My Inquiry
My Account
Analog Devices Inc. LT3840IUFE#TRPBF
- Part No.:
- LT3840IUFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LT3840IUFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,116
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3840IUFE#TRPBF from Analog Devices is a high-voltage synchronous step-down switching regulator controller supporting 2.5V to 60V input, delivering accurate current limit control and 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 average output current regulation via ICTRL/IMON interface - used in industrial DC power systems requiring wide-input, high-efficiency regulation.
For engineers reviewing the LT3840IUFE#TRPBF datasheet, LT3840IUFE#TRPBF pinout, LT3840IUFE#TRPBF application, or LT3840IUFE#TRPBF equivalent, key selection criteria include its 38-lead 4mm × 6mm QFN package, –40°C to 125°C operating range, integrated buck-boost auxiliary supply, accurate 95mV peak current sense threshold, and dual-mode soft-start/tracking capability.
Technical Context
The LT3840IUFE#TRPBF implements a constant-frequency, peak-current-mode control architecture with independent voltage and average-current regulation loops. Its internal 7.5V auxiliary buck-boost regulator enables full-range operation from 2.5V to 60V VIN while driving large N-channel MOSFETs without external bias supplies.
It supports three light-load modes (Burst, pulse-skipping, continuous) selected via MODE pin, integrates reverse-current protection, and provides real-time current monitoring through IMON with 20× gain and filtered average output. The IC also includes precision OVLO/UVLO thresholds (±1.25V), PG open-drain output, and synchronized switching up to 1MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - enables direct regulation from 12V, 24V, 48V, and automotive battery rails without pre-regulation. |
| Switching Frequency | 50kHz to 1MHz - set by RT resistor; allows optimization of efficiency vs. size in high-power DC/DC designs. |
| Peak Current Sense Threshold | 95mV (typ) - sets maximum inductor peak current with ±15mV tolerance; enables precise overcurrent protection. |
| Quiescent Current | 75µA at 12VIN - extends battery life in portable or always-on industrial systems using Burst Mode. |
| Auxiliary Supply Output | 7.5V ±0.25V - powers TG/BG drivers and internal circuitry across full input range; eliminates need for external bias rail. |
| Operating Temperature | –40°C to 125°C - qualified for harsh industrial and automotive under-hood environments. |
| Package | 38-lead 4mm × 6mm QFN with exposed thermal pad - provides low θJC = 4°C/W for high-power thermal management. |
Pinout & Package
LT3840IUFE#TRPBF uses a 38-lead plastic QFN package (4mm × 6mm) with exposed GND pad (Pin 39) soldered directly to PCB ground plane for thermal and electrical integrity. θJA = 38°C/W, θJC = 4°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AUXVIN (Pin 1) | Auxiliary bias supply input | Accepts 2.5V–60V input to feed internal buck-boost regulator; withstands transients up to 80V. |
| SYNC (Pin 3) | External clock synchronization input | Allows frequency locking to system clock; requires internal oscillator set 15% below external minimum frequency. |
| TK/SS (Pin 6) | Soft-start and output voltage tracking input | Internal 9µA current source ramps capacitor for controlled VOUT slew; accepts external voltage for supply sequencing. |
| FB (Pin 7) | Feedback input for output voltage regulation | Sets regulated VOUT via resistor divider; reference voltage = 1.250V ±13mV over temperature. |
| MODE (Pin 11) | Light-load operation mode select | GND = Burst Mode (ultra-low IQ); FB = pulse-skipping; INTVCC = continuous conduction mode. |
| OVLO (Pin 12) | Input overvoltage lockout input | Disables switching when AUXVIN exceeds 60V; maintains INTVCC regulation during fault. |
| EN (Pin 14) | Main enable with shutdown threshold | 1.25V rising threshold; pulls into <1µA shutdown state when below 0.3V. |
| IMON (Pin 18) | Average output current monitor output | Provides 1V per 50mV sensed differential voltage (20× gain); filtered by external capacitor for telemetry. |
| ICTRL (Pin 19) | Programmable average current limit setpoint | Voltage applied here (0–1V) scales max average output current; floating = 50mV default threshold. |
