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Analog Devices Inc. LT3973IMSE-5#TRPBF
- Part No.:
- LT3973IMSE-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3973IMSE-5#TRPBF.pdf
- Description:
- IC REG BUCK 5V 750MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,656
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Product details
Overview
LT3973IMSE-5#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 750mA monolithic step-down DC/DC regulator with integrated boost and catch diodes, 2.5µA quiescent current, fixed 5V output, and operation down to 4.2V input - designed for automotive cold-crank battery regulation, industrial power supplies, and portable equipment bias rails.
For engineers reviewing the LT3973IMSE-5#TRPBF datasheet, LT3973IMSE-5#TRPBF pinout, LT3973IMSE-5#TRPBF application, or LT3973IMSE-5#TRPBF equivalent, key selection criteria include its 530mV minimum dropout voltage, 90% power-good threshold accuracy, 1.21V internal reference tolerance, and thermal shutdown protection in the 10-lead MSOP package.
Technical Context
The LT3973IMSE-5#TRPBF implements constant-frequency current-mode control with programmable switching frequency (200kHz–2.2MHz via RT resistor), enabling fast transient response and stable loop behavior across wide input ranges. Its bipolar NPN switch driver uses an external BOOST capacitor to achieve full saturation, sustaining high efficiency even during automotive dropout conditions.
Burst Mode® operation reduces no-load input current to 1.8µA while maintaining output ripple below 10mVP-P; the integrated catch diode current limit (1.15A typ.) and switch current limit (1.65A typ.) provide coordinated fault protection during short-circuit or overvoltage events without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.2V to 42V - supports direct connection to 12V/24V automotive batteries including cold-crank transients. |
| Output Voltage | Fixed 5.00V ±1.2% - internally trimmed; eliminates external feedback resistors and improves load/line regulation stability. |
| Quiescent Current | 2.5µA at 12VIN → 5VOUT - enables always-on systems with multi-year battery life in low-power applications. |
| Switching Frequency | 200kHz to 2.2MHz - adjustable via RT-to-GND resistor; allows optimization of inductor size vs. EMI vs. efficiency trade-offs. |
| Maximum Output Current | 750mA - sustained under thermal limits (θJA = 45°C/W); limited by switch and catch diode current thresholds. |
| Minimum Dropout Voltage | 530mV - ensures regulation when VIN drops near VOUT, critical for automotive start-stop and brownout resilience. |
| Power Good Threshold | 90% of regulated output - open-drain PG flag asserts after VOUT stabilizes, enabling system sequencing and fault monitoring. |
Pinout & Package
LT3973IMSE-5#TRPBF is housed in a thermally enhanced 10-lead plastic MSOP package (3mm × 3mm footprint) with exposed pad (Pin 11) soldered to PCB ground for optimal thermal performance (θJA = 45°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Fixed-output regulation node | Internally connected to precision 5V feedback divider; connects directly to output capacitor and load. |
| OUT (Pin 2) | Dropout regulation & boost charge path | Provides dropout headroom control and supplies current to charge the BOOST capacitor during low-VIN operation. |
| EN/UVLO (Pin 3) | Enable and undervoltage lockout input | Active-high enable with 1.19V rising threshold and 30mV hysteresis; disables regulator and reduces IQ to 0.75µA in shutdown. |
| VIN (Pin 4) | Main power input | Supplies internal circuitry and switch driver; requires local 4.7µF ceramic bypass capacitor. |
| GND (Pin 5 & Pin 11) | Signal and power ground | Pin 5 is signal GND; Pin 11 is exposed thermal pad - must be soldered to PCB ground plane for thermal and electrical integrity. |
| 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 voltage source | Drives internal NPN switch base; requires external 0.47µF ceramic capacitor between BOOST and SW pins. |
| BD (Pin 8) | Bias diode anode | Accepts external bias (≥3.2V) to improve efficiency; also powers internal regulator when BD > 3.2V. |
| PG (Pin 9) | Power good open-drain output | Sinks current when VOUT < 90% of target; requires external pull-up for logic-level signaling to host controller. |
| RT (Pin 10) | Frequency programming input | Resistor from RT to GND sets switching frequency; 215kΩ yields ~600kHz per datasheet Table 1. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost and catch diodes | Eliminates four external diodes, reducing BOM count, board area, and forward-drop losses in compact designs. |
| Low-ripple Burst Mode® operation | Maintains <10mVP-P output ripple at light loads while achieving 1.8µA no-load IQ, ideal for sensor nodes and standby circuits. |
| Accurate programmable UVLO | EN/UVLO threshold (1.19V ±70mV) enables precise battery undervoltage cutoff without external comparators or dividers. |
| Thermal shutdown with hysteresis | Protects against sustained overload or poor heatsinking; automatically recovers after junction temperature falls below hysteresis threshold. |
| Internal 1.21V reference with 0.1nA bias | Enables ultra-low-power feedback networks; supports high-value resistors (>1MΩ) to minimize divider current in battery-powered systems. |
Applications
| Automotive Battery Regulation | Industrial Power Supplies |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery rail during cold-crank (down to 3.5V) and load-dump transients (up to 42V). IC Role / Device Role / Timing Role: Primary buck converter delivering stable 5V to infotainment microcontrollers, CAN transceivers, and sensor hubs. Use Value: 530mV dropout and 2.5µA quiescent current ensure continuous operation and extended battery life in always-on modules. | Use Scenario: Providing isolated 5V bias for PLC I/O modules, motor drivers, and fieldbus interface ICs in harsh factory environments. IC Role / Device Role / Timing Role: Main 5V supply for digital logic, ADC references, and gate drivers requiring high PSRR and low noise. Use Value: Integrated diodes and thermal shutdown eliminate discrete protection components, improving reliability and reducing failure points. |
