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Analog Devices Inc. LT3971EDD-5#TRPBF
- Part No.:
- LT3971EDD-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3971EDD-5#TRPBF.pdf
- Description:
- IC REG BUCK 5V 1.2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,589
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Product details
Overview
LT3971EDD-5#TRPBF from Analog Devices (formerly Linear Technology) is a fixed 5V, 1.2A monolithic buck switching regulator in a 10-lead 3mm × 3mm DFN package with exposed pad. It operates from 4.3V to 38V input, delivers ultralow 2.8µA quiescent current in regulation, and maintains <15mVP-P output ripple via low-ripple Burst Mode® operation - ideal for automotive battery-powered systems requiring long standby life.
For engineers reviewing the LT3971EDD-5#TRPBF datasheet, LT3971EDD-5#TRPBF pinout, LT3971EDD-5#TRPBF application, or LT3971EDD-5#TRPBF equivalent, key selection criteria include its fixed 5V output, 2.8µA no-load IQ, 1.2A output capability, 200kHz–2MHz adjustable frequency, and integrated power good flag with 9% threshold hysteresis.
Technical Context
The LT3971EDD-5#TRPBF implements constant-frequency current-mode control with internal compensation, enabling fast transient response and stable loop behavior across wide line/load conditions. Its bipolar NPN main switch (0.33Ω RDS(ON) equiv.) is driven by a bootstrap circuit using the BOOST and BD pins, supporting full saturation up to 38V input.
Burst Mode® operation activates below ~92mA load, reducing supply current to 1.7µA during sleep intervals while delivering discrete energy pulses - preserving efficiency without compromising output voltage accuracy. The device includes an accurate 1V enable threshold, soft-start via SS pin, and open-drain PG flag asserting when VOUT reaches 91% of nominal 5V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±1.5% over –40°C to 125°C; internally trimmed 10MΩ feedback divider eliminates external resistors. |
| Input Voltage Range | 4.3V to 38V DC; minimum start-up voltage is 5.0V at 5V output; supports direct connection to 12V/24V/36V automotive batteries. |
| Quiescent Current | 2.8µA typical at no load (12VIN → 5VOUT); enables >10-year battery life in always-on vehicle modules. |
| Max Output Current | 1.2A continuous; peak switch current limit ≥2.4A ensures robustness during cold-crank or load-dump transients. |
| Switching Frequency | Adjustable 200kHz–2MHz via RT resistor; synchronizable 250kHz–2MHz; higher frequencies allow smaller magnetics (e.g., 4.7µH @ 800kHz). |
| Output Ripple | <15mVP-P in typical 5V application with 22µF ceramic output capacitor; enabled by low-ripple Burst Mode® architecture. |
| Power Good Flag | Open-drain PG asserts high when VOUT ≥4.55V (91% of 5V); 5.5% hysteresis prevents chatter near regulation boundary. |
Pinout & Package
LT3971EDD-5#TRPBF uses a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed GND pad (Pin 11), rated for –40°C to 125°C junction temperature. The exposed pad must be soldered to PCB for thermal and electrical performance.
| 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 10nF–100nF ceramic capacitor to 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; requires local 1µF ceramic bypass to GND. |
| 5 EN | Enable Control | Hysteretic 1.005V rising / 0.975V falling threshold; pulls VIN current to 700nA in shutdown. |
| 6 VOUT | Fixed Output Sense | Internally regulated to 5.00V; connects to output capacitor and load; replaces FB pin in adjustable variants. |
| 7 SS | Soft-Start Ramp | Controls inrush current via external capacitor; ramp time sets peak current limit slew rate at startup. |
| 8 RT | Frequency Set | Resistor to GND programs switching frequency (e.g., 49.9kΩ = 800kHz); enables EMI optimization. |
| 9 PG | Power Good Flag | Open-drain output; requires external pull-up; signals valid regulation after VOUT reaches 4.55V. |
| 10 SYNC | External Clock Sync | Ground for Burst Mode; tie to external clock (250kHz–2MHz) for synchronized pulse-skipping. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 2.8µA IQ at no load enables multi-year operation on coin cells or automotive standby batteries. |
| Low-Ripple Burst Mode® | Maintains <15mVP-P output ripple while achieving >85% efficiency at 1mA load - critical for noise-sensitive analog circuits. |
| Integrated Power Good Flag | PG asserts only after VOUT stabilizes within 9% of 5V, eliminating false system wakeups during brown-in events. |
| Thermally Optimized DFN | θJA = 45°C/W with exposed pad soldered; supports 1.2A continuous output without heatsink in 70°C ambient. |
| Robust Fault Tolerance | Withstands 38V input continuously; BOOST pin rated to 55V; includes internal current limiting and thermal shutdown. |
Applications
| Automotive Body Control Module | Industrial IoT Sensor Node |
|---|---|
Use Scenario: Powering microcontroller, CAN transceiver, and EEPROM in door module with 12V battery input subject to cold-crank (–40°C) and load-dump (40V) transients. IC Role / Device Role / Timing Role: Primary 5V buck regulator providing clean, regulated rail with guaranteed start-up down to 5.0V input and shutdown IQ <1µA. Use Value: Eliminates need for external LDO post-regulator; sustains MCU operation during 6V battery dips; reduces system standby power by 4× vs. legacy controllers. | Use Scenario: Battery-powered wireless sensor node monitoring temperature/humidity in remote factory equipment, transmitting data every 5 minutes. IC Role / Device Role / Timing Role: Main power converter supplying 5V to MCU and RF transceiver; enters deep-sleep mode between transmissions. Use Value: Achieves 2.8µA no-load IQ and <15mV ripple - extends AA-cell lifetime beyond 5 years while maintaining RF signal integrity. |
| Portable Medical Diagnostic Device | Smart Building Occupancy Sensor |
