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Analog Devices Inc. LT3973IMSE#TRPBF
- Part No.:
- LT3973IMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3973IMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 750MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,955
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Product details
Overview
LT3973IMSE#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 750mA monolithic synchronous step-down regulator with integrated boost and catch Schottky diodes, 2.5µA quiescent current, and adjustable switching frequency (200kHz–2.2MHz). It delivers fixed 5V output in thermally enhanced 10-lead MSOP package and is engineered for automotive cold-crank regulation where input may dip to 4.2V while maintaining regulated output.
For engineers reviewing the LT3973IMSE#TRPBF datasheet, LT3973IMSE#TRPBF pinout, LT3973IMSE#TRPBF application, or LT3973IMSE#TRPBF equivalent, key selection criteria include ultralow IQ (1.9µA at 12VIN), 530mV minimum dropout voltage, power good flag, programmable UVLO, and thermal shutdown - all validated across –40°C to 125°C junction temperature.
Technical Context
The LT3973IMSE#TRPBF employs current-mode control for fast transient response and loop stability, with internal bipolar NPN switch driven via BOOST pin to ensure full saturation. Its Burst Mode® operation maintains <10mVP-P output ripple at light loads while sustaining 90% regulation accuracy.
It integrates dual protection mechanisms: catch diode current limiting (1.15A typical) and thermal shutdown, plus an accurate programmable undervoltage lockout (1.19V rising threshold, 45mV hysteresis) and power good flag signaling when VOUT reaches 90% of target. The OUT pin enables dropout regulation down to 530mV VIN–VOUT differential.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 42V - supports automotive battery systems including cold-crank (≥4.2V required for FB regulation) |
| Output Voltage | Fixed 5V ±1.2% - internally trimmed; no external feedback resistors needed |
| Max Output Current | 750mA - limited by switch current (1.65A typ) and catch diode valley current (1.15A typ) |
| Quiescent Current | 1.9µA at 12VIN - enables always-on systems with multi-year battery life |
| Switching Frequency | 200kHz to 2.2MHz - set externally via RT-to-GND resistor; enables compact magnetics |
| Minimum Dropout Voltage | 530mV - ensures regulation during deep input sag (e.g., automotive cranking) |
| Power Good Threshold | 90% of VOUT - open-drain PG flag asserts after soft-start completes and output stabilizes |
Pinout & Package
LT3973IMSE#TRPBF is housed in a 10-lead plastic MSOP package with exposed thermal pad (Pin 11 = GND), θJA = 45°C/W. The exposed pad must be soldered to PCB for thermal performance and electrical grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB/VOUT (Pin 1) | Feedback / Fixed Output Sense | For LT3973IMSE#TRPBF (5V variant), this pin is VOUT - internally connected to fixed 5V divider; no external resistor network required |
| OUT (Pin 2) | Dropout Regulation Node | Connects to output rail; enables minimum dropout enforcement (530mV) and boost capacitor charging during low-VIN operation |
| EN/UVLO (Pin 3) | Enable & Programmable Undervoltage Lockout | Active-high enable; 1.19V rising threshold with 45mV hysteresis - allows precise input brownout detection |
| VIN (Pin 4) | Main Power Input | Supplies internal circuitry and switch driver; requires local 4.7µF ceramic bypass |
| GND (Pin 5 & Exposed Pad 11) | Signal & Thermal Ground | Common return for all circuits; exposed pad is electrically GND and mandatory for thermal dissipation |
| SW (Pin 6) | Switch Node | Drives external inductor; connects to cathode of catch diode and anode of boost diode |
| BOOST (Pin 7) | Bootstrap Drive Supply | Provides >VIN voltage to fully saturate internal bipolar NPN switch; requires external 0.47µF ceramic capacitor |
| BD (Pin 8) | Boost Diode Anode Input | Accepts external boost diode anode; also powers internal bias regulator when BD >3.2V (improves efficiency) |
| PG (Pin 9) | Power Good Flag | Open-drain output; pulled low until VOUT ≥90% of 5V; valid only when EN high and VIN >4.2V |
| RT (Pin 10) | Frequency Set Input | Resistor from RT to GND programs switching frequency (200kHz–2.2MHz); sets oscillator timing |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow Quiescent Current | 1.9µA at 12VIN - extends battery runtime in always-on automotive and IoT applications |
| Integrated Power Diodes | On-die boost and catch Schottky diodes - eliminate two external components and reduce board area |
| Burst Mode® Operation | <10mVP-P output ripple at light load - maintains high efficiency without audible noise or EMI spikes |
| Accurate Programmable UVLO | 1.19V rising threshold with 45mV hysteresis - enables precise system-level brownout recovery control |
| Thermal Shutdown Protection | Activates above 165°C junction - prevents permanent damage during overload or poor heatsinking |
| Power Good Flag | Open-drain PG signals 90% VOUT - provides reliable power sequencing signal for microcontrollers and FPGAs |
Applications
| Automotive Battery Regulation | Industrial Sensor Node Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to stable 5V during engine cranking, where input sags to 4.2V. IC Role / Device Role / Timing Role: Primary buck regulator with dropout enforcement and ultralow IQ for always-on telematics modules. Use Value: Maintains 5V output with 530mV minimum dropout and 1.9µA quiescent current - avoids system reset during cold-crank events. |
Use Scenario: Powering low-power industrial sensors (e.g., pressure, temperature) in remote locations with long-life batteries. IC Role / Device Role / Timing Role: Primary DC-DC converter enabling multi-year operation via Burst Mode® and sub-2µA shutdown current. Use Value: Delivers 750mA peak current while consuming only 1.9µA at 12VIN, extending battery life beyond 10 years in sleep mode. |
