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Analog Devices Inc. LT3970IDDB-3.3#TRPBF
- Part No.:
- LT3970IDDB-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3970IDDB-3.3#TRPBF.pdf
- Description:
- IC REG BUCK 3.3V 350MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,459
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Product details
Overview
LT3970IDDB-3.3#TRPBF from Analog Devices is a 40V, 350mA fixed-output step-down regulator in a 10-lead (3mm × 2mm) DFN package, featuring 2.5µA quiescent current, integrated boost and catch diodes, and a 3.3V output voltage accurate to ±1.2% over –40°C to 125°C. It delivers low-ripple Burst Mode operation (<5mVP-P) and supports automotive battery regulation with AEC-Q100 qualification.
For engineers reviewing the LT3970IDDB-3.3#TRPBF datasheet, LT3970IDDB-3.3#TRPBF pinout, LT3970IDDB-3.3#TRPBF application, or LT3970IDDB-3.3#TRPBF equivalent, key selection factors include its 3.3V fixed output, 350mA valley catch diode current limit, 0.7µA shutdown current, power good flag with 90% VOUT threshold, and compatibility with high-input-voltage industrial and automotive power rails up to 40V.
Technical Context
The LT3970IDDB-3.3#TRPBF implements constant-frequency current-mode control with internal compensation, enabling fast transient response and stable loop behavior without external compensation components. Its architecture integrates a bipolar NPN power switch, on-die boost diode, and catch Schottky diode - eliminating four external components versus discrete buck controllers.
Burst Mode operation reduces input supply current to 1.7µA at light loads while maintaining output ripple below 5mVP-P; the power good (PG) flag asserts when VOUT reaches 90% of nominal 3.3V, and the enable pin features a precise 1V rising threshold with 30mV hysteresis for reliable sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1.2% over –40°C to 125°C; eliminates external feedback resistors and associated layout sensitivity. |
| Max Input Voltage | 40V continuous; supports direct connection to 24V/36V industrial and automotive battery rails without pre-regulation. |
| Output Current | 350mA valley current limit on catch diode; defines maximum sustainable load under short-circuit or high-duty-cycle conditions. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT; enables always-on systems with multi-year battery life in portable or remote sensors. |
| Shutdown Current | 0.7µA; ensures minimal parasitic drain during system sleep or off-state, critical for energy-harvesting and low-power IoT nodes. |
| Power Good Threshold | 90% of 3.3V (2.97V); provides deterministic system reset or processor wake-up signaling with 12mV hysteresis. |
| Package | 10-lead (3mm × 2mm) DFN with exposed thermal pad; achieves θJA = 76°C/W for compact, thermally robust PCB layouts. |
Pinout & Package
LT3970IDDB-3.3#TRPBF uses a 10-lead (3mm × 2mm) plastic DFN package with exposed thermal pad (Pin 11) soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Fixed-output voltage node | Internally regulated 3.3V output; connects directly to load and output capacitor - no external feedback divider required. |
| EN (Pin 2) | Enable control input | Hysteretic 1V rising / 0.97V falling threshold; ties to VIN for always-on operation or to microcontroller GPIO for controlled startup/shutdown. |
| VIN (Pin 3) | Main power input | Supplies internal circuitry and power switch; requires local 1–4.7µF ceramic bypass close to pin to suppress high-frequency switching noise. |
| GND (Pins 4, 5) | Analog/digital ground reference | Low-impedance return path for control logic and power stage; must be connected to thermal pad (Pin 11) for optimal thermal performance. |
| SW (Pin 6) | Switch node | Drives external inductor; carries high di/dt square wave - requires tight layout with minimal trace length and area to reduce EMI. |
| BOOST (Pin 7) | Bootstrap drive voltage | Connects to external capacitor between BOOST and SW; generates >VIN voltage to fully saturate internal bipolar NPN switch. |
| BD (Pin 8) | Boost diode anode | Accepts external boost diode anode; also sources bias current to internal regulator when BD > 3.2V, improving light-load efficiency. |
