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Analog Devices Inc. LT3973HMSE#TRPBF
- Part No.:
- LT3973HMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3973HMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 750MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,498
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Product details
Overview
LT3973HMSE#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 750mA monolithic step-down regulator with integrated boost and catch diodes, 2.5µA quiescent current, and adjustable switching frequency (200kHz–2.2MHz). It operates in low-ripple Burst Mode® and maintains regulation down to 530mV dropout - critical for automotive cold-crank conditions. Used in high-reliability power rails for industrial sensors and automotive ECUs.
For engineers reviewing the LT3973HMSE#TRPBF datasheet, LT3973HMSE#TRPBF pinout, LT3973HMSE#TRPBF application, or LT3973HMSE#TRPBF equivalent, key selection criteria include its H-grade (–40°C to 150°C) junction temperature rating, integrated diode architecture eliminating external Schottky losses, and programmable UVLO with 0.75µA shutdown current.
Technical Context
The LT3973HMSE#TRPBF employs current-mode control for fast transient response and stable loop behavior across wide input (4.2V–42V) and output voltage ranges. Its internal bipolar NPN switch is driven via an external BOOST capacitor, enabling full saturation even at high duty cycles up to ~97.5% during dropout.
Burst Mode® operation reduces no-load input current to 1.8µA while maintaining output ripple below 10mVP-P; the power-good flag (PG) asserts when VOUT reaches 90% of regulation, and the EN/UVLO pin provides accurate, hysteresis-enabled enable control with 1.19V rising threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 42V - supports 12V/24V/36V automotive and industrial bus inputs without pre-regulation. |
| Output Current | 750mA - sufficient for powering microcontrollers, CAN transceivers, and analog front-ends directly. |
| 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 - adjustable via RT resistor; higher frequencies allow smaller magnetics and reduced EMI filter size. |
| Minimum Dropout Voltage | 530mV - ensures regulation during automotive cold-crank (e.g., VIN drops to 4.5V while VOUT = 3.3V remains stable). |
| Operating Junction Temp | –40°C to +150°C - H-grade qualification enables deployment in engine bay, motor drives, and high-ambient industrial enclosures. |
| Feedback Reference | 1.21V ±1.2% over temperature - enables precise output programming with standard resistor dividers. |
Pinout & Package
LT3973HMSE#TRPBF uses a thermally enhanced 10-lead Plastic MSOP package with exposed pad (Pin 11 = GND), θJA = 45°C/W. The exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB (Pin 1) | Feedback reference input | Regulated to 1.21V; connects to resistor divider tap for adjustable output voltage configuration. |
| OUT (Pin 2) | Dropout regulation node | Internally monitors VIN–VOUT differential; ties to VOUT to enforce ≥530mV dropout margin during low-VIN operation. |
| EN/UVLO (Pin 3) | Enable and undervoltage lockout input | Active-high enable with 1.19V rising threshold and 30mV hysteresis; supports programmable brown-out protection. |
| VIN (Pin 4) | Main power input | Supplies internal circuitry and switch driver; requires local 4.7µF ceramic bypass capacitor. |
| GND (Pin 5 & Pin 11) | Power and signal ground | Pin 5 is signal GND; Pin 11 is exposed thermal pad - both must connect to solid ground plane for thermal performance and noise immunity. |
| SW (Pin 6) | Switch node | Connects to inductor; carries high di/dt switching current - layout critical for EMI and efficiency. |
| BOOST (Pin 7) | Bootstrap drive supply | Drives internal NPN switch base; requires external 0.47µF ceramic capacitor between BOOST and SW. |
| BD (Pin 8) | Bias diode anode | Accepts external bias (≥3.2V) to improve efficiency by powering internal regulator from VOUT instead of VIN. |
| PG (Pin 9) | Power-good open-drain flag | Asserts high (via external pull-up) when FB reaches 90% of target - used for system sequencing and fault monitoring. |
| RT (Pin 10) | Frequency set resistor | Resistor to GND sets switching frequency from 200kHz to 2.2MHz; enables optimization for size vs. efficiency trade-offs. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost and catch diodes | Eliminates two external Schottky diodes, reducing BOM count, board area, and conduction losses in compact designs. |
| Low-ripple Burst Mode® operation | Maintains <10mVP-P output ripple at light loads while drawing only 1.8µA input current - ideal for noise-sensitive analog circuits. |
| Accurate programmable UVLO | EN/UVLO threshold (1.19V ±30mV) allows precise system-level brown-out detection without external comparators. |
| Thermal shutdown and current limiting | Combines catch diode valley current limit (1.15A typ) and switch peak current limit (1.65A typ) for robust short-circuit protection. |
| Power-good flag with hysteresis | PG asserts at 90% of regulation with 0.8% hysteresis - provides clean, glitch-free system power sequencing signals. |
Applications
| Automotive Body Control Module (BCM) | Industrial IoT Sensor Node |
|---|---|
Use Scenario: Powering microcontroller, LIN transceiver, and EEPROM in under-hood BCM exposed to –40°C to +125°C ambient. IC Role / Device Role / Timing Role: Primary 3.3V/5V buck regulator delivering 750mA with cold-crank support and low quiescent current. Use Value: Maintains regulation during 4.5V battery dips; 2.5µA IQ extends sleep-mode battery life; H-grade temp rating ensures reliability at 150°C junction. |
Use Scenario: Supplying ultra-low-power MCU, LoRaWAN radio, and environmental sensor in sealed outdoor enclosure. IC Role / Device Role / Timing Role: Always-on 3.3V regulator enabling multi-year battery operation via Burst Mode® and 1.8µA no-load current. Use Value: Sub-10mV ripple avoids RF interference; integrated diodes reduce component count; 42V input withstands lightning-induced surges. |
