My Inquiry
My Account
Analog Devices Inc. LT3840HFE#PBF
- Part No.:
- LT3840HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3840HFE#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,680
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3840HFE#PBF 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 and programmable 50kHz–1MHz switching frequency. It features Burst Mode operation (75µA IQ), precise ±1% FB regulation, and robust protection including OVLO/UVLO, PG, and reverse-current prevention - deployed in automotive power supplies and industrial DC distribution systems.
For engineers reviewing the LT3840HFE#PBF datasheet, LT3840HFE#PBF pinout, LT3840HFE#PBF application, or LT3840HFE#PBF equivalent, key selection considerations include its –40°C to 150°C junction temperature rating, 28-lead TSSOP package with exposed thermal pad, synchronous N-channel gate drive capability (7.5V, <20ns rise/fall), and dual-loop control for voltage + average current regulation.
Technical Context
The LT3840HFE#PBF implements a constant-frequency, peak-current-mode architecture with independent voltage and average-current control loops. Its internal buck-boost auxiliary regulator generates a regulated 7.5V INTVCC rail - enabling efficient gate drive across the full 2.5V–60V VIN range without external bias.
It supports three light-load modes via MODE pin configuration: Burst Mode (75µA IQ), pulse-skipping, or continuous conduction. Current sensing uses differential SENSE+/SENSE– inputs with 20× amplification, feeding both IMON telemetry and ICTRL-programmable current limit (40–52.5mV threshold).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - enables direct integration into 12V, 24V, 48V, and battery-backed industrial/automotive rails without pre-regulation. |
| Operating Junction Temp | –40°C to 150°C - qualified for under-hood automotive and high-ambient industrial environments per H-grade specification. |
| Quiescent Current | 75µA at 12VIN - extends battery runtime in always-on systems by minimizing no-load power loss. |
| Switching Frequency | 50kHz to 1MHz (RT-programmable) - balances efficiency vs. magnetics size; supports noise-sensitive band avoidance. |
| FB Regulation Accuracy | ±1% (1.232V to 1.263V) - ensures tight output voltage tolerance over temperature and line for precision power rails. |
| Auxiliary Bias Output | 7.5V ±3% INTVCC - powers large N-channel MOSFET gates with low dropout, eliminating need for external LDO or bias supply. |
| Current Limit Threshold | 95mV (peak), 47.5–52.5mV (average) - provides accurate, programmable overcurrent protection with ±2% tolerance over temp. |
Pinout & Package
LT3840HFE#PBF is housed in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29 = GND). The package supports high-power dissipation (θJA = 30°C/W) and requires soldering of the exposed pad to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (14) | Main input supply rail | Accepts 2.5V–60V; powers internal circuitry and feeds auxiliary bias stage; decoupled with 0.1µF ceramic. |
| TG (22) | Top-gate driver output | 7.5V, high-current N-channel MOSFET gate drive with 150ns min on-time and non-overlap protection. |
| BG (25) | Bottom-gate driver output | 7.5V, high-current N-channel MOSFET gate drive with reverse-current comparator disabling BG near zero current. |
| SENSE+ / SENSE– (19/20) | Differential current sense inputs | Measure inductor current via external shunt; 20× amplified signal feeds IMON and ICTRL-based current limit loop. |
| IMON (16) | Average output current monitor | Analog voltage proportional to average load current (1V per 50mV sensed); filtered externally for telemetry/diagnostics. |
| ICTRL (17) | Programmable current limit setpoint | Voltage input (0–1V) scaling average current limit threshold from 40mV to 52.5mV - enables dynamic current limiting. |
| MODE (10) | Light-load operation mode select | GND = Burst Mode (ultra-low IQ), FB = pulse-skipping, INTVCC = continuous conduction - configures efficiency vs. ripple trade-off. |
| PG (9) | Open-drain power-good indicator | Asserts high when FB is within ±10% of regulation; sinks 65µA max - used for system sequencing and fault signaling. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated auxiliary buck-boost regulator | Generates stable 7.5V INTVCC rail from 2.5V–60V input - eliminates external bias supply and enables high-efficiency gate drive across full VIN range. |
| Accurate dual-loop control | Independent voltage regulation (FB/VC loop) and average current regulation (ICTRL/ICOMP loop) - supports constant-voltage and constant-current applications. |
| Robust input transient protection | Withstands 80V input transients via AUXVIN OVLO; includes precision UVLO/OVLO thresholds with hysteresis for reliable startup and fault shutdown. |
| Programmable soft-start & tracking | TK/SS pin accepts external ramp or reference voltage - enables controlled output slew rate and supply sequencing with no external components required. |
| Reverse-current prevention | Internal comparator disables BG before inductor current reverses - maintains DCM operation in Burst Mode and prevents shoot-through during light loads. |
Applications
| Automotive Power Supply | Industrial DC Distribution |
|---|---|
|
Use Scenario: 24V battery-fed ECU power rail requiring stable 3.3V/5V/12V outputs with cold-crank (4.5V) and load-dump (60V+) resilience. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-side/lower-side MOSFETs, regulating output while monitoring average current for overload detection. Use Value: Wide 2.5V–60V input range and 80V transient tolerance eliminate need for front-end protection stages; H-grade temp rating ensures reliability under hood. |
Use Scenario: 48V datacenter or factory-floor distributed power system stepping down to 12V intermediate bus with telemetry and current limiting. IC Role / Device Role / Timing Role: Voltage + current-regulated controller providing programmable OCP, IMON feedback, and synchronized switching for multi-rail coordination. Use Value: Integrated 7.5V gate drive sustains efficiency at high VIN; RT-programmable frequency allows EMI compliance; ICTRL enables adaptive current limiting. |
| High-Voltage LED Driver | Programmable Current Source |
|
