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Analog Devices Inc. LT3970IMS#PBF
- Part No.:
- LT3970IMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3970IMS#PBF.pdf
- Description:
- IC REG BUCK ADJ 350MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:330
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Product details
Overview
LT3970IMS#PBF from Analog Devices is a 40V, 350mA monolithic step-down switching regulator with integrated boost and catch diodes, 2.5µA quiescent current, adjustable 200kHz–2.2MHz switching frequency, and power good flag. It operates from 4.2V to 40V input and delivers 1.21V to 25V output voltage in a 10-lead MSOP package, designed for automotive battery regulation and industrial power supplies.
For engineers reviewing the LT3970IMS#PBF datasheet, LT3970IMS#PBF pinout, LT3970IMS#PBF application, or LT3970IMS#PBF equivalent, this page provides verified technical context, confirmed pin functions, real-world load/efficiency behavior, and validated alternative options for automotive-grade buck conversion where low IQ, wide VIN, and integrated diodes are critical.
Technical Context
The LT3970IMS#PBF uses constant-frequency current-mode control with internal slope compensation for stable loop dynamics and fast transient response. Its bipolar NPN switch is driven via an external BOOST capacitor to ensure full saturation across input voltage range.
Burst Mode operation reduces quiescent current to 1.7µA at light loads while maintaining output ripple below 5mVP-P; the catch diode current limit (350mA typical) and switch current limit (535mA min) jointly constrain maximum deliverable output current under fault conditions.
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 - limited by valley current sense on integrated catch diode; sufficient for microcontrollers, sensors, and interface ICs. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT - enables always-on systems with multi-year battery life in portable or remote applications. |
| Switching Frequency | 200kHz to 2.2MHz - set externally via RT resistor; higher frequencies allow smaller magnetics but reduce max VIN/VOUT ratio. |
| Feedback Reference | 1.21V ±1.2% - precise internal reference enabling accurate output programming from 1.21V to 25V using two external resistors. |
| Power Good Threshold | 90% of regulated output - open-drain PG flag asserts when VOUT reaches 90% of target, supporting safe system sequencing. |
| Enable Threshold | 1.0V ±30mV - accurate hysteresis enables reliable enable/disable control directly from logic-level signals or microcontroller GPIO. |
Pinout & Package
LT3970IMS#PBF is housed in a 10-lead plastic MSOP package (θJA = 100°C/W), with exposed pad not present (unlike DFN variant). All pins are surface-mount compatible and require standard reflow profiles per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback input | Regulated to 1.21V; connects to resistor divider tap for adjustable output voltage configuration. |
| EN (Pin 2) | Enable control | Hysteretic input with 1.0V rising threshold; pulls device into 0.7µA shutdown when low. |
| VIN (Pin 3) | Main power input | Supplies internal circuitry and switch; must be locally bypassed with ≥1µF X7R ceramic capacitor. |
| GND (Pins 4, 5) | Ground reference | Dual ground pins reduce PCB trace inductance and improve thermal dissipation in high-current paths. |
| SW (Pin 6) | Switch node | Connects to inductor; carries pulsed current up to 535mA peak; requires tight layout to minimize EMI. |
| BOOST (Pin 7) | Bootstrap drive | Drives internal NPN switch; requires external capacitor between BOOST and SW to generate >VIN gate drive. |
| BD (Pin 8) | Bias diode anode | Accepts external bias voltage >3.2V (e.g., VOUT) to improve efficiency by powering internal regulator externally. |
| PG (Pin 9) | Power good flag | Open-drain output; pulled low until FB reaches 90% of regulation; valid only when EN = high and VIN > 4.2V. |
| RT (Pin 10) | Frequency setting | Resistor-to-ground sets switching frequency from 200kHz to 2.2MHz; tolerance directly impacts fSW accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost & Catch Diodes | Eliminates four external components; reduces BOM count, board area, and layout complexity in space-constrained designs. |
| Low-Ripple Burst Mode | Maintains <5mVP-P output ripple at light loads while drawing only 1.7µA, enabling clean power for noise-sensitive analog circuits. |
| AEC-Q100 Qualified | Rated for –40°C to 125°C junction temperature; qualified for automotive battery regulation and infotainment subsystems. |
| Internal Compensation | Reduces design time and component count; no external compensation network required for stable operation across full load range. |
| Catch Diode Current Limit | 350mA valley limit protects against short-circuit faults without external sensing; works in tandem with 535mA switch peak limit. |
Applications
| Automotive Battery Regulation | Industrial Sensor Power Supply |
|---|---|
|
Use Scenario: Regulating 12V–36V vehicle battery rail to 3.3V for CAN transceivers and microcontrollers in engine control units. IC Role / Device Role / Timing Role: Primary DC/DC converter providing isolated, low-noise, always-on power with AEC-Q100 compliance. Use Value: 2.5µA IQ extends battery runtime during key-off; integrated diodes eliminate thermal hotspots from discrete Schottky placement. |
Use Scenario: Powering 4–20mA loop-powered sensors and precision ADCs in factory automation PLC modules. IC Role / Device Role / Timing Role: High-input-voltage buck regulator delivering stable 5V/3.3V with minimal dropout across wide temperature range. Use Value: 40V absolute max rating tolerates load-dump transients; PG flag enables safe sensor initialization before data acquisition. |
| Portable Medical Device Power | IoT Edge Node Power Management |
|
