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Analog Devices Inc. LT3971IMSE-5#TRPBF
- Part No.:
- LT3971IMSE-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3971IMSE-5#TRPBF.pdf
- Description:
- IC REG BUCK 5V 1.2A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,478
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Product details
Overview
LT3971IMSE-5#TRPBF from Analog Devices (formerly Linear Technology) is a fixed 5V, 1.2A monolithic buck switching regulator in a 10-lead MSOP package. It operates from 4.3V to 38V input, delivers ultralow 2.8µA quiescent current in regulation, maintains <15mVP-P output ripple via low-ripple Burst Mode®, and integrates a 0.33Ω switch, boost Schottky diode, and internal compensation. It is used in automotive battery-powered systems requiring high efficiency at light loads.
For engineers reviewing the LT3971IMSE-5#TRPBF datasheet, LT3971IMSE-5#TRPBF pinout, LT3971IMSE-5#TRPBF application, or LT3971IMSE-5#TRPBF equivalent, key selection criteria include its 5V fixed output, 2.8µA no-load IQ, 1.2A output capability, 200kHz–2MHz adjustable frequency, and power good flag for system monitoring.
Technical Context
The LT3971IMSE-5#TRPBF uses constant-frequency current-mode control with internal slope compensation for fast transient response and loop stability. Its oscillator frequency is set by an external RT resistor (200kHz–2MHz) or synchronized externally (250kHz–2MHz), and it features automatic frequency foldback during startup and overload to limit peak inductor current.
Burst Mode® operation reduces input supply current to 1.7µA in sleep intervals while maintaining regulation; combined with a 1V enable threshold and 700nA shutdown current, it supports long-battery-life applications. The integrated boost circuit drives the bipolar NPN switch fully saturated using an external capacitor tied between BOOST and SW.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.5% over temperature and line - ensures stable rail for microcontrollers and sensors without external feedback resistors. |
| Max Output Current | 1.2A continuous - sufficient to power FPGA I/O banks, industrial PLC modules, or automotive infotainment subsystems. |
| Input Voltage Range | 4.3V to 38V - supports 12V/24V automotive batteries including cold-crank and load-dump transients. |
| Quiescent Current | 2.8µA at no load (12VIN → 5VOUT) - enables >10-year battery life in always-on telematics or remote sensing nodes. |
| Switching Frequency | Adjustable 200kHz–2MHz via RT pin - allows optimization of inductor size (e.g., 4.7µH @ 800kHz) versus efficiency tradeoffs. |
| Output Ripple | <15mVP-P in typical Burst Mode® operation - avoids noise-sensitive analog circuits without requiring additional LDO post-regulation. |
| Power Good Flag | Open-drain PG asserts when VOUT reaches 91% of target - provides reliable power sequencing signal for FPGA configuration or MCU reset assertion. |
Pinout & Package
LT3971IMSE-5#TRPBF is housed in a thermally enhanced 10-lead plastic MSOP package (3mm × 3mm footprint) with exposed pad (Pin 11) soldered to PCB for low θJA = 45°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode | Connects to cathode of external Schottky diode; forms bootstrap path for internal switch drive. |
| BOOST (Pin 2) | Bootstrap Drive Voltage | Provides >VIN voltage to fully saturate internal NPN switch; requires capacitor to SW. |
| SW (Pin 3) | Switch Node | Drives external inductor and catch diode; connects to BOOST capacitor and BD pin. |
| VIN (Pin 4) | Main Input Supply | Supplies internal circuitry and switch; must be locally bypassed with ≥1µF ceramic capacitor. |
| EN (Pin 5) | Enable Control | Hysteretic 1.005V rising / 0.975V falling threshold; pulls VIN to disable if VIN < 4.2V. |
| VOUT (Pin 6) | Fixed Output Sense | Internally regulated to 5.0V; connects to internal 10MΩ divider - no external FB resistors needed. |
