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Analog Devices Inc. LT3973EMSE-5#PBF
- Part No.:
- LT3973EMSE-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3973EMSE-5#PBF.pdf
- Description:
- IC REG BUCK 5V 750MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:109
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Product details
Overview
LT3973EMSE-5#PBF from Analog Devices (formerly Linear Technology) is a fixed 5V, 750mA monolithic step-down switching regulator with integrated power switch, catch diode, and boost diode. It operates from 4.2V to 42V input, delivers ultralow 2.5µA quiescent current at 12VIN, maintains <10mVP-P output ripple in Burst Mode, and features a power good flag and programmable undervoltage lockout - ideal for automotive cold-crank battery regulation.
For engineers reviewing the LT3973EMSE-5#PBF datasheet, LT3973EMSE-5#PBF pinout, LT3973EMSE-5#PBF application, or LT3973EMSE-5#PBF equivalent, key selection criteria include its 5V fixed output, 10-lead MSOP package with exposed thermal pad, 530mV minimum dropout voltage, -40°C to 125°C operating range, and compatibility with high-efficiency low-IQ power architectures requiring stable regulation under wide VIN transients.
Technical Context
The LT3973EMSE-5#PBF implements constant-frequency current-mode control with adjustable switching frequency (200kHz–2.2MHz via RT resistor), enabling fast transient response and robust loop stability. Its internal bipolar NPN switch is driven by a charge-pump boosted gate voltage (via BOOST pin), ensuring full saturation even during automotive dropout conditions.
Burst Mode operation reduces quiescent current to 1.8µA at light loads while maintaining <10mVP-P output ripple; an internal catch diode current limit (1.15A typical) and thermal shutdown provide fault protection. The device regulates VOUT to 5.0V ±1.2% over temperature and line, with power good signaling at 90% of final output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% (guaranteed over –40°C to 125°C junction) |
| Max Output Current | 750mA continuous (limited by thermal design and switch/catch diode current limits) |
| Input Voltage Range | 4.2V to 42V (supports automotive battery systems including cold-crank down to 4.2V) |
| Quiescent Current | 2.5µA at 12VIN → 5VOUT; 0.75µA in shutdown (enables always-on systems) |
| Switching Frequency | Programmable 200kHz–2.2MHz via RT-to-GND resistor (enables optimization of size vs. efficiency) |
| Output Ripple | <10mVP-P in Burst Mode (meets low-noise requirements for sensitive analog/RF circuitry) |
| Minimum Dropout | 530mV (maintains regulation when VIN drops near VOUT, e.g., during engine cranking) |
Pinout & Package
LT3973EMSE-5#PBF uses a thermally enhanced 10-lead plastic MSOP package with exposed GND pad (Pin 11), θJA = 45°C/W. The exposed pad must be soldered to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB/VOUT (Pin 1) | Feedback / Fixed Output Sense | For LT3973EMSE-5#PBF: internally connected to fixed 5V divider; no external resistor required |
| OUT (Pin 2) | Dropout Regulation Node | Tied to VOUT to enforce ≥530mV dropout; critical for cold-crank operation |
| EN/UVLO (Pin 3) | Enable & Programmable UVLO Input | Active-high enable; threshold 1.19V rising with 30mV hysteresis; enables battery undervoltage cutoff |
| VIN (Pin 4) | Main Power Input | Supplies internal circuitry and switch; requires local 4.7µF ceramic bypass |
| GND (Pin 5 & Exposed Pad 11) | Power & Signal Ground | Common reference for all circuits; exposed pad must be soldered for thermal management |
| SW (Pin 6) | Switch Node | Connects to inductor; carries high di/dt switching current; layout critical for EMI |
| BOOST (Pin 7) | Charge-Pump Drive | Drives external boost capacitor to generate >VIN gate drive for NPN switch saturation |
| BD (Pin 8) | Boost Diode Anode | Connects to boost diode anode; also powers internal bias regulator when >3.2V |
| PG (Pin 9) | Power Good Flag | Open-drain output active when VOUT reaches 90% of 5V; used for system sequencing |
| RT (Pin 10) | Frequency Set | Resistor-to-GND sets switching frequency (e.g., 215kΩ = 600kHz per datasheet) |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power Switch & Diodes | Eliminates 3 external components (high-side switch, catch diode, boost diode), reducing BOM count and layout area |
| Ultralow Quiescent Current | 2.5µA IQ enables >1-year battery life in always-on automotive modules (e.g., telematics, CAN wake-up receivers) |
| Low-Ripple Burst Mode | Maintains <10mVP-P output noise at microamp loads - avoids interference with precision ADCs or RF receivers |
| Accurate Power Good Flag | Signals valid 5V rail within 10% tolerance, enabling safe microcontroller reset and peripheral enable sequencing |
| Automotive-Capable Thermal Range | –40°C to 125°C junction rating with validated performance ensures reliability in under-hood environments |
| Programmable Undervoltage Lockout | Configurable EN/UVLO threshold prevents erratic operation during battery brownouts (e.g., <6V in start-stop systems) |
Applications
| Automotive Body Control Module (BCM) | Industrial Sensor Transmitter |
|---|---|
Use Scenario: Powering microcontroller, CAN transceiver, and LIN interface in a vehicle door module during cold-crank (VIN dips to 4.2V). IC Role / Device Role / Timing Role: Primary 5V buck regulator providing stable, low-noise supply with dropout recovery and UVLO cutoff. Use Value: Maintains 5V regulation down to 4.2V input and 530mV dropout, preventing MCU reset during engine cranking. |
Use Scenario: Supplying 5V to a 4–20mA current-loop transmitter in hazardous-area process instrumentation. IC Role / Device Role / Timing Role: Isolated 5V DC-DC stage delivering low-IQ power to analog front-end and HART modem. Use Value: 2.5µA quiescent current minimizes self-heating in sealed enclosures; Burst Mode preserves signal integrity. |
