My Inquiry
My Account
Analog Devices Inc. LT8705EUHF#TRPBF
- Part No.:
- LT8705EUHF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LT8705EUHF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK-BOOST 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,583
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT8705EUHF#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous 4-switch buck-boost DC/DC controller IC designed for wide-input, wide-output voltage regulation in high-reliability power systems. It supports 2.8V–80V input and 1.3V–80V output, integrates quad N-channel gate drivers, and delivers up to 98% efficiency in synchronous rectification mode - enabling use in solar charge controllers, automotive 48V/12V bidirectional converters, and telecom voltage stabilizers.
For engineers reviewing the LT8705EUHF#TRPBF datasheet, LT8705EUHF#TRPBF pinout, LT8705EUHF#TRPBF application, or LT8705EUHF#TRPBF equivalent, key selection criteria include its 100kHz–400kHz synchronizable switching frequency, integrated input/output current monitoring with programmable thresholds, servo feedback loop status indicators, and support for forced continuous, discontinuous, or Burst Mode® operation at light loads.
Technical Context
The LT8705EUHF#TRPBF implements a current-mode control architecture with four independent feedback loops: input voltage (FBIN), output voltage (FBOUT), input current (IMON_IN), and output current (IMON_OUT). Its VC pin serves as a diode-AND of error amplifier outputs EA1–EA4, enabling seamless transition between buck, boost, and buck-boost operating regions without mode switching artifacts.
It features dedicated open-drain servo pins (SRVO_FBIN, SRVO_FBOUT, SRVO_IIN, SRVO_IOUT) that indicate real-time activation status of each feedback loop, and includes an internal 6.35V LDO (INTVCC) with switchover to EXTVCC ≥6.4V, plus a standalone 3.3V/12mA LDO (LDO33) for auxiliary circuitry - all within a single 38-lead QFN package rated for –40°C to 125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 2.8V to 80V - supports direct connection to automotive battery (cold-crank), solar arrays, and industrial HV rails without pre-regulation. |
| VOUT Range | 1.3V to 80V - enables bidirectional voltage conversion across wide load and source conditions. |
| Switching Frequency | 100kHz to 400kHz - adjustable via RT resistor; synchronizable to external clock for EMI reduction in multi-rail systems. |
| Efficiency | Up to 98% - achieved via synchronous rectification and low-loss gate drivers optimized for N-channel MOSFETs. |
| Gate Drivers | Quad N-channel drivers (TG1/BG1/TG2/BG2) with 20ns rise/fall times - drives high-side and low-side switches in both buck and boost legs independently. |
| Current Monitoring | Programmable IMON_IN and IMON_OUT outputs - provide analog current signals proportional to sensed input/output currents for protection and telemetry. |
| Operating Temp | –40°C to 125°C - qualified for automotive under-hood and industrial ambient environments. |
Pinout & Package
LT8705EUHF#TRPBF is housed in a 38-lead (5mm × 7mm) plastic QFN package with exposed thermal pad (Pin 39 = GND). The package supports high-voltage isolation and enhanced thermal dissipation for continuous high-power operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SHDN (Pin 1) | Shutdown Control | Active-low enable; pulls quiescent current to ≤1µA when grounded - critical for system-level power sequencing. |
| CSP/CSN (Pins 3/2) | Inductor Current Sense Input | Differential inputs for main inductor current sensing; sets peak current limit via VC and RSENSE value. |
| FBIN/FBOUT (Pins 5/6) | Voltage Feedback Inputs | Resistor-divider inputs for input and output voltage regulation loops - enable dual-loop stabilization in battery charging or regenerative systems. |
| IMON_IN/IMON_OUT (Pins 7/10) | Current Monitor Outputs | Analog current-source outputs proportional to input/output current - used for overcurrent protection and telemetry without external op-amps. |
| SRVO_FBIN/SRVO_FBOUT (Pins 25/28) | Servo Loop Status Indicators | Open-drain outputs pulled low when respective FBIN or FBOUT loop is active - enables real-time diagnostics and fault isolation. |
| TG1/BG1/TG2/BG2 (Pins 22/14/18/16) | N-Channel Gate Drivers | High-speed drivers for four external MOSFETs - TG1/BG1 control first switch leg (VIN side), TG2/BG2 control second leg (VOUT side). |
