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Analog Devices Inc. LT3971IMSE16#TRPBF
- Part No.:
- LT3971IMSE16#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3971IMSE16#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,484
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Product details
Overview
LT3971IMSE16#TRPBF from Analog Devices (formerly Linear Technology) is a 38V, 1.2A monolithic synchronous step-down regulator in a 16-lead MSOP package with enhanced pin-to-pin fault tolerance. It delivers ultralow 2.8µA quiescent current in Burst Mode, supports 200kHz–2MHz adjustable switching frequency, and integrates a 0.33Ω bipolar NPN switch, boost Schottky diode, and power-good flag. It is used in automotive battery regulation and portable power supplies requiring wide VIN and low standby power.
For engineers reviewing the LT3971IMSE16#TRPBF datasheet, LT3971IMSE16#TRPBF pinout, LT3971IMSE16#TRPBF application, or LT3971IMSE16#TRPBF equivalent, key selection criteria include input voltage range (4.3V–38V), output voltage programmability (1.19V–30V), soft-start control via SS pin, synchronization capability (250kHz–2MHz), and thermal performance enabled by exposed pad grounding.
Technical Context
The LT3971IMSE16#TRPBF employs constant-frequency current-mode control with internal compensation for fast transient response and loop stability. Its architecture includes an oscillator synchronized via RT resistor or external clock on SYNC pin, VC node clamping for current limiting, and active soft-start via SS pin voltage ramp.
Burst Mode operation reduces no-load supply current to 2.8µA while maintaining output ripple below 15mVP-P; frequency foldback during startup and overload prevents excessive peak inductor current. The 16-lead MSOP variant adds NC pins (2, 4, 6, 11) for FMEA-compliant 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. |
| Max Output Current | 1.2A - sufficient for powering microcontrollers, sensors, and communication ICs in embedded systems. |
| Quiescent Current | 2.8µA at no load - enables multi-year battery life in always-on IoT and telematics applications. |
| Switching Frequency | 200kHz to 2MHz - adjustable via RT resistor; higher frequencies allow smaller magnetics, lower frequencies improve dropout and high-VIN operation. |
| Feedback Reference | 1.19V ±1.3% - sets precise output voltage with external resistor divider; internal 10MΩ divider in fixed-output variants not applicable here. |
| Power Good Threshold | 91% of VOUT - open-drain PG signal asserts when regulated output reaches stable value, enabling system sequencing. |
| Enable Threshold | 1.01V typical rising threshold - allows clean shutdown with simple resistive divider from VIN or microcontroller GPIO. |
| Thermal Resistance | θJA = 40°C/W - improved over 10-lead MSOP due to larger exposed pad area in 16-lead package. |
Pinout & Package
LT3971IMSE16#TRPBF uses a 16-lead plastic MSOP package with exposed thermal pad (Pin 17) that must be soldered to PCB ground for optimal thermal performance. The package features four NC pins (2, 4, 6, 11) to enhance fault tolerance per FMEA requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (BD) | Boost Diode Anode | Connects to cathode of external Schottky diode; tied to VOUT in standard buck configuration. |
| 2 (NC) | No Connect | Floating improves fault tolerance; no internal connection; must remain unconnected. |
| 3 (BOOST) | Bootstrap Drive | Drives internal NPN switch base above SW; requires external capacitor between BOOST and SW. |
| 4 (NC) | No Connect | Floating improves fault tolerance; no internal connection; must remain unconnected. |
| 5 (SW) | Switch Node | Internal NPN collector output; connects to inductor, catch diode cathode, and BOOST capacitor. |
| 6 (NC) | No Connect | Floating improves fault tolerance; no internal connection; must remain unconnected. |
| 7 (VIN) | Main Power Input | Supplies internal circuitry and switch; requires local ceramic bypass capacitor (≥1µF). |
| 8 (EN) | Enable Control | Hysteretic input (0.975V/1.005V); pulls LT3971IMSE16#TRPBF into 700nA shutdown when low. |
| 9 (FB) | Feedback Input | Regulated to 1.19V; connects to resistor divider tap for adjustable output voltage configuration. |
| 10 (FB) | Feedback Input (Redundant) | Dual FB pins provide layout flexibility and noise immunity in high-noise environments. |
| 11 (NC) | No Connect | Floating improves fault tolerance; no internal connection; must remain unconnected. |
