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Analog Devices Inc. LT3971EMSE16#PBF
- Part No.:
- LT3971EMSE16#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3971EMSE16#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,973
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Product details
Overview
LT3971EMSE16#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, internal compensation, and a 16-lead MSOP package with enhanced pin-to-pin fault tolerance. It delivers fixed or adjustable output voltages (1.19V–30V), supports 200kHz–2MHz switching frequency, and integrates a 0.33Ω switch, boost Schottky diode, and power-good flag - ideal for automotive battery regulation and portable power supplies.
For engineers reviewing the LT3971EMSE16#PBF datasheet, LT3971EMSE16#PBF pinout, LT3971EMSE16#PBF application, or LT3971EMSE16#PBF equivalent, key selection criteria include its 700nA shutdown current, 1V enable threshold with hysteresis, low-ripple Burst Mode operation (<15mVP-P), soft-start capability via SS pin, and thermal performance enabled by exposed-pad packaging.
Technical Context
The LT3971EMSE16#PBF implements a constant-frequency, current-mode control architecture with internal slope compensation and an oscillator programmable via RT resistor (200kHz–2MHz). Its bipolar NPN main switch is driven from either VIN or BOOST, enabling full saturation across wide input ranges up to 38V.
It features frequency foldback during startup/overload, active VC-clamp current limiting, and a dedicated open-drain PG flag asserting when FB reaches 91% of regulation voltage. The 16-lead MSOP variant adds NC pins (2, 4, 6, 11) for FMEA fault tolerance without altering core regulation behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.3V to 38V - supports direct connection to 12V/24V automotive batteries and industrial rails without pre-regulation. |
| Quiescent Current (No Load) | 2.8µA - enables multi-year battery life in always-on IoT sensors and telematics modules. |
| Max Output Current | 1.2A - sufficient to power microcontrollers, CAN transceivers, and small displays from a single buck stage. |
| Switching Frequency Range | 200kHz to 2MHz - allows optimization between EMI compliance (lower fSW) and compact magnetics (higher fSW). |
| Feedback Reference Voltage | 1.19V ±1.3% - sets output accuracy for adjustable configurations; internal 10MΩ divider enables fixed 3.3V/5V variants. |
| Enable Threshold | 1.01V typical with 30mV hysteresis - ensures clean, noise-immune startup/shutdown sequencing in noisy environments. |
| Power Good Accuracy | ±9% of VOUT - provides reliable system-level power sequencing and brown-out detection. |
Pinout & Package
LT3971EMSE16#PBF uses a thermally enhanced 16-lead plastic MSOP package with exposed pad (Pin 17 = GND), θJA = 40°C/W. Pin count and layout differ from 10-lead MSOP versions; NC pins (2, 4, 6, 11) improve fault tolerance without functional impact.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode | Connects to cathode of external Schottky; forms bootstrap path for high-side drive. |
| BOOST (Pin 3) | Bootstrap Drive Voltage | Supplies >VIN voltage to internal NPN base; requires external capacitor to SW. |
| SW (Pin 5) | Switch Node | Drives inductor; connects to BD, BOOST cap, and catch diode cathode. |
| VIN (Pin 7) | Main Power Input | Bypassed locally; powers internal circuitry and switch collector. |
| EN (Pin 8) | Enable Control | Hysteretic 1V threshold; pulls device into 700nA shutdown when low. |
| FB (Pin 9, 10) | Feedback Input | Regulated to 1.19V; connects to resistor divider tap for adjustable outputs. |
| SS (Pin 12) | Soft-Start Control | Capacitor to GND ramps peak current limit; prevents inrush into large output caps. |
| RT (Pin 13) | Frequency Set | Resistor to GND programs switching frequency (200kHz–2MHz). |
| PG (Pin 14) | Power Good Flag | Open-drain output asserts high when VOUT ≥ 91% of target - used for system reset or sequencing. |
| SYNC (Pin 15) | External Clock Input | Ground for Burst Mode; tie to clock source for synchronization (increases IQ to 1.5mA). |
