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Analog Devices Inc. LT3840IFE#TRPBF
- Part No.:
- LT3840IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3840IFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,533
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Product details
Overview
LT3840IFE#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 constant-frequency operation, 75µA quiescent current in Burst Mode, and precise ±1% FB regulation (1.25V) for industrial power systems requiring stable wide-input DC/DC conversion.
For engineers reviewing the LT3840IFE#TRPBF datasheet, LT3840IFE#TRPBF pinout, LT3840IFE#TRPBF application, or LT3840IFE#TRPBF equivalent, key selection considerations include its dual-mode current limit (peak + average), IMON current monitor output, internal OVLO/UVLO thresholds (60V/2.5V), soft-start/tracking via TK/SS, and compatibility with large N-channel MOSFETs in high-current (>20A) designs.
Technical Context
The LT3840IFE#TRPBF implements a fixed-frequency, peak current mode control architecture with independent voltage and average current regulation loops. Its integrated 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 supplies.
It supports three light-load operating modes (Burst, pulse-skipping, continuous) selected via the MODE pin, and includes reverse-current protection, power-good (PG) reporting, output overvoltage protection (OVP), and synchronized switching via the SYNC pin. The ICTRL pin enables programmable average current limiting with 50mV typical threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - Enables direct connection to automotive batteries, industrial 48V rails, and unregulated DC sources without pre-regulation. |
| FB Regulation Voltage | 1.250V ±1% - Sets output voltage accuracy via external resistor divider; supports precise 3.3V, 5V, 12V, or custom outputs. |
| Switching Frequency | 50kHz to 1MHz - Adjustable via RT resistor; balances efficiency (lower fSW) vs. size (higher fSW) and avoids sensitive EMI bands. |
| Quiescent Current | 75µA at 12VIN - Extends battery runtime in standby; achieved in Burst Mode with low output ripple. |
| Auxiliary Supply | 7.5V INTVCC @ 100mA - Powers internal circuitry and large N-MOSFET gate drivers; eliminates need for external bias supply. |
| Current Limit Accuracy | ±5% peak sense (95mV typ), ±3% average sense (50mV typ) - Ensures reliable overcurrent protection and programmable constant-current operation. |
| Protection Features | OVLO (60V), UVLO (2.5V), OVP (12% above VFB), thermal shutdown - Safeguards against input transients, brownouts, and output faults. |
Pinout & Package
LT3840IFE#TRPBF is packaged in a 28-lead plastic TSSOP (FE package) with exposed pad (Pin 29 = GND). Thermal resistance θJA = 30°C/W; exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (14) | Main input supply rail | Accepts 2.5V–60V; powers internal bias circuits and provides reference for UVLO/OVLO comparators. |
| EN (13) | Enable control input | Logic-level enable with 1.25V threshold; pulls device into ultra-low-IQ shutdown when <0.3V. |
| FB (7) | Feedback input | Compares output voltage (via resistor divider) to 1.25V reference; controls VC node for voltage regulation. |
| ICTRL (17) | Average current limit programming | Voltage input (0–1V) sets max average output current; 0V = 50mV sense threshold, 1V = 0mV (disable). |
| IMON (16) | Current monitor output | Analog voltage proportional to average output current (20× amplified VSENSE); used for telemetry and diagnostics. |
| TG (22), BG (25) | High-side / low-side gate drivers | 7.5V CMOS outputs capable of driving multiple parallel N-MOSFETs; non-overlap timing prevents shoot-through. |
| SENSE+ (19), SENSE– (20) | Differential current sense inputs | Measure voltage across external sense resistor; enable accurate peak and average current limiting. |
| PG (9) | Power good open-drain output | Asserts high when VOUT is within ±3% of target; signals system controller that supply is stable. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated auxiliary buck-boost regulator | Generates stable 7.5V INTVCC from 2.5V–60V input-eliminates external bias supply and enables high-efficiency gate drive across full VIN range. |
| Programmable average current limit | Set via ICTRL voltage (0–1V); enables precise constant-current operation for LED drivers or battery charging applications. |
| Three selectable light-load modes | Burst Mode (MODE=GND), pulse-skipping (MODE=FB), continuous (MODE=INTVCC)-optimizes efficiency vs. noise vs. transient response. |
| Accurate input protection thresholds | UVLO (2.5V ±5mV), OVLO (60V ±125mV) with hysteresis-prevents operation outside safe input range while tolerating transients up to 80V. |
| Soft-start and output tracking | TK/SS pin accepts external ramp or voltage reference-controls output slew rate and enables supply sequencing in multi-rail systems. |
Applications
| Industrial Power Supplies | Automotive DC/DC Conversion |
|---|---|
|
Use Scenario: 48V distributed power architecture in factory automation PLCs and motor drives. IC Role / Device Role / Timing Role: Primary synchronous buck controller regulating 12V or 5V from 48V bus with high efficiency and robust transient response. Use Value: Wide 2.5V–60V input range accommodates 48V nominal with load dump transients; 75µA IQ extends uptime during standby. |
Use Scenario: Start-stop compatible 12V rail generation from vehicle battery (6V–16V nominal, up to 36V transients). IC Role / Device Role / Timing Role: High-reliability step-down controller with UVLO/OVLO protection and AEC-Q100-compatible temperature grade (–40°C to 125°C). Use Value: Internal 7.5V gate drive ensures MOSFET turn-on even at cold-crank 6V; PG signal enables microcontroller power sequencing. |
| Distributed DC Power Systems | Programmable Constant-Current Sources |
|
