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Analog Devices Inc. LT3972IMSE#PBF
- Part No.:
- LT3972IMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3972IMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:188
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Product details
Overview
LT3972IMSE#PBF from Analog Devices (formerly Linear Technology) is a monolithic current-mode step-down switching regulator with integrated 95mΩ NPN switch and boost Schottky diode, supporting 3.6V–33V input, 0.79V–30V adjustable output, 3.5A max load, 200kHz–2.4MHz programmable frequency, and 75μA quiescent current in Burst Mode. It delivers high efficiency for automotive battery regulation and industrial distributed supplies.
For engineers reviewing the LT3972IMSE#PBF datasheet, LT3972IMSE#PBF pinout, LT3972IMSE#PBF application, or LT3972IMSE#PBF equivalent, key selection considerations include its 10-pin MSOP package with exposed pad, thermal protection, power good flag, soft-start via RUN/SS, and synchronization capability across 250kHz–2MHz - all critical for robust wide-input DC/DC design.
Technical Context
The LT3972IMSE#PBF implements constant-frequency current-mode control with internal error amplifier, slope compensation, and active VC clamp for precise peak-current limiting. Its oscillator uses an external RT resistor to set switching frequency from 200kHz to 2.4MHz, enabling optimization of inductor size versus efficiency and dropout voltage.
It features dual bias sourcing: internal regulator draws from VIN by default but switches to BD pin when VBD > 3V, reducing no-load current and improving light-load efficiency. The device enters low-ripple Burst Mode below ~100mA load, maintaining <15mVP-P output ripple while drawing only 75μA from VIN at 12VIN/3.3VOUT.
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 and industrial rails without pre-regulation. |
| Output Current | Up to 3.5A DC - supports high-power microcontrollers, FPGAs, and sensor modules in space-constrained designs. |
| Quiescent Current | 75μA in Burst Mode at 12VIN/3.3VOUT - extends battery life in always-on systems like telematics and remote sensors. |
| Switching Frequency | 200kHz to 2.4MHz (RT-programmable) - allows trade-off between small 2.2μH inductors (at 2MHz) and higher efficiency at lower frequencies. |
| Feedback Reference | 0.790V ±10mV over temperature - enables accurate, stable output regulation with standard resistor dividers. |
| Power Good Flag | Open-collector PG asserts high when VOUT reaches 91% of target - provides reliable system sequencing and fault detection without external monitoring circuitry. |
| Thermal Protection | Internal junction shutdown above 150°C (H-grade), 125°C (I/E-grade) - prevents damage during overload or poor heatsinking in sealed enclosures. |
Pinout & Package
LT3972IMSE#PBF is housed in a thermally enhanced 10-lead plastic MSOP package with exposed pad (Pin 11) that must be soldered to PCB ground for optimal thermal performance (θJA = 45°C/W, θJC = 10°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (1) | Boost diode anode connection | Supplies bias current to internal regulator; enables efficiency boost when connected to ≥3V rail (e.g., VOUT). |
| BOOST (2) | Bootstrap drive node | Provides >VIN voltage to fully saturate internal NPN switch; requires external capacitor + Schottky diode. |
| SW (3) | Switch node | Connects to inductor, catch diode cathode, and boost capacitor; carries high dI/dt switching current. |
| VIN (4) | Main input supply | Primary power source for internal regulator and switch; must be locally bypassed with ≥10μF ceramic capacitor. |
| RUN/SS (5) | Enable & soft-start control | Logic-level shutdown (<0.2V = off); ramp voltage here sets output voltage slew rate during startup. |
| SYNC (6) | External clock input | Accepts TTL/CMOS clock (250kHz–2MHz); ties to GND for autonomous Burst Mode operation. |
| PG (7) | Power good open-collector output | Sinks current until VFB ≥ 91% of 0.79V; requires external pull-up for system reset or sequencing logic. |
| FB (8) | Feedback input | Regulated to 0.790V; connects to resistor divider tap for precise output voltage programming. |
| VC (9) | Error amplifier output | Controls peak switch current; RC network to ground sets loop compensation and stability. |
| RT (10) | Oscillator frequency set | Resistor to GND programs switching frequency (e.g., 63.4kΩ = 600kHz per datasheet Figure 1). |
| Exposed Pad (11) | Thermal & electrical ground | Must be soldered to PCB ground plane; primary path for heat dissipation and noise reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external diode, reduces BOM count and board area, and ensures optimal timing with internal switch. |
| Low-Ripple Burst Mode | Maintains <15mVP-P output ripple at light loads while achieving 75μA IQ, avoiding audible ceramic capacitor noise. |
| Overvoltage Lockout (OVL) | Disables switching at VIN > 33V (min), protecting downstream circuitry during load dump or hot-swap events up to 62V. |
| Saturating Switch Design | 95mΩ on-resistance at full load enables high efficiency (>90% at 12V→5V/2A) without requiring external MOSFET drivers. |
| Programmable Soft-Start | Controlled VOUT ramp via RC on RUN/SS prevents inrush current and stabilizes multi-rail power sequencing. |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
|
Use Scenario: Powering infotainment head units and ADAS cameras from 12V/24V vehicle battery with load dump immunity. IC Role / Device Role / Timing Role: Primary buck converter providing stable 5V/3.3V rails with OVL protection and thermal shutdown. Use Value: Withstands 62V transients without external TVS, reducing system cost and footprint while meeting ISO 7637-2 Pulse 5a requirements. |
Use Scenario: Local point-of-load conversion in industrial PLC backplanes with varying input voltages (18–36V DC). IC Role / Device Role / Timing Role: High-efficiency, thermally robust DC/DC regulator delivering 3.3V/3.5A to FPGA I/O banks and communication peripherals. Use Value: Exposed-pad MSOP package enables conduction cooling in dense layouts; 75μA IQ minimizes standby losses across hundreds of nodes. |