| SENSE+ / SENSE– (Pins 21/22) | Differential current sense inputs | Measure RSENSE voltage drop; common-mode range = 0–60V; offset ≤5mV ensures accuracy at low currents. |
| TG / BG (Pins 25/29) | High-current N-MOSFET gate drivers | 7.5V drive swing, 20ns rise/fall, 75ns non-overlap - prevents shoot-through in synchronous buck stage. |
| INTVCC (Pin 30) | Internal 7.5V bias supply output | Delivers up to 100mA; powers internal logic and gate drivers; cannot be back-driven. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated auxiliary buck-boost regulator | Generates stable 7.5V gate drive supply from 2.5V–60V input - eliminates external bias IC and improves efficiency across full VIN range. |
| Accurate average current regulation | Programmable 40–52.5mV ICTRL threshold with 20× amplified IMON output - enables precision constant-current sources and load telemetry. |
| Selectably low-ripple Burst Mode® | 75µA IQ with controlled inductor current zero-crossing - reduces light-load losses while maintaining low output voltage ripple. |
| Robust input transient protection | 80V absolute max rating on AUXVIN/VIN; internal OVLO disables switching at 60V while sustaining INTVCC - protects against load dump and surge events. |
| Flexible soft-start and tracking | TK/SS pin supports both capacitor-ramped soft-start and external voltage tracking - enables reliable power sequencing in multi-rail systems. |
Applications
| Industrial DC Power Systems | Distributed Telecom Power |
|---|---|
|
Use Scenario: Regulating 48V or 54V telecom rectifier output to 12V/5V intermediate bus in remote radio units. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current, wide-input conversion with precise current limiting. Use Value: Integrated 7.5V auxiliary supply eliminates discrete bias rail, reducing BOM count and improving reliability across –40°C to 125°C ambient. |
Use Scenario: Converting 36–75V DC distribution bus to 3.3V/5V for FPGA, DSP, and memory subsystems in base station equipment. IC Role / Device Role / Timing Role: High-efficiency, synchronizable controller enabling noise-sensitive RF co-location via 1MHz switching. Use Value: SYNC pin allows alignment with system clock to avoid beat frequencies; PG output enables safe power-up sequencing. |
| Automotive Battery Management | Test & Measurement Equipment |
|
Use Scenario: Stepping down 12V/24V vehicle battery to stable 5V/3.3V for CAN/LIN controllers and sensors under cold-crank (4.5V) and load-dump (80V) conditions. IC Role / Device Role / Timing Role: Wide-VIN controller with UVLO/OVLO protection and reverse-current blocking for robust automotive power domain. Use Value: Accurate 1.25V FB reference and 95mV current sense ensure stable regulation despite battery voltage fluctuations and EMI. |
Use Scenario: Programmable current-limited supply for DUT powering in automated test fixtures requiring real-time current feedback. IC Role / Device Role / Timing Role: Constant-current regulator with IMON telemetry and ICTRL programming for adaptive load control. Use Value: IMON voltage (0.4–1.05V) linearly tracks average output current - enables closed-loop calibration and fault logging without external ADC. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3890EUFD#PBF | Dual-output, 60V input, 2-phase interleaved; higher integration but larger 40-lead QFN package. | Designed for multiphase, lower-ripple applications; lacks single-channel simplicity and IMON telemetry granularity. | Choose LTC3890EUFD#PBF only when dual outputs or phase interleaving are required; LT3840IUFE#TRPBF offers better cost and layout simplicity for single-channel designs. |
| LM5116MH/NOPB | 65V max input, no integrated auxiliary supply; requires external 7–12V bias; 200kHz–1MHz range; no IMON/ICTRL interface. | Targeted at cost-sensitive industrial converters where auxiliary supply can be provided externally. | LM5116MH/NOPB suits designs with existing bias rails and simpler current monitoring needs; LT3840IUFE#TRPBF delivers superior integration and telemetry for new high-performance designs. |
Compared with LTC3890EUFD#PBF and LM5116MH/NOPB, the LT3840IUFE#TRPBF uniquely combines wide-input operation, self-contained 7.5V gate drive, accurate average current regulation, and real-time IMON telemetry in a compact 38-lead QFN - making it optimal for space-constrained, high-reliability single-output systems.