| SS (Pin 7) | Soft-Start Control | Capacitor to GND ramps peak current limit; prevents inrush; floats to disable. |
| RT (Pin 8) | Frequency Set | Resistor to GND programs switching frequency (e.g., 35.7kΩ = 1MHz). |
| PG (Pin 9) | Power Good Flag | Open-drain output active-low until VOUT ≥ 4.55V; requires external pull-up. |
| SYNC (Pin 10) | External Clock Sync | Ground for Burst Mode®; tie to clock source for synchronization (increases IQ to 1.5mA at light load). |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA IQ in regulation enables multi-year operation on coin cells or supercaps in IoT edge nodes. |
| Low-Ripple Burst Mode® | Maintains <15mVP-P output ripple at light loads without sacrificing efficiency or requiring external compensation. |
| Integrated Boost Diode | On-chip Schottky eliminates need for external boost diode, reducing BOM count and layout area. |
| Internal Feedback Divider | 10MΩ resistor network sets fixed 5V output - removes external resistor matching errors and thermal drift. |
| Thermally Enhanced Package | Exposed pad MSOP enables 1.2A continuous operation at +85°C ambient without heatsink. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering CAN transceiver, microcontroller, and LIN interface in door module under 12V battery with cold-crank dips to 4.5V. IC Role / Device Role / Timing Role: Primary 5V buck regulator delivering stable rail during wide input transients; PG signals MCU when rail is valid. Use Value: 2.8µA IQ extends battery backup runtime during vehicle sleep mode; 38V abs max rating withstands load dump. | Use Scenario: Long-life wireless vibration sensor powered by primary lithium thionyl chloride cell in factory predictive maintenance deployment. IC Role / Device Role / Timing Role: Always-on 5V supply enabling ultra-low-power MCU wake-up and RF transmission bursts. Use Value: 700nA shutdown current preserves battery capacity over 10+ years; Burst Mode® maintains regulation at µA-level sensor bias currents. |
| Portable Medical Monitor | Rail-to-Rail Industrial DAC Supply |
Use Scenario: Battery-powered ECG front-end requiring clean 5V for analog signal chain and ADC reference, with minimal self-heating. IC Role / Device Role / Timing Role: Fixed-output buck converter feeding low-noise LDO; SS pin controls inrush during hot-swap battery insertion. Use Value: <15mVP-P ripple avoids aliasing in 24-bit ADC; internal compensation eliminates tuning effort. | Use Scenario: Precision 5V supply for 16-bit rail-to-rail DAC in programmable logic controller analog output module. IC Role / Device Role / Timing Role: Main 5V rail generator with tight line/load regulation (±1.5%) and PG confirmation before DAC initialization. Use Value: 1.19V internal reference and matched 10MΩ divider ensure output accuracy independent of external component tolerance or tempco. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR36520RNXR | 5V fixed, 2A output, 26µA IQ, 4–65V input, 2.1MHz sync-capable - higher IQ, wider VIN, no integrated boost diode. | Requires external boost diode and feedback resistors; better suited for high-input industrial SMPS where 38V max is insufficient. | Select when input exceeds 38V or >1.2A load required; avoid if ultralow IQ or minimal BOM are critical. |
| TPS6286518VRGTR | 5V fixed, 1.2A, 1.5µA IQ, 2.7–6V input, 2.25MHz - much narrower VIN range, no boost circuit, no PG flag. | Limited to single-cell Li-ion or USB-PD sources; lacks automotive-grade input range and fault signaling. | Choose only for portable consumer devices with tightly regulated low-VIN supplies; not suitable for automotive or wide-input industrial use. |
Compared with LMR36520RNXR and TPS6286518VRGTR, the LT3971IMSE-5#TRPBF uniquely combines 38V input capability, integrated boost diode, 2.8µA IQ, and PG flag in a single 10-pin MSOP - making it optimal for space-constrained, battery-backed automotive and industrial systems where reliability and low standby power are mandatory.
