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Analog Devices Inc. LT3840MPFE#TRPBF
- Part No.:
- LT3840MPFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3840MPFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,957
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Product details
Overview
LT3840MPFE#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, ±1.25% FB regulation (MP-grade), and operates across –55°C to 150°C junction temperature.
For engineers reviewing the LT3840MPFE#TRPBF datasheet, LT3840MPFE#TRPBF pinout, LT3840MPFE#TRPBF application, or LT3840MPFE#TRPBF equivalent, this page delivers verified technical context, package-specific pin functions, real-world application cards, and two validated alternative parts - all grounded in the official Rev B datasheet and manufacturer specifications.
Technical Context
The LT3840MPFE#TRPBF implements a constant-frequency, peak-current-mode control architecture with dual-loop regulation: voltage loop via FB/VC error amplifier and average current loop via ICTRL/IMON/ICOMP. Its internal buck-boost auxiliary regulator generates a regulated 7.5V INTVCC rail from 2.5V–60V VIN, enabling efficient gate drive of multiple N-channel MOSFETs without external bias supplies.
It supports three light-load operating modes-Burst Mode (MODE = GND), pulse-skipping (MODE = FB), and continuous conduction (MODE = INTVCC)-with 75µA quiescent current at 12VIN→3.3VOUT. Protection includes input OVLO/UVLO (precision thresholds with hysteresis), output OVP, power good (PG), and reverse-current limiting via SENSE+/- differential sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 60V - enables direct operation from 12V, 24V, 48V industrial rails and automotive battery systems without pre-regulation. |
| Output Voltage Range | Up to 60V - supports wide-range adjustable outputs including 3.3V, 5V, 12V, 24V, and higher via FB resistor divider. |
| Switching Frequency | 50kHz to 1MHz - set by RT resistor; allows optimization of efficiency vs. size (e.g., 300kHz typical with 49.9kΩ). |
| FB Regulation Accuracy | ±1.25% over –55°C to 150°C - ensures stable output under extreme thermal conditions in aerospace/military applications. |
| Quiescent Current | 75µA at 12VIN → 3.3VOUT - extends battery runtime in portable or remote-sensor systems using Burst Mode. |
| Auxiliary Bias Output | 7.5V ±3.3% (INTVCC) - powers TG/BG drivers and internal circuitry across full input range; eliminates need for external LDO. |
| Current Limit Accuracy | ±10% peak sense threshold (95mV typ) - provides repeatable overcurrent protection for high-reliability power stages. |
Pinout & Package
LT3840MPFE#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 |
|---|---|---|
| AUXSW1 (Pin 1) | Auxiliary bias supply switching node | Connects to inductor of internal buck-boost regulator; critical for generating 7.5V INTVCC rail. |
| PGND (Pin 2) | High-current ground return for auxiliary supply | Must tie directly to INTVCC capacitor negative and system ground to minimize noise and voltage drop. |
| AUXVIN (Pin 3) | Auxiliary bias supply input | Accepts 2.5V–60V; bypassed with low-ESR capacitor to PGND for stable auxiliary regulation. |
| SYNC (Pin 4) | External clock synchronization input | Allows frequency locking to external source; requires internal oscillator set ≥15% below sync clock min frequency. |
| RT (Pin 5) | Oscillator frequency programming | Resistor value sets switching frequency (e.g., 49.9kΩ = 300kHz); determines inductor size and efficiency trade-off. |
| TK/SS (Pin 6) | Soft-start and output voltage tracking input | Internal 9µA current source charges external capacitor; enables controlled ramp-up and supply sequencing. |
| FB (Pin 7) | Feedback input for output voltage regulation | Sets VOUT via resistor divider; also feeds PG and OVP comparators; reference = 1.250V (MP-grade). |
| VC (Pin 8) | Compensation node for voltage control loop | External RC network stabilizes error amplifier; connects to FB through compensation network. |
| PG (Pin 9) | Open-drain power-good indicator | Asserts high when FB is within 87–93% of regulation; used for system enable sequencing and fault detection. |
| MODE (Pin 10) | Light-load operation mode select | GND = Burst Mode (low IQ); FB = pulse-skipping; INTVCC = continuous conduction. |
| OVLO (Pin 11) | Input overvoltage lockout input | Precision threshold (1.25V) disables switching during transients >80V; INTVCC remains active for bias. |
| UVLO (Pin 12) | Input undervoltage lockout input | Enables controller only when input exceeds 1.25V threshold; prevents unstable startup at low VIN. |
| EN (Pin 13) | Main enable/shutdown control | 1.25V rising threshold; pulls into ultra-low-IQ shutdown (<1µA) when below 0.3V. |
| VIN (Pin 14) | Main input supply rail | 2.5V–60V primary input; decoupled with 0.1µF ceramic capacitor close to pin for noise immunity. |
| GND (Pins 15, 29) | Signal and power ground | Exposed pad (Pin 29) is GND and must be soldered to PCB ground plane for thermal management and noise control. |
| IMON (Pin 16) | Average output current monitor output | Voltage proportional to average load current (e.g., 1.00V @ 50mV sense); filtered by external capacitor for telemetry. |
| ICTRL (Pin 17) | Programmable average current limit setpoint | Voltage input (0–1V) scales maximum average current; floating = 50mV default (1V sense × 20× gain = 50mV avg). |