| GND (Pin 16, Exposed Pad 17) | Signal & Thermal Ground | Exposed pad must be soldered to PCB plane for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA at no load preserves battery capacity in always-on automotive ECUs and remote sensors. |
| Low-Ripple Burst Mode | Maintains <15mVP-P output ripple while sustaining high efficiency down to µA-level loads. |
| Internal Compensation | Eliminates external compensation components - reduces BOM count and design iteration time. |
| Integrated Boost Diode | On-die Schottky reduces component count and PCB area vs. discrete bootstrap solutions. |
| Fault-Tolerant 16-Lead MSOP | NC pins (2, 4, 6, 11) prevent misconnection-induced failure in safety-critical systems. |
Applications
| Automotive Battery Regulation | Portable Product Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V for infotainment MCU and CAN FD transceivers under cold-crank (4.3V min) and load-dump (38V max) conditions. IC Role / Device Role / Timing Role: Primary buck converter delivering stable 3.3V rail with 2.8µA IQ to extend sleep-mode battery life. Use Value: Enables >10-year battery backup for telematics units without requiring external LDO post-regulation. | Use Scenario: Powering handheld medical monitors with Li-ion battery input (3.0V–4.2V) and dual-rail needs (3.3V logic + 5V USB interface). IC Role / Device Role / Timing Role: Adjustable-output buck supplying 3.3V/5V from single-cell input; soft-start prevents inrush into display backlight capacitors. Use Value: Eliminates need for separate 5V boost converter - reduces solution size by 35% and improves overall efficiency by 8%. |
| Industrial Sensor Node | Smart Meter Auxiliary Supply |
Use Scenario: Converting 24V DC industrial bus to 3.3V for ultra-low-power wireless sensor nodes operating in unattended field deployments. IC Role / Device Role / Timing Role: Always-on regulator maintaining 3.3V for BLE SoC and analog front-end; PG flag triggers wake-up on valid supply. Use Value: Achieves 15-year battery life using standard AA cells due to 700nA shutdown current and Burst Mode efficiency. | Use Scenario: Deriving isolated 5V auxiliary rail from 220VAC line-powered meter supply for real-time clock and communication ICs. IC Role / Device Role / Timing Role: Secondary buck after AC/DC stage; operates at 800kHz to minimize transformer size and EMI filter footprint. Use Value: Reduces auxiliary supply height by 40% vs. legacy 100kHz designs while meeting IEC 62053-21 ripple requirements. |
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 | Higher 3.5A rating, 2.5µA IQ, but requires external bootstrap diode and lacks integrated BD pin. | Better suited for higher-current industrial PLC I/O modules; not drop-in due to different pinout and external diode requirement. | Select when >1.2A output or lower IQ is critical and board space allows external diode placement. |
| TPS54202DRCT | 2.5µA IQ, 4.5V–28V input, but only 2A switch and no integrated boost diode; uses D-CAP2 control. | Optimized for cost-sensitive consumer electronics; lacks PG flag and fault-tolerant pinout. | Choose for high-volume, non-automotive applications where PG signaling and FMEA robustness are not required. |
Compared with LT8610EMSE#PBF and TPS54202DRCT, the LT3971EMSE16#PBF uniquely combines integrated boost diode, 16-lead fault-tolerant packaging, and guaranteed 2.8µA quiescent current across –40°C to 125°C - making it optimal for space-constrained, safety-aware automotive and industrial buck stages.
Availability
LT3971EMSE16#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, portable product power, and industrial sensor node applications requiring stable component supply, long-term lifecycle support, and AEC-Q200-aligned reliability.
Supply support for LT3971EMSE16#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 precision power portfolio with rigorous automotive and industrial qualification standards.
The LT3971 product line targets high-reliability, wide-input-voltage DC/DC conversion in harsh environments - specifically engineered for automotive subsystems, battery-powered instrumentation, and industrial controls demanding ultralow IQ and robust fault handling.
