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Analog Devices Inc. LT3680EDD#TRPBF
- Part No.:
- LT3680EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3680EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3.5A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:8,146
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Product details
Overview
LT3680EDD#TRPBF from Analog Devices is a 36V, 3.5A monolithic buck switching regulator with adjustable switching frequency (200kHz–2.4MHz), 75µA quiescent current in Burst Mode, integrated 95mΩ bipolar NPN switch and boost Schottky diode, and power good flag-designed for automotive battery regulation, industrial supplies, and portable product power rails.
For engineers reviewing the LT3680EDD#TRPBF datasheet, LT3680EDD#TRPBF pinout, LT3680EDD#TRPBF application, or LT3680EDD#TRPBF equivalent, key selection criteria include input voltage range (3.6V–36V), output voltage programmability (0.79V–30V), thermal performance in the 3mm × 3mm DFN package, and synchronization capability (250kHz–2MHz) for EMI-sensitive systems.
Technical Context
The LT3680EDD#TRPBF employs current-mode control with an internal error amplifier (gm = 500 µ℧), VC pin-based loop compensation, and frequency foldback during startup/overload to limit peak inductor current. Its bipolar NPN switch is driven via an external BOOST capacitor and integrated Schottky diode (BD pin), enabling full saturation at high duty cycles.
It features low-ripple Burst Mode operation (≤15mVP-P) with bias current drawn from VOUT when >3V, RUN/SS-controlled soft-start, and a power good comparator asserting when FB reaches 91% of 0.790V reference-valid only when VIN > 3.6V and RUN/SS is high.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V - supports wide-range industrial and automotive battery inputs without external pre-regulation. |
| Max Output Current | 3.5A - sustained delivery with internal 4.6A–6.6A switch current limit (duty-cycle dependent). |
| Quiescent Current | 75µA at 12VIN/3.3VOUT in Burst Mode - enables always-on systems with multi-year battery life. |
| Switching Frequency | 200kHz to 2.4MHz (RT-programmable) - allows tradeoff between inductor size (higher fSW) and efficiency/dropout (lower fSW). |
| Feedback Reference | 0.790V ±10mV - precise, temperature-stable reference enabling accurate output voltage setting from 0.79V to 30V. |
| Thermal Range | –40°C to +125°C junction - qualified for extended industrial and under-hood automotive environments. |
| Shutdown Current | <0.5µA - ensures negligible leakage during system sleep or standby states. |
Pinout & Package
LT3680EDD#TRPBF is housed in a thermally enhanced 10-lead (3mm × 3mm) plastic DFN package with exposed pad (Pin 11) soldered to PCB for low θJA = 45°C/W and θJC = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode Interface | Connects to Schottky diode anode; supplies bias current to internal regulator when VBD > 3V - improves light-load efficiency. |
| BOOST (Pin 2) | Switch Driver Boost Supply | Provides >VIN voltage to fully saturate internal bipolar NPN switch; requires external capacitor and diode network. |
| SW (Pin 3) | Power Switch Output | Drives external inductor and catch diode; carries full switching current and high di/dt - requires tight layout and low-inductance path. |
| VIN (Pin 4) | Main Input Supply | Supplies internal regulator and switch driver; must be locally bypassed with ≥10µF X7R ceramic capacitor near pin. |
| RUN/SS (Pin 5) | Enable & Soft-Start Control | Logic-level enable (≥2.5V = on, ≤0.2V = shutdown); RC ramp on this pin sets output voltage slew rate during startup. |
| SYNC (Pin 6) | External Clock Input | Accepts 250kHz–2MHz clock for EMI reduction; edges must have <1µs rise/fall time - floating not allowed. |
| PG (Pin 7) | Power Good Open-Collector Flag | Asserts high (via external pull-up) when VOUT reaches 91% of target - valid only if VIN > 3.6V and RUN/SS enabled. |
| FB (Pin 8) | Feedback Input | Regulated to 0.790V; connects to resistor divider tap - determines output voltage with ±1.3% accuracy over temperature. |