| PG (Pin 9) | Power good open-drain flag | Asserts high (via external pull-up) when VOUT ≥ 2.97V; signals valid regulation to MCU or FPGA for safe initialization sequence. |
| RT (Pin 10) | Frequency setting | Resistor-to-ground sets switching frequency from 200kHz to 2.2MHz; higher frequencies allow smaller magnetics but reduce max input voltage range. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost and catch diodes | Eliminates four external diodes, reducing BOM count, board area, and forward voltage losses in high-current paths. |
| Low-ripple Burst Mode operation | Maintains <5mVP-P output ripple at light loads while achieving 1.7µA IQ, enabling clean power for noise-sensitive analog circuits. |
| AEC-Q100 qualified (I-grade) | Rated for –40°C to 125°C junction temperature with full automotive reliability testing - suitable for engine bay, ADAS, and infotainment power supplies. |
| Internal current limiting | 350mA catch diode valley current limit and 535–865mA switch peak current limit provide dual-layer fault protection against shorted outputs and overloads. |
| Accurate power good flag | PG asserts at precisely 90% of 3.3V (2.97V) with 12mV hysteresis, enabling deterministic system-level power sequencing without external comparators. |
Applications
| Automotive Battery Regulation | Industrial Sensor Node Power |
|---|---|
|
Use Scenario: Regulating 12V–36V vehicle battery to stable 3.3V for microcontrollers, CAN transceivers, and analog front-ends in body control modules. IC Role / Device Role / Timing Role: Primary DC/DC converter providing isolated, low-noise 3.3V rail with AEC-Q100 compliance and wide input tolerance. Use Value: Enables direct battery connection without pre-regulator stages; 2.5µA quiescent current extends battery life during vehicle sleep mode. |
Use Scenario: Powering wireless sensor nodes in factory automation systems where 24V plant rails must be converted to 3.3V for ultra-low-power MCUs and RF ICs. IC Role / Device Role / Timing Role: Fixed-output buck regulator delivering regulated 3.3V with minimal external components and robust thermal performance in enclosed enclosures. Use Value: 350mA output supports simultaneous operation of MCU, BLE radio, and analog sensors; DFN package allows dense, cost-effective PCB layouts. |
| Portable Medical Device Supply | Smart Building Controller Rail |
|
Use Scenario: Generating 3.3V from dual-cell Li-ion (6–8.4V) or 9V alkaline batteries in handheld diagnostic tools requiring long runtime and low EMI. IC Role / Device Role / Timing Role: High-efficiency step-down regulator operating in Burst Mode during standby to minimize battery drain. Use Value: 0.7µA shutdown current and 1.7µA light-load IQ extend battery life beyond 5 years in intermittent-use devices. |
Use Scenario: Providing 3.3V power to HVAC controllers, occupancy sensors, and lighting gateways powered from 24V PoE or building management systems. IC Role / Device Role / Timing Role: Robust, fixed-output DC/DC converter handling wide input transients and meeting EN 55022 Class B EMI limits. Use Value: Integrated diodes and internal compensation simplify design validation; 40V absolute max rating withstands 24V line surges per IEC 61000-4-5. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609SIS8#TRPBF | 42V input, 2.5A output, 2.5µA IQ, synchronous rectification, 3mm × 4mm SO-8 package | Higher current capability and synchronous design improve efficiency above 200mA; larger package increases board area | Select when >350mA load or >90% efficiency at mid-load is required; not drop-in due to different pinout and layout. |
| TPS62840DLCR | 6V input max, 1A output, 0.36µA IQ, 1.8mm × 1.6mm WCSP package, integrated inductor option available | Ultra-low IQ ideal for coin-cell applications; limited to ≤6V input - unsuitable for automotive or industrial 12V+ rails | Choose only for battery-powered sub-6V systems prioritizing minimum quiescent current; incompatible with 40V input requirement. |
Compared with LT3970IDDB-3.3#TRPBF, LT8609SIS8#TRPBF offers higher output current and synchronous efficiency but requires PCB redesign, while TPS62840DLCR delivers dramatically lower IQ but cannot support the 40V input range essential for automotive and industrial use cases.