| 12 (SS) | Soft-Start Control | Capacitor to GND ramps peak current limit; controls inrush; floats to disable soft-start. |
| 13 (RT) | Frequency Set | Resistor to GND programs switching frequency from 200kHz to 2MHz per datasheet table. |
| 14 (PG) | Power Good Flag | Open-drain output; pulled high externally; signals VOUT ≥91% of target after startup. |
| 15 (SYNC) | External Clock Input | Accepts 250kHz–2MHz clock; grounding enables low-ripple Burst Mode; floating disables sync. |
| 16 (GND) | Signal Ground | Reference for internal circuitry; connects to PCB ground plane and exposed pad. |
| 17 (GND) | Exposed Thermal Pad | Mandatory solder connection to PCB ground plane; primary path for heat dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA at no load enables >10-year battery life in always-on sensor nodes and telematics modules. |
| Low Ripple Burst Mode | Maintains <15mVP-P output ripple at light loads while sustaining high efficiency-critical for noise-sensitive analog circuits. |
| Internally Compensated Current Mode | Eliminates need for external compensation network; ensures stable operation across line/load/temperature with fast transient response. |
| Enhanced Fault Tolerance | Four NC pins (2, 4, 6, 11) in 16-lead MSOP reduce risk of misconnection-induced failure in safety-critical automotive designs. |
| Accurate Power Good Flag | PG asserts only when output reaches 91% of final regulation voltage-enables reliable system power sequencing and reset management. |
| Adjustable Soft-Start | SS pin accepts external capacitor to control inrush current slope-prevents input rail sag and avoids false brown-out detection. |
Applications
| Automotive Battery Regulation | Portable Medical Device Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for infotainment ECUs and ADAS sensors under cold-crank (4.5V) and load-dump (38V) conditions. IC Role / Device Role / Timing Role: Primary DC/DC buck converter providing isolated, low-noise, and highly efficient power with robust input transients handling. Use Value: 38V absolute max rating and 2.8µA quiescent current ensure compliance with ISO 16750-2 and enable extended parking mode operation. | Use Scenario: Powering handheld ultrasound units and glucose monitors with single-cell Li-ion (3.0–4.2V) or dual-cell alkaline (1.8–3.2V) batteries. IC Role / Device Role / Timing Role: Step-down regulator delivering stable 3.3V to MCU, display driver, and analog front-end with minimal standby drain. Use Value: 4.3V minimum input allows operation down to near end-of-life battery voltage; 1.2A output supports pulsed high-current transducer drivers. |
| Industrial Sensor Node Supply | Railway Signaling Interface Power |
Use Scenario: Converting 24V DC industrial bus to 3.3V for wireless LoRaWAN or NB-IoT sensor transceivers operating in remote, unattended locations. IC Role / Device Role / Timing Role: Primary power stage enabling long-term field deployment with ultra-low maintenance intervals. Use Value: 2.8µA quiescent current extends battery life beyond 10 years; wide temperature range (–40°C to 125°C) ensures reliability in outdoor enclosures. | Use Scenario: Generating isolated 5V supply from 72V/110V railway traction battery for CAN transceivers and LED status indicators in signaling cabinets. IC Role / Device Role / Timing Role: High-input-voltage buck converter providing EMI-robust, low-noise auxiliary power with built-in PG monitoring. Use Value: 38V max input accommodates derated operation with input filter; PG flag validates power integrity before enabling critical signaling logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMSE#PBF | Fixed 3.3V output; 1.5A rating; 3.5µA IQ; no SYNC pin; 10-lead MSOP | Not adjustable; lacks synchronization and PG flag; lower max input (15V) | Select only if fixed 3.3V output and lower input voltage suffice; no soft-start or frequency tuning. |
| MP2451DT-LF-Z | 2.5A rating; 28µA IQ; 3.5–36V input; no PG or SYNC; 8-lead SOIC | Higher IQ degrades battery life; no power good or sync; less thermal performance | Choose for cost-sensitive, non-battery applications where 28µA IQ is acceptable and PG/SYNC are unnecessary. |
Compared with LTC3630EMSE#PBF and MP2451DT-LF-Z, the LT3971IMSE16#TRPBF uniquely combines ultralow 2.8µA quiescent current, 38V input capability, programmable output, power-good signaling, and fault-tolerant 16-lead packaging-making it optimal for automotive, railway, and long-life battery-powered systems.
