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Analog Devices Inc. LT3840EUFE#TRPBF
- Part No.:
- LT3840EUFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LT3840EUFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,705
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Product details
Overview
LT3840EUFE#TRPBF from Analog Devices is a high-voltage synchronous step-down switching regulator controller supporting 2.5V to 60V input, delivering accurate current-limited output up to 60V with integrated 7.5V auxiliary bias supply for MOSFET gate drive. It features programmable 50kHz–1MHz switching frequency, 75µA quiescent current in Burst Mode, and precise ±1% FB regulation (1.250V typical) for industrial power systems.
For engineers reviewing the LT3840EUFE#TRPBF datasheet, LT3840EUFE#TRPBF pinout, LT3840EUFE#TRPBF application, or LT3840EUFE#TRPBF equivalent, this page delivers verified technical context, validated package mapping to 38-lead 4mm × 6mm QFN, confirmed pin functions including IMON/ICTRL for current monitoring and programming, and real-world design implications of its dual-loop (voltage + average current) control architecture.
Technical Context
The LT3840EUFE#TRPBF implements a constant-frequency, peak-current-mode voltage control loop with an externally compensated VC node, where the error amplifier compares FB against a 1.250V reference to set inductor peak current. Its dual-loop capability extends to average current regulation via ICTRL voltage programming and IMON feedback, enabling precision constant-current operation.
An integrated monolithic buck-boost auxiliary regulator generates a regulated 7.5V INTVCC supply (±2.5% over temperature) from 2.5V–60V input, eliminating external bias rails and enabling efficient gate drive across the full VIN range. Protection includes internal OVLO (up to 80V transient tolerance), UVLO, OVP, PG, and reverse-current prevention via SENSE+/- differential sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - supports wide-range industrial, automotive, and distributed DC supplies without external pre-regulation. |
| Output Voltage Range | Up to 60V - enables high-side buck configurations for battery charging, LED drivers, and programmable power supplies. |
| Switching Frequency | 50kHz to 1MHz (RT-programmable) - balances efficiency vs. size: lower fSW reduces MOSFET switching loss; higher fSW shrinks inductor/capacitor footprint. |
| FB Regulation Accuracy | ±1% (1.250V typical) - ensures tight output voltage stability across load, line, and temperature for precision power rails. |
| Quiescent Current | 75µA at 12VIN → 3.3VOUT in Burst Mode - extends battery runtime in portable or always-on systems by minimizing light-load power loss. |
| Auxiliary Supply | 7.5V INTVCC (±2.5%) generated internally - powers gate drivers and IC logic without external LDO, maintaining efficiency from 2.5V VIN. |
| Current Limit Accuracy | ±5% peak sense threshold (95mV typ) and ±3% average current sense (50mV typ) - enables reliable overcurrent protection and programmable constant-current sourcing. |
Pinout & Package
LT3840EUFE#TRPBF is housed in a 38-lead plastic QFN package (4mm × 6mm), with exposed thermal pad (Pin 39) soldered to PCB ground for optimal thermal performance (θJC = 4°C/W). Pin count and layout match the UFE variant specified in Analog Devices' official ordering table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AUXSW1 (Pin 36) | Auxiliary supply switching node | Connects to inductor of internal buck-boost bias regulator; critical for generating stable 7.5V INTVCC across full VIN range. |
| IMON (Pin 18) | Average output current monitor output | Provides 20× amplified, filtered representation of sensed current (e.g., 1V = 50mV across RSENSE); used for telemetry and diagnostics. |
| ICTRL (Pin 19) | Average current limit programming input | Voltage applied here (0–1V) sets maximum average output current threshold; floating = 1V default (50mV sense voltage). |
| SENSE+ / SENSE– (Pins 21/22) | Differential current sense inputs | Measure voltage drop across external sense resistor; enable accurate peak and average current limiting with ±1mV offset. |
| TG / BG (Pins 25/29) | Top/bottom N-MOSFET gate drivers | 7.5V logic-level outputs with 75ns non-overlap timing; drive multiple parallel low-RDS(ON) FETs for high-current applications. |
| INTVCC (Pin 30) | Internal 7.5V bias supply output | Power source for internal circuitry and gate drivers; cannot be back-driven; requires local 1µF ceramic decoupling to GND. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated auxiliary buck-boost regulator | Generates 7.5V INTVCC from 2.5V–60V input, eliminating external bias supply and enabling full-range efficiency without dropout or thermal derating. |
| Programmable average current regulation | ICTRL pin accepts 0–1V to scale maximum average output current from 0% to 100% of full-scale sense threshold (50mV), enabling flexible CC/CV designs. |
| Selectably low-ripple Burst Mode® | Reduces quiescent current to 75µA while suppressing output voltage ripple-ideal for battery-powered systems requiring both ultra-low IQ and clean output. |
| Accurate dual-protection thresholds | UVLO/OVLO pins offer ±1.5mV hysteresis and 1.25V precision thresholds, enabling robust input rail monitoring with minimal external components. |
| Power Good with tracking-aware logic | PG asserts only when FB is within 90%–93% of target and EN is active; deasserts during TK/SS soft-start ramp or fault conditions, ensuring safe sequencing. |
Applications
| Industrial Power Supplies | Automotive DC-DC Conversion |
|---|---|
|
Use Scenario: 24V/48V bus-to-12V/5V conversion in factory automation controllers with strict EMI and thermal constraints. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-efficiency, high-current power delivery with programmable soft-start and voltage tracking. Use Value: Integrated 7.5V bias supply eliminates need for external LDO, reducing BOM count and improving thermal margin at elevated ambient temperatures. |
Use Scenario: Start-stop battery management system supplying 3.3V/5V rails to microcontrollers and sensors from 6V–60V cold-crank transients. IC Role / Device Role / Timing Role: Wide-input controller with 80V transient tolerance and accurate UVLO/OVLO for robust operation during engine cranking and load dump. Use Value: 75µA Burst Mode IQ extends microcontroller sleep time between wake-ups, directly increasing battery longevity in always-on vehicle modules. |
