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Analog Devices Inc. LT3970IDDB#TRPBF
- Part No.:
- LT3970IDDB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3970IDDB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 350MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,011
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Product details
Overview
LT3970IDDB#TRPBF from Analog Devices is a 40V, 350mA monolithic step-down regulator with integrated boost and catch diodes, 2.5µA quiescent current, adjustable switching frequency (200kHz–2.2MHz), and power good flag - designed for automotive battery regulation and industrial supplies requiring ultra-low IQ and high input voltage tolerance.
For engineers reviewing the LT3970IDDB#TRPBF datasheet, LT3970IDDB#TRPBF pinout, LT3970IDDB#TRPBF application, or LT3970IDDB#TRPBF equivalent, key selection criteria include its 350mA catch diode current limit, 1.21V FB reference accuracy over –40°C to 125°C, low-ripple Burst Mode operation (<5mVP-P), and AEC-Q100 qualification for automotive use.
Technical Context
The LT3970IDDB#TRPBF implements constant-frequency current-mode control with internal slope compensation, enabling fast transient response and stable loop behavior across wide input ranges. Its bipolar NPN switch is driven via an external BOOST capacitor to ensure full saturation, while dual current limiting (switch peak at 700mA typ, catch diode valley at 400mA typ) protects against shorted outputs and overvoltage faults.
Burst Mode operation reduces quiescent current to 1.7µA at light loads while maintaining output ripple below 5mVP-P; the open-drain PG flag asserts when FB reaches 90% of regulation, and EN features accurate 1V rising threshold with 30mV hysteresis - all validated for –40°C to 125°C operation in the DDB package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 40V - supports direct connection to 12V/24V/36V automotive and industrial rails without pre-regulation. |
| Output Current | 350mA - defined by catch diode valley current limit, not switch peak limit; enables robust fault handling. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT - enables always-on systems with multi-year battery life in portable applications. |
| Switching Frequency | 200kHz to 2.2MHz - set externally via RT resistor; allows optimization of inductor size vs. efficiency trade-offs. |
| Feedback Reference | 1.21V ±15mV over –40°C to 125°C - ensures precise output regulation across automotive temperature range. |
| Power Good Threshold | 90% of FB voltage (±120mV offset) - provides reliable startup sequencing signal with 12mV hysteresis. |
| Shutdown Current | 0.7µA - enables ultra-low-power system-level sleep modes with minimal leakage impact. |
Pinout & Package
LT3970IDDB#TRPBF is housed in a 10-lead (3mm × 2mm) plastic DFN package with exposed thermal pad (Pin 11) soldered to PCB ground for enhanced thermal performance (θJA = 76°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulated to 1.21V; connects to resistor divider tap for adjustable output voltage (1.21V–25V). |
| EN (Pin 2) | Enable control | Hysteretic 1V rising / 0.97V falling threshold; draws only 1nA bias current. |
| VIN (Pin 3) | Main power input | Supplies internal circuitry and switch; requires local ceramic bypass (≥1µF). |
| GND (Pins 4, 5, 11) | Ground reference | Multiple ground connections including exposed pad; must be solidly soldered for thermal and EMI integrity. |
| SW (Pin 6) | Switch node | Connects to inductor; carries high di/dt switching current; critical for layout and EMI control. |
| BOOST (Pin 7) | Bootstrap drive | Drives internal NPN switch; requires external capacitor to generate voltage > VIN. |
| BD (Pin 8) | Boost diode anode | Connects to external boost diode anode; also powers internal regulator when >3.2V. |
| PG (Pin 9) | Power good flag | Open-drain output; pulled high externally when FB ≥ 90% of target; valid only if VIN > 4.2V and EN high. |
| RT (Pin 10) | Frequency setting | Resistor-to-ground sets switching frequency; 41.2kΩ yields ~800kHz typical. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated diodes | On-die boost and catch Schottky diodes eliminate 2 external components and reduce board area. |
| Low-ripple Burst Mode | Maintains <5mVP-P output ripple at light loads while reducing IQ to 1.7µA - ideal for sensor nodes. |
| AEC-Q100 qualification | Rated for automotive applications (Grade I: –40°C to 125°C junction), including transients and reliability testing. |
| Internal compensation | Eliminates need for external compensation network - simplifies design and improves production consistency. |
| Catch diode current limit | 400mA valley limit prevents thermal runaway during output shorts - complements 700mA switch peak limit. |
Applications
| Automotive Battery Regulation | Industrial Power Supplies |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery rail to 3.3V/5V for infotainment microcontrollers and CAN transceivers under cold-crank (4.2V) and load-dump (40V) conditions. IC Role / Device Role / Timing Role: Primary buck regulator providing stable, low-noise power with AEC-Q100 compliance and robust fault protection. Use Value: Eliminates need for external TVS and pre-regulator stages due to 40V absolute max input and integrated current limiting. | Use Scenario: Powering PLC I/O modules and field sensors in factory automation systems with wide-input 24VDC industrial supplies subject to line surges and brownouts. IC Role / Device Role / Timing Role: High-voltage input DC/DC converter delivering regulated 3.3V/5V with ultra-low standby current for energy-efficient operation. Use Value: 2.5µA quiescent current enables always-on monitoring circuits without compromising battery backup runtime. |
| Portable Medical Devices | Remote Sensing Nodes |
