technology) is a monolithic 33V-input, 3.5A synchronous step-down switching regulator with adjustable 200kHz–2.4MHz 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 power supplies.
For engineers reviewing the LT3972EDD#PBF datasheet, LT3972EDD#PBF pinout, LT3972EDD#PBF application, or LT3972EDD#PBF equivalent, key selection factors include its 95mΩ switch RDS(on), thermal shutdown, power good flag, soft-start via RUN/SS, and compatibility with 3mm × 3mm DFN-10 package for high-density PCB layouts.
Technical Context
The LT3972EDD#PBF uses current-mode control with an internal 0.79V reference and error amplifier driving the VC pin to regulate output voltage via external resistor divider. Its oscillator is resistor-programmed (RT pin) and supports synchronization (SYNC pin) across 250kHz–2MHz.
It integrates a bipolar NPN power switch with 95mΩ on-resistance, boost capacitor drive circuitry, and active clamp on VC for current limiting. Operation includes low-ripple Burst Mode at light loads, frequency foldback during startup/overload, and overvoltage lockout at 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/32V industrial or automotive batteries without pre-regulation. |
| Max Output Current | 3.5A - supports mid-power applications like FPGA core rails or motor control logic supplies. |
| Quiescent Current | 75µA at 12VIN → 3.3VOUT in Burst Mode - extends battery life in always-on IoT sensors and telematics modules. |
| Switching Frequency | 200kHz to 2.4MHz (RT-programmable) - allows trade-off between small magnetics (high-f) and efficiency (low-f) per design constraints. |
| Feedback Reference | 0.790V ±10mV - enables precise output setting down to sub-1V with standard 1% resistors and stable loop compensation. |
| Power Good Flag | Open-collector PG asserts when VOUT reaches 91% of target - provides reliable system reset sequencing for microcontrollers and ASICs. |
| Thermal Protection | Internal junction temperature shutdown - prevents damage during sustained overload or poor heatsinking in enclosed enclosures. |
| Package | 10-pin 3mm × 3mm DFN with exposed pad - achieves θJA = 45°C/W for compact, thermally robust layout without heatsink. |
Pinout & Package
LT3972EDD#PBF 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). The package supports high-power density designs in space-constrained industrial and automotive modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost diode anode connection | Supplies bias current to internal regulator; connects to external Schottky anode to generate BOOST voltage above VIN for switch saturation. |
| BOOST (Pin 2) | Bootstrap drive node | Provides >VIN gate drive to internal bipolar NPN switch; requires external capacitor and Schottky diode for full saturation and low conduction loss. |
| SW (Pin 3) | Switch node | Connects to inductor, catch diode cathode, and BOOST capacitor; carries high di/dt switching current - demands tight layout and Kelvin grounding. |
| VIN (Pin 4) | Main input supply | Supplies power to internal regulator and switch; must be locally bypassed with ≥10µF X7R ceramic capacitor close to pin. |
| RUN/SS (Pin 5) | Enable & soft-start control | Pull ≥2.5V to enable; tie to GND for shutdown (<1µA IQ); RC network here sets controlled VOUT ramp rate during startup. |
| SYNC (Pin 6) | External clock input | Accepts TTL/CMOS clock (250kHz–2MHz) to synchronize switching and reduce EMI; ground for standalone Burst Mode operation. |
| PG (Pin 7) | Power good open-collector output | Sinks current when VFB < 91% of regulation; requires external pull-up to monitor output stability before system boot. |
| FB (Pin 8) | Feedback input | Regulated to 0.790V; connects to resistor divider from VOUT - determines output voltage with ±1.3% accuracy over temp. |
| VC (Pin 9) | Error amplifier output | Controls peak switch current; external RC compensation network here stabilizes loop response and prevents oscillation. |
| RT (Pin 10) | Frequency set resistor | Resistor to GND programs fSW from 200kHz to 2.4MHz; value selected per Figure 1 in datasheet for target frequency and layout constraints. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode Driver | Eliminates need for external bootstrap diode; reduces BOM count and layout area while ensuring reliable switch saturation up to 33V input. |
| Low-Ripple Burst Mode Operation | Maintains <15mVP-P output ripple at light loads while achieving 75µA IQ - critical for noise-sensitive analog circuits and battery-powered instrumentation. |
| Adjustable Switching Frequency | 200kHz–2.4MHz range allows optimization of inductor size (e.g., 4.7µH at 600kHz) vs. efficiency (e.g., 200kHz for 12V→3.3V @ 3A) without changing IC. |
| Power Good Flag with Hysteresis | PG asserts at 91% VREF with 10mV hysteresis - ensures clean, glitch-free system reset signaling even during line/load transients. |
| Overvoltage Lockout (OVL) | Disables switching at 33V (min), tolerating 62V transients - protects downstream circuitry in 24V automotive systems subject to load dump. |
| Soft-Start via RUN/SS Pin | RC-controlled voltage ramp on RUN/SS limits inrush current and prevents output overshoot during startup into large capacitive loads. |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for infotainment head units and ADAS camera modules. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, low-noise DC-DC conversion with OVL protection against 62V load dump. Use Value: Enables single-stage conversion without pre-regulator, reducing cost and board area while meeting AEC-Q200 stress requirements via -40°C to 125°C operation. |
Use Scenario: Local point-of-load regulation in programmable logic controllers (PLCs) with multiple 3.3V/12V subsystems. IC Role / Device Role / Timing Role: High-efficiency, thermally robust buck regulator delivering 3.5A to FPGA I/O banks or communication interfaces. Use Value: Exposed-pad DFN package dissipates heat effectively in confined enclosures; Burst Mode extends standby time during idle cycles. |
