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Analog Devices Inc. LT3690EUFE#TRPBF
- Part No.:
- LT3690EUFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 26-WFQFN Exposed Pad
- Datasheet:
-
LT3690EUFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 4A 26QFN
- Quantity:
- Payment:
- Shipping:
Inventory:461
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Product details
Overview
LT3690EUFE#TRPBF from Analog Devices is a 36V, 4A synchronous step-down DC/DC regulator with 1.5MHz programmable switching frequency, 70µA quiescent current in Burst Mode, and integrated 30mΩ low-side N-channel MOSFET. It delivers regulated 3.3V or 5V outputs for automotive infotainment power rails, industrial PLC I/O modules, and distributed 24V-to-5V conversion.
For engineers reviewing the LT3690EUFE#TRPBF datasheet, LT3690EUFE#TRPBF pinout, LT3690EUFE#TRPBF application, or LT3690EUFE#TRPBF equivalent, key selection criteria include input voltage range (3.9V–36V), output voltage adjustability (0.8V–20V), thermal performance in 4mm × 6mm QFN, and robust protection features including overvoltage lockout up to 60V transients.
Technical Context
The LT3690EUFE#TRPBF employs current-mode control with slope compensation for fast transient response and stable loop behavior across wide duty cycles. Its internal architecture integrates a bipolar high-side switch and synchronous N-channel low-side switch, eliminating external catch diodes while enabling >90% efficiency at full load.
Operation includes programmable undervoltage lockout via resistor divider on UVLO, power-good flag signaling 90% output regulation, and frequency foldback during startup or overload. The device supports external synchronization (170kHz–1.5MHz) and soft-start/tracking via SS pin with internal 2µA current source.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.9V to 36V continuous; withstands 60V non-repetitive transients - enables direct connection to 24V/36V industrial or automotive batteries without pre-regulation. |
| Output Current | 4A maximum - supports single-rail powering of FPGA I/O banks, microcontroller cores, or multi-sensor subsystems. |
| Switching Frequency | Programmable 170kHz to 1.5MHz via RT resistor - allows optimization between small magnetics (high-freq) and high-efficiency/low-noise (low-freq). |
| Quiescent Current | 70µA in Burst Mode at 12VIN→3.3VOUT - extends battery life in always-on monitoring systems. |
| Feedback Reference | 0.8V ±12mV over temperature - enables precise output regulation with standard 1% resistors and supports wide output range (0.8V–20V). |
| Thermal Resistance | θJA = 40°C/W, θJC = 2.7°C/W - requires minimal PCB copper area for thermal management in compact designs. |
| Protection Features | Overvoltage lockout (38.2V typ), thermal shutdown, short-circuit robustness, and frequency foldback - ensures safe operation under fault conditions without external circuitry. |
Pinout & Package
LT3690EUFE#TRPBF is housed in a thermally enhanced 26-lead 4mm × 6mm plastic QFN package with two exposed pads: Pin 27 (SW) and Pin 28 (GND). Both exposed pads must be soldered to large PCB copper areas for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1–4, 23–26, Exposed Pad 27) | Switch node | Drives inductor and boost capacitor; connects internally to all SW pins and exposed pad - forms primary power path and requires low-inductance layout. |
| FB (Pin 9) | Feedback input | Regulates output by servoing to 0.8V reference - connects to resistor divider tap; adjacent GND (Pin 10) recommended for accuracy. |
| RT (Pin 7) | Oscillator programming | Sets switching frequency via resistor to GND (Pin 10); 32.4kΩ yields 600kHz - enables precise noise spectrum control. |
| PG (Pin 18) | Power good flag | Open-collector output active when FB reaches 90% of target - signals system controller that output is stable and ready. |
| EN (Pin 17) | Enable control | Active-high logic input; ≥1.5V enables regulation, ≤0.4V forces shutdown with <1µA supply current - supports sequencing and standby modes. |
| UVLO (Pin 12) | Undervoltage lockout | 1.25V threshold; external resistor divider from VIN sets wake-up point - prevents erratic operation during brownout conditions. |