| SW1/SW2 (Pins 21/19) | Switch Node Terminals | Connect to external MOSFET sources; tolerate up to 81V - define switching node voltages for bootstrap capacitor charging. |
| EXTVCC/INTVCC (Pins 29/35) | Power Supply Inputs | EXTVCC powers INTVCC above 6.4V; INTVCC supplies gate drivers and internal logic - ensures stable bias under wide VIN transients. |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost topology | Eliminates need for separate buck and boost stages - reduces BOM count, PCB area, and magnetic component cost in bidirectional power systems. |
| Four independent feedback loops | Enables simultaneous regulation of input voltage, output voltage, input current, and output current - essential for solar MPPT, battery charging, and regenerative braking. |
| Synchronizable fixed-frequency operation | Prevents beat frequencies in multi-converter systems and simplifies EMI filter design by locking switching edges to a master clock. |
| Integrated 3.3V/12mA LDO | Provides clean, regulated supply for external sensors, ADCs, or microcontrollers - avoids need for discrete LDO in space-constrained designs. |
| Adjustable UVLO with hysteresis | Configurable startup/shutdown thresholds on VIN and EXTVCC - prevents brownout oscillation during battery sag or cold-crank events. |
Applications
| Solar Charge Controller | Automotive 48V/12V Bidirectional Converter |
|---|---|
Use Scenario: Regulates variable PV array voltage (20–80V) to charge 12V or 48V battery banks while enforcing maximum power point tracking and current limits. IC Role / Device Role / Timing Role: Primary buck-boost controller managing dual-loop (VIN, IOUT) regulation and providing servo status for MPPT algorithm execution. Use Value: Enables >95% conversion efficiency across full solar irradiance range and eliminates need for separate DC-DC stages in hybrid vehicle energy management. | Use Scenario: Transfers power bidirectionally between 48V mild-hybrid rail and 12V legacy subsystems during start-stop, regenerative braking, and load leveling. IC Role / Device Role / Timing Role: Synchronous 4-switch controller executing seamless buck/boost transitions with <200ns dead-time control and precise current limiting. Use Value: Supports 5kW+ peak power transfer with <1% output voltage deviation during transient load steps - meeting ISO 16750-2 automotive electrical stress requirements. |
| Telecom Voltage Stabilizer | Industrial Battery Backup System |
Use Scenario: Maintains stable 48V output from fluctuating -48V DC plant supply or backup batteries during grid outages, with strict hold-up time and current limiting. IC Role / Device Role / Timing Role: High-voltage buck-boost regulator implementing input voltage and output current feedback loops for fault-tolerant operation. Use Value: Delivers 98% efficiency at full load and maintains regulation down to 2.8V input - extending runtime and reducing thermal stress in NEBS-compliant enclosures. | Use Scenario: Powers critical infrastructure (e.g., PLCs, safety controllers) from lithium-ion or lead-acid batteries during AC mains failure, with programmable charge/discharge current profiles. IC Role / Device Role / Timing Role: Dual-loop (VOUT, IOUT) controller supporting constant-current charging and constant-voltage termination with real-time current telemetry. Use Value: Integrates precision current monitoring and servo status outputs - eliminating external current-sense amplifiers and reducing BOM by 3 components per channel. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3780EUF#PBF | Same 4-switch architecture but limited to 60V max VIN/VOUT; no integrated IMON outputs or servo pins. | Suitable for lower-voltage industrial SMPS where current telemetry is handled externally. | Select LTC3780EUF#PBF only if system voltage stays below 60V and discrete current sensing is acceptable. |
| MPQ4333AGL-Z | Monolithic 4-switch buck-boost IC with integrated MOSFETs; max 36V VIN, no programmable frequency or servo indicators. | Better for compact, low-to-mid power (<100W) applications where layout simplicity outweighs voltage range and diagnostic needs. | Choose MPQ4333AGL-Z when board space is constrained and full 80V operation is unnecessary. |
Compared with LTC3780EUF#PBF and MPQ4333AGL-Z, the LT8705EUHF#TRPBF uniquely combines 80V rating, integrated current monitoring with servo status, and synchronizable frequency - making it the only option for high-voltage, high-diagnostic-fidelity bidirectional power conversion in automotive and telecom infrastructure.