| ICOMP (Pin 18) | Average current loop compensation node | RC network stabilizes current control loop; separates current regulation dynamics from voltage loop. |
| SENSE+ / SENSE– (Pins 19, 20) | Differential current sense inputs | Measure voltage across RSENSE; 20× internal gain enables accurate current monitoring down to millivolt levels. |
| SW (Pin 21) | High-side switch node | Connects to source of bottom MOSFET and BOOST capacitor; carries high di/dt switching currents. |
| TG (Pin 22) | Top-gate driver output | Drives gate of high-side N-MOSFET; 7.5V swing, 20ns rise/fall, 75ns non-overlap prevents shoot-through. |
| BOOST (Pin 23) | Bootstrap supply for TG driver | Connected to ceramic capacitor referenced to SW; sustains high-side gate drive during 100% duty cycle. |
| BGRTN (Pin 24) | Bottom-gate driver return path | High-current return for BG driver; ties to INTVCC capacitor negative and system ground. |
| BG (Pin 25) | Bottom-gate driver output | Drives gate of low-side N-MOSFET; complements TG with matched timing and drive strength. |
| INTVCC (Pin 26) | Internal 7.5V bias supply output | Powers internal logic and gate drivers; max 100mA output; cannot be back-driven. |
| AUXSW2 (Pin 27) | Second auxiliary switching node | Completes buck-boost topology with AUXSW1; connects to second inductor winding or shared inductor tap. |
| AUXBST (Pin 28) | Auxiliary bootstrap drive | Provides gate drive for auxiliary regulator switches; referenced to AUXSW1 via external capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated buck-boost auxiliary regulator | Generates stable 7.5V INTVCC from 2.5V–60V input - eliminates external bias supply and improves efficiency at high VIN. |
| Accurate programmable current limit | ±10% peak sense threshold + 50mV average limit with ICTRL voltage scaling - enables precise overcurrent protection and constant-current sourcing. |
| Three selectable light-load modes | Burst Mode (75µA IQ), pulse-skipping, or continuous conduction - optimizes efficiency across full load range without external components. |
| Robust input transient protection | Withstands 80V input transients via AUXVIN OVLO while maintaining INTVCC regulation - critical for automotive and industrial environments. |
| Full-temperature-grade MP specification | 100% tested over –55°C to 150°C junction range - qualified for extended-temperature military, avionics, and downhole applications. |
Applications
| Industrial DC Power Distribution | Automotive Battery Management Systems |
|---|---|
|
Use Scenario: 48V intermediate bus conversion to 12V/5V loads in factory automation PLCs and motor drives. IC Role / Device Role / Timing Role: Primary synchronous buck controller managing high-efficiency, high-current step-down with precise current limiting. Use Value: Wide 2.5V–60V input accommodates brownouts and surges; 7.5V INTVCC ensures reliable gate drive even at 48V nominal input. |
Use Scenario: Regulating 12V starter battery output to stable 3.3V/5V for ADAS sensors and infotainment ECUs. IC Role / Device Role / Timing Role: High-voltage controller handling cold-crank (4.5V) to load-dump (40V+) transients while maintaining output regulation. Use Value: Input OVLO/UVLO with hysteresis prevents false triggering; MP-grade temp range supports under-hood placement. |
| Avionics Power Supplies | Test & Measurement Equipment |
|
Use Scenario: Converting 28V aircraft bus to isolated 5V/±15V rails for flight control modules requiring MIL-STD-704 compliance. IC Role / Device Role / Timing Role: Core controller implementing soft-start, tracking, and PG signaling for safe power sequencing across multiple subsystems. Use Value: TK/SS pin enables voltage tracking between rails; –55°C to 150°C rating meets DO-160 environmental requirements. |
Use Scenario: Programmable DC power supply output stage delivering 0–30V at up to 20A with digital current monitoring. IC Role / Device Role / Timing Role: Precision current-mode controller with IMON feedback and ICTRL programmability for closed-loop current regulation. Use Value: 20× amplified SENSE signal and 50mV average current threshold enable <1% current accuracy across temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3890EMSE#PBF | Wider VIN range (4V–60V), dual-output, integrated MOSFET drivers, but no auxiliary buck-boost bias generator. | Requires external 7.5V bias supply; better suited for dual-rail designs where auxiliary generation is handled separately. | Select LTC3890EMSE#PBF when dual-output capability and channel interleaving are required, and external bias is acceptable. |
| LM5116MH/NOPB | 4.5V–60V input, no integrated auxiliary regulator, lower IQ (100µA), no IMON/ICTRL current monitoring features. | Lacks average current regulation and telemetry; suitable for simpler constant-voltage-only applications. | Choose LM5116MH/NOPB for cost-sensitive, single-output industrial supplies where current monitoring is not required. |
Compared with LTC3890EMSE#PBF and LM5116MH/NOPB, the LT3840MPFE#TRPBF uniquely integrates a self-powered 7.5V auxiliary regulator and full average current control - making it optimal for high-reliability, single-output, current-monitored systems operating across extreme temperatures and input ranges.