| BST (Pin 22) | Bootstrap drive | Provides gate drive voltage >VIN for high-side switch via external capacitor - ensures full saturation of internal bipolar transistor. |
| BIAS (Pin 19) | Bias supply input | Accepts external ≥3V source (e.g., VOUT) to power internal regulators - improves efficiency by reducing VIN current draw. |
| VCCINT (Pin 20) | Internal driver supply | Outputs ~5V to drive low-side MOSFET gate; requires 1µF ceramic capacitor to GND (Pin 21) - critical for reliable synchronous rectification. |
| SYNC (Pin 5) | External clock sync | Accepts 170kHz–1.5MHz logic-level signal; tied to GND for Burst Mode, to VOUT for PWM - eliminates beat frequencies in multi-rail systems. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous power stage | 30mΩ low-side N-MOSFET eliminates Schottky diode, reducing conduction loss and board area in 4A applications. |
| Burst Mode operation | Maintains <15mVP-P output ripple at light loads while achieving 70µA IQ - ideal for always-on sensors and IoT edge nodes. |
| Programmable undervoltage lockout | Resistor-divider configurable threshold with hysteresis - enables custom brownout recovery behavior without external comparators. |
| Robust transient protection | Withstands 60V input transients and disables switching above 38.2V OVLO - protects downstream circuitry in automotive and industrial environments. |
| Thermally optimized QFN | Exposed SW and GND pads with θJC = 2.7°C/W - allows 4A continuous operation with minimal heatsinking in space-constrained enclosures. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering display controllers, audio codecs, and USB hubs in 12V vehicle electrical systems with cold-crank immunity. IC Role / Device Role / Timing Role: Primary 12V-to-5V/3.3V buck converter delivering clean, regulated power with transient ride-through capability. Use Value: 60V transient tolerance and 3.9V minimum start-up enable reliable operation during engine cranking and load-dump events. | Use Scenario: Generating isolated 5V rails for digital I/O expansion cards in 24V factory automation cabinets. IC Role / Device Role / Timing Role: High-current local DC/DC regulator supplying multiple optocoupler drivers and level-shifters. Use Value: 4A output current and 36V max input simplify design of universal I/O modules compatible with 12V/24V/36V field buses. |
| Distributed Telecom Supply | Medical Sensor Hub |
Use Scenario: Point-of-load conversion from 48V backplane to 3.3V for FPGA-based baseband processing units. IC Role / Device Role / Timing Role: Synchronous buck regulator synchronized to system clock via SYNC pin to minimize EMI coupling. Use Value: 1.5MHz programmable frequency allows use of 2.2µH inductors and compact 1206 MLCCs, reducing solution size by >30% vs lower-frequency alternatives. | Use Scenario: Battery-powered wearable sensor aggregator requiring ultra-low quiescent current and precise 1.8V analog rail. IC Role / Device Role / Timing Role: Adjustable-output buck converter operating in Burst Mode during sleep intervals to extend battery life. Use Value: 70µA IQ and 0.8V reference enable ±1% output accuracy with minimal battery drain over multi-week monitoring cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QPWPRQ1 | 42V max input, 0.6A output, integrated FETs but lower current rating; no BIAS pin for efficiency optimization. | Targeted at lower-power automotive body electronics; lacks 4A capability and programmable UVLO. | Select when input voltage exceeds 36V or AEC-Q100 qualification is mandatory; not suitable for 4A loads. |
| MPQ4470AGL-Z | 36V max input, 4A output, 500kHz fixed frequency; no SYNC, no programmable UVLO, no PG flag. | Cost-optimized industrial use; missing key features for automotive or high-reliability systems. | Choose for simple, fixed-frequency applications where Burst Mode, power good signaling, and flexible sequencing are unnecessary. |
Compared with LM5164QPWPRQ1 and MPQ4470AGL-Z, the LT3690EUFE#TRPBF provides higher integration (BIAS pin, PG flag, programmable UVLO), superior light-load efficiency (70µA vs >100µA), and broader frequency tuning (170kHz–1.5MHz), making it optimal for demanding automotive and industrial power designs requiring flexibility and reliability.