Availability
LT8705EUHF#TRPBF is available at Aetrix Electronics and suitable for solar charge controllers, automotive 48V/12V bidirectional converters, and telecom voltage stabilizers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT8705EUHF#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors for precision signal chain and power applications.
The LT8705EUHF#TRPBF belongs to Analog Devices' high-voltage power controller product line, engineered specifically for robust, wide-input-range DC/DC conversion in automotive, industrial, and renewable energy systems where reliability, efficiency, and diagnostic capability are critical.
FAQ
What is the maximum input voltage supported by the LT8705EUHF#TRPBF?
The LT8705EUHF#TRPBF supports a maximum input voltage of 80V, as specified in its absolute maximum ratings and validated across the full –40°C to 125°C operating junction temperature range. This allows direct interface with high-voltage solar arrays, 48V automotive systems during load dump, and telecom –48V DC plants without external clamping or pre-regulation - a key differentiator versus 60V-class controllers like the LTC3780.
Does the LT8705EUHF#TRPBF require external MOSFETs?
Yes, the LT8705EUHF#TRPBF is a controller IC and requires four external N-channel MOSFETs - two for the input-side (M1/M2) and two for the output-side (M3/M4) of the 4-switch buck-boost topology. It integrates high-speed gate drivers (TG1/BG1/TG2/BG2) with 20ns rise/fall times and built-in shoot-through protection delays, but does not include power switches on-die.
How does the LT8705EUHF#TRPBF handle mode transitions between buck and boost operation?
The LT8705EUHF#TRPBF uses a seamless current-mode control architecture with a single VC pin that diode-ANDs outputs from four independent error amplifiers (EA1–EA4). This eliminates discontinuities during VIN-to-VOUT crossover, maintaining regulation without manual mode selection or external circuitry - unlike dual-mode controllers requiring hysteresis or external comparators.
Can the LT8705EUHF#TRPBF monitor both input and output currents simultaneously?
Yes, the LT8705EUHF#TRPBF provides dedicated IMON_IN and IMON_OUT pins that deliver analog current-source outputs proportional to sensed input and output currents. These outputs are referenced to the internal 1.208V regulation voltage and support programmable current limits - enabling real-time telemetry and overcurrent protection without external amplifiers or ADCs.
What is the purpose of the SRVO_FBIN and SRVO_FBOUT pins on the LT8705EUHF#TRPBF?
The SRVO_FBIN and SRVO_FBOUT pins on the LT8705EUHF#TRPBF are open-drain logic outputs that go low when the input voltage (FBIN) or output voltage (FBOUT) feedback loop is actively regulating. They provide real-time status of loop engagement - useful for system diagnostics, fault logging, and adaptive control algorithms that respond to loop dominance shifts during transients.
LT8705EUHF#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-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 2.8V ~ 80V
- Frequency - Switching:
- 100kHz ~ 400kHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LT8705EUHF#TRPBF FAQ
1.How can I place an order for LT8705EUHF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8705EUHF#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 LT8705EUHF#TRPBF reliable?
The price and inventory of LT8705EUHF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8705EUHF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8705EUHF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8705EUHF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8705EUHF#TRPBF?
LT8705EUHF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8705EUHF#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 LT8705EUHF#TRPBF?
For technical support, including LT8705EUHF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8705EUHF#TRPBF requirements.
6.How does Aetrix verify that LT8705EUHF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8705EUHF#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 LT8705EUHF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8705EUHF#TRPBF?
All LT8705EUHF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8705EUHF#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 LT8705EUHF#TRPBF part is unused and in its original packaging.
Return procedure for LT8705EUHF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT8705EUHF#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…