| VC (Pin 9) | Error Amplifier Output | Controls peak switch current; external RC network here sets loop compensation - no ESR dependency for stability. |
| RT (Pin 10) | Oscillator Frequency Set | Resistor to ground programs switching frequency (200kHz–2.4MHz); value selected per Figure 1 in datasheet. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external BD diode; reduces BOM count and layout area while maintaining efficient switch drive above 3VOUT. |
| Low-Ripple Burst Mode Operation | Maintains ≤15mVP-P output ripple at light loads - avoids audible noise and preserves signal integrity in sensitive analog circuits. |
| Saturating Bipolar NPN Switch | 95mΩ RCE(SAT) at 3.5A - delivers high efficiency across wide VIN/VOUT ratios without MOSFET gate-drive complexity. |
| Programmable Frequency Synchronization | Enables deterministic EMI placement between 250kHz–2MHz - critical for compliance in automotive and medical applications. |
| Thermally Enhanced DFN Package | 3mm × 3mm footprint with exposed GND pad - achieves 10°C/W junction-to-case resistance for reliable 3.5A operation without heatsink. |
Applications
| Automotive Battery Regulation | Industrial Distributed Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery supply to 3.3V or 5V for infotainment microcontrollers and CAN transceivers. IC Role / Device Role / Timing Role: Primary DC/DC step-down regulator with input transient tolerance up to 36V and cold-crank support down to 3.6V. Use Value: Maintains stable output during load-dump (up to 36V) and cranking (down to ~6V), with 75µA quiescent current preserving battery during parking mode. |
Use Scenario: Providing isolated 12V/15V rails from 24V/48V factory bus for PLC I/O modules and sensor signal conditioning. IC Role / Device Role / Timing Role: High-voltage input buck controller delivering regulated power to downstream LDOs and ADCs. Use Value: Wide 3.6V–36V input range accommodates unregulated industrial bus fluctuations; SYNC pin enables synchronized switching across multiple rails to suppress beat frequencies. |
| Portable Product Power Management | Wall Adapter-Fed Systems |
Use Scenario: Converting single-cell Li-ion (4.2V) or dual-cell (8.4V) battery to 3.3V for wireless MCU and RF front-end. IC Role / Device Role / Timing Role: High-efficiency primary regulator with soft-start and power-good signaling for sequenced system boot. Use Value: 75µA Burst Mode IQ extends runtime in sleep states; RUN/SS pin enables controlled power-up sequencing with external microcontroller. |
Use Scenario: Stepping down 12V/15V/24V wall adapter output to 5V/3.3V for embedded networking equipment and PoE-powered devices. IC Role / Device Role / Timing Role: Compact, high-current buck converter replacing discrete solutions in space-constrained AC/DC secondary side. Use Value: 3mm × 3mm DFN package fits dense layouts; integrated BOOST diode and 3.5A capability eliminate need for external FET drivers or catch diodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#TRPBF | 42V input, 3.5A, 2MHz, 2.5µA IQ (Silent Switcher), requires external bootstrap diode | Better EMI performance and lower IQ, but larger MSOP-16 package and no integrated BD diode | Preferred for noise-sensitive applications where board space permits MSOP-16 and external diode routing is acceptable. |
| TPS54360DDAR | 60V input, 3.5A, 100kHz–2.5MHz, 145µA IQ, MOSFET-based, no integrated BD diode | Higher max input voltage and MOSFET efficiency at high VIN, but lacks BD integration and has higher light-load IQ | Chosen when input exceeds 36V or when MOSFET conduction loss dominates over bipolar switch losses in high-VIN/low-VOUT designs. |
Compared with LT8610EMSE#TRPBF and TPS54360DDAR, the LT3680EDD#TRPBF uniquely integrates the boost Schottky diode and delivers lowest quiescent current (75µA) in its 36V class while maintaining compact 3mm × 3mm DFN packaging - making it optimal for space- and efficiency-constrained industrial and automotive DC/DC stages.
