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Analog Devices Inc. LT3971EDD#TRPBF
- Part No.:
- LT3971EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3971EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:769
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Product details
Overview
LT3971EDD#TRPBF from Analog Devices (formerly Linear Technology) is a 38V, 1.2A monolithic synchronous step-down regulator in a 10-lead 3mm × 3mm DFN package with exposed pad. It delivers ultralow 2.8µA quiescent current in regulation, supports adjustable switching frequency from 200kHz to 2MHz via RT pin, and features power good flag, soft-start, and low-ripple Burst Mode operation maintaining <15mVP-P output ripple - ideal for automotive battery-powered systems requiring long standby life.
For engineers reviewing the LT3971EDD#TRPBF datasheet, LT3971EDD#TRPBF pinout, LT3971EDD#TRPBF application, or LT3971EDD#TRPBF equivalent, key selection criteria include input voltage range (4.3V–38V), fixed or adjustable output configuration, thermal performance of the DFN-10 package, and compatibility with external synchronization or Burst Mode optimization.
Technical Context
The LT3971EDD#TRPBF implements constant-frequency current-mode control with internal compensation, enabling fast transient response and stable loop behavior across wide load and line variations. Its bipolar NPN main switch (0.33Ω RDS(on)-equivalent) is driven by a bootstrap circuit using the BOOST and BD pins, requiring an external Schottky diode for charge pump operation.
Burst Mode operation reduces no-load input current to 2.8µA while holding output ripple below 15mVP-P; frequency foldback during startup and overload protects against excessive peak inductor current. The EN pin features 1.01V rising threshold with 30mV hysteresis, and PG asserts when FB reaches 91% of regulation voltage.
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 |
| Max Output Current | 1.2A - sustained DC load capability with internal 2.4A switch current limit (min) |
| Quiescent Current | 2.8µA at no load - enables >10-year battery life in always-on sensor nodes |
| Switching Frequency | 200kHz to 2MHz - set by RT resistor; enables compact magnetics (e.g., 4.7µH @ 800kHz) |
| Output Ripple (Burst) | <15mVP-P - achieved with standard 22µF ceramic output capacitor in typical layout |
| Feedback Reference | 1.19V ±1.3% - precise internal reference enables accurate adjustable output (1.19V–30V) or fixed variants |
| Shutdown Current | 700nA - ensures negligible drain during system sleep states |
Pinout & Package
LT3971EDD#TRPBF uses a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed GND pad (Pin 11) requiring PCB soldering for optimal thermal resistance (θJA = 45°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 BD | Boost Diode Anode | Connects to cathode of external Schottky diode; forms charge pump return path for BOOST drive |
| 2 BOOST | Bootstrap Drive | Supplies >VIN voltage to switch driver; requires external capacitor between BOOST and SW |
| 3 SW | Switch Node | Internal NPN collector output; connects to inductor, catch diode cathode, and BOOST capacitor |
| 4 VIN | Main Power Input | Supplies IC bias and switch current; must be locally bypassed with ≥1µF ceramic |
| 5 EN | Enable Control | Hysteretic 1.01V enable threshold; pulls device into 700nA shutdown when low |
| 6 FB | Feedback Input | Regulated to 1.19V; connects to resistor divider tap for adjustable output configuration |
| 7 SS | Soft-Start Ramp | Controls inrush current via external capacitor; ramp time sets peak current slew rate |
| 8 RT | Frequency Set | Resistor-to-GND sets switching frequency (200kHz–2MHz); determines inductor size tradeoff |
| 9 PG | Power Good Flag | Open-drain output asserting high when VOUT ≥91% of target; requires pull-up resistor |
| 10 SYNC | Sync Input | Ground for Burst Mode; tie to external clock (250kHz–2MHz) for synchronized pulse-skipping |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow IQ Regulation | 2.8µA supply current at no load preserves battery capacity in always-on applications |
| Low-Ripple Burst Mode | Maintains <15mVP-P output ripple while achieving >85% efficiency at 1mA load |
| Internal Compensation | Eliminates external compensation network - reduces BOM count and layout sensitivity |
| Accurate Power Good Flag | PG asserts within 100ms of regulation; 91% threshold ensures reliable system sequencing |
| Thermally Optimized DFN | Exposed pad (Pin 11) soldered to PCB achieves θJC = 10°C/W for 1.2A continuous operation |
Applications
| Automotive Body Control Module | Industrial IoT Sensor Node |
|---|---|
Use Scenario: Powering microcontroller, CAN transceiver, and temperature/humidity sensors from 12V battery rail with >10-year shelf life requirement. IC Role / Device Role / Timing Role: Primary 3.3V buck regulator delivering 1.2A peak with ultralow quiescent current and robust cold-crank immunity (4.3V start). Use Value: 2.8µA no-load IQ extends battery life beyond 10 years; 38V absolute max rating withstands load dump transients. | Use Scenario: Solar-charged remote environmental monitor operating intermittently in desert conditions (-40°C to +125°C junction). IC Role / Device Role / Timing Role: Main system regulator converting 18–36V solar input to stable 3.3V for MCU and LoRa radio, leveraging Burst Mode for µA-level sleep current. Use Value: Guaranteed operation over –40°C to +125°C; 1.2A output supports radio transmit bursts; DFN package enables compact conformal coating. |
| Portable Medical Diagnostic Device | Railway Signaling Interface |
