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Analog Devices Inc. LT8708EUHG#TRPBF
- Part No.:
- LT8708EUHG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT8708EUHG#TRPBF.pdf
- Description:
- 80V SYNCHRONOUS 4-SWITCH BUCK-BO
- Quantity:
- Payment:
- Shipping:
Inventory:376
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Product details
Overview
LT8708EUHG#TRPBF from Analog Devices is a high-voltage synchronous 4-switch buck-boost DC/DC controller with bidirectional power capability, operating from 2.8V to 80V input and regulating output from 1.3V to 80V. It supports independent forward/reverse current limiting on both input and output sides, implements six regulation modes (VIN/VOUT voltage, IIN/IOUT current), and achieves up to 99% efficiency in synchronous rectification. It is used in automotive 48V systems, dual-battery energy transfer, and solar charge management.
For engineers reviewing the LT8708EUHG#TRPBF datasheet, LT8708EUHG#TRPBF pinout, LT8708EUHG#TRPBF application, or LT8708EUHG#TRPBF equivalent, key selection criteria include bidirectional conduction mode control (HCM/CCM/DCM/Burst), independent IMON resistor-based current limits, wide-input/high-voltage switching capability (SW1/SW2 rated to 81V), and AEC-Q100 qualification for automotive-grade reliability.
Technical Context
The LT8708EUHG#TRPBF employs a four-switch buck-boost topology with integrated gate drivers for TG1/BG1/TG2/BG2, enabling seamless transition between buck, boost, and buck-boost regions without external diodes. Its control architecture includes five error amplifiers (EA1–EA5) dedicated to VIN voltage, VOUT voltage, and forward/reverse current regulation on both sides.
Operation is configured via DIR (unidirectional/bidirectional flow direction) and MODE (CCM/HCM/DCM/Burst) pins, with real-time switching-mode reconfiguration supported. Current sensing uses differential inputs (CSPIN/CSNIN, CSPOUT/CSNOUT) referenced to up to 80V common-mode voltages, and internal slope compensation ensures stability across all conduction modes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 80V - supports 12V/24V/48V automotive, telecom, and battery systems without pre-regulation. |
| Output Voltage Range | 1.3V to 80V - enables single-inductor bidirectional regulation across wide VIN/VOUT ratios. |
| Switching Frequency | 100kHz to 400kHz - adjustable via RT resistor; supports SYNC input for clock synchronization in multi-phase designs. |
| Current Limit Accuracy | ±10% typical over temperature - enables precise IIN/IOUT forward/reverse protection using four independent external resistors. |
| Operating Junction Temp | –40°C to 125°C - specified for industrial and automotive environments; E-grade device with 150°C TJMAX. |
| Package | 40-lead 5mm × 8mm QFN with high-voltage pin spacing - optimized for creepage/clearance in >60V applications. |
| AEC-Q100 Grade | Not qualified - LT8708EUHG#TRPBF is industrial-grade; automotive versions use #W suffix (e.g., LT8708IUHG#WTRPBF). |
Pinout & Package
LT8708EUHG#TRPBF is housed in a 40-lead (5mm × 8mm) plastic QFN package with exposed thermal pad (Pin 41 = GND). Pin spacing meets high-voltage isolation requirements for ≥80V operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW1, SW2 | Power switch node connections | High-side and low-side switch nodes for buck-boost power stage; rated to 81V absolute max. |
| TG1, BG1, TG2, BG2 | NMOS gate drivers | Independent high- and low-side drivers for external NMOS FETs; 20ns rise/fall time into 3300pF load. |
| CSPIN/CSNIN, CSPOUT/CSNOUT | Differential current sense inputs | Four isolated current monitor inputs supporting ±100mV differential range at 0–80V common-mode voltage. |
| DIR, MODE | Functional configuration pins | DIR sets power flow direction (forward/reverse); MODE selects conduction mode (CCM/HCM/DCM/Burst) with defined voltage thresholds. |
| VINCHIP, EXTVCC | Primary and auxiliary supply inputs | VINCHIP powers chip core (2.8–80V); EXTVCC provides alternate bias (switchover at 6.4V) to reduce dissipation. |
| FBIN, FBOUT | Voltage feedback inputs | Separate precision inputs for input and output voltage regulation; each references 1.205V internal bandgap with <±1% tolerance. |