Availability
LT3840IUFE#TRPBF is available at Aetrix Electronics and suitable for industrial DC power systems, distributed telecom power, automotive battery management, and test & measurement equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3840IUFE#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 LT3840IUFE#TRPBF belongs to Analog Devices' Power by Linear™ high-voltage controller family, designed specifically for rugged, wide-input synchronous buck conversion in harsh environments where efficiency, reliability, and integrated protection are critical.
FAQ
What is the maximum input voltage rating for the LT3840IUFE#TRPBF?
The LT3840IUFE#TRPBF has an absolute maximum input rating of 80V on AUXVIN and VIN pins, with guaranteed operation up to 60V. Internal OVLO disables switching above 60V while maintaining INTVCC regulation - enabling robust protection against automotive load-dump and industrial surge events. This specification is validated across the full –40°C to 125°C operating range for the LT3840IUFE#TRPBF.
How does the LT3840IUFE#TRPBF implement accurate average output current regulation?
The LT3840IUFE#TRPBF regulates average output current by comparing a 20× amplified version of the SENSE+–SENSE– differential voltage against either a 1V internal reference or an externally applied ICTRL voltage (0–1V). When the amplified sense voltage exceeds the smaller of those two thresholds, the VC node is pulled low to reduce peak inductor current. The LT3840IUFE#TRPBF also outputs the averaged current signal on IMON with 0.4–1.05V scaling, enabling real-time telemetry without external amplification.
Can the LT3840IUFE#TRPBF operate without an external auxiliary bias supply?
Yes - the LT3840IUFE#TRPBF integrates a monolithic buck-boost auxiliary regulator that generates a regulated 7.5V supply (INTVCC) from the same 2.5V–60V input rail. This eliminates the need for any external bias source, simplifying design and improving efficiency across the entire input range. The LT3840IUFE#TRPBF delivers up to 100mA from INTVCC to power gate drivers and internal circuitry, with no back-drive capability.
What are the supported light-load operation modes for the LT3840IUFE#TRPBF?
The LT3840IUFE#TRPBF supports three selectable light-load modes via the MODE pin: Burst Mode (MODE = GND) for ultra-low 75µA quiescent current, pulse-skipping mode (MODE = FB) for moderate efficiency with discontinuous conduction, and continuous conduction mode (MODE = INTVCC) for lowest output ripple. Each mode maintains reverse-current protection and seamless transition across load steps - a key capability confirmed in the LT3840IUFE#TRPBF datasheet Rev B.
Does the LT3840IUFE#TRPBF provide output voltage tracking capability?
Yes - the LT3840IUFE#TRPBF implements output voltage tracking via the TK/SS pin, which accepts an external voltage reference to force VOUT to follow another supply during startup. Internally, the error amplifier regulates FB to the smaller of the 1.25V reference or the TK/SS voltage. An internal 9µA current source also allows soft-start ramping when a capacitor is connected to TK/SS. This dual-function capability is fully specified and tested for the LT3840IUFE#TRPBF across temperature.
LT3840IUFE#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)
LT3840IUFE#TRPBF FAQ
1.How can I place an order for LT3840IUFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840IUFE#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 LT3840IUFE#TRPBF reliable?
The price and inventory of LT3840IUFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840IUFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3840IUFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840IUFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840IUFE#TRPBF?
LT3840IUFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840IUFE#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 LT3840IUFE#TRPBF?
For technical support, including LT3840IUFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840IUFE#TRPBF requirements.
6.How does Aetrix verify that LT3840IUFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3840IUFE#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 LT3840IUFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3840IUFE#TRPBF?
All LT3840IUFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840IUFE#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 LT3840IUFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3840IUFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3840IUFE#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