FAQ
What is the maximum input voltage supported by the LT3971EMSE16#PBF?
The LT3971EMSE16#PBF supports up to 38V input continuously, with absolute maximum ratings specifying VIN ≤ 38V and BOOST ≤ 55V. Operation above 38V violates Absolute Maximum Ratings and risks permanent damage. In practice, maximum usable input depends on switching frequency and duty cycle constraints - for example, at 2MHz, VIN(OP-MAX) drops to ~24V to maintain regulation; consult the "Input Voltage Range" section of the LT3971EMSE16#PBF datasheet for frequency-dependent limits.
Does the LT3971EMSE16#PBF require an external bootstrap diode?
No, the LT3971EMSE16#PBF integrates a boost Schottky diode connected to the BD pin, eliminating the need for an external bootstrap diode. This is confirmed in the "Features" list ("integrated boost Schottky diode") and Block Diagram. External diodes are only required for the catch diode (anode to SW, cathode to VOUT) in non-synchronous configurations - though the LT3971EMSE16#PBF's internal switch and BD pin support fully integrated operation when paired with appropriate inductor and output capacitor.
How does the LT3971EMSE16#PBF achieve 2.8µA quiescent current?
The LT3971EMSE16#PBF achieves 2.8µA quiescent current through low-ripple Burst Mode operation: during light loads, it delivers discrete current pulses to the output capacitor and enters deep sleep between bursts, reducing circuit activity. This is distinct from standard pulse-skipping - the LT3971EMSE16#PBF maintains <15mVP-P ripple while drawing just 2.8µA from VIN at no load. Critical enablers include optimized biasing of internal amplifiers, gated clock distribution, and minimized leakage paths - all verified in the Electrical Characteristics table under "Quiescent Current from VIN".
What is the purpose of the NC pins on the LT3971EMSE16#PBF package?
The NC pins (2, 4, 6, 11) on the LT3971EMSE16#PBF serve a fault-tolerance function: they are unconnected internally and intentionally left floating to prevent incorrect routing or solder bridging from causing functional failure. As documented in the "Fault Tolerance of MS16E Package" section, this design enhances FMEA robustness in safety-critical applications like automotive ADAS power supplies - unlike the 10-lead MSOP, the 16-lead variant uses these NC pins to isolate sensitive signals (e.g., EN, SYNC, PG) from potential short-circuit paths.
Can the LT3971EMSE16#PBF be synchronized to an external clock?
Yes, the LT3971EMSE16#PBF can be synchronized using the SYNC pin (Pin 15): tie it to a CMOS-compatible clock source (0.6V–1.0V threshold) to align switching edges. However, doing so disables low-ripple Burst Mode and forces pulse-skipping at light loads, increasing quiescent current from 2.8µA to 1.5mA. For ultralow-power applications, SYNC must be grounded. Synchronization is recommended only when EMI reduction via frequency dithering or multi-phase interleaving is required - always verify ripple and efficiency tradeoffs in the target application.
LT3971EMSE16#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
LT3971EMSE16#PBF FAQ
1.How can I place an order for LT3971EMSE16#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971EMSE16#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 LT3971EMSE16#PBF reliable?
The price and inventory of LT3971EMSE16#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971EMSE16#PBF is usually 5 days.
3.What payment methods are accepted for LT3971EMSE16#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971EMSE16#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971EMSE16#PBF?
LT3971EMSE16#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971EMSE16#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 LT3971EMSE16#PBF?
For technical support, including LT3971EMSE16#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971EMSE16#PBF requirements.
6.How does Aetrix verify that LT3971EMSE16#PBF is sourced from the original manufacturer or authorized distributors?
All LT3971EMSE16#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 LT3971EMSE16#PBF meets industry standards.
7.What is the process for return or replacement of LT3971EMSE16#PBF?
All LT3971EMSE16#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971EMSE16#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 LT3971EMSE16#PBF part is unused and in its original packaging.
Return procedure for LT3971EMSE16#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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