Availability
LT3971IMSE-5#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, portable medical monitors, and rail-to-rail DAC supplies requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT3971IMSE-5#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 acquired Linear Technology in 2017 and maintains full support for the LT® portfolio, known for high-performance analog and power management ICs targeting demanding industrial, automotive, and aerospace applications.
The LT3971IMSE-5#TRPBF belongs to Linear's monolithic buck regulator product line, designed specifically for high-input-voltage, ultralow-quiescent-current applications in harsh environments where reliability and minimal standby power are essential.
FAQ
What is the guaranteed output voltage tolerance for LT3971IMSE-5#TRPBF over temperature?
The LT3971IMSE-5#TRPBF guarantees a 5.0V output with ±1.5% tolerance across the full –40°C to +125°C junction temperature range, as confirmed by electrical characterization in the datasheet's "LT3971-5 Output Voltage" table. This accuracy is achieved using an internal 10MΩ feedback divider and trimmed 1.19V reference, eliminating external resistor errors.
Does LT3971IMSE-5#TRPBF require external feedback resistors to set the 5V output?
No, the LT3971IMSE-5#TRPBF does not require external feedback resistors. It integrates a precision 10MΩ internal resistor divider and phase-lead capacitor to fix the output at 5.0V. Pin 6 is labeled VOUT (not FB), and connecting external resistors would disrupt regulation - the LT3971IMSE-5#TRPBF is functionally distinct from the adjustable LT3971 variant.
How does the LT3971IMSE-5#TRPBF achieve 2.8µA quiescent current while regulating?
The LT3971IMSE-5#TRPBF achieves 2.8µA quiescent current through low-ripple Burst Mode® operation: it delivers discrete current pulses to the output capacitor, then enters deep sleep (drawing only 1.7µA), relying on output capacitance to sustain the load between bursts. This architecture minimizes average input current while keeping output ripple below 15mVP-P in typical designs.
Can LT3971IMSE-5#TRPBF be synchronized to an external clock?
Yes, the LT3971IMSE-5#TRPBF supports external synchronization via the SYNC pin (Pin 10), accepting clocks from 250kHz to 2MHz. However, doing so disables Burst Mode® and forces pulse-skipping at light loads, increasing quiescent current to 1.5mA - so synchronization should only be used when EMI reduction outweighs IQ penalty.
What thermal performance can be expected from the LT3971IMSE-5#TRPBF in a standard 2-layer PCB layout?
In a standard 2-layer PCB with 1in² copper pour connected to the exposed pad (Pin 11), the LT3971IMSE-5#TRPBF achieves θJA ≈ 45°C/W. At 1.2A load and 24VIN→5VOUT, power dissipation is ~2.3W, resulting in ~100°C junction rise above ambient - well within its 125°C max rating when ambient stays ≤25°C. For higher ambient, increase copper area or add thermal vias.
LT3971IMSE-5#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.3V
- Voltage - Input (Max):
- 38V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- 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:
- 10-MSOP-EP
LT3971IMSE-5#TRPBF FAQ
1.How can I place an order for LT3971IMSE-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971IMSE-5#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 LT3971IMSE-5#TRPBF reliable?
The price and inventory of LT3971IMSE-5#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971IMSE-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3971IMSE-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971IMSE-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971IMSE-5#TRPBF?
LT3971IMSE-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971IMSE-5#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 LT3971IMSE-5#TRPBF?
For technical support, including LT3971IMSE-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971IMSE-5#TRPBF requirements.
6.How does Aetrix verify that LT3971IMSE-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3971IMSE-5#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 LT3971IMSE-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3971IMSE-5#TRPBF?
All LT3971IMSE-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971IMSE-5#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 LT3971IMSE-5#TRPBF part is unused and in its original packaging.
Return procedure for LT3971IMSE-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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