| Portable Medical Diagnostic Device | Smart Building Occupancy Sensor |
Use Scenario: Powering ADC, op-amps, and Bluetooth LE radio in a handheld ultrasound probe powered by Li-ion battery. IC Role / Device Role / Timing Role: Efficient 5V conversion from 3.0–4.2V battery range, supporting burst-mode acquisition and sleep states. Use Value: 1.8µA shutdown current extends battery runtime between clinical sessions; <10mV ripple avoids image artifacts. |
Use Scenario: Providing regulated 5V to PIR sensor, MCU, and sub-GHz wireless SoC in battery-operated occupancy sensors. IC Role / Device Role / Timing Role: Always-on power source with programmable UVLO to disable system before battery depletion. Use Value: 0.75µA shutdown IQ enables >5-year shelf life; PG flag synchronizes wake-up with stable rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMS8E-5#PBF | 42V input, 500mA, 3.5µA IQ, 8-lead MSOP, no integrated catch diode | Requires external Schottky; lower max current but smaller footprint | Choose when board space is constrained and 500mA suffices; verify external diode thermal performance. |
| TPS54340DDAR | 42V input, 3.5A, 145µA IQ, SO-8, external MOSFETs required | Higher current capability but significantly higher quiescent current; no integrated diodes | Choose only if >750mA load or cost-driven BOM optimization outweighs IQ penalty and layout complexity. |
Compared with LTC3630EMS8E-5#PBF and TPS54340DDAR, the LT3973EMSE-5#PBF uniquely combines 750mA output, 2.5µA IQ, integrated diodes, and automotive temperature range in a single 10-lead MSOP - making it optimal for space-constrained, ultra-low-power 5V systems where reliability under wide VIN transients is critical.
Availability
LT3973EMSE-5#PBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, portable medical diagnostics, and smart building controls requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT3973EMSE-5#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 acquired Linear Technology in 2017 and maintains its legacy of high-performance power management ICs with rigorous automotive and industrial qualification.
The LT3973 family was designed specifically for ultralow-quiescent-current, wide-input-voltage DC/DC conversion in harsh environments - targeting automotive battery regulation, portable instrumentation, and always-on IoT edge devices.
FAQ
What is the guaranteed output voltage accuracy of the LT3973EMSE-5#PBF over temperature?
The LT3973EMSE-5#PBF delivers 5.0V output with ±1.2% initial accuracy over the full –40°C to 125°C junction temperature range, as specified in the Electrical Characteristics table. This includes line, load, and temperature variation - verified by production testing and statistical process control, not just typical curves.
Does the LT3973EMSE-5#PBF require external diodes or MOSFETs?
No. The LT3973EMSE-5#PBF integrates the main power switch, catch diode, and boost diode on-die. Only an external inductor, input/output capacitors, RT resistor, and optional boost capacitor are required - eliminating three discrete components and associated layout complexity.
How does the LT3973EMSE-5#PBF maintain regulation during automotive cold-crank events?
The LT3973EMSE-5#PBF maintains regulation down to 4.2V input using two mechanisms: (1) a minimum dropout voltage of 530mV enforced via the OUT pin connection, and (2) extended duty cycle up to ~97.5% enabled by BOOST capacitor charge management - both critical for cold-crank survival.
What is the role of the BD pin on the LT3973EMSE-5#PBF?
The BD pin on the LT3973EMSE-5#PBF serves dual functions: it connects to the anode of the external boost diode, and - when held above 3.2V - supplies bias current to the internal regulator, improving efficiency by reducing VIN supply current during normal operation.
Can the LT3973EMSE-5#PBF be used with input voltages below 4.2V?
The LT3973EMSE-5#PBF will begin switching below 4.2V (down to ~3V), but regulation degrades: FB reference voltage drops, and output accuracy falls outside spec. For reliable 5V regulation, VIN must remain ≥4.2V - consistent with automotive battery minimums and datasheet operating range.
LT3973EMSE-5#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- 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):
- 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
LT3973EMSE-5#PBF FAQ
1.How can I place an order for LT3973EMSE-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973EMSE-5#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 LT3973EMSE-5#PBF reliable?
The price and inventory of LT3973EMSE-5#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3973EMSE-5#PBF is usually 5 days.
3.What payment methods are accepted for LT3973EMSE-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973EMSE-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973EMSE-5#PBF?
LT3973EMSE-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973EMSE-5#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 LT3973EMSE-5#PBF?
For technical support, including LT3973EMSE-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973EMSE-5#PBF requirements.
6.How does Aetrix verify that LT3973EMSE-5#PBF is sourced from the original manufacturer or authorized distributors?
All LT3973EMSE-5#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 LT3973EMSE-5#PBF meets industry standards.
7.What is the process for return or replacement of LT3973EMSE-5#PBF?
All LT3973EMSE-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973EMSE-5#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 LT3973EMSE-5#PBF part is unused and in its original packaging.
Return procedure for LT3973EMSE-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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