Availability
LT3690EUFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment power supplies, industrial PLC I/O modules, and distributed telecom supply applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3690EUFE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive safety markets.
The LT3690EUFE#TRPBF belongs to Analog Devices' Power by Linear™ family of high-voltage monolithic DC/DC regulators, designed specifically for robust, high-efficiency power conversion in harsh environments with wide input ranges and stringent reliability requirements.
FAQ
What is the maximum continuous input voltage rating for the LT3690EUFE#TRPBF?
The LT3690EUFE#TRPBF has a maximum continuous input voltage rating of 36V. It can withstand non-repetitive 60V transients for up to 1 second when junction temperature remains below 125°C. Operation above 38.2V triggers overvoltage lockout, halting switching to protect downstream circuitry. This makes the LT3690EUFE#TRPBF suitable for 24V and 36V industrial and automotive systems with load-dump immunity.
How does the LT3690EUFE#TRPBF achieve 70µA quiescent current?
The LT3690EUFE#TRPBF achieves 70µA quiescent current through its proprietary low-ripple Burst Mode operation, which shuts down most internal circuitry between switching bursts while maintaining tight output regulation and sub-15mV ripple. This mode activates automatically at light loads and is enabled by default when SYNC is grounded. The LT3690EUFE#TRPBF's optimized bias architecture and integrated power switches further reduce static current consumption without compromising startup time or regulation accuracy.
Can the LT3690EUFE#TRPBF be synchronized to an external clock?
Yes, the LT3690EUFE#TRPBF supports external clock synchronization via the SYNC pin (Pin 5), accepting logic-level signals from 170kHz to 1.5MHz with 20%–80% duty cycle. When synchronized, the internal oscillator locks to the external frequency, eliminating beat frequencies in multi-rail systems and simplifying EMI filtering. If unused, SYNC should be tied to GND for Burst Mode or to VOUT for standard PWM operation - no pull-up or pull-down resistors are required.
What thermal considerations apply to the LT3690EUFE#TRPBF's exposed pads?
The LT3690EUFE#TRPBF features two exposed pads: Pin 27 (SW) and Pin 28 (GND), both of which must be soldered to large PCB copper areas to achieve specified thermal resistance (θJA = 40°C/W, θJC = 2.7°C/W). The SW pad carries high di/dt current and serves as the primary thermal path for the high-side switch; inadequate copper area will cause excessive junction temperature rise and premature thermal shutdown. Recommended layout includes ≥4 thermal vias per pad connected to inner-layer ground or power planes.
Does the LT3690EUFE#TRPBF require an external Schottky diode?
No, the LT3690EUFE#TRPBF does not require an external Schottky diode because it integrates a synchronous 30mΩ N-channel MOSFET as the low-side switch. This replaces the traditional catch diode, eliminating forward voltage drop and associated conduction losses. The internal synchronous rectification improves full-load efficiency by up to 5% compared to diode-based solutions and reduces thermal stress on the IC. No external diode is needed or recommended in standard configurations.
LT3690EUFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 26-WFQFN 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):
- 3.9V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 4A
- Frequency - Switching:
- 138kHz ~ 1.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 26-QFN (4x6)
LT3690EUFE#TRPBF FAQ
1.How can I place an order for LT3690EUFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3690EUFE#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 LT3690EUFE#TRPBF reliable?
The price and inventory of LT3690EUFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3690EUFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3690EUFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3690EUFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3690EUFE#TRPBF?
LT3690EUFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3690EUFE#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 LT3690EUFE#TRPBF?
For technical support, including LT3690EUFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3690EUFE#TRPBF requirements.
6.How does Aetrix verify that LT3690EUFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3690EUFE#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 LT3690EUFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3690EUFE#TRPBF?
All LT3690EUFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3690EUFE#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 LT3690EUFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3690EUFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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