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Analog Devices Inc. LT3973EDD-5#TRPBF
- Part No.:
- LT3973EDD-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3973EDD-5#TRPBF.pdf
- Description:
- IC REG BUCK 5V 750MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,185
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Product details
Overview
LT3973EDD-5#TRPBF from Analog Devices (formerly Linear Technology) is a fixed 5V, 750mA monolithic step-down DC/DC 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 supports automotive cold-crank dropout with 530mV minimum dropout voltage.
For engineers reviewing the LT3973EDD-5#TRPBF datasheet, LT3973EDD-5#TRPBF pinout, LT3973EDD-5#TRPBF application, or LT3973EDD-5#TRPBF equivalent, key selection criteria include its fixed 5V output, 10-lead 3mm × 3mm DFN package with exposed thermal pad, -40°C to 125°C operating range, and integrated protection features including catch diode current limit and thermal shutdown.
Technical Context
The LT3973EDD-5#TRPBF implements constant-frequency current-mode control with programmable switching frequency (200kHz–2.2MHz via RT pin), enabling fast transient response and stable loop behavior. Its architecture integrates a bipolar NPN main switch, on-die Schottky catch and boost diodes, and internal 1.21V reference for feedback regulation - with the LT3973-5 variant using an internal resistor divider to fix VOUT at 5.00V ±1.2% over temperature.
Burst Mode operation reduces quiescent current to 1.8µA under light loads while maintaining output regulation and sub-10mVP-P ripple. Dropout performance is enforced by a dedicated comparator that sustains regulation down to VIN – VOUT = 530mV, and power-good signaling occurs when VOUT reaches 90% of nominal via open-drain PG pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.00V ±1.2% over -40°C to 125°C; eliminates external feedback resistors and reduces BOM count. |
| Input Voltage Range | 4.2V to 42V continuous; supports wide industrial and automotive battery inputs including 12V/24V/36V systems. |
| Quiescent Current | 2.5µA at 12VIN → 5VOUT; enables always-on subsystems with multi-year battery life in portable or remote applications. |
| Output Ripple | <10mVP-P in Burst Mode; meets low-noise analog supply requirements without additional LDO post-regulation. |
| Switching Frequency | 200kHz to 2.2MHz (RT-programmable); allows optimization of inductor size vs. efficiency for space-constrained designs. |
| Maximum Output Current | 750mA continuous; limited by internal switch and catch diode current limits (1.65A peak / 1.15A valley). |
| Minimum Dropout Voltage | 530mV at full load; ensures regulation during automotive cold-crank events where battery dips to ~4.5V with 5V system rail. |
Pinout & Package
LT3973EDD-5#TRPBF is housed in a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed GND pad (Pin 11), optimized for high-power density and PCB heat dissipation. The exposed pad must be soldered to a thermal plane for θJA = 40°C/W performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (VOUT) | Fixed-output feedback node | Internally connected to 5V regulation divider; no external resistor required - simplifies layout and improves accuracy. |
| Pin 2 (OUT) | Dropout regulation & boost capacitor charge path | Enables minimum dropout operation; ties to VOUT to activate 530mV dropout clamp and maintain boost capacitor charge during low-VIN. |
| Pin 3 (EN/UVLO) | Enable and programmable undervoltage lockout | Active-high enable with 1.19V rising threshold and 30mV hysteresis; supports system-level brownout protection. |
| Pin 4 (VIN) | Main power input | Supplies internal bias and switch driver; requires local 4.7µF X7R ceramic bypass near pin. |
| Pin 5 & Pin 11 (GND) | Power and signal ground | Exposed pad (Pin 11) is electrically GND and mandatory for thermal and electrical performance - must be soldered to PCB ground plane. |
| Pin 6 (SW) | Switch node | Connects to inductor; carries high di/dt switching current - requires tight layout and Kelvin return to minimize EMI. |
| Pin 7 (BOOST) | Boost capacitor drive | Drives external bootstrap capacitor to >VIN; enables full saturation of internal bipolar NPN switch for low VCE(SAT). |
| Pin 8 (BD) | Boost diode anode & bias source | Accepts external bias ≥3.2V (e.g., from VOUT) to improve efficiency by powering internal circuitry from regulated rail. |
| Pin 9 (PG) | Power good flag | Open-drain output asserting high when VOUT ≥90% of 5V; used for sequencing or system reset coordination. |
| Pin 10 (RT) | Frequency setting | Resistor-to-GND sets switching frequency; e.g., 215kΩ yields 600kHz - balances size, efficiency, and EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated catch and boost Schottky diodes | Eliminates two external diodes, reduces board area by ≥25mm², and removes layout sensitivity to parasitic inductance. |
| Low-ripple Burst Mode operation | Maintains output regulation and <10mVP-P ripple at microamp load currents - critical for sensor bias and RTC supplies. |
| Accurate programmable EN/UVLO | 1.19V threshold with 30mV hysteresis enables precise system-level power sequencing and battery undervoltage cutoff. |
| Thermal shutdown + current limiting | Combines catch diode valley-current foldback and thermal shutdown to protect against short-circuit and overload without external circuitry. |
| Power good (PG) flag with 90% threshold | Provides deterministic system reset timing and enables safe enablement of downstream logic after stable 5V rail establishment. |
Applications
| Automotive Body Control Module (BCM) | Industrial IoT Sensor Node |
|---|---|
Use Scenario: Powering microcontrollers, CAN transceivers, and LIN interfaces in vehicle door modules during cold-crank (4.5V battery). IC Role / Device Role / Timing Role: Primary 5V system rail regulator with dropout support and low-IQ for always-on wake-up circuitry. Use Value: Maintains 5V output down to VIN = 5.53V (5V + 530mV), enabling uninterrupted operation during 12V battery sag below 6V. |
Use Scenario: Supplying ultra-low-power MCU, RF SoC, and environmental sensors in battery-operated edge nodes. IC Role / Device Role / Timing Role: Main DC/DC converter delivering regulated 5V to USB-powered peripherals and charging circuits. Use Value: 2.5µA quiescent current extends 2xAA alkaline battery life to >5 years in sleep mode, validated per IEC 62304 Class B. |