| IMON_INP/INN/ON/OP | Current regulation outputs | Analog outputs proportional to sensed currents; used to set forward/reverse current limits via external resistors. |
| CLKOUT, SYNC | Timing interface pins | CLKOUT provides synchronized clock output (adjustable duty cycle); SYNC accepts external clock for master-slave synchronization. |
Key Features
| Feature | Design Value |
|---|---|
| Six independent regulation loops | Simultaneous control of VIN, VOUT, IIN(Fwd/Rvs), IOUT(Fwd/Rvs) - eliminates need for external controllers in dual-battery backup systems. |
| Bidirectional conduction support | HCM (Hybrid Conduction Mode) enables efficient partial-load reverse power flow without discontinuous ringing or instability. |
| Real-time mode reconfiguration | DIR and MODE pins can be changed dynamically during operation - allows adaptive system-level power routing without restart. |
| High-voltage current sensing | CSPIN/CSNIN and CSPOUT/CSNOUT tolerate 0–80V common-mode voltage - enables direct high-side current monitoring without level-shifting circuitry. |
| Integrated LDO33 regulator | 3.3V/22mA regulated output - powers external logic or ADCs; includes UVLO (3.04V) and load regulation (<±1%). |
Applications
| Automotive Dual-Battery System | Solar Energy Storage Interface |
|---|---|
Use Scenario: Bidirectional power transfer between 12V starter battery and 48V mild-hybrid rail during engine start/stop cycles. IC Role / Device Role / Timing Role: Primary buck-boost controller managing voltage and current in both directions; regulates VOUT during boost (12V→48V) and VIN during buck (48V→12V). Use Value: Eliminates need for separate buck and boost ICs; reduces BOM count and PCB area while maintaining <±1% voltage regulation accuracy. | Use Scenario: MPPT-enabled solar charger transferring energy from PV array to lithium-titanate battery bank with regenerative discharge capability. IC Role / Device Role / Timing Role: Core DC/DC controller implementing voltage-loop MPPT and current-limited bidirectional charging/discharging. Use Value: Supports full 4-quadrant operation (VIN>VOUT, VIN<VOUT, IIN>0/IOUT>0, IIN<0/IOUT<0) with independent current limit settings per quadrant. |
| Industrial UPS Backup Converter | Telecom 48V/54V Hot-Swap Module |
Use Scenario: Seamless switchover between AC-derived 48V DC bus and supercapacitor backup bank during grid outage. IC Role / Device Role / Timing Role: Bidirectional controller maintaining constant VOUT during normal operation and regulating IIN during capacitor recharge after recovery. Use Value: Enables zero-interruption power delivery using single-inductor architecture; avoids transformer-based isolation overhead and improves transient response. | Use Scenario: Hot-swap module regulating 54V telecom rectifier output down to stable 48V for distributed loads, with reverse-current blocking during insertion. IC Role / Device Role / Timing Role: Buck-boost controller operating in unidirectional CCM mode (DIR=high) with reverse-current protection activated via IMON_INN threshold. Use Value: Prevents backfeeding into upstream rectifiers during hot-plug events; maintains <100ns response to reverse-current faults via dedicated IMON_INN comparator path. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7821EFE#TRPBF | Fixed-ratio hybrid converter (no VOUT regulation); no bidirectional capability; requires external MOSFETs only for high-side switches. | Designed for high-efficiency fixed-ratio step-down in datacenter PDNs; lacks current/voltage regulation loops for battery systems. | Select LTC7821 when fixed 2:1 or 3:1 conversion with ultra-low EMI is required, and bidirectional control is unnecessary. |
| MPQ4332GR-AEC1-Z | Monolithic 3.5A 36V buck-boost; integrates power FETs; no bidirectional support; max VIN/VOUT = 36V. | Targeted at compact consumer/industrial DC/DC where integration and size outweigh flexibility; limited to sub-36V applications. | Choose MPQ4332 for space-constrained 12V/24V systems needing integrated FETs and simplified layout, but not bidirectional operation. |
Compared with LTC7821EFE#TRPBF and MPQ4332GR-AEC1-Z, the LT8708EUHG#TRPBF uniquely delivers full 4-quadrant regulation, 80V capability, and programmable conduction modes - making it the only option among the three suitable for automotive dual-battery energy arbitrage and high-voltage solar storage interfaces.