| Portable Product Power | Gate Drive Bias |
Use Scenario: Powering handheld test equipment, medical monitors, and ruggedized tablets operating from Li-ion or 24V industrial batteries. IC Role / Device Role / Timing Role: Efficient 5V conversion stage feeding PMICs, USB regulators, and display controllers. Use Value: 750mA output and 42V max input support wide-input battery packs; Burst Mode extends runtime in sleep states. | Use Scenario: Generating clean 5V bias for high-side N-channel MOSFET drivers in half-bridge and H-bridge inverters. IC Role / Device Role / Timing Role: Dedicated gate supply decoupled from main power rail to prevent shoot-through and ensure robust turn-on. Use Value: Low output ripple (<10mVP-P) and fast transient response maintain gate voltage integrity during switching transitions. |
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-5#TRPBF | Lower IQ (1.2µA), same 5V fixed output, but only 300mA output current and 15V max input. | Suitable for ultra-low-power, low-current applications where 42V input capability is unnecessary. | Select when system load ≤300mA and input voltage never exceeds 15V; not suitable for automotive or wide-input industrial use. |
| TPS54340DDAR | Adjustable output (0.8V–28V), 3.5A output, 42V input, but requires external diodes and has higher IQ (146µA). | Used where output voltage flexibility or higher current is required, accepting larger solution size and lower light-load efficiency. | Choose when design needs programmable VOUT or >750mA current; accept added BOM cost and reduced battery life versus LT3973IMSE-5#TRPBF. |
Compared with LTC3630EMSE-5#TRPBF, LT3973IMSE-5#TRPBF delivers 2.5× more output current and supports 2.8× higher input voltage, making it viable for automotive and industrial 24V systems; versus TPS54340DDAR, LT3973IMSE-5#TRPBF reduces component count and improves no-load efficiency but sacrifices output adjustability and peak current capability.
Availability
LT3973IMSE-5#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial power supplies, and portable product power applications requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT3973IMSE-5#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 high-performance analog and power management portfolio with rigorous qualification standards for automotive and industrial markets.
The LT3973 family was designed specifically for high-input-voltage, ultralow-quiescent-current DC/DC conversion in space-constrained, thermally demanding environments such as automotive ECUs and industrial sensors.
FAQ
What is the maximum input voltage rating for LT3973IMSE-5#TRPBF?
The absolute maximum input voltage for LT3973IMSE-5#TRPBF is 42V on the VIN pin, with 55V absolute maximum on the BOOST pin. Continuous operation above 42V violates Absolute Maximum Ratings and may cause permanent damage. The device regulates correctly up to 42V under normal conditions, and its dropout performance remains functional down to 4.2V input.
Does LT3973IMSE-5#TRPBF require external diodes?
No, LT3973IMSE-5#TRPBF integrates both the boost diode and catch diode on-die, eliminating the need for external diodes. This reduces bill-of-materials count, PCB area, and conduction losses. The internal catch diode supports up to 1.15A valley current, and the boost diode handles typical bootstrap charging currents up to 13mA.
How is the switching frequency set on LT3973IMSE-5#TRPBF?
The switching frequency of LT3973IMSE-5#TRPBF is set by connecting a resistor between the RT pin (Pin 10) and ground. For example, a 215kΩ resistor sets fSW ≈ 600kHz. The supported range is 200kHz to 2.2MHz, with values tabulated in the datasheet's Table 1. No external capacitor or oscillator component is required.
What is the purpose of the OUT pin on LT3973IMSE-5#TRPBF?
The OUT pin (Pin 2) on LT3973IMSE-5#TRPBF serves two functions: (1) it provides dropout regulation headroom control, enforcing a minimum 530mV difference between VIN and VOUT; and (2) it supplies current to charge the BOOST capacitor during low-input-voltage operation. It must be connected to the output node (VOUT) for proper dropout behavior.
Is LT3973IMSE-5#TRPBF pin-compatible with other variants in the LT3973 family?
Yes, all LT3973 variants-including LT3973IMSE-5#TRPBF, LT3973IMSE-3.3#TRPBF, and the adjustable LT3973IMSE#TRPBF-share identical 10-lead MSOP pinouts and thermal pad configuration. Only the internal feedback network differs: LT3973IMSE-5#TRPBF has a factory-trimmed 5V output, while others use FB or VOUT pins for external or fixed regulation.
LT3973IMSE-5#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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.2V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- 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-5#TRPBF FAQ
1.How can I place an order for LT3973IMSE-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973IMSE-5#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-5#TRPBF reliable?
The price and inventory of LT3973IMSE-5#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-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3973IMSE-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973IMSE-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973IMSE-5#TRPBF?
LT3973IMSE-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973IMSE-5#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-5#TRPBF?
For technical support, including LT3973IMSE-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973IMSE-5#TRPBF requirements.
6.How does Aetrix verify that LT3973IMSE-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3973IMSE-5#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-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3973IMSE-5#TRPBF?
All LT3973IMSE-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973IMSE-5#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-5#TRPBF part is unused and in its original packaging.
Return procedure for LT3973IMSE-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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