Use Scenario: Constant-current driver for high-brightness LED strings in signage or street lighting, operating from 36V–56V nominal input. IC Role / Device Role / Timing Role: Synchronous buck controller configured in constant-current mode using ICTRL and IMON for closed-loop regulation and diagnostics. Use Value: Accurate 47.5–52.5mV average current sense threshold enables ±2% current regulation; IMON provides real-time telemetry for thermal derating. |
Use Scenario: Lab-grade programmable current source for sensor biasing, battery charging, or test equipment requiring 0.1A–20A adjustable output. IC Role / Device Role / Timing Role: Dual-loop controller enforcing precise average current limit while maintaining stable output voltage via FB loop. Use Value: ICTRL voltage input allows analog current programming; TK/SS enables smooth current ramp-up; PG confirms regulation status. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3890HDE#PBF | Dual-output, 60V input, integrated MOSFET drivers; higher IQ (120µA), no integrated auxiliary regulator - requires external 7.5V bias. | Preferred for dual-rail systems; less suitable for single-rail designs where board space or bias complexity must be minimized. | Select LTC3890HDE#PBF only when dual-output capability or higher gate drive current (>5A peak) is required; LT3840HFE#PBF offers simpler BOM and lower IQ. |
| LM5116MH/NOPB | 60V input, external MOSFET drivers, no integrated auxiliary supply; 100µA IQ; lacks IMON/ICTRL current regulation - only voltage-mode control. | Suitable for cost-sensitive, non-telemetry applications; cannot support constant-current mode or real-time current monitoring. | Choose LM5116MH/NOPB for basic voltage regulation where current loop functionality and ultra-low IQ are not needed; LT3840HFE#PBF adds critical current control and diagnostic capability. |
Compared with LTC3890HDE#PBF and LM5116MH/NOPB, the LT3840HFE#PBF uniquely integrates a self-powered 7.5V auxiliary regulator and dual-loop (voltage + average current) control - reducing component count and enabling programmable current limiting and telemetry in a single 28-pin TSSOP package rated for 150°C operation.
Availability
LT3840HFE#PBF is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC distribution systems, high-voltage LED drivers, and programmable current sources requiring stable component supply across extended temperature ranges.
Supply support for LT3840HFE#PBF 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 LT3840HFE#PBF belongs to Analog Devices' Power by Linear™ family of high-voltage DC/DC controllers, designed specifically for rugged, wide-input industrial and automotive power conversion with emphasis on efficiency, protection, and design simplicity.
FAQ
What is the maximum input voltage rating for LT3840HFE#PBF, and how does it handle transients?
The LT3840HFE#PBF supports continuous operation from 2.5V to 60V input and withstands input transients up to 80V. Its AUXVIN pin includes an overvoltage lockout (OVLO) that disables the auxiliary bias regulator above 60V, while internal circuitry remains protected. This enables robust deployment in automotive and industrial environments subject to load dump or cold-crank events without external clamping.
How does LT3840HFE#PBF achieve ultra-low quiescent current, and what is its typical value?
The LT3840HFE#PBF achieves 75µA quiescent current in Burst Mode operation (MODE = GND) by dynamically disabling internal circuitry during light-load sleep cycles. During sleep, both external MOSFETs are turned off, and most bias currents are shut down - while maintaining regulation via output capacitor hold-up. This value is measured at 12VIN and is guaranteed across the full –40°C to 150°C operating range for the H-grade device.
Can LT3840HFE#PBF regulate output current, and how is the limit programmed?
Yes, the LT3840HFE#PBF supports accurate average output current regulation via its ICTRL pin. Applying a voltage between 0V and 1V to ICTRL scales the average current limit threshold from 40mV to 52.5mV across the SENSE+ and SENSE– pins. The IMON pin provides a buffered, filtered analog voltage proportional to average load current - enabling closed-loop current control and telemetry without additional ICs.
What package type and thermal characteristics apply to LT3840HFE#PBF?
The LT3840HFE#PBF is supplied in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29 = GND). Its thermal resistance is θJA = 30°C/W and θJC = 10°C/W when the exposed pad is properly soldered to a PCB ground plane. This package supports operation up to 150°C junction temperature - validated for automotive under-hood and high-ambient industrial use cases.
Does LT3840HFE#PBF require an external bias supply for gate driving?
No, the LT3840HFE#PBF does not require an external bias supply. It integrates a monolithic buck-boost auxiliary regulator that generates a regulated 7.5V INTVCC rail from the main VIN input (2.5V–60V). This rail powers both internal circuitry and the high-current TG/BG gate drivers - eliminating external LDOs or bias windings and ensuring consistent gate drive performance across the entire input range.
LT3840HFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- 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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3840HFE#PBF FAQ
1.How can I place an order for LT3840HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840HFE#PBF 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 LT3840HFE#PBF reliable?
The price and inventory of LT3840HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840HFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3840HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840HFE#PBF?
LT3840HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840HFE#PBF 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 LT3840HFE#PBF?
For technical support, including LT3840HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840HFE#PBF requirements.
6.How does Aetrix verify that LT3840HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3840HFE#PBF 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 LT3840HFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3840HFE#PBF?
All LT3840HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840HFE#PBF, 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 LT3840HFE#PBF part is unused and in its original packaging.
Return procedure for LT3840HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3840HFE#PBF 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…