Availability
LT8708EUHG#TRPBF is available at Aetrix Electronics and suitable for automotive 48V systems, bidirectional charging infrastructure, and industrial UPS backup converters requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT8708EUHG#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8708EUHG#TRPBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-voltage, high-efficiency, and bidirectionally controllable DC/DC conversion in demanding energy-transfer applications.
FAQ
What is the maximum input voltage rating for the LT8708EUHG#TRPBF?
The LT8708EUHG#TRPBF supports an absolute maximum input voltage of 80V on the VINCHIP pin and 81V on the SW1/SW2 pins. This enables direct connection to 48V automotive rails, telecom -48V systems, and high-voltage battery stacks without external clamping or pre-regulation stages. The LT8708EUHG#TRPBF datasheet specifies these ratings under Absolute Maximum Ratings (Table on page 3).
Does the LT8708EUHG#TRPBF support true bidirectional power flow with independent current limiting?
Yes, the LT8708EUHG#TRPBF supports full bidirectional power flow with four independent current limits: forward input, reverse input, forward output, and reverse output - each set by a dedicated external resistor. This capability is implemented via separate IMON_INP/INN/ON/OP pins and corresponding error amplifiers, allowing precise control of energy transfer direction and magnitude in both quadrants. The LT8708EUHG#TRPBF block diagram (page 15) confirms this architecture.
What package type and thermal characteristics does the LT8708EUHG#TRPBF use?
The LT8708EUHG#TRPBF uses a 40-lead 5mm × 8mm plastic QFN package (UHG) with exposed thermal pad (Pin 41 = GND). Its thermal resistance is θJA = 36°C/W and θJC = 3.8°C/W, enabling reliable operation at full load in industrial ambient temperatures up to 85°C with minimal heatsinking. The LT8708EUHG#TRPBF package description appears on page 63 of the datasheet.
Can the LT8708EUHG#TRPBF operate in discontinuous conduction mode (DCM) and how is it configured?
Yes, the LT8708EUHG#TRPBF supports DCM operation, selectable via the MODE pin. When MODE voltage is set between 1.6V and 2.0V, the controller enters DCM mode - reducing light-load losses and eliminating reverse inductor current. DCM is confirmed in the Features list (page 1) and detailed in the Operation section (page 20). The LT8708EUHG#TRPBF also supports HCM and Burst Mode for further efficiency optimization.
Is the LT8708EUHG#TRPBF AEC-Q100 qualified for automotive use?
No, the LT8708EUHG#TRPBF is an industrial-grade part (E-grade, –40°C to 125°C). Automotive-qualified versions carry the #W suffix (e.g., LT8708IUHG#WTRPBF) and are explicitly marked "AUTOMOTIVE PRODUCTS" in the Order Information table (page 4). The LT8708EUHG#TRPBF datasheet states that only #W-suffixed variants meet AEC-Q100 requirements.
LT8708EUHG#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-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:
- 1
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 2.8V ~ 80V
- Frequency - Switching:
- 100kHz ~ 400kHz
- Duty Cycle (Max):
- 80%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (5x8)
LT8708EUHG#TRPBF FAQ
1.How can I place an order for LT8708EUHG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8708EUHG#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 LT8708EUHG#TRPBF reliable?
The price and inventory of LT8708EUHG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8708EUHG#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8708EUHG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8708EUHG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8708EUHG#TRPBF?
LT8708EUHG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8708EUHG#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 LT8708EUHG#TRPBF?
For technical support, including LT8708EUHG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8708EUHG#TRPBF requirements.
6.How does Aetrix verify that LT8708EUHG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8708EUHG#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 LT8708EUHG#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8708EUHG#TRPBF?
All LT8708EUHG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8708EUHG#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 LT8708EUHG#TRPBF part is unused and in its original packaging.
Return procedure for LT8708EUHG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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