Availability
LT3680EDD#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed power, and portable product power management requiring stable component supply, long-lifecycle assurance, and traceable sourcing.
Supply support for LT3680EDD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3680EDD#TRPBF belongs to Analog Devices' Power by Linear™ family of monolithic DC/DC regulators, engineered specifically for high-input-voltage, high-efficiency, and low-quiescent-current applications in harsh environments.
FAQ
What is the maximum input voltage rating for LT3680EDD#TRPBF?
The absolute maximum input voltage (VIN) for LT3680EDD#TRPBF is 36V. During normal regulation, transients up to 36V are acceptable regardless of switching frequency. However, during startup, short-circuit, or overload conditions, the safe maximum input voltage depends on switching frequency and minimum on-time - for example, at 2.4MHz, VIN(MAX) is reduced to ~24V to avoid violating tON(MIN) constraints. Always verify against the input voltage range equation in the Applications Information section of the LT3680EDD#TRPBF datasheet.
Does LT3680EDD#TRPBF require an external boost diode?
No, LT3680EDD#TRPBF integrates a boost Schottky diode connected to the BD pin, eliminating the need for an external diode in standard configurations. The BD pin supplies bias current to the internal regulator and enables efficiency improvement by drawing bias from VOUT when >3V. An external diode is only required if using the BOOST pin for enhanced drive - in which case a Schottky diode (e.g., Diodes Inc. PDS340) must be placed between BD and BOOST pins per the recommended layout.
What is the function of the VC pin on LT3680EDD#TRPBF?
The VC pin on LT3680EDD#TRPBF is the output of the internal error amplifier and directly controls peak switch current. It serves as the loop compensation node: an external RC network from VC to GND sets the dominant pole and zero for stable current-mode control. Unlike voltage-mode controllers, LT3680EDD#TRPBF does not require output capacitor ESR for stability - enabling use of low-ESR ceramic capacitors. The VC pin also features active clamping to implement current limit and is internally clamped to the RUN/SS voltage during soft-start.
Can LT3680EDD#TRPBF synchronize to an external clock?
Yes, LT3680EDD#TRPBF supports external clock synchronization via the SYNC pin (Pin 6), accepting TTL/CMOS-compatible signals from 250kHz to 2MHz. Clock edges must have rise/fall times faster than 1µs, and the pin must never be left floating - tie to GND for Burst Mode or connect to a clean system clock source. Synchronization eliminates beat frequencies in multi-rail systems and enables deterministic EMI placement for EMC compliance, especially in automotive and industrial applications.
What thermal considerations apply to LT3680EDD#TRPBF in the DFN package?
LT3680EDD#TRPBF in the 3mm × 3mm DFN package (DD) has θJA = 45°C/W and θJC = 10°C/W, contingent on proper PCB design: the exposed pad (Pin 11) must be soldered to a minimum 100mm² copper pour with ≥4 thermal vias to inner/ground planes. At 3.5A continuous load and 12VIN/3.3VOUT, junction temperature rise is ~45°C above ambient - ensuring reliable operation within the –40°C to +125°C rated range. Derating is required above 85°C ambient or with inadequate copper area.
LT3680EDD#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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.79V
- Voltage - Output (Max):
- 30V
- Current - Output:
- 3.5A
- Frequency - Switching:
- 230kHz ~ 2.45MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3680EDD#TRPBF FAQ
1.How can I place an order for LT3680EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3680EDD#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 LT3680EDD#TRPBF reliable?
The price and inventory of LT3680EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3680EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3680EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3680EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3680EDD#TRPBF?
LT3680EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3680EDD#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 LT3680EDD#TRPBF?
For technical support, including LT3680EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3680EDD#TRPBF requirements.
6.How does Aetrix verify that LT3680EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3680EDD#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 LT3680EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3680EDD#TRPBF?
All LT3680EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3680EDD#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 LT3680EDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3680EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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