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Analog Devices Inc. LT3840MPFE#PBF
- Part No.:
- LT3840MPFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3840MPFE#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,911
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Product details
Overview
LT3840MPFE#PBF from Analog Devices is a high-voltage synchronous step-down switching regulator controller supporting 2.5V to 60V input, delivering precise current-limited output with 75µA quiescent current in Burst Mode, integrated 7.5V auxiliary bias supply, and programmable 50kHz–1MHz switching frequency - used in automotive power supplies and industrial DC distribution systems.
For engineers reviewing the LT3840MPFE#PBF datasheet, LT3840MPFE#PBF pinout, LT3840MPFE#PBF application, or LT3840MPFE#PBF equivalent, key selection criteria include its –55°C to 150°C extended temperature grade, accurate average current limit (±2.5% over temp), 7.5V INTVCC regulation tolerance (±3.3%), dual-mode enable/UVLO/OVLO protection, and TSSOP-28 package compatibility with thermal pad grounding.
Technical Context
The LT3840MPFE#PBF implements a constant-frequency, peak-current-mode control architecture with independent voltage and average-current regulation loops. Its internal buck-boost auxiliary regulator generates a stable 7.5V gate drive supply across the full 2.5V–60V VIN range, eliminating external bias requirements and enabling high-efficiency operation at both low and high input voltages.
It integrates precision threshold comparators for UVLO (1.25V ±5mV), OVLO (1.25V ±5mV), and EN (1.25V ±5mV), all with hysteresis, plus reverse-current protection that disables BG before inductor current reversal. The IMON pin provides 20× amplified, filtered average current sensing with 1% full-scale accuracy at 50mV sense voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - supports wide-range industrial and automotive battery inputs without external pre-regulation. |
| Operating Temperature | –55°C to +150°C - fully tested and guaranteed, enabling use in under-hood automotive and harsh-environment industrial applications. |
| Quiescent Current | 75µA at 12VIN - extends battery runtime in always-on systems via low-power Burst Mode operation. |
| Switching Frequency | 50kHz to 1MHz (RT-programmable) - balances efficiency vs. size; 300kHz typical with 49.9kΩ resistor. |
| INTVCC Regulation | 7.5V ±0.25V - powers gate drivers and internal circuitry; eliminates need for external bias rail. |
| Average Current Limit Accuracy | ±2.5% over temperature - enables precise current-source operation for LED drivers or battery charging. |
| FB Reference Voltage | 1.250V ±13mV (MP-grade) - sets output voltage with high stability across full operating range. |
Pinout & Package
LT3840MPFE#PBF is housed in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29) soldered to PCB ground for thermal management (θJA = 30°C/W). Pin functions are validated per Analog Devices Rev B datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 14) | Main input supply rail | Accepts 2.5V–60V; decoupled with 0.1µF ceramic capacitor to GND for noise immunity. |
| EN (Pin 13) | Enable control with shutdown mode | 1.25V threshold enables IC; <0.3V forces 1µA shutdown current - critical for system-level power sequencing. |
| FB (Pin 7) | Feedback input for output voltage regulation | Compares against 1.25V reference; also feeds PG and OVP comparators - single-point monitoring for safety-critical designs. |
| IMON (Pin 16) | Average output current monitor output | Provides 20× amplified, low-ripple voltage proportional to IOUT - enables real-time telemetry without external op-amps. |
| TG / BG (Pins 22 / 25) | Top/bottom N-MOSFET gate drivers | 7.5V drive capability with 20ns rise/fall time; non-overlap timing prevents shoot-through in high-current synchronous buck stages. |
| SENSE+ / SENSE– (Pins 19 / 20) | Differential current sense inputs | Measure RSENSE voltage drop with ±1mV offset; support bidirectional sensing and reverse-current protection. |
| INTVCC (Pin 26) | Internal 7.5V bias supply output | Powers internal logic and gate drivers; cannot be back-driven - requires local 1µF ceramic bypass to PGND. |
| GND / Exposed Pad (Pins 15, 29) | Signal and power ground reference | Exposed pad must be soldered to PCB ground plane for thermal and EMI performance - not optional. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated auxiliary buck-boost regulator | Generates stable 7.5V INTVCC from 2.5V–60V input - removes dependency on external bias supply and improves efficiency at low VIN. |
| Programmable average current limit | Set via ICTRL voltage (0–1V) or floating for 50mV default; enables precise constant-current operation for LED or battery applications. |
| Three light-load operating modes | Burst Mode (MODE=GND), pulse-skipping (MODE=FB), or continuous (MODE=INTVCC) - selectable per system efficiency/noise trade-off. |
| Comprehensive fault protection | Independent UVLO, OVLO, output OVP, PG, and reverse-current detection - reduces need for external supervision ICs. |
| Output voltage tracking & soft-start | TK/SS pin supports external ramp or supply tracking; internal 9µA charge current enables controlled startup and fault recovery. |
Applications
| Automotive Power Supply | Industrial DC Distribution |
|---|---|
|
Use Scenario: 12V/24V vehicle battery powering infotainment head units and ADAS sensors requiring stable 3.3V/5V rails. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-current conversion with input transients up to 80V. Use Value: Extended –55°C to 150°C operation ensures reliability in engine bay environments; integrated OVLO/UVLO eliminates need for discrete protection. |
Use Scenario: 48V telecom or factory automation bus stepping down to 12V/15V for PLC I/O modules and motor drives. IC Role / Device Role / Timing Role: High-efficiency, current-limited DC/DC controller enabling scalable power delivery with telemetry via IMON. Use Value: Accurate average current limit (±2.5%) allows safe parallel operation of multiple converters; 75µA IQ extends uptime in standby states. |