Availability
LT3970IDDB-3.3#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial sensor node power, portable medical device supply, and smart building controller rail applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3970IDDB-3.3#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets with precision power, sensing, and signal chain solutions.
The LT3970 series was designed specifically for high-input-voltage, low-quiescent-current step-down regulation in space-constrained and thermally demanding environments - targeting automotive subsystems, industrial controls, and portable instrumentation.
FAQ
What is the output voltage tolerance of the LT3970IDDB-3.3#TRPBF over temperature?
The LT3970IDDB-3.3#TRPBF delivers a fixed 3.3V output with ±1.2% accuracy over the full –40°C to 125°C operating junction temperature range, as specified in the Electrical Characteristics table (typical value 3.3V, min 3.26V, max 3.34V at –40°C to 125°C). This tight tolerance eliminates need for post-production calibration in most applications.
Does the LT3970IDDB-3.3#TRPBF require external feedback resistors?
No, the LT3970IDDB-3.3#TRPBF does not require external feedback resistors. As a fixed-output variant, it internally programs 3.3V regulation at the VOUT pin (Pin 1), removing external resistor divider components and associated layout sensitivity - simplifying design and improving long-term stability.
What is the maximum allowable input voltage for continuous operation of the LT3970IDDB-3.3#TRPBF?
The LT3970IDDB-3.3#TRPBF supports continuous operation up to 40V input voltage, as defined in the Absolute Maximum Ratings. Its functional operating range is 4.2V to 40V, making it suitable for direct connection to 24V and 36V industrial and automotive battery systems without pre-regulation stages.
How does the power good (PG) flag behave on the LT3970IDDB-3.3#TRPBF?
The PG pin on the LT3970IDDB-3.3#TRPBF is an open-drain output that remains low until VOUT reaches 90% of 3.3V (2.97V), then pulls high via external pull-up. It is valid only when EN is high and VIN > 4.2V, providing deterministic system reset signaling with 12mV hysteresis to prevent chatter near regulation threshold.
Is the LT3970IDDB-3.3#TRPBF pin-compatible with other LT3970 variants in the same package?
Yes, the LT3970IDDB-3.3#TRPBF shares identical pinout and package (10-lead DFN) with all other LT3970-IDDB variants (e.g., LT3970IDDB-5#TRPBF, LT3970IDDB#TRPBF), enabling board-level flexibility to select fixed 3.3V, 5V, or adjustable output versions without layout changes - provided external components (e.g., RT resistor, inductor, capacitors) are validated per variant requirements.
LT3970IDDB-3.3#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):
- 4.2V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 350mA
- Frequency - Switching:
- 200kHz ~ 2.25MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x2)
LT3970IDDB-3.3#TRPBF FAQ
1.How can I place an order for LT3970IDDB-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3970IDDB-3.3#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 LT3970IDDB-3.3#TRPBF reliable?
The price and inventory of LT3970IDDB-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3970IDDB-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3970IDDB-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3970IDDB-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3970IDDB-3.3#TRPBF?
LT3970IDDB-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3970IDDB-3.3#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 LT3970IDDB-3.3#TRPBF?
For technical support, including LT3970IDDB-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3970IDDB-3.3#TRPBF requirements.
6.How does Aetrix verify that LT3970IDDB-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3970IDDB-3.3#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 LT3970IDDB-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3970IDDB-3.3#TRPBF?
All LT3970IDDB-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3970IDDB-3.3#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 LT3970IDDB-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LT3970IDDB-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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