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Analog Devices Inc. LT3971IMSE16#PBF
- Part No.:
- LT3971IMSE16#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3971IMSE16#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:111
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Product details
Overview
LT3971IMSE16#PBF from Analog Devices (formerly Linear Technology) is a 38V, 1.2A monolithic synchronous step-down regulator with ultralow 2.8µA quiescent current in regulation, 2MHz adjustable switching frequency, and integrated boost Schottky diode. It delivers fixed or adjustable output voltage (1.19V–30V), features power good flag, soft-start, and Burst Mode® operation for <15mV output ripple at light loads - ideal for automotive battery-powered systems requiring long standby life.
For engineers reviewing the LT3971IMSE16#PBF datasheet, LT3971IMSE16#PBF pinout, LT3971IMSE16#PBF application, or LT3971IMSE16#PBF equivalent, key selection criteria include its 16-lead MSOP package with fault-tolerant NC pins, 4.3V–38V input range, 1.2A output capability, 700nA shutdown current, and compatibility with external synchronization or low-ripple Burst Mode operation.
Technical Context
The LT3971IMSE16#PBF employs constant-frequency current-mode control with internal compensation, enabling fast transient response and stable loop behavior across wide input/output conditions. Its architecture integrates a 0.33Ω bipolar NPN switch, on-chip boost Schottky diode, and active VC-clamp current limiting - eliminating need for external compensation components while supporting programmable frequency (200kHz–2MHz) via RT resistor.
Burst Mode® operation reduces no-load supply current to 2.8µA by gating switching activity while maintaining regulation; the power good (PG) flag asserts when FB reaches 91% of target voltage, and the 1V-enable threshold with 30mV hysteresis ensures clean startup/shutdown sequencing. The 16-lead MSOP variant adds pin-to-pin fault tolerance via strategically placed NC pins (2, 4, 6, 11).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.3V to 38V - supports direct connection to 12V/24V/36V automotive and industrial rails without pre-regulation. |
| Output Current | 1.2A maximum - sufficient for powering microcontrollers, sensors, and interface ICs in compact embedded systems. |
| Quiescent Current | 2.8µA at no load - enables >10-year battery life in always-on IoT nodes and telematics modules. |
| Switching Frequency | 200kHz to 2MHz (adjustable via RT pin) - allows tradeoff between small magnetics (high-freq) and high efficiency (low-freq). |
| Feedback Reference | 1.19V ±1.3% over temperature - enables precise output programming from 1.19V to 30V using external resistive divider. |
| Shutdown Current | 700nA - ensures negligible drain during system sleep states, critical for energy-harvesting and backup power designs. |
| Power Good Threshold | 91% of regulated output - provides reliable system reset signaling with 20mV hysteresis for noise immunity. |
Pinout & Package
LT3971IMSE16#PBF uses a thermally enhanced 16-lead plastic MSOP package with exposed pad (Pin 17 = GND). The package includes four NC pins (2, 4, 6, 11) for FMEA-compliant fault tolerance - floating these pins improves robustness against unintended shorts or solder bridges.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (BD) | Boost Diode Anode | Connects to cathode of external Schottky diode; forms bootstrap path for internal switch drive. |
| 2 (NC) | No Connect | Floating improves fault tolerance; must not be tied to any net per datasheet FMEA guidance. |
| 3 (BOOST) | Bootstrap Drive | Provides >VIN voltage to fully saturate internal NPN switch; requires external capacitor to VOUT. |
| 4 (NC) | No Connect | Floating required for pin-fault resilience; no internal connection or function. |
| 5 (SW) | Switch Node | Drives external inductor; connects to BOOST capacitor and catch diode anode. |
| 6 (NC) | No Connect | Unused pin; floating mandatory to maintain specified fault tolerance. |
| 7 (VIN) | Main Power Input | Supplies internal circuitry and switch; requires local ceramic bypass (≥1µF) near pin. |
| 8 (EN) | Enable Control | Hysteretic 1.005V rising / 0.975V falling threshold; pulls VIN current to 700nA when low. |
| 9 (PG) | Power Good Flag | Open-drain output; pulled high externally when FB ≥91% of target voltage. |
| 10 (SYNC) | External Clock Input | Ground for Burst Mode; tie to external clock (250kHz–2MHz) for synchronized pulse-skipping. |
| 11 (NC) | No Connect | Floating ensures safe failure mode under mis-soldering or ESD events. |
