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Analog Devices Inc. LT3972EMSE#PBF
- Part No.:
- LT3972EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3972EMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:662
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Product details
Overview
LT3972EMSE#PBF from Analog Devices (formerly Linear Technology) is a monolithic current-mode step-down switching regulator IC supporting 3.6V–33V input, delivering up to 3.5A output at adjustable voltage (0.79V–30V), operating at 200kHz–2.4MHz with 75μA quiescent current in Burst Mode. It integrates a 95mΩ NPN switch, boost Schottky diode, and power-good flag-used in automotive battery regulation and industrial distributed supplies.
For engineers reviewing the LT3972EMSE#PBF datasheet, LT3972EMSE#PBF pinout, LT3972EMSE#PBF application, or LT3972EMSE#PBF equivalent, key selection factors include its 62V transient tolerance, thermal shutdown, soft-start via RUN/SS, synchronous capability (250kHz–2MHz), and MSOP-10 package with exposed pad for thermal management.
Technical Context
The LT3972EMSE#PBF implements constant-frequency current-mode control with internal oscillator set by RT resistor, enabling precise duty-cycle regulation and fast transient response. Its bipolar NPN switch is driven via BOOST pin with external capacitor-diode network to ensure saturation at high VIN.
Burst Mode operation reduces quiescent current to 75μA while maintaining <15mVP-P output ripple; bias current can be drawn from VOUT when >3V to improve light-load efficiency. Overvoltage lockout triggers at 33V (min), protecting downstream circuitry during 62V transients.
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 continuous-supports high-current point-of-load conversion without external pass devices. |
| Quiescent Current | 75μA at 12VIN→3.3VOUT in Burst Mode-extends battery life in always-on systems. |
| Switching Frequency | Adjustable 200kHz–2.4MHz via RT pin-allows optimization of inductor size vs. efficiency and EMI. |
| Feedback Voltage | 790mV ±10mV-sets output accuracy and enables precise resistor-divider programming from 0.79V to 30V. |
| Power Good Flag | Open-collector PG asserts when VOUT reaches 91% of target-provides reliable system power sequencing and fault detection. |
| Thermal Protection | Internal junction temperature shutdown-prevents damage under sustained overload or poor PCB thermal design. |
| Package | 10-pin MSOP with exposed pad-offers low θJA = 45°C/W for compact, thermally robust layouts. |
Pinout & Package
LT3972EMSE#PBF is housed in a 10-lead plastic MSOP package with exposed pad (Pin 11) soldered to PCB for thermal conduction. Pin numbering follows standard top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost diode anode connection | Supplies bias current to internal regulator; connects to external Schottky diode anode. |
| BOOST (Pin 2) | Bootstrap drive voltage 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 power switch; must be locally bypassed with ≥10μF ceramic capacitor. |
| RUN/SS (Pin 5) | Enable & soft-start control | Logic-level enable (≥2.5V = on); RC network here sets controlled output voltage ramp rate. |
| SYNC (Pin 6) | External clock input | Accepts 250kHz–2MHz square wave for synchronization-reduces EMI in multi-regulator systems. |
| PG (Pin 7) | Power good open-collector output | Sinks current when VOUT < 91% of regulation-requires external pull-up for system monitoring. |
| FB (Pin 8) | Feedback input | Regulated to 790mV; connects to resistor divider tap-determines output voltage setpoint. |
| VC (Pin 9) | Error amplifier output | Controls peak switch current; RC compensation network here stabilizes loop dynamics. |
| RT (Pin 10) | Oscillator frequency setting | Resistor-to-ground sets switching frequency per published table-enables precise EMI tuning. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates need for external boost diode-reduces BOM count and layout area in compact designs. |
| Low-Ripple Burst Mode | Maintains <15mVP-P output ripple at light loads while achieving 75μA IQ-critical for noise-sensitive analog or RF subsystems. |
| Output Bias from VOUT | Draws regulator bias current from output when VOUT > 3V-improves light-load efficiency without external components. |
| Overvoltage Lockout | Disables switching at VIN > 33V (min)-protects load during load-dump or alternator surge events in automotive applications. |
| Saturating Switch Design | 95mΩ on-resistance NPN switch-delivers high efficiency across wide VIN/VOUT ratios without gate-drive complexity. |
| Exposed Pad Thermal Path | MSOP package includes GND-connected exposed pad (Pin 11)-enables ≤45°C/W junction-to-ambient thermal resistance with proper PCB copper. |
Applications
| Automotive Battery Regulation | Distributed Supply Regulation |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery rail to 3.3V/5V for infotainment ECUs or ADAS sensors under cold-crank (≤3.6V) and load-dump (≤62V) conditions. IC Role / Device Role / Timing Role: Primary buck controller providing stable, transient-robust DC-DC conversion with integrated OVP and thermal protection. Use Value: Eliminates need for external TVS or discrete OVP circuitry; 75μA quiescent current meets automotive "parked mode" requirements. | Use Scenario: Powering isolated microcontrollers, ADCs, and communication interfaces in factory automation PLCs with wide-input industrial supplies (18–36V). IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator delivering 3.5A at 5V/3.3V with programmable frequency to avoid sensitive frequency bands. Use Value: Adjustable 200kHz–2.4MHz switching allows EMI compliance in dense board layouts; SYNC pin enables deterministic multi-rail timing. |
| Industrial Supplies | Wall Transformer Regulation |