Use Scenario: Powering handheld diagnostic tools and wearable monitors using single-cell Li-ion (4.2V) or dual-cell packs (8.4V), requiring long battery life and low EMI. IC Role / Device Role / Timing Role: Efficient step-down regulator operating in Burst Mode during sleep cycles to minimize system power draw. Use Value: <5mVP-P ripple ensures clean analog front-end supply for precision ADCs and low-noise amplifiers. | Use Scenario: Solar-powered environmental sensors transmitting data intermittently via LoRaWAN or NB-IoT, where energy harvesting and multi-year battery life are critical. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter enabling deep-sleep operation between wake-up events. Use Value: 0.7µA shutdown current and 1.7µA Burst Mode IQ extend primary lithium battery life beyond 10 years. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630AEDD#PBF | Higher 3.3V fixed output, 100mA max, no PG flag, 17µA IQ - lacks catch diode integration and automotive temp grade. | Suitable for space-constrained, lower-current applications where PG signaling is unnecessary. | Select only if output is fixed at 3.3V and load ≤100mA; not drop-in due to different pinout and missing PG/RT pins. |
| TPS54332DR | 3.5A output, external diode, 4.5µA IQ, no AEC-Q100 rating, SOIC-8 package - higher current but larger footprint and no integrated diodes. | Better for high-current industrial supplies where thermal headroom exceeds 350mA. | Choose when >350mA continuous load is required and external diode layout is acceptable; not pin-compatible. |
Compared with LTC3630AEDD#PBF and TPS54332DR, LT3970IDDB#TRPBF uniquely combines AEC-Q100 qualification, integrated diodes, 350mA capability, and sub-3µA IQ in a 3mm × 2mm DFN - making it optimal for compact, automotive-grade, ultra-low-power buck conversion where board space and reliability are critical.
Availability
LT3970IDDB#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial power supplies, and portable medical devices requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LT3970IDDB#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.
The LT3970 series is part of Analog Devices' Power by Linear portfolio, engineered specifically for high-input-voltage, ultra-low-quiescent-current DC/DC conversion in harsh environments such as automotive and industrial systems.
FAQ
What is the operating temperature range for LT3970IDDB#TRPBF?
The LT3970IDDB#TRPBF is rated for –40°C to 125°C junction temperature and is qualified per AEC-Q100 Grade I standards. This range is fully specified in the electrical characteristics table, including feedback voltage (1.195V to 1.225V), EN threshold (0.94V to 1.06V), and PG offset (80mV to 160mV), ensuring reliable operation in automotive under-hood and industrial control cabinet environments.
Does LT3970IDDB#TRPBF require external diodes?
No, LT3970IDDB#TRPBF integrates both the boost diode and catch Schottky diode on-die. The BD pin connects to the anode of the internal boost diode, and the SW pin interfaces directly with the inductor without requiring an external catch diode - reducing BOM count, PCB area, and potential failure points in automotive and industrial designs.
How is the switching frequency set on LT3970IDDB#TRPBF?
The switching frequency of LT3970IDDB#TRPBF is set by an external resistor connected between the RT pin (Pin 10) and ground. Using the datasheet's RT vs. frequency table, a 41.2kΩ resistor yields ~800kHz, while 768kΩ gives 200kHz. Frequency is adjustable from 200kHz to 2.2MHz, enabling optimization of inductor size, efficiency, and EMI performance for each application.
What is the purpose of the BD pin on LT3970IDDB#TRPBF?
The BD pin on LT3970IDDB#TRPBF serves two functions: it connects to the anode of the internal boost diode used to drive the NPN switch, and it supplies bias current to the internal regulator when held above 3.2V - typically by connecting to the regulated output. This dual role improves efficiency by reducing VIN current draw during normal operation and enabling stable startup under low-input conditions.
Can LT3970IDDB#TRPBF be used for fixed 5V output without external resistors?
No - LT3970IDDB#TRPBF is the adjustable version and requires an external resistor divider on the FB pin to set output voltage. For fixed 5V output, the pin-compatible LT3970IDDB-5#TRPBF variant should be used, which internally programs VOUT to 5.0V ±1.2% over temperature and eliminates the need for R1/R2 feedback resistors.
LT3970IDDB#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):
- 4.2V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 25V
- 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#TRPBF FAQ
1.How can I place an order for LT3970IDDB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3970IDDB#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#TRPBF reliable?
The price and inventory of LT3970IDDB#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#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3970IDDB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3970IDDB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3970IDDB#TRPBF?
LT3970IDDB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3970IDDB#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#TRPBF?
For technical support, including LT3970IDDB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3970IDDB#TRPBF requirements.
6.How does Aetrix verify that LT3970IDDB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3970IDDB#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#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3970IDDB#TRPBF?
All LT3970IDDB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3970IDDB#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#TRPBF part is unused and in its original packaging.
Return procedure for LT3970IDDB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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