Use Scenario: Battery-powered handheld ultrasound probe requiring silent, ripple-free analog supply for ADC front-end. IC Role / Device Role / Timing Role: Low-noise 5V intermediate rail generator feeding LDOs for analog signal chain; operates in Burst Mode during standby. Use Value: <15mVP-P ripple eliminates switching artifacts in 16-bit ADC measurements; 2MHz option allows tiny 2.2µH inductor. | Use Scenario: Power conversion for EN50155-compliant signaling module accepting 24V–110V DC input with strict EMI limits. IC Role / Device Role / Timing Role: Pre-regulator stepping 72V nominal rail to 12V for downstream converters; configured at 400kHz for EMI filtering headroom. Use Value: 38V max input accommodates 110V transients; SYNC pin enables deterministic EMI spreading; MSOP-16 variant available for fault-tolerant designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMSE#TRPBF | 40V input, 1.5A, 3.5µA IQ, integrated MOSFETs, no BOOST/BD pins | Eliminates external Schottky diode but lacks programmable frequency and PG flag | Select when board space is critical and external diode cost/layout complexity must be avoided |
| TPS54202DRCT | 28V input, 2A, 26µA IQ, integrated FETs, 2.5V–6V VIN(min), no Burst Mode | Higher IQ and narrower input range; uses PWM-only light-load control | Select for cost-sensitive industrial supplies where 26µA IQ is acceptable and 38V operation not required |
Compared with LTC3630EMSE#TRPBF and TPS54202DRCT, LT3971EDD#TRPBF uniquely balances ultralow IQ (2.8µA), 38V input tolerance, and flexible external component control - making it optimal for automotive and long-life battery systems where both input ruggedness and standby efficiency are non-negotiable.
Availability
LT3971EDD#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial IoT sensor nodes, portable medical diagnostics, and railway signaling interfaces requiring stable component supply across extended temperature and long-lifecycle programs.
Supply support for LT3971EDD#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 product support, documentation, and manufacturing continuity for the LT® portfolio.
The LT3971EDD#TRPBF belongs to Linear's high-voltage monolithic buck regulator family, designed specifically for automotive, industrial, and battery-powered systems demanding wide input range, ultralow quiescent current, and robust thermal performance in compact packages.
FAQ
What is the minimum input voltage required for LT3971EDD#TRPBF to regulate a 3.3V output?
The LT3971EDD#TRPBF requires a minimum input voltage of 4.3V to maintain accurate feedback regulation at any output voltage. For a 3.3V output, this corresponds to a practical dropout of ~1V under light loads. At higher switching frequencies, the minimum input may increase slightly due to duty cycle limitations imposed by minimum on-time (80ns).
Does LT3971EDD#TRPBF require an external Schottky diode, and why?
Yes, LT3971EDD#TRPBF requires an external Schottky diode connected between BD and VOUT. The BD pin serves as the anode return path for the internal bootstrap capacitor charging circuit, which drives the BOOST pin above VIN to fully saturate the internal bipolar NPN switch. Without this diode, the boost circuit cannot function, preventing proper switch operation.
How does the LT3971EDD#TRPBF achieve 2.8µA quiescent current while regulating?
The LT3971EDD#TRPBF achieves 2.8µA quiescent current through low-ripple Burst Mode operation: during light loads, it delivers discrete current pulses to the output capacitor and then enters deep sleep, powering down oscillator, error amplifier, and gate drivers. The 2.8µA figure represents average input current across burst cycles - confirmed at 12VIN/3.3VOUT with no load.
Can LT3971EDD#TRPBF be synchronized to an external clock, and what is the impact on efficiency?
Yes, LT3971EDD#TRPBF can be synchronized by applying a 250kHz–2MHz clock to the SYNC pin. However, doing so disables Burst Mode and forces pulse-skipping at light loads, increasing quiescent current from 2.8µA to ~1.5mA. For maximum light-load efficiency, SYNC must be grounded.
What thermal design considerations apply to the LT3971EDD#TRPBF DFN package?
The LT3971EDD#TRPBF DFN package requires the exposed pad (Pin 11) to be soldered to a minimum 100mm² copper area on the PCB for effective heat dissipation. With θJA = 45°C/W, 1.2A continuous operation at 125°C ambient requires ≤25°C rise - achievable only with adequate copper pour and optional thermal vias to inner ground planes.
LT3971EDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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:
- 10-DFN (3x3)
LT3971EDD#TRPBF FAQ
1.How can I place an order for LT3971EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971EDD#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 LT3971EDD#TRPBF reliable?
The price and inventory of LT3971EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3971EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3971EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971EDD#TRPBF?
LT3971EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971EDD#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 LT3971EDD#TRPBF?
For technical support, including LT3971EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971EDD#TRPBF requirements.
6.How does Aetrix verify that LT3971EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3971EDD#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 LT3971EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3971EDD#TRPBF?
All LT3971EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971EDD#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 LT3971EDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3971EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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