Use Scenario: Converting two Li-ion cells (6V–8.4V) to 3.3V for Bluetooth LE radios and biosensor front-ends in wearable health monitors. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter enabling multi-week operation on single charge cycle. Use Value: 1.7µA Burst Mode current minimizes standby drain; small MSOP footprint fits compact flex PCB layouts. |
Use Scenario: Supplying 3.3V to LoRaWAN gateways and environmental sensor nodes deployed in remote locations with solar/battery hybrid power. IC Role / Device Role / Timing Role: Wide-VIN buck regulator interfacing with unregulated energy harvesting sources and backup batteries. Use Value: 4.2V minimum VIN allows start-up from partially discharged batteries; BD pin enables efficiency boost via VOUT biasing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609SISM#PBF | 42V input, 2.5A output, 2.5µA IQ, synchronous rectification, 3mm × 4mm LQFN | Higher current capability and synchronous architecture; lacks integrated catch diode current limiting | Choose when >350mA load or higher efficiency at medium loads is required; requires external MOSFET layout |
| TPS63020DSJR | 4.2V–17V input, 2A buck-boost, 25µA IQ, fixed 3.3V/5V options, 2mm × 2mm QFN | Buck-boost topology supports VIN < VOUT; higher IQ; no PG flag or adjustable frequency | Choose for single-cell Li-ion or variable-input applications where VIN may dip below VOUT; not suitable for 24V+ rails |
Compared with LT3970IMS#PBF, LT8609SISM#PBF offers higher output current and synchronous efficiency but requires external FET layout and lacks valley-current fault protection; TPS63020DSJR provides buck-boost flexibility for low-input scenarios but cannot handle 40V transients or match the ultra-low IQ in Burst Mode.
Availability
LT3970IMS#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial sensor power supplies, and portable medical device power requiring stable component supply, AEC-Q100 qualification, and long-term lifecycle support.
Supply support for LT3970IMS#PBF 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, signal chain, and RF solutions.
The LT3970 series is part of Analog Devices' Power by Linear portfolio, engineered for high-reliability DC/DC conversion in harsh environments-specifically targeting automotive, industrial, and portable applications demanding wide VIN, ultra-low IQ, and integrated protection.
FAQ
What is the operating temperature range for LT3970IMS#PBF?
The LT3970IMS#PBF is rated for –40°C to 125°C junction temperature and is qualified to AEC-Q100 Grade I standards. This makes it suitable for under-hood automotive applications and industrial environments where ambient temperatures exceed 85°C. The "I" grade designation confirms full specification guarantee across this extended range, unlike the "E" grade which is only guaranteed from 0°C to 125°C.
Does LT3970IMS#PBF require an external catch diode?
No, LT3970IMS#PBF integrates both the boost diode and catch diode on-die, eliminating the need for external diodes. This integration reduces component count, PCB area, and thermal management complexity. The internal catch diode is rated for 350mA valley current and includes current-limit protection that activates during short-circuit events to prevent damage.
How is the switching frequency set on LT3970IMS#PBF?
The switching frequency of LT3970IMS#PBF is set by connecting a resistor between the RT pin (Pin 10) and ground. Values from 42.2kΩ to 768kΩ configure frequencies from 2.2MHz down to 200kHz, per Table 1 in the datasheet. The resistor's tolerance directly affects frequency accuracy, so 1% metal-film types are recommended for stable operation across temperature.
Can LT3970IMS#PBF be used in Burst Mode for noise-sensitive applications?
Yes, LT3970IMS#PBF automatically enters Low Ripple Burst Mode at light loads, maintaining output ripple below 5mVP-P while reducing quiescent current to 1.7µA. However, audible ceramic capacitor noise may occur at audio frequencies during very light loads; this can be mitigated by selecting non-piezoelectric capacitors or adding a small damping resistor in series with the phase-lead capacitor.
What is the purpose of the BD pin on LT3970IMS#PBF?
The BD (Bias Diode) pin on LT3970IMS#PBF accepts an external voltage >3.2V-typically the regulated output-to power the internal bias regulator. When active, this improves conversion efficiency by reducing VIN current draw, especially at higher input voltages. It also enables efficient operation when VIN is near the minimum 4.2V, where internal bias from VIN would otherwise degrade performance.
LT3970IMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- 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-MSOP
LT3970IMS#PBF FAQ
1.How can I place an order for LT3970IMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3970IMS#PBF 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 LT3970IMS#PBF reliable?
The price and inventory of LT3970IMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3970IMS#PBF is usually 5 days.
3.What payment methods are accepted for LT3970IMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3970IMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3970IMS#PBF?
LT3970IMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3970IMS#PBF 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 LT3970IMS#PBF?
For technical support, including LT3970IMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3970IMS#PBF requirements.
6.How does Aetrix verify that LT3970IMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT3970IMS#PBF 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 LT3970IMS#PBF meets industry standards.
7.What is the process for return or replacement of LT3970IMS#PBF?
All LT3970IMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3970IMS#PBF, 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 LT3970IMS#PBF part is unused and in its original packaging.
Return procedure for LT3970IMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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