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Analog Devices Inc. LT3970HMS#TRPBF
- Part No.:
- LT3970HMS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3970HMS#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 350MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,337
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Product details
Overview
LT3970HMS#TRPBF from Analog Devices is a 40V, 350mA monolithic step-down switching regulator with integrated boost and catch diodes, 2.5µA quiescent current, adjustable switching frequency (200kHz–2.2MHz), and power good flag. It operates across –40°C to 150°C and delivers regulated output from 1.21V to 25V in automotive battery regulation and industrial power supplies.
For engineers reviewing the LT3970HMS#TRPBF datasheet, LT3970HMS#TRPBF pinout, LT3970HMS#TRPBF application, or LT3970HMS#TRPBF equivalent, key selection criteria include its H-grade temperature rating (–40°C to 150°C), low-noise Burst Mode operation (<5mVP-P ripple), integrated diode architecture, and accurate 1V enable threshold with 0.7µA shutdown current.
Technical Context
The LT3970HMS#TRPBF implements 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, enabling high efficiency across wide input ranges (4.2V–40V).
Burst Mode operation reduces quiescent current to 1.7µA at light loads while maintaining output ripple below 5mVP-P; the power good (PG) comparator asserts when FB reaches 90% of regulation voltage, with 120mV hysteresis offset and open-drain output. Catch diode current limiting (400mA typical) provides short-circuit protection independent of switch current limit (700mA typical).
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 - maximum continuous load limited by catch diode valley current, not switch peak current. |
| 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 - programmable via RT resistor; higher frequencies allow smaller magnetics but reduce max duty cycle. |
| Feedback Reference | 1.21V ±1.2% over –40°C to 150°C - enables precise output programming from 1.21V to 25V using external resistive divider. |
| Power Good Threshold | 90% of regulation voltage with 120mV hysteresis - provides reliable startup sequencing and fault detection in safety-critical systems. |
| Enable Threshold | 1.0V rising edge with 30mV hysteresis - ensures clean, noise-immune enable/disable control without external Schmitt triggers. |
Pinout & Package
LT3970HMS#TRPBF 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 |
|---|---|---|
| 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) | Signal and power ground | Dual ground pins minimize ground bounce; both must connect to low-impedance PCB ground plane. |
| SW (Pin 6) | Switch node | Drives external inductor; carries high di/dt square wave; requires tight layout to minimize EMI. |
| BOOST (Pin 7) | Bootstrap drive | Connects to external capacitor charged above VIN to fully saturate internal bipolar NPN switch. |
| BD (Pin 8) | Boost diode anode | Provides bias power to internal regulator when >3.2V; improves efficiency by sourcing control power from VOUT. |
| PG (Pin 9) | Power good flag | Open-drain output pulled high externally; asserts when FB reaches 90% of target voltage. |
| RT (Pin 10) | Frequency set | Resistor-to-ground sets switching frequency from 200kHz to 2.2MHz per Table 1 in datasheet. |
Key Features
| Feature | Design Value |
|---|---|
| Low Ripple Burst Mode® | Maintains <5mVP-P output ripple at light loads while reducing IQ to 1.7µA - critical for noise-sensitive analog and RF subsystems. |
| Integrated Boost & Catch Diodes | Eliminates 2 external diodes and associated board space; reduces BOM count and layout complexity in compact designs. |
| AEC-Q100 Qualified H-Grade | Rated for –40°C to 150°C junction temperature with full electrical characterization - suitable for under-hood automotive applications. |
| Internal Sense Limits Catch Diode Current | 400mA valley current limit protects against shorted outputs without requiring external current-sense resistors or ICs. |
| Accurate Power Good Flag | 120mV hysteresis and 90% threshold provide robust sequencing margin in multi-rail systems with varying load transients. |
Applications
| Automotive Battery Regulation | Industrial Sensor Power Supply |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for microcontrollers, CAN transceivers, and ADCs in engine control units. IC Role / Device Role / Timing Role: Primary DC/DC converter providing isolated, low-noise, thermally robust power with AEC-Q100 compliance. Use Value: Enables direct battery connection without pre-regulator; 150°C rating supports placement near hot engine compartments. | Use Scenario: Powering precision 4–20mA loop-powered sensors and wireless IoT nodes in factory automation equipment. IC Role / Device Role / Timing Role: High-efficiency, ultra-low-IQ buck regulator delivering stable 3.3V from wide-input industrial rails (18–36V). Use Value: 2.5µA quiescent current extends battery life in maintenance-free sensor deployments; integrated diodes reduce footprint on dense PCBs. |
| Portable Medical Device Power | Avionics Subsystem Regulation |
