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Analog Devices Inc. LT3970IMS-3.3#PBF
- Part No.:
- LT3970IMS-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3970IMS-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 350MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:150
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Product details
Overview
LT3970IMS-3.3#PBF from Analog Devices is a 40V, 350mA fixed-output step-down regulator in a 10-lead MSOP package, featuring 2.5µA quiescent current, integrated boost and catch diodes, and a 3.3V output with ±1.2% accuracy over –40°C to 125°C. It delivers low-ripple Burst Mode operation (<5mVP-P) and supports automotive battery regulation, portable power, and industrial supplies.
For engineers reviewing the LT3970IMS-3.3#PBF datasheet, LT3970IMS-3.3#PBF pinout, LT3970IMS-3.3#PBF application, or LT3970IMS-3.3#PBF equivalent, key selection criteria include its 3.3V fixed output, 2.5µA IQ at 12VIN, 0.7µA shutdown current, 1V EN threshold, and AEC-Q100 qualification for automotive use.
Technical Context
The LT3970IMS-3.3#PBF implements a constant-frequency, current-mode buck architecture with internal compensation and an integrated bipolar NPN power switch driven via BOOST pin voltage boosting. Its control loop uses an error amplifier servoing the VC node to regulate output by comparing VOUT against an internal 1.21V reference (for adjustable variants) or directly against the fixed 3.3V output rail (for -3.3 variants).
Burst Mode operation reduces input current to 1.7µA at light loads while maintaining <5mVP-P ripple; a power good flag signals when VOUT reaches 90% of nominal; and catch diode current limiting (400mA typical) provides short-circuit protection without external components.
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 ensures stable regulation across automotive temperature range. |
| Quiescent Current | 2.5µA at 12VIN to 3.3VOUT - enables multi-year battery life in always-on portable and telematics systems. |
| Max Input Voltage | 40V operating, 40V VIN absolute max - supports direct connection to 24V/36V industrial and automotive battery rails with transient margin. |
| Output Current | 350mA continuous - sufficient for powering microcontrollers, sensors, and interface ICs in compact embedded systems. |
| Switching Frequency | Adjustable 200kHz–2.2MHz via RT resistor - allows optimization of inductor size (e.g., 22µH at 600kHz) and EMI profile per application constraints. |
| Power Good Flag | Open-drain PG asserts high when VOUT ≥ 90% of 3.3V - provides reliable system-level power sequencing and fault detection without external comparators. |
| Enable Threshold | 1.0V rising-edge EN threshold with 30mV hysteresis - ensures clean startup/shutdown control even with noisy supply rails. |
| AEC-Q100 Grade | I-grade (–40°C to 125°C) - qualified for automotive infotainment, body electronics, and ADAS subsystems requiring zero-defect reliability. |
Pinout & Package
LT3970IMS-3.3#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.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Fixed output voltage sense and regulation node | Internally connected to precision divider; regulates to 3.3V - no external FB resistor required, simplifying layout and reducing BOM count. |
| EN (Pin 2) | Enable control input | Hysteretic 1.0V threshold enables precise power sequencing; tied to VIN for always-on operation. |
| VIN (Pin 3) | Main power input | Supplies internal circuitry and switch; requires local 1–4.7µF X7R ceramic bypass to suppress high-di/dt switching noise. |
| GND (Pins 4, 5) | Signal and power ground | Dual GND pins reduce ground impedance and improve thermal dissipation in high-current paths. |
| SW (Pin 6) | Switch node | Connects to inductor; carries pulsed current up to 700mA peak - requires tight layout with minimal trace inductance. |
| BOOST (Pin 7) | Bootstrap drive voltage source | Accepts external capacitor to generate >VIN voltage for full NPN switch saturation - critical for efficiency at high duty cycles. |
| BD (Pin 8) | Boost diode anode connection | Provides bias current to internal regulator when >3.2V - improves efficiency by sourcing control power from regulated output. |
| PG (Pin 9) | Power good open-drain output | Sinks current when VOUT < 2.97V; requires external pull-up for MCU reset or status monitoring. |
| RT (Pin 10) | Frequency setting input | Resistor-to-ground sets switching frequency (e.g., 226kΩ = 600kHz); enables EMI tuning and component size trade-offs. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost & catch diodes | Eliminates 2 external Schottky diodes - reduces board area, assembly cost, and thermal stress in space-constrained designs. |
| Low-ripple Burst Mode | Maintains <5mVP-P output ripple at light loads while drawing only 1.7µA - preserves signal integrity in noise-sensitive analog and RF circuits. |
| Internal current limit protection | 350mA valley current limit on catch diode and 700mA peak switch limit - prevents damage during output shorts without external current-sense circuitry. |
| Accurate power good flag | 10% regulation window (2.97V–3.3V) with 12mV hysteresis - enables robust system-level power monitoring with no calibration needed. |
| Automotive-grade qualification | AEC-Q100 I-grade (–40°C to 125°C) with controlled manufacturing - meets TS 16949 requirements for automotive OEM and Tier-1 applications. |
Applications
| Automotive Body Control Module | Industrial Sensor Node |
|---|---|
Use Scenario: Powering CAN transceivers, LIN controllers, and door lock actuators in 12V/24V vehicle electrical systems with cold-crank tolerance. IC Role / Device Role / Timing Role: Primary 3.3V point-of-load regulator delivering stable, low-noise supply under wide-input transients (4.2V–40V). Use Value: AEC-Q100 qualification and 2.5µA quiescent current enable compliance with ISO 16750-2 pulse tests and extended battery-off drain budgets. | Use Scenario: Supplying ultra-low-power microcontrollers and MEMS pressure/temperature sensors in remote IIoT field devices powered by 24V DC or energy harvesting. IC Role / Device Role / Timing Role: Fixed-output buck converter providing regulated 3.3V rail with minimal external components and no feedback network. Use Value: 350mA output current and 0.7µA shutdown current support intermittent wake-up operation and multi-year deployment without maintenance. |