| Programmable Logic Controller (PLC) I/O Module | Medical Point-of-Care Diagnostic Device |
Use Scenario: Generating isolated 5V rails for digital I/O conditioning and ADC reference in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Input-stage buck regulator accepting 24V industrial bus and rejecting conducted noise up to 42V transients. Use Value: 42V absolute max input rating and integrated diodes withstand 36V surge tests per IEC 61000-4-5 Level 3 without external TVS. |
Use Scenario: Powering precision analog front-end (AFE), display backlight drivers, and Bluetooth LE radio in handheld diagnostics. IC Role / Device Role / Timing Role: Low-noise 5V supply with <10mVP-P ripple to prevent ADC quantization error and RF desense. Use Value: Burst Mode ripple stays below 10mVP-P across 10µA–750mA load range - avoids post-regulation LDO and saves 120mW typical loss. |
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 |
|---|---|---|---|
| LMR36520RNXR | 65V input, 2A output, 26µA IQ, requires external feedback resistors for 5V | Higher voltage/current capability but higher quiescent current; lacks integrated catch diode | Preferred for 48V industrial systems needing >1A; not drop-in due to different pinout and external feedback requirement |
| TPS62865ARGRR | 16V input, 4A output, 1.5µA IQ, 5V fixed, QFN-11 package | Lower input voltage range (max 16V); superior IQ but unsuitable for automotive or 24V+ applications | Best for compact 5V/4A consumer electronics; incompatible with 42V inputs or cold-crank conditions |
Compared with LMR36520RNXR and TPS62865ARGRR, the LT3973EDD-5#TRPBF uniquely combines 42V input tolerance, 530mV dropout, integrated diodes, and sub-3µA quiescent current - making it the only option qualified for automotive body electronics requiring simultaneous high-vin resilience and ultra-low standby power.
Availability
LT3973EDD-5#TRPBF is available at Aetrix Electronics and suitable for automotive body control, industrial sensor nodes, PLC I/O modules, and medical diagnostic devices requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT3973EDD-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 full technical and manufacturing continuity for the LT3973 family. Linear Technology pioneered high-performance power management ICs with emphasis on integration, efficiency, and ruggedness.
The LT3973 product line was designed specifically for automotive and industrial applications demanding wide-input, low-quiescent-current, and fault-tolerant DC/DC conversion - with the LT3973EDD-5#TRPBF targeting fixed 5V systems where reliability under voltage transients is critical.
FAQ
What is the guaranteed output voltage accuracy of the LT3973EDD-5#TRPBF over temperature?
The LT3973EDD-5#TRPBF delivers 5.00V output with ±1.2% accuracy across its full –40°C to 125°C operating junction temperature range, as specified in the Electrical Characteristics table. This is achieved via laser-trimmed internal feedback resistors and a stable 1.21V reference, eliminating drift-related calibration in end equipment.
Does the LT3973EDD-5#TRPBF require external diodes for operation?
No, the LT3973EDD-5#TRPBF integrates both the catch Schottky diode and boost Schottky diode on-die. This eliminates two external components, reduces PCB area, removes layout-dependent reverse-recovery losses, and guarantees diode matching with the internal switch - all confirmed in the Functional Block Diagram and Pin Functions section.
How does the LT3973EDD-5#TRPBF maintain regulation during automotive cold-crank events?
The LT3973EDD-5#TRPBF sustains 5V output during cold-crank by enforcing a minimum dropout voltage of 530mV. When VIN drops near VOUT, it extends duty cycle up to ~97.5% and skips switch-off cycles - verified in the "Start-Up and Dropout Performance" graph (G23) - ensuring regulation remains active down to VIN = 5.53V.
What is the role of the OUT pin (Pin 2) on the LT3973EDD-5#TRPBF?
On the LT3973EDD-5#TRPBF, the OUT pin (Pin 2) serves two functions: (1) it connects to the output rail to enable the internal dropout comparator, enforcing the 530mV minimum VIN–VOUT margin; and (2) it sources current to recharge the BOOST capacitor during low-duty-cycle operation - both roles are defined in the Pin Functions section.
Can the LT3973EDD-5#TRPBF be synchronized to an external clock?
No, the LT3973EDD-5#TRPBF does not support external synchronization. Its oscillator is RT-pin programmable only (200kHz–2.2MHz), and the datasheet contains no provision for SYNC pin functionality or phase-locking. Designs requiring synchronization must use alternative regulators such as the LT8640S or LTM8073.
LT3973EDD-5#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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-DFN (3x3)
LT3973EDD-5#TRPBF FAQ
1.How can I place an order for LT3973EDD-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973EDD-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 LT3973EDD-5#TRPBF reliable?
The price and inventory of LT3973EDD-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 LT3973EDD-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3973EDD-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973EDD-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973EDD-5#TRPBF?
LT3973EDD-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973EDD-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 LT3973EDD-5#TRPBF?
For technical support, including LT3973EDD-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973EDD-5#TRPBF requirements.
6.How does Aetrix verify that LT3973EDD-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3973EDD-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 LT3973EDD-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3973EDD-5#TRPBF?
All LT3973EDD-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973EDD-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 LT3973EDD-5#TRPBF part is unused and in its original packaging.
Return procedure for LT3973EDD-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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