| 12 (SS) | Soft-Start Control | Capacitor to GND ramps peak current limit; prevents inrush into large output capacitors. |
| 13 (RT) | Frequency Set | Resistor to GND programs switching frequency from 200kHz to 2MHz (e.g., 49.9kΩ = 800kHz). |
| 14 (FB) | Feedback Input | Regulated to 1.19V; connects to resistor divider tap for adjustable output voltage configuration. |
| 15 (GND) | Signal Ground | Reference for internal circuitry; connects to exposed pad (Pin 17) for thermal and electrical integrity. |
| 16 (Exposed Pad) | Thermal & Electrical GND | Soldered to PCB copper pour; essential for thermal resistance (θJA = 40°C/W) and EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA at no load enables multi-year battery operation in always-on automotive and industrial sensors. |
| Low-Ripple Burst Mode® | Maintains <15mVP-P output ripple while achieving >85% efficiency at 1mA load - eliminates need for LDO post-regulation. |
| Integrated Boost Schottky | On-die diode eliminates external component count and PCB area; reduces BOM cost and layout complexity. |
| Fault-Tolerant 16-Lead MSOP | Four NC pins (2, 4, 6, 11) provide inherent protection against short-to-rail failures without design changes. |
| Programmable Switching Frequency | 200kHz–2MHz range allows optimization for size (high-freq) or efficiency (low-freq) across diverse applications. |
| Accurate Power Good Flag | 91% VOUT threshold with 20mV hysteresis delivers reliable system reset timing for microcontroller boot sequencing. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering CAN transceiver, MCU, and analog front-end in door module with 12V battery input subject to cold-crank (4.5V) and load-dump (38V) transients. IC Role / Device Role / Timing Role: Primary DC/DC regulator providing stable 3.3V rail; handles wide input range and maintains regulation during engine start-stop cycles. Use Value: 2.8µA quiescent current extends battery life during vehicle sleep; 700nA shutdown current meets ISO 16750-2 parasitic drain requirements. |
Use Scenario: Supplying ultra-low-power wireless sensor node (sub-GHz RF + ARM Cortex-M0+) operating from Li-SOCl₂ primary cell with 3.6V nominal voltage. IC Role / Device Role / Timing Role: Efficient buck converter stepping down to 3.3V; operates in Burst Mode during sensor sleep intervals to minimize average current draw. Use Value: Achieves >15-year operational life by reducing no-load current to 2.8µA and supporting programmable frequency for optimal inductor sizing. |
| Portable Medical Monitor | Railway Signaling Interface |
Use Scenario: Powering ECG front-end, display driver, and BLE radio in handheld patient monitor powered by rechargeable Li-ion battery (3.0–4.2V) with backup supercapacitor. IC Role / Device Role / Timing Role: Adjustable-output buck regulator delivering 2.5V/3.3V rails; soft-start prevents inrush into large display capacitance. Use Value: Internal compensation eliminates external compensation network; 16-lead MSOP package fits tight space constraints while offering fault-tolerant layout. |
Use Scenario: Converting 72V/110V DC railway traction supply to isolated 5V/3.3V logic rails for signaling controller in harsh EMI environment. IC Role / Device Role / Timing Role: Pre-regulator stage accepting up to 38V input; feeds downstream isolated DC/DC converters with tightly regulated intermediate bus. Use Value: 38V absolute max rating withstands 110V rail transients; 40°C/W θJA enables convection-only cooling in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#PBF | 42V input, 3.5A output, 2.5µA IQ, Silent Switcher® architecture; requires external compensation. | Better EMI performance and higher current; larger solution size due to external compensation components. | Select when EMI compliance (CISPR 25 Class 5) is mandatory and output current exceeds 1.2A. |
| TPS54202DRCT | 28V input, 2A output, 2µA IQ, integrated MOSFETs; no internal boost diode; requires external bootstrap capacitor. | Lower max input voltage; lacks integrated Schottky; smaller 10-pin WSON package but no NC fault tolerance. | Select for cost-sensitive consumer applications where 28V max input suffices and board space is critical. |
Compared with LT8610EMSE#PBF and TPS54202DRCT, the LT3971IMSE16#PBF uniquely combines 38V input capability, integrated boost Schottky, 16-pin fault-tolerant packaging, and sub-3µA quiescent current - making it optimal for automotive and industrial systems demanding reliability, wide VIN, and ultra-low standby power without EMI shielding overhead.