| Industrial Supplies | Wall Transformer Regulation |
|
Use Scenario: Replacing linear regulators in factory automation sensors where 24V field bus powers 3.3V microcontrollers. IC Role / Device Role / Timing Role: Wide-input buck controller with programmable frequency to avoid EMI-sensitive bands (e.g., 433MHz ISM). Use Value: 200kHz–2.4MHz range allows selecting 1.2MHz to shrink magnetics while maintaining >88% efficiency at full load. |
Use Scenario: Regulating unregulated 9–24V AC/DC adapter outputs to clean 5V USB power for embedded gateways. IC Role / Device Role / Timing Role: High-input buck converter with Burst Mode and power good signaling for safe USB enumeration. Use Value: PG flag confirms VOUT stability before enabling USB PHY; 75μA IQ meets Energy Star Level VI standby requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8640SIV#PBF | 42V input, 4A, Silent Switcher® architecture; 2.5μA IQ in Burst Mode; requires external bootstrap capacitor. | Better EMI performance and lower IQ, but larger 20-lead LQFN package and higher cost; suited for noise-sensitive medical or RF systems. | Choose LT8640S when ultra-low EMI and sub-3μA quiescent current are mandatory; accept larger footprint and layout complexity. |
| TPS54332DR | 28V input, 3.5A, 57mΩ MOSFETs; 125μA IQ; no integrated boost diode; requires external bootstrap diode/capacitor. | Lower cost and TI's WEBENCH support; lacks OVL and PG flag; not rated for 62V transients. | Choose TPS54332 for cost-sensitive industrial controls where 36V max input suffices and external components are acceptable. |
Compared with LT8640SIV#PBF and TPS54332DR, the LT3972IMSE#PBF uniquely combines integrated boost diode, 62V transient tolerance, and 75μA Burst Mode IQ in a compact MSOP package - making it optimal for automotive and ruggedized industrial DC/DC where reliability, simplicity, and thermal performance are prioritized over ultra-low EMI or lowest possible BOM cost.
Availability
LT3972IMSE#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed supplies, and wall transformer regulation requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT3972IMSE#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 and maintains its high-performance analog and power management portfolio with rigorous automotive and industrial qualification standards.
The LT3972IMSE#PBF belongs to Linear's monolithic buck regulator family designed for wide-input, high-reliability applications in harsh environments - emphasizing thermal robustness, transient immunity, and integration to reduce external component count.
FAQ
What is the operating temperature range for the LT3972IMSE#PBF?
The LT3972IMSE#PBF is specified for –40°C to +125°C junction temperature and is qualified for industrial applications. Its thermal shutdown activates at 150°C, and the exposed pad must be soldered to PCB ground to achieve θJA = 45°C/W. This rating matches the "I" grade in the ordering matrix and is validated across the full range per datasheet Section 2.
Does the LT3972IMSE#PBF require an external bootstrap diode?
No - the LT3972IMSE#PBF integrates a boost Schottky diode connected to the BD pin, eliminating the need for an external diode. The BD pin serves both as the anode connection and bias supply for the internal regulator. An external capacitor is still required between BOOST and SW pins to generate the necessary gate-drive voltage above VIN.
How does the LT3972IMSE#PBF achieve 75μA quiescent current?
The LT3972IMSE#PBF achieves 75μA IQ in Burst Mode by disabling non-essential circuitry between switching bursts - including oscillator, error amplifier, and gate driver - while maintaining regulation via periodic sampling. This occurs automatically below ~100mA load and is confirmed at 12VIN/3.3VOUT per datasheet Figure 1 and Electrical Characteristics table.
Can the LT3972IMSE#PBF synchronize to an external clock?
Yes - the LT3972IMSE#PBF accepts external synchronization via the SYNC pin (Pin 6) across 250kHz to 2MHz. Clock edges must have rise/fall times <1μs. When not used, SYNC must be tied to GND to enable autonomous Burst Mode operation. Synchronization is confirmed in the Pin Functions and Applications Information sections of the datasheet.
What is the minimum input voltage required for the LT3972IMSE#PBF to regulate?
The LT3972IMSE#PBF requires a minimum input voltage of 3.6V to operate, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Below this, the internal regulator cannot sustain bias, and regulation ceases. This value is measured at the VIN pin and accounts for PCB trace drops under load.
LT3972IMSE#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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3972IMSE#PBF FAQ
1.How can I place an order for LT3972IMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3972IMSE#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 LT3972IMSE#PBF reliable?
The price and inventory of LT3972IMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3972IMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3972IMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3972IMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3972IMSE#PBF?
LT3972IMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3972IMSE#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 LT3972IMSE#PBF?
For technical support, including LT3972IMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3972IMSE#PBF requirements.
6.How does Aetrix verify that LT3972IMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3972IMSE#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 LT3972IMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3972IMSE#PBF?
All LT3972IMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3972IMSE#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 LT3972IMSE#PBF part is unused and in its original packaging.
Return procedure for LT3972IMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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