| Programmable Constant-Current Sources | Distributed DC Power Systems |
|
Use Scenario: Precision LED driver for architectural lighting requiring dimmable, thermally stable current output up to 5A. IC Role / Device Role / Timing Role: Dual-loop controller regulating both output voltage and average current via ICTRL/IMON interface for closed-loop current accuracy. Use Value: ±3% average current sense accuracy and 20× buffered IMON output enable real-time current telemetry without additional op-amps or ADCs. |
Use Scenario: Intermediate bus converter in telecom equipment converting –48V or +54V to 12V for downstream POL converters. IC Role / Device Role / Timing Role: High-voltage synchronous controller with SYNC input for system-level clock synchronization and noise management across multiple rails. Use Value: 50kHz–1MHz programmable frequency allows alignment with system clock tree to avoid beat frequencies and simplify EMI filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EUFD#TRPBF | Wider VIN range (4V–80V), integrated 5V/100mA LDO, no auxiliary buck-boost; requires external bias for gate drive above 5V. | Better suited for ultra-high-input systems (e.g., 72V industrial buses) but lacks LT3840EUFE#TRPBF's self-contained 7.5V gate drive. | Select LTC3891EUFD#TRPBF when input exceeds 60V or when integrated LDO simplifies auxiliary rail generation. |
| LM5116MH/NOPB | Lower VIN max (75V), no integrated auxiliary supply, fixed 100kHz–1MHz freq, no IMON/ICTRL current monitoring interface. | Cost-optimized for high-volume industrial supplies where current telemetry and programmable CC mode are unnecessary. | Choose LM5116MH/NOPB for cost-sensitive, single-loop voltage-regulated applications without current-loop requirements. |
Compared with LTC3891EUFD#TRPBF and LM5116MH/NOPB, the LT3840EUFE#TRPBF uniquely integrates a self-powered 7.5V gate drive supply and dual-loop (voltage + average current) control-enabling compact, high-accuracy CC/CV designs without external bias or current-sense amplifiers.
Availability
LT3840EUFE#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive DC-DC conversion, programmable constant-current sources, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3840EUFE#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 (now part of Analog Devices, Inc. following merger with Linear Technology) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3840EUFE#TRPBF belongs to Linear Technology's high-voltage synchronous controller product line, designed specifically for rugged, wide-input industrial and automotive power conversion where self-contained gate drive, accurate current regulation, and transient resilience are critical.
FAQ
What is the operating temperature range for the LT3840EUFE#TRPBF?
The LT3840EUFE#TRPBF is rated for operation from –40°C to +125°C junction temperature. This grade (E-grade) is specified and tested across that full range, making it suitable for demanding industrial and under-hood automotive environments where thermal reliability is essential. The device uses internal thermal shutdown protection to safeguard against sustained overtemperature conditions.
How does the LT3840EUFE#TRPBF generate its gate drive voltage without an external supply?
The LT3840EUFE#TRPBF integrates a monolithic buck-boost auxiliary regulator that generates a regulated 7.5V INTVCC supply directly from the main VIN input (2.5V–60V). This eliminates the need for an external bias rail and ensures consistent gate drive strength across the entire input range-critical for maintaining high efficiency and MOSFET RDS(ON) control at low VIN.
Can the LT3840EUFE#TRPBF operate in constant-current mode, and how is it configured?
Yes, the LT3840EUFE#TRPBF supports accurate constant-current regulation via its dual-loop architecture. Apply a voltage (0–1V) to the ICTRL pin to set the maximum average output current threshold; the IMON pin provides a buffered, 20× amplified representation of the sensed current for feedback or monitoring. This enables precision LED drivers or battery chargers without external current-sense amplifiers.
What protection features are built into the LT3840EUFE#TRPBF?
The LT3840EUFE#TRPBF includes comprehensive protection: input overvoltage lockout (OVLO) up to 80V transient tolerance, precision undervoltage lockout (UVLO), output overvoltage protection (OVP) via FB pin, power good (PG) status flag, reverse-current prevention, and thermal shutdown. These features reduce external component count and improve system robustness in harsh electrical environments.
Is the LT3840EUFE#TRPBF pin-compatible with other LT3840 variants like the TSSOP version?
No, the LT3840EUFE#TRPBF (38-lead 4mm × 6mm QFN) is not pin-compatible with the 28-lead TSSOP variants (e.g., LT3840EFE#TRPBF). Pin count, layout, and terminal assignments differ significantly-especially for AUXSW1/AUXSW2, PGND, and exposed pad grounding. PCB layout must be redesigned when migrating between FE and UFE packages.
LT3840EUFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.5V ~ 60V
- Frequency - Switching:
- 50kHz ~ 1MHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (4x6)
LT3840EUFE#TRPBF FAQ
1.How can I place an order for LT3840EUFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840EUFE#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 LT3840EUFE#TRPBF reliable?
The price and inventory of LT3840EUFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840EUFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3840EUFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840EUFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840EUFE#TRPBF?
LT3840EUFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840EUFE#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 LT3840EUFE#TRPBF?
For technical support, including LT3840EUFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840EUFE#TRPBF requirements.
6.How does Aetrix verify that LT3840EUFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3840EUFE#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 LT3840EUFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3840EUFE#TRPBF?
All LT3840EUFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840EUFE#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 LT3840EUFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3840EUFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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