Availability
LT3971IMSE16#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, portable medical device power, industrial sensor node supply, and railway signaling interface power requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3971IMSE16#TRPBF 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 (including legacy Linear Technology products) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, automotive, industrial, and communications markets.
The LT3971 product line was designed specifically for high-input-voltage, ultralow-quiescent-current DC/DC conversion in harsh environments-targeting automotive, railway, and battery-backed industrial applications where reliability and efficiency at light loads are critical.
FAQ
What is the maximum input voltage rating for the LT3971IMSE16#TRPBF?
The LT3971IMSE16#TRPBF has an absolute maximum input voltage rating of 38V on the VIN pin. This allows direct connection to 24V industrial buses and automotive systems under load-dump conditions. Operation above 38V risks permanent damage. For sustained operation, design margin should keep VIN ≤36V, especially at elevated temperatures where internal switch stress increases.
Does the LT3971IMSE16#TRPBF support adjustable output voltage?
Yes, the LT3971IMSE16#TRPBF supports fully adjustable output voltage from 1.19V to 30V using an external resistor divider connected to the FB pin. Unlike fixed-output variants (e.g., LT3971-3.3), this part does not contain internal feedback resistors-its 1.19V reference requires external R1/R2 to set VOUT = 1.19V × (1 + R1/R2). Precision 1% resistors are recommended for tight regulation.
How does the LT3971IMSE16#TRPBF achieve 2.8µA quiescent current?
The LT3971IMSE16#TRPBF achieves 2.8µA quiescent current through optimized low-power circuitry and patented low-ripple Burst Mode operation. In this mode, the controller delivers discrete current pulses to the output capacitor and then enters deep sleep-shutting down oscillator, error amplifier, and gate drivers-reducing total input current to 2.8µA while maintaining regulation and <15mV ripple in typical applications.
What is the purpose of the NC pins in the LT3971IMSE16#TRPBF 16-lead MSOP package?
The NC pins (2, 4, 6, 11) in the LT3971IMSE16#TRPBF package are intentionally unconnected to internal circuitry and serve an FMEA-driven fault-tolerance function. By floating them, designers eliminate risk of incorrect routing or solder bridging that could compromise regulation. Their presence distinguishes the 16-lead variant from the 10-lead MSOP and supports functional safety requirements in automotive ASIL-B designs.
Can the LT3971IMSE16#TRPBF be synchronized to an external clock?
Yes, the LT3971IMSE16#TRPBF can be synchronized to an external clock applied to the SYNC pin, supporting frequencies from 250kHz to 2MHz. When synchronized, the device operates in pulse-skipping mode at light loads (increasing IQ to ~1.5mA), unlike Burst Mode (2.8µA) which requires SYNC grounded. Synchronization eliminates beat frequencies in multi-rail systems and enables deterministic EMI filtering.
LT3971IMSE16#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LT3971IMSE16#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971IMSE16#TRPBF 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#TRPBF reliable?
The price and inventory of LT3971IMSE16#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971IMSE16#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3971IMSE16#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971IMSE16#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971IMSE16#TRPBF?
LT3971IMSE16#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971IMSE16#TRPBF 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#TRPBF?
For technical support, including LT3971IMSE16#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971IMSE16#TRPBF requirements.
6.How does Aetrix verify that LT3971IMSE16#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3971IMSE16#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3971IMSE16#TRPBF?
All LT3971IMSE16#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971IMSE16#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LT3971IMSE16#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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