| Portable Medical Monitor | Railway Signaling Interface |
Use Scenario: Powering display drivers, ADCs, and Bluetooth LE modules in handheld patient monitors operating from single-cell Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: High-efficiency step-down regulator converting 3.6V–40V input to clean 3.3V for mixed-signal subsystems. Use Value: Low-ripple Burst Mode ensures ECG/SpO₂ signal fidelity; integrated diodes reduce solution size for compact, certified medical enclosures. | Use Scenario: Providing isolated 3.3V logic supply for RS-485 transceivers and FPGA configuration in EN 50121-compliant railway signaling cabinets with 72V nominal bus. IC Role / Device Role / Timing Role: Robust DC-DC converter handling wide input (4.2V–40V) and surviving 100V transients per IEC 61000-4-5 Level 4. Use Value: 40V absolute maximum VIN and internal current limiting eliminate need for upstream TVS or current-limiting FETs, simplifying front-end design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMS-3.3#PBF | Same manufacturer, pin-compatible MSOP-10, but higher 100mA max output and lower 1.2µA IQ - lacks catch diode integration and AEC-Q100 rating. | Targeted at ultra-low-power logic rails only; unsuitable for 350mA loads or automotive environments. | Select only if load current ≤100mA and lowest possible IQ is primary requirement. |
| TPS62130ARGTR | 3.3V fixed-output buck (3A capable), 17µA IQ, 3–17V input, no integrated catch diode - requires external Schottky and feedback resistors. | Higher current capability but larger solution size and less suitable for 40V input or automotive qualification. | Choose when >350mA output or wider input range (3–17V) is needed, and external diode placement is acceptable. |
Compared with LTC3630EMS-3.3#PBF and TPS62130ARGTR, LT3970IMS-3.3#PBF uniquely combines 350mA output, 40V input, integrated diodes, AEC-Q100 qualification, and sub-3µA quiescent current - making it optimal for space-, power-, and reliability-constrained automotive and industrial buck applications.
Availability
LT3970IMS-3.3#PBF is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor nodes, portable medical monitors, and railway signaling interfaces requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT3970IMS-3.3#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, Inc. 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 was designed as a family of high-voltage, low-quiescent-current buck regulators targeting automotive battery-powered systems and industrial equipment where input voltage can exceed 24V and standby current must be minimized.
FAQ
What is the output voltage tolerance of the LT3970IMS-3.3#PBF over temperature?
The LT3970IMS-3.3#PBF delivers a fixed 3.3V output with ±1.2% initial accuracy over the full –40°C to 125°C operating junction temperature range. Electrical Characteristics table specifies min/max values of 3.26V (–40°C) to 3.34V (125°C) at rated load, ensuring stable regulation across automotive thermal extremes without external trimming.
Does the LT3970IMS-3.3#PBF require external diodes?
No, the LT3970IMS-3.3#PBF integrates both the boost diode and catch Schottky diode on-die. This eliminates two external components, reduces PCB area, improves thermal performance, and ensures matched diode characteristics - unlike many competing buck regulators that require discrete external diodes for proper operation.
How does the LT3970IMS-3.3#PBF achieve low quiescent current in Burst Mode?
The LT3970IMS-3.3#PBF achieves 1.7µA input current in Burst Mode by completely shutting down oscillator, error amplifier, and gate drive circuitry between switching bursts. Only essential bias and wake-up comparators remain active - enabling multi-year battery life in always-on applications such as telematics and remote sensors without sacrificing output ripple performance.
Is the LT3970IMS-3.3#PBF pin-compatible with other variants in the LT3970 family?
Yes, all LT3970 variants - including LT3970IMS-3.3#PBF, LT3970IMS-5#PBF, and LT3970IMS#PBF - share identical 10-lead MSOP pinouts and package dimensions. The only functional difference lies in internal feedback configuration: VOUT pin (Pin 1) is hardwired to 3.3V for LT3970IMS-3.3#PBF, eliminating external resistors required by the adjustable version.
What is the minimum input voltage required for the LT3970IMS-3.3#PBF to regulate 3.3V output?
The LT3970IMS-3.3#PBF requires a minimum input voltage of 4.2V to operate, as specified in Absolute Maximum Ratings and Electrical Characteristics. At 3.3V output, practical minimum VIN depends on switching frequency and duty cycle limits - e.g., at 600kHz, minimum VIN is ~5.0V due to tOFF(MIN) constraints - but the device will not start below 4.2V regardless of configuration.
LT3970IMS-3.3#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:
- 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-MSOP
LT3970IMS-3.3#PBF FAQ
1.How can I place an order for LT3970IMS-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3970IMS-3.3#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-3.3#PBF reliable?
The price and inventory of LT3970IMS-3.3#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-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LT3970IMS-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3970IMS-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3970IMS-3.3#PBF?
LT3970IMS-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3970IMS-3.3#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-3.3#PBF?
For technical support, including LT3970IMS-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3970IMS-3.3#PBF requirements.
6.How does Aetrix verify that LT3970IMS-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LT3970IMS-3.3#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-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LT3970IMS-3.3#PBF?
All LT3970IMS-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3970IMS-3.3#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-3.3#PBF part is unused and in its original packaging.
Return procedure for LT3970IMS-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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