| Programmable Logic Controller (PLC) I/O Module | Medical Patient Monitor Auxiliary Rail |
Use Scenario: Generating isolated 5V rail for digital I/O drivers in DIN-rail mounted PLC with 24VDC field supply. IC Role / Device Role / Timing Role: Non-isolated 24V-to-5V buck converter with high input voltage tolerance and robust fault protection. Use Value: 42V max input handles 24V transients; current limiting prevents damage during field wiring shorts; thermal shutdown protects against enclosure overheating. |
Use Scenario: Providing clean, low-noise 3.3V supply for ADC reference and ECG front-end in Class II medical device. IC Role / Device Role / Timing Role: Secondary regulated rail with tight feedback accuracy (±1.2%) and minimal conducted EMI. Use Value: 1.21V reference stability over temperature ensures consistent ADC performance; low ripple avoids signal corruption in sensitive analog paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3973IMSE#TRPBF | I-grade (–40°C to 125°C) vs. H-grade (–40°C to 150°C); identical electrical specs and pinout. | Suitable for non-under-hood industrial or commercial applications where junction temperature stays ≤125°C. | Select LT3973IMSE#TRPBF when ambient conditions do not require 150°C junction capability - lower cost and same footprint. |
| LT3973HDD#TRPBF | Same H-grade rating but in 3mm × 3mm DFN package (θJA = 40°C/W vs. 45°C/W); identical functionality and pinout mapping. | Better thermal performance in space-constrained layouts; requires different PCB land pattern and reflow profile. | Choose LT3973HDD#TRPBF when board area is limited and thermal design prioritizes lower θJA, accepting DFN assembly requirements. |
Compared with LT3973IMSE#TRPBF, the LT3973HMSE#TRPBF delivers extended high-temperature operation essential for engine compartment or high-power-density industrial use; versus LT3973HDD#TRPBF, it trades slightly higher thermal resistance for MSOP's ease of prototyping and visual inspection.
Availability
LT3973HMSE#TRPBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, and medical auxiliary power supplies requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT3973HMSE#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 acquired Linear Technology in 2017 and continues its legacy of high-performance analog and power management ICs for demanding applications.
The LT3973 family is designed for high-input-voltage, low-quiescent-current DC/DC conversion in automotive, industrial, and medical systems where reliability under extreme thermal and electrical stress is mandatory.
FAQ
What is the maximum junction temperature rating for LT3973HMSE#TRPBF?
The LT3973HMSE#TRPBF is rated for operation from –40°C to +150°C junction temperature. This H-grade qualification is verified per Linear Technology/Analog Devices specifications and enables use in under-hood automotive locations and high-ambient industrial environments where standard I-grade parts (–40°C to 125°C) would exceed thermal limits.
Does LT3973HMSE#TRPBF require external diodes?
No, the LT3973HMSE#TRPBF integrates both the boost diode and catch diode on-die. This eliminates the need for two external Schottky diodes, reducing bill-of-materials cost, PCB area, and conduction losses - a key differentiator versus traditional buck controllers requiring external FETs and diodes.
How does LT3973HMSE#TRPBF achieve low quiescent current in Burst Mode®?
The LT3973HMSE#TRPBF achieves 1.8µA no-load input current in Burst Mode® by completely disabling its oscillator, error amplifier, and gate driver between energy bursts. Only essential bias circuitry remains active, minimizing static power draw while maintaining output regulation within 10mVP-P ripple - critical for battery-powered systems.
What is the purpose of the OUT pin on LT3973HMSE#TRPBF?
The OUT pin on LT3973HMSE#TRPBF serves as a dropout comparator input. When tied to VOUT, it enforces a minimum 530mV VIN–VOUT differential, ensuring the internal switch remains saturated and the BOOST capacitor stays charged during low-input-voltage conditions such as automotive cold-crank - preserving regulation down to VIN = VOUT + 0.53V.
Can LT3973HMSE#TRPBF be used with a fixed 5V output without external resistors?
No - the LT3973HMSE#TRPBF is the adjustable version of the family and requires an external resistor divider on the FB pin to set output voltage. For fixed 5V output, use LT3973HMSE-5#TRPBF, which has internal feedback resistors and pins FB/VOUT configured as VOUT. The part number suffix determines output configuration.
LT3973HMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) 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):
- 42V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 24V
- Current - Output:
- 750mA
- Frequency - Switching:
- 195kHz ~ 2.15MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3973HMSE#TRPBF FAQ
1.How can I place an order for LT3973HMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973HMSE#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 LT3973HMSE#TRPBF reliable?
The price and inventory of LT3973HMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3973HMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3973HMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973HMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973HMSE#TRPBF?
LT3973HMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973HMSE#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 LT3973HMSE#TRPBF?
For technical support, including LT3973HMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973HMSE#TRPBF requirements.
6.How does Aetrix verify that LT3973HMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3973HMSE#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 LT3973HMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3973HMSE#TRPBF?
All LT3973HMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973HMSE#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 LT3973HMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3973HMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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