Availability
LT3840MPFE#TRPBF is available at Aetrix Electronics and suitable for industrial DC power distribution, automotive battery management systems, avionics power supplies, and test & measurement equipment requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LT3840MPFE#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 ICs.
The LT3840MPFE#TRPBF belongs to Linear Technology's high-voltage synchronous controller product line, designed specifically for rugged, wide-input industrial, automotive, and aerospace power conversion where reliability across extreme temperature and transient conditions is mandatory.
FAQ
What is the operating temperature range for the LT3840MPFE#TRPBF?
The LT3840MPFE#TRPBF is 100% tested and guaranteed over a junction temperature range of –55°C to 150°C. This extended grade makes it suitable for harsh-environment applications such as downhole oil & gas tools, avionics, and military electronics where standard commercial or industrial grades would fail.
How does the LT3840MPFE#TRPBF generate its gate drive voltage without an external bias supply?
The LT3840MPFE#TRPBF integrates a monolithic buck-boost switching regulator that generates a regulated 7.5V INTVCC rail directly from the main VIN (2.5V–60V). This eliminates the need for an external bias supply and ensures consistent gate drive performance across the entire input range - unlike linear-bias controllers that suffer dropout or excessive dissipation at high VIN.
Can the LT3840MPFE#TRPBF be used for constant-current applications like LED drivers or battery charging?
Yes - the LT3840MPFE#TRPBF supports accurate average current regulation via the ICTRL pin and IMON output. With a precision 50mV average current sense threshold (scalable down to 40mV) and 20× amplified SENSE signal, it enables closed-loop constant-current operation for LED drivers, lab power supplies, and battery charge controllers.
What protection features are built into the LT3840MPFE#TRPBF?
The LT3840MPFE#TRPBF includes input OVLO/UVLO with hysteresis, output OVP, power good (PG) reporting, reverse-current limiting, thermal shutdown, and robust 80V transient tolerance on AUXVIN. Its current-mode architecture also provides inherent cycle-by-cycle overcurrent protection via the SENSE+/- inputs.
Is the LT3840MPFE#TRPBF pin-compatible with other LT3840 variants like the LT3840EFE#TRPBF?
Yes - all LT3840 variants in the FE (28-lead TSSOP) package, including LT3840MPFE#TRPBF, LT3840EFE#TRPBF, and LT3840IFE#TRPBF, share identical pinout, footprint, and electrical interface. Only the temperature grade, FB regulation tolerance, and test coverage differ - allowing drop-in replacement where thermal requirements permit.
LT3840MPFE#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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3840MPFE#TRPBF FAQ
1.How can I place an order for LT3840MPFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3840MPFE#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 LT3840MPFE#TRPBF reliable?
The price and inventory of LT3840MPFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3840MPFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3840MPFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3840MPFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3840MPFE#TRPBF?
LT3840MPFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3840MPFE#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 LT3840MPFE#TRPBF?
For technical support, including LT3840MPFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3840MPFE#TRPBF requirements.
6.How does Aetrix verify that LT3840MPFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3840MPFE#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 LT3840MPFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3840MPFE#TRPBF?
All LT3840MPFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3840MPFE#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 LT3840MPFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3840MPFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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