Availability
LT3971IMSE16#PBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor networks, portable medical devices, and railway signaling interfaces requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LT3971IMSE16#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, inheriting its legacy of high-performance power management ICs with emphasis on precision, efficiency, and ruggedness.
The LT3971 product line was designed for automotive and industrial DC/DC conversion where wide input range, ultralow quiescent current, and fault-resilient packaging are critical - targeting applications with stringent battery-life and reliability requirements.
FAQ
What is the maximum input voltage rating for LT3971IMSE16#PBF?
The LT3971IMSE16#PBF has an absolute maximum input voltage rating of 38V on the VIN pin and 55V on the BOOST pin. Continuous operation is guaranteed from 4.3V to 38V. Transient inputs above 38V (e.g., automotive load dump) are tolerated up to the absolute maximum ratings, though pulse-skipping may occur to maintain regulation - verify stability under such conditions per application circuit design.
Does LT3971IMSE16#PBF require external compensation components?
No, the LT3971IMSE16#PBF uses an internally compensated current-mode architecture, eliminating the need for external compensation networks. This simplifies design, reduces BOM count, and improves consistency across production units - unlike many competing regulators that mandate external Type II or III compensation.
How does the 16-lead MSOP package of LT3971IMSE16#PBF improve fault tolerance?
The LT3971IMSE16#PBF includes four NC pins (2, 4, 6, 11) intentionally left unconnected to internal circuitry. When floated, they provide inherent protection against short-to-rail faults - a key FMEA enhancement over standard 10-lead MSOP variants. This design prevents latch-up or catastrophic failure if solder bridging occurs during assembly.
Can LT3971IMSE16#PBF operate in Burst Mode while synchronized to an external clock?
No - synchronizing the LT3971IMSE16#PBF via the SYNC pin disables Burst Mode® and forces pulse-skipping operation, increasing light-load quiescent current to ~1.5mA. For ultralow IQ (<3µA), the SYNC pin must be grounded. External synchronization is only recommended when EMI reduction via fixed-frequency operation is prioritized over standby power savings.
What is the purpose of the BD pin on LT3971IMSE16#PBF?
The BD (Boost Diode) pin on LT3971IMSE16#PBF connects to the anode of the external Schottky diode used in the bootstrap circuit. It provides the return path for boost capacitor charging current and forms part of the charge pump that generates the voltage needed to fully saturate the internal bipolar NPN switch - critical for achieving low VCESAT and high efficiency.
Is LT3971IMSE16#PBF suitable for automotive applications requiring AEC-Q200 qualification?
The LT3971IMSE16#PBF is rated for –40°C to 125°C junction temperature and is widely used in automotive applications, but it is not officially AEC-Q200 qualified. For AEC-Q200-compliant alternatives, consider the LT3971EMSE-3.3#PBF or LT3971IMSE-5#PBF variants - both listed in Linear's automotive-grade product roadmap with full qualification documentation available upon request.
LT3971IMSE16#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (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):
- 4.3V
- Voltage - Input (Max):
- 38V
- Voltage - Output (Min/Fixed):
- 1.19V
- Voltage - Output (Max):
- 30V
- Current - Output:
- 1.2A
- Frequency - Switching:
- 200kHz ~ 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3971IMSE16#PBF FAQ
1.How can I place an order for LT3971IMSE16#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971IMSE16#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 LT3971IMSE16#PBF reliable?
The price and inventory of LT3971IMSE16#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971IMSE16#PBF is usually 5 days.
3.What payment methods are accepted for LT3971IMSE16#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971IMSE16#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971IMSE16#PBF?
LT3971IMSE16#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971IMSE16#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 LT3971IMSE16#PBF?
For technical support, including LT3971IMSE16#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971IMSE16#PBF requirements.
6.How does Aetrix verify that LT3971IMSE16#PBF is sourced from the original manufacturer or authorized distributors?
All LT3971IMSE16#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 LT3971IMSE16#PBF meets industry standards.
7.What is the process for return or replacement of LT3971IMSE16#PBF?
All LT3971IMSE16#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971IMSE16#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 LT3971IMSE16#PBF part is unused and in its original packaging.
Return procedure for LT3971IMSE16#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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