| LED Driver Control | Test Equipment Power |
|
Use Scenario: Constant-current driver for high-brightness LED arrays in signage or stage lighting with dimming interface. IC Role / Device Role / Timing Role: Precision current regulator using ICTRL and IMON feedback - replaces dedicated LED driver ICs. Use Value: 20× differential sense amplification and 1% full-scale accuracy at 50mV enable sub-1% current regulation without calibration. |
Use Scenario: Lab-grade bench power supply module requiring low-noise, programmable output with current limiting and telemetry. IC Role / Device Role / Timing Role: Core controller implementing voltage + current regulation loops with synchronized switching for EMI control. Use Value: SYNC pin enables phase alignment with other converters; RT programming allows optimization for low-noise 100–300kHz bands. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EMSE#PBF | Wider 4V–60V input, dual-output, no integrated auxiliary regulator - requires external 7.5V bias; lower IQ (45µA). | Preferred for multi-rail systems needing independent outputs; less suitable for single-rail, space-constrained designs. | Select when dual-output capability or lower quiescent current outweighs need for self-contained bias generation. |
| LM5116MH/NOPB | 4.5V–100V input, no integrated auxiliary supply, no IMON or average current limit - relies on external current sense amp. | Suited for ultra-high-input applications (e.g., 72V industrial); lacks built-in current monitoring for telemetry. | Choose for >60V input or cost-sensitive designs where external current sensing is acceptable. |
Compared with LTC3891EMSE#PBF and LM5116MH/NOPB, the LT3840MPFE#PBF uniquely integrates a 7.5V auxiliary regulator, average current limit with IMON telemetry, and extended –55°C to 150°C operation - making it optimal for compact, high-reliability single-output systems where board space and thermal robustness are critical.
Availability
LT3840MPFE#PBF is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC distribution systems, and LED driver control requiring stable component supply across extreme temperature ranges and long production lifecycles.
Supply support for LT3840MPFE#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 (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 LT3840MPFE#PBF belongs to Linear Technology's high-voltage synchronous controller product line, designed specifically for ruggedized DC/DC conversion in automotive, industrial, and aerospace applications demanding extended temperature operation and integrated protection.
FAQ
What is the operating temperature range of the LT3840MPFE#PBF?
The LT3840MPFE#PBF is 100% tested and guaranteed over –55°C to +150°C junction temperature. This extended range exceeds standard automotive AEC-Q100 Grade 1 (–40°C to +125°C) and supports under-hood and industrial environments where ambient temperatures exceed 100°C. Thermal derating above 125°C is required per datasheet Note 2.
How does the LT3840MPFE#PBF generate its gate drive voltage?
The LT3840MPFE#PBF uses an integrated monolithic buck-boost switching regulator to generate a regulated 7.5V INTVCC supply - independent of input voltage - enabling efficient gate drive for large N-channel MOSFETs across the full 2.5V–60V input range. This eliminates the need for external bias supplies or linear regulators that waste power at high VIN.
Can the LT3840MPFE#PBF operate as a constant-current source?
Yes. The LT3840MPFE#PBF supports precise constant-current operation via its average current limit loop. Applying a voltage to ICTRL (0–1V) sets the maximum average output current; the IMON pin provides a 20× amplified, filtered representation of actual average current - enabling closed-loop current regulation and telemetry without external components.
What protection features are integrated into the LT3840MPFE#PBF?
The LT3840MPFE#PBF integrates input UVLO and OVLO with 1.25V ±5mV thresholds and hysteresis, output OVP, power good (PG), reverse-current detection, and thermal shutdown. Its auxiliary regulator remains active during OVLO events to maintain bias - ensuring fast recovery once input returns to safe range.
Is the LT3840MPFE#PBF pin-compatible with other LT3840 variants?
Yes. The LT3840MPFE#PBF shares identical pinout, footprint, and electrical characteristics with LT3840EFE#PBF, LT3840IFE#PBF, and LT3840HFE#PBF in the 28-lead TSSOP package. Only the temperature grade and test screening differ - allowing direct substitution in existing designs requiring extended temperature operation.
LT3840MPFE#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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3840MPFE#PBF FAQ
1.How can I place an order for LT3840MPFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840MPFE#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 LT3840MPFE#PBF reliable?
The price and inventory of LT3840MPFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840MPFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3840MPFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840MPFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840MPFE#PBF?
LT3840MPFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840MPFE#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 LT3840MPFE#PBF?
For technical support, including LT3840MPFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840MPFE#PBF requirements.
6.How does Aetrix verify that LT3840MPFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3840MPFE#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 LT3840MPFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3840MPFE#PBF?
All LT3840MPFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840MPFE#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 LT3840MPFE#PBF part is unused and in its original packaging.
Return procedure for LT3840MPFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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