Use Scenario: Handheld ultrasound probe powered by Li-ion battery (8.4V–12.6V), requiring stable 5V for analog front-end and FPGA. IC Role / Device Role / Timing Role: High-efficiency step-down regulator with fast load transient response to handle pulsed ultrasound transmit bursts. Use Value: Delivers 1.2A peak current with <10µs recovery from 0.5A→1A step; maintains <15mV ripple to prevent image artifacts. | Use Scenario: Ceiling-mounted PIR + BLE occupancy sensor running on 3.6V primary lithium battery, stepping up to 5V for motion detection logic. IC Role / Device Role / Timing Role: Fixed-output buck converter enabling direct use of 5V peripherals without external feedback network. Use Value: Internal 10MΩ divider removes two precision resistors and 10pF phase-lead cap - simplifies BOM and layout, improves long-term voltage drift stability. |
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, 2.7V–65V input, 2.1MHz sync-capable; uses MOSFET switch, no BOOST/BD pins. | Higher max current and input range; lacks Burst Mode®; higher IQ unsuitable for ultra-low-power standby. | Select when >1.2A load or >38V input required; avoid if sub-5µA IQ is mandatory. |
| TPS62840DRVR | 5V fixed, 1A output, 0.35µA IQ, 1.8V–6.5V input, 1.8MHz; nanopower buck with integrated inductor option. | Narrower input range; lower current; optimized for single-cell Li-ion, not automotive 12V/24V. | Select for compact, ultra-low-IQ designs with ≤6.5V input; not suitable for 12V+ battery systems. |
Compared with LMR36520RNXR and TPS62840DRVR, the LT3971EDD-5#TRPBF uniquely balances 38V automotive input tolerance, 1.2A capability, and 2.8µA ultralow IQ - making it optimal for battery-backed industrial and automotive modules where wide VIN and extreme standby efficiency are jointly required.
Availability
LT3971EDD-5#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial IoT sensor nodes, portable medical diagnostics, and smart building occupancy sensors requiring stable component supply with extended temperature support (–40°C to 125°C).
Supply support for LT3971EDD-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 its high-performance power management portfolio with rigorous automotive-grade qualification and long-term product longevity commitments.
The LT3971 series was designed specifically for automotive and industrial applications demanding ultralow quiescent current, wide input voltage range, and robust fault tolerance - targeting battery-powered modules that must operate reliably for 15+ years in harsh environments.
FAQ
What is the guaranteed output voltage accuracy of the LT3971EDD-5#TRPBF over temperature?
The LT3971EDD-5#TRPBF guarantees 5.00V output with ±1.5% tolerance over the full –40°C to 125°C junction temperature range, as confirmed by electrical characterization data showing 4.93V to 5.07V min/max at temperature extremes. This accuracy is achieved via laser-trimmed internal 10MΩ feedback resistors and a precision 1.19V reference, eliminating external resistor drift errors.
Can the LT3971EDD-5#TRPBF operate from a 4.5V input source?
No - the LT3971EDD-5#TRPBF requires a minimum input voltage of 5.0V to regulate 5V output, as specified in the "Minimum Input Voltage to Run" curve (Figure 3971 G20). At 4.5V input, the device cannot sustain duty cycle needed for 5V output and will drop out of regulation; for sub-5V inputs, select the LT3971 adjustable version with external feedback.
How does the LT3971EDD-5#TRPBF achieve 2.8µA quiescent current while maintaining regulation?
The LT3971EDD-5#TRPBF achieves 2.8µA IQ through low-ripple Burst Mode® operation: during light loads, it delivers discrete current pulses to the output capacitor, then enters deep sleep where most internal circuitry (oscillator, error amp, gate drivers) is disabled. The 2.8µA figure includes residual leakage and minimal bias currents - verified at 12VIN → 5VOUT with no load.
Is an external catch diode required for the LT3971EDD-5#TRPBF, and what specifications must it meet?
Yes - the LT3971EDD-5#TRPBF requires an external Schottky diode connected between SW and VOUT. Per datasheet recommendations, it must have ≤1µA reverse leakage at room temperature and ≤0.77V forward voltage at 100mA to minimize conduction loss and preserve light-load efficiency. Diodes like DFLS2100 (Diodes Inc.) meet these requirements.
Does the LT3971EDD-5#TRPBF support synchronization to an external clock, and what impact does it have on efficiency?
Yes - the LT3971EDD-5#TRPBF supports external clock synchronization via the SYNC pin (250kHz–2MHz range). However, when synchronized, it operates in pulse-skipping mode instead of Burst Mode®, increasing light-load quiescent current from 2.8µA to 1.5mA. For ultralow-power applications, SYNC must be grounded to retain Burst Mode® benefits.
LT3971EDD-5#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:
- 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-DFN (3x3)
LT3971EDD-5#TRPBF FAQ
1.How can I place an order for LT3971EDD-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3971EDD-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 LT3971EDD-5#TRPBF reliable?
The price and inventory of LT3971EDD-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 LT3971EDD-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3971EDD-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3971EDD-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3971EDD-5#TRPBF?
LT3971EDD-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3971EDD-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 LT3971EDD-5#TRPBF?
For technical support, including LT3971EDD-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3971EDD-5#TRPBF requirements.
6.How does Aetrix verify that LT3971EDD-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3971EDD-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 LT3971EDD-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3971EDD-5#TRPBF?
All LT3971EDD-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3971EDD-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 LT3971EDD-5#TRPBF part is unused and in its original packaging.
Return procedure for LT3971EDD-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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