Use Scenario: Replacing linear regulators in DIN-rail mounted power modules requiring 3.5A output from unregulated 24VDC bus with high ambient temperature (up to 125°C). IC Role / Device Role / Timing Role: Thermally robust buck controller with -40°C to 125°C rated junction temperature and exposed-pad MSOP package. Use Value: Internal thermal shutdown prevents field failures; 95mΩ switch minimizes conduction loss at full load. | Use Scenario: Converting rectified AC wall adapter output (e.g., 36VDC) to regulated 12V/5V for consumer electronics with strict no-load power limits. IC Role / Device Role / Timing Role: Low-quiescent-current buck converter operating in Burst Mode to meet Energy Star standby power requirements. Use Value: 75μA IQ and bias-from-VOUT capability achieve <100mW no-load input power-exceeds Level VI efficiency standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609EMSE#PBF | 42V max input, 2.5A output, 2.2MHz fixed freq, 2.5μA IQ; uses MOSFET switch instead of bipolar. | Better suited for ultra-low-IQ applications but lower current rating; lacks BD pin and boost diode integration. | Select when <3μA shutdown current and 42V input are critical; avoid if >3A output or boost-diode-integrated design is required. |
| MP2451DT-LF-Z | 36V max input, 0.6A output, 2MHz fixed freq, 260μA IQ; no PG, no SYNC, no BOOST pin. | Cost-optimized for low-power IoT nodes-not viable for 3.5A loads or automotive transients. | Select only for space-constrained, low-current (<1A) applications where OVP, PG, and thermal robustness are secondary. |
Compared with LT8609EMSE#PBF and MP2451DT-LF-Z, the LT3972EMSE#PBF uniquely balances 3.5A output, 62V transient tolerance, integrated boost diode, and 75μA Burst Mode IQ-making it optimal for mid-power automotive and industrial buck designs where reliability and feature completeness outweigh ultra-low-IQ or cost-only priorities.
Availability
LT3972EMSE#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 guaranteed -40°C to 125°C operation.
Supply support for LT3972EMSE#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 power management portfolio with rigorous automotive and industrial qualification.
The LT3972 product line delivers robust, high-current buck regulation for harsh environments-designed specifically for automotive, industrial, and telecom infrastructure where input transients, thermal stress, and long-term reliability are critical.
FAQ
What is the maximum input voltage rating for LT3972EMSE#PBF in continuous operation?
The LT3972EMSE#PBF supports continuous operation up to 33V input. Its absolute maximum rating is 62V for non-repetitive 1-minute transients. Operation above 33V (typical OVP threshold) disables switching to protect downstream circuitry, making it suitable for automotive load-dump scenarios. The LT3972EMSE#PBF datasheet specifies 33V minimum overvoltage lockout, with 35V typical and 37V maximum thresholds.
Does LT3972EMSE#PBF require an external boost diode?
No-the LT3972EMSE#PBF integrates a boost Schottky diode internally, connected to the BD pin. Only an external boost capacitor is required between BOOST and SW pins. This eliminates one external component versus controllers requiring discrete bootstrap diodes, simplifying layout and improving reliability. The LT3972EMSE#PBF's BD pin supplies bias current to the internal regulator and must be connected per the recommended schematic.
How does LT3972EMSE#PBF achieve 75μA quiescent current?
The LT3972EMSE#PBF achieves 75μA quiescent current through low-ripple Burst Mode operation, which shuts down most internal circuitry between switching bursts at light loads. Additionally, when VOUT exceeds 3V, the LT3972EMSE#PBF draws bias current from the output rather than VIN-further reducing input supply current. This dual mechanism is confirmed in the LT3972EMSE#PBF datasheet's Electrical Characteristics table and Typical Performance graphs.
What package type and thermal characteristics does LT3972EMSE#PBF use?
The LT3972EMSE#PBF uses a 10-lead plastic MSOP package with exposed pad (Pin 11 = GND). Its thermal resistance is θJA = 45°C/W and θJC = 10°C/W when the exposed pad is properly soldered to PCB copper. This package enables compact layouts while supporting continuous 3.5A output in industrial ambient temperatures up to 125°C junction-verified in the LT3972EMSE#PBF's Operating Junction Temperature Range specification.
Can LT3972EMSE#PBF synchronize to an external clock?
Yes-the LT3972EMSE#PBF supports external clock synchronization via the SYNC pin (Pin 6), accepting square-wave inputs from 250kHz to 2MHz. This allows deterministic switching alignment across multiple regulators to reduce beat frequencies and EMI peaks. When unused, SYNC must be tied to GND for proper Burst Mode operation. The LT3972EMSE#PBF's synchronization range and timing requirements are detailed in the Applications Information section of its datasheet.
LT3972EMSE#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
LT3972EMSE#PBF FAQ
1.How can I place an order for LT3972EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3972EMSE#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 LT3972EMSE#PBF reliable?
The price and inventory of LT3972EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3972EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3972EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3972EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3972EMSE#PBF?
LT3972EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3972EMSE#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 LT3972EMSE#PBF?
For technical support, including LT3972EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3972EMSE#PBF requirements.
6.How does Aetrix verify that LT3972EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3972EMSE#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 LT3972EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3972EMSE#PBF?
All LT3972EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3972EMSE#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 LT3972EMSE#PBF part is unused and in its original packaging.
Return procedure for LT3972EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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