Use Scenario: Generating 3.3V/5V from Li-ion (3.0–4.2V) or dual-cell alkaline (2.4–3.6V) batteries in handheld diagnostic tools. IC Role / Device Role / Timing Role: Adjustable-output buck converter operating down to 4.2VIN, supporting battery voltage sag during discharge. Use Value: Burst Mode maintains <5mV ripple during sleep states; 0.7µA shutdown current prevents battery drain during storage. | Use Scenario: Providing 5V rail for flight control processors and inertial measurement units (IMUs) in unmanned aerial vehicles. IC Role / Device Role / Timing Role: Radiation-tolerant (by design), high-reliability buck regulator with PG flag for system health monitoring. Use Value: Power good signal validates supply integrity before processor boot; 150°C rating accommodates conduction-cooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3970EMS#TRPBF | E-grade MSOP variant rated for –40°C to 125°C; identical electrical specs except wider temp tolerance. | Suitable for commercial/industrial environments where ambient temperature stays below 125°C. | Select LT3970EMS#TRPBF for cost-sensitive non-automotive applications with lower thermal stress. |
| LT3970EDDB#TRPBF | DFN package (3mm × 2mm); same H-grade temp range but different thermal resistance (θJA = 76°C/W vs 100°C/W). | Better power density and thermal performance in space-constrained layouts; requires exposed pad soldering. | Choose LT3970EDDB#TRPBF when PCB area is critical and thermal management via copper pour is feasible. |
Compared with LT3970EMS#TRPBF, the LT3970HMS#TRPBF offers extended junction temperature capability essential for under-hood automotive use; versus LT3970EDDB#TRPBF, it trades slightly higher thermal resistance for simplified assembly without exposed pad requirements.
Availability
LT3970HMS#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial sensor power supplies, and portable medical device power requiring stable component supply across extended temperature ranges.
Supply support for LT3970HMS#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 was designed as a family of high-voltage, low-quiescent-current buck regulators targeting automotive and harsh-environment applications where reliability, small size, and wide input range are critical.
FAQ
What is the maximum junction temperature specification for LT3970HMS#TRPBF?
The LT3970HMS#TRPBF is guaranteed over the full –40°C to 150°C operating junction temperature range per Analog Devices' characterization and testing. This H-grade rating makes it suitable for under-hood automotive applications where ambient temperatures exceed 125°C. Derating curves in the datasheet show lifetime reduction above 125°C, so thermal design must ensure sustained operation remains within this limit.
Does LT3970HMS#TRPBF require external diodes for boost or catch functions?
No, the LT3970HMS#TRPBF integrates both the boost diode and catch diode on-die. This eliminates two external components, reduces PCB area, and simplifies layout. The BD pin connects to the anode of the internal boost diode, and the SW pin interfaces directly with the inductor without needing an external catch diode. This integration is confirmed in the block diagram and pin function descriptions of the official datasheet.
How does the power good (PG) flag behave during startup and fault conditions for LT3970HMS#TRPBF?
The PG pin of LT3970HMS#TRPBF is an open-drain output that remains low until the FB pin reaches 90% of its regulated voltage, with 120mV hysteresis. It is only valid when VIN > 4.2V and EN is high. During output short circuits or undervoltage lockout, PG goes low to signal loss of regulation. This behavior enables reliable power sequencing and system-level fault detection in safety-critical designs.
Can LT3970HMS#TRPBF operate with input voltages below 4.2V?
No, the absolute minimum operating input voltage for LT3970HMS#TRPBF is 4.2V as specified in the Electrical Characteristics table. Below this, the internal regulator cannot sustain bias, and the EN threshold becomes invalid. If shutdown is required at lower VIN, EN must be grounded externally. The device will not regulate or assert PG below 4.2V, even if VIN momentarily dips during transients.
What is the purpose of the BD pin on LT3970HMS#TRPBF, and how should it be connected?
On LT3970HMS#TRPBF, the BD pin connects to the anode of the internal boost diode and also serves as an auxiliary bias input. When BD is held above 3.2V (e.g., tied to VOUT), the internal regulator draws power from BD instead of VIN, improving conversion efficiency. In standard configurations, BD is connected through a Schottky diode to the BOOST capacitor node. This dual-role design optimizes efficiency across load conditions without adding external components.
LT3970HMS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- 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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP
LT3970HMS#TRPBF FAQ
1.How can I place an order for LT3970HMS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3970HMS#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 LT3970HMS#TRPBF reliable?
The price and inventory of LT3970HMS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3970HMS#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3970HMS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3970HMS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3970HMS#TRPBF?
LT3970HMS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3970HMS#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 LT3970HMS#TRPBF?
For technical support, including LT3970HMS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3970HMS#TRPBF requirements.
6.How does Aetrix verify that LT3970HMS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3970HMS#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 LT3970HMS#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3970HMS#TRPBF?
All LT3970HMS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3970HMS#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 LT3970HMS#TRPBF part is unused and in its original packaging.
Return procedure for LT3970HMS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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