Use Scenario: Telecom rectifier shelf supplying intermediate bus (e.g., 24V or 36V) from 48V or 54V backplane. IC Role / Device Role / Timing Role: High-efficiency, high-current controller supporting >20A output with parallel MOSFETs and remote sensing. Use Value: Accurate current monitor (IMON) enables real-time load monitoring; SYNC pin allows system-wide clock synchronization. |
Use Scenario: Precision LED driver or lab-grade current source requiring stable 0–5A output with telemetry. IC Role / Device Role / Timing Role: Average current regulation controller using ICTRL programming and IMON feedback for closed-loop current control. Use Value: ±3% average current limit accuracy and 20× amplified IMON output enable high-fidelity current measurement without external op-amps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3890EFE#TRPBF | Dual-output controller; includes second channel, higher IQ (120µA), no integrated auxiliary regulator (requires external bias). | Suitable for dual-rail systems (e.g., ±12V) but adds complexity for single-output use; lacks LT3840IFE#TRPBF's self-contained 7.5V bias. | Choose LTC3890EFE#TRPBF only when dual outputs or phase interleaving are required; otherwise LT3840IFE#TRPBF offers simpler, more integrated solution. |
| MP2918GL-Z | Monolithic 60V buck converter (integrated MOSFETs); lower max current (12A), no IMON or ICTRL pins, fixed 500kHz fSW. | Targeted at space-constrained, medium-power applications; lacks programmable current limit and current monitoring capability. | Select MP2918GL-Z for cost-sensitive, lower-current designs where integration outweighs flexibility; LT3840IFE#TRPBF preferred for >15A, programmable, or telemetry-enabled systems. |
Compared with LTC3890EFE#TRPBF and MP2918GL-Z, the LT3840IFE#TRPBF uniquely combines wide-input operation, integrated 7.5V auxiliary supply, programmable average current limit, and analog current monitor in a single TSSOP package-making it optimal for high-flexibility, high-reliability industrial and automotive DC/DC controllers.
Availability
LT3840IFE#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, automotive DC/DC conversion, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to 125°C.
Supply support for LT3840IFE#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 Maxim Integrated) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving industrial, automotive, communications, and healthcare markets.
The LT3840IFE#TRPBF belongs to the LT® high-voltage controller product line, designed specifically for rugged, wide-input synchronous buck conversion in harsh environments where reliability, precision, and integration are critical.
FAQ
What is the maximum input voltage rating for the LT3840IFE#TRPBF?
The LT3840IFE#TRPBF has an absolute maximum input voltage rating of 80V on the VIN and AUXVIN pins per its Absolute Maximum Ratings table. However, its functional operating range is specified from 2.5V to 60V. Operation above 60V triggers the internal OVLO protection, disabling switching while maintaining INTVCC regulation-ensuring safe recovery after transient events.
How does the LT3840IFE#TRPBF achieve low quiescent current in battery-powered systems?
The LT3840IFE#TRPBF achieves 75µA quiescent current by entering Burst Mode operation when configured with MODE tied to GND. In this mode, the controller cycles between active regulation and deep sleep-turning off both external MOSFETs and most internal circuitry-while relying on output capacitance to sustain load current. This significantly reduces average power draw during light loads.
Can the LT3840IFE#TRPBF be used for constant-current applications like LED drivers?
Yes, the LT3840IFE#TRPBF supports precise constant-current operation via its average current regulation loop. Applying a voltage to the ICTRL pin sets the maximum average output current threshold, while the IMON pin provides a 20× amplified analog representation of actual average current-enabling closed-loop control and telemetry without additional sensing circuitry.
What is the purpose of the auxiliary bias supply in the LT3840IFE#TRPBF?
The auxiliary bias supply in the LT3840IFE#TRPBF is an integrated buck-boost switching regulator that generates a regulated 7.5V INTVCC rail. This eliminates reliance on linear regulators or external bias supplies, enabling efficient gate drive for large N-channel MOSFETs across the full 2.5V–60V input range-critical for high-efficiency operation at both low and high VIN.
Does the LT3840IFE#TRPBF support synchronization to an external clock?
Yes, the LT3840IFE#TRPBF supports external clock synchronization via the SYNC pin. When driven with a TTL/CMOS clock signal, the internal oscillator locks to the external frequency-provided the internal free-running frequency (set by RT) is at least 15% lower than the minimum external clock frequency. This enables noise reduction and EMI management in multi-converter systems.
LT3840IFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) 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:
- 28-TSSOP-EP
LT3840IFE#TRPBF FAQ
1.How can I place an order for LT3840IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840IFE#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 LT3840IFE#TRPBF reliable?
The price and inventory of LT3840IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3840IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840IFE#TRPBF?
LT3840IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840IFE#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 LT3840IFE#TRPBF?
For technical support, including LT3840IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840IFE#TRPBF requirements.
6.How does Aetrix verify that LT3840IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3840IFE#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 LT3840IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3840IFE#TRPBF?
All LT3840IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840IFE#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 LT3840IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3840IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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