| Gate Drive Bias Supply | Portable Medical Device Power |
Use Scenario: Generating isolated 5V bias for high-side MOSFET gate drivers in motor control inverters. IC Role / Device Role / Timing Role: Compact, high-reliability buck stage supplying clean 5V to driver ICs with fast transient response. Use Value: Integrated diodes and current-mode control deliver <10mVP-P ripple and 750mA current - ensures robust gate drive under dynamic load. |
Use Scenario: Powering portable diagnostic devices (e.g., pulse oximeters, glucose meters) requiring FDA-compliant, low-noise 5V rails. IC Role / Device Role / Timing Role: Primary power management IC with medical-grade thermal safety and precise 5V regulation. Use Value: 5V ±1.2% accuracy, 90% PG flag, and –40°C to 125°C operation meet IEC 60601-1 environmental requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMSE#TRPBF | 40V input, 500mA output, 3.5µA IQ, no integrated diodes - requires external catch diode | Lacks integrated diodes and has lower current rating; suitable only for lower-power, space-tolerant designs | Select if lower cost and simpler layout outweigh need for 750mA output and ultralow IQ |
| TPS62130ARGTR | 17V input, 3A output, 17µA IQ, integrated FETs but no boost/catch diodes - uses external diodes | Higher current but narrower input range (17V max); not rated for automotive cold-crank (4.2V min) | Choose only for non-automotive 12V systems requiring >750mA, accepting higher IQ and no dropout optimization |
Compared with LTC3630EMSE#TRPBF and TPS62130ARGTR, LT3973IMSE#TRPBF uniquely combines 42V input, 750mA output, 1.9µA IQ, integrated diodes, and 530mV dropout - making it the only option qualified for demanding automotive and battery-critical applications without design compromises.
Availability
LT3973IMSE#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial sensor node power, gate drive bias supplies, and portable medical device power requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3973IMSE#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 maintains its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification standards.
The LT3973 product line was designed specifically for high-input-voltage, ultralow-quiescent-current DC-DC conversion in automotive, industrial, and battery-powered systems - emphasizing reliability under extreme voltage transients and thermal stress.
FAQ
What is the operating temperature range for LT3973IMSE#TRPBF?
The LT3973IMSE#TRPBF is specified for operation from –40°C to +125°C junction temperature. This I-grade rating makes it suitable for under-hood automotive applications and industrial environments where ambient temperatures exceed 85°C. The MSOP package's exposed pad must be soldered to PCB copper for effective thermal conduction.
Does LT3973IMSE#TRPBF require external diodes?
No, LT3973IMSE#TRPBF integrates both the boost Schottky diode and catch Schottky diode on-die. This eliminates two external components, reduces board area, and improves reliability. The BD pin connects to the anode of the internal boost diode, and SW connects directly to the cathode of the internal catch diode - no external diodes are needed for basic operation.
How is the 5V output set on LT3973IMSE#TRPBF?
LT3973IMSE#TRPBF is the fixed 5V variant - Pin 1 is labeled VOUT (not FB), and the internal feedback divider is factory-trimmed to regulate precisely to 5V ±1.2%. No external resistors are required. This differs from the adjustable LT3973 version (which uses FB pin and external R1/R2) and simplifies design for dedicated 5V applications.
What is the minimum input voltage required for LT3973IMSE#TRPBF to regulate 5V?
LT3973IMSE#TRPBF requires a minimum input voltage of 4.2V to maintain accurate 5V regulation, per its absolute minimum operating voltage specification. Below 4.2V, the part may still switch but will not hold 5V output due to FB reference degradation. During automotive cold-crank, it sustains regulation down to 4.2V with 530mV dropout enforced via the OUT pin.
Can LT3973IMSE#TRPBF be used in Burst Mode® and continuous conduction mode?
Yes, LT3973IMSE#TRPBF automatically enters Burst Mode® at light loads to achieve ultralow IQ (1.9µA) and <10mVP-P ripple, then seamlessly transitions to continuous conduction mode above ~100mA load. This dual-mode operation is internal and requires no external configuration - optimizing efficiency across the full 0–750mA load range.
LT3973IMSE#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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3973IMSE#TRPBF FAQ
1.How can I place an order for LT3973IMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973IMSE#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 LT3973IMSE#TRPBF reliable?
The price and inventory of LT3973IMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3973IMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3973IMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973IMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973IMSE#TRPBF?
LT3973IMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973IMSE#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 LT3973IMSE#TRPBF?
For technical support, including LT3973IMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973IMSE#TRPBF requirements.
6.How does Aetrix verify that LT3973IMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3973IMSE#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 LT3973IMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3973IMSE#TRPBF?
All LT3973IMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973IMSE#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 LT3973IMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3973IMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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