| Industrial Supplies | Wall Transformer Regulation |
Use Scenario: Powering industrial sensors and field transmitters from wide-range 9–36V DC inputs. IC Role / Device Role / Timing Role: Input-tolerant buck controller maintaining stable 5V output despite brownouts and surges in factory environments. Use Value: 3.6V minimum input enables operation during undervoltage events; thermal shutdown prevents failure under prolonged overload. |
Use Scenario: Replacing linear regulators in AC/DC wall adapters for USB-C PD accessories requiring 5V/3A output. IC Role / Device Role / Timing Role: High-frequency (2.4MHz) buck converter enabling ultra-small inductors and capacitors in compact adapter designs. Use Value: Reduces solution size by >50% vs. 500kHz designs while maintaining >90% efficiency at full load and low audible noise in Burst Mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#PBF | 42V max input, 3.5A, 2MHz sync capability, 2.5µA IQ; uses MOSFET switch (vs. bipolar), no integrated boost diode driver. | Better suited for ultra-low-IQ battery apps; requires external bootstrap diode and higher gate drive complexity. | Select LT8610EMSE#PBF when <3µA shutdown current or 42V input margin is required; avoid if board space prohibits adding external diode. |
| MP2451DT-LF-Z | 36V max input, 2A, fixed 2MHz, 1.2mA IQ; no PG flag, no SYNC, no Burst Mode - only PWM mode. | Lower cost for non-critical consumer power rails where efficiency at light load and sequencing signals are not needed. | Select MP2451DT-LF-Z for cost-sensitive, high-volume applications with fixed 5V/3.3V outputs and no requirement for power sequencing or low-noise operation. |
Compared with LT8610EMSE#PBF and MP2451DT-LF-Z, the LT3972EDD#PBF uniquely combines 33V input, integrated boost diode driver, 75µA Burst Mode, and PG flag in a 3mm × 3mm DFN - making it optimal for space-constrained, thermally demanding industrial and automotive DC-DC stages requiring reliability and feature completeness.
Availability
LT3972EDD#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, distributed supply regulation, and industrial power supplies requiring stable component supply, long-term lifecycle support, and AEC-Q200-aligned performance.
Supply support for LT3972EDD#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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3972EDD#PBF belongs to Linear's high-voltage monolithic buck regulator product line, designed specifically for robust, wide-input industrial and automotive power conversion where integration, thermal performance, and transient resilience are critical.
FAQ
What is the maximum input voltage rating for LT3972EDD#PBF in continuous operation?
The LT3972EDD#PBF operates continuously up to 33V input; its absolute maximum rating is 62V for non-repetitive 1-minute transients. Above 35V (typical), the device disables switching to protect downstream circuitry while sustaining the overvoltage condition safely. This makes LT3972EDD#PBF suitable for 24V automotive systems with load-dump immunity.
Does LT3972EDD#PBF require an external bootstrap diode?
No - the LT3972EDD#PBF integrates a boost diode driver (BD pin) that controls an external Schottky diode, but the diode itself is external. The IC does not contain the Schottky die; however, the BD pin's internal regulator and current drive eliminate need for a separate bootstrap IC or charge pump, simplifying layout versus fully discrete solutions.
What is the purpose of the VC pin on LT3972EDD#PBF, and how is it used?
VC is the error amplifier output controlling peak switch current. It must be compensated with an external RC network to ground to stabilize the current-mode loop. The LT3972EDD#PBF's VC pin also features an active clamp tied to RUN/SS voltage, enabling soft-start functionality - a key differentiator from basic buck controllers lacking integrated ramp control.
Can LT3972EDD#PBF be synchronized to an external clock, and what is the supported frequency range?
Yes - the SYNC pin accepts external TTL/CMOS clock signals from 250kHz to 2MHz. When synchronized, LT3972EDD#PBF locks its switching edge to the external source, reducing EMI in multi-rail systems. If unused, SYNC must be grounded to retain low-ripple Burst Mode operation at light loads.
What thermal derating applies to LT3972EDD#PBF in the 3mm × 3mm DFN package?
The LT3972EDD#PBF in DFN-10 has θJA = 45°C/W and θJC = 10°C/W. With the exposed pad soldered to ≥1cm² copper area, it delivers full 3.5A output up to +85°C ambient. Above 85°C, output current must be reduced per the thermal derating curve in the datasheet - e.g., ~2.8A at +100°C ambient - to maintain TJ ≤ 125°C.
LT3972EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3972EDD#PBF FAQ
1.How can I place an order for LT3972EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3972EDD#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 LT3972EDD#PBF reliable?
The price and inventory of LT3972EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3972EDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3972EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3972EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3972EDD#PBF?
LT3972EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3972EDD#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 LT3972EDD#PBF?
For technical support, including LT3972EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3972EDD#PBF requirements.
6.How does Aetrix verify that LT3972EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3972EDD#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 LT3972EDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3972EDD#PBF?
All LT3972EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3972EDD#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 LT3972EDD#PBF part is unused and in its original packaging.
Return procedure for LT3972EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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