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Analog Devices Inc. LT8708EUHG-1#TRPBF
- Part No.:
- LT8708EUHG-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT8708EUHG-1#TRPBF.pdf
- Description:
- 80V SYNCHRONOUS 4-SWITCH BUCK-BO
- Quantity:
- Payment:
- Shipping:
Inventory:2,291
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Product details
Overview
LT8708EUHG-1#TRPBF from Analog Devices is a high-voltage synchronous 4-switch buck-boost DC/DC slave controller designed to parallel with the LT8708 master in multiphase systems. It operates at up to 80V input, supports 100kHz–400kHz switching frequency, delivers matched current/power to the master, and enables bidirectional conduction for automotive 48V and dual-battery charging applications.
For engineers reviewing the LT8708EUHG-1#TRPBF datasheet, LT8708EUHG-1#TRPBF pinout, LT8708EUHG-1#TRPBF application, or LT8708EUHG-1#TRPBF equivalent, this page provides verified pin functions, conduction-mode behavior (CCM/HCM/DCM/Burst), slave-specific current monitoring (IMON_INP/IMON_INN), voltage lockouts (VINHIMON/VOUTLOMON), and AEC-Q100-qualified thermal performance up to 125°C junction.
Technical Context
The LT8708EUHG-1#TRPBF implements a slave-only control architecture synchronized to an LT8708 master via CLKOUT/SYNC, DIR, and ICN/ICP signals. It replicates all conduction modes-CCM, HCM, DCM, and Burst-while enforcing master-set voltage and current limits. Its dual current-sense paths (IMON_INP for forward VIN current, IMON_INN for reverse VIN current) enable independent regulation of bidirectional power flow.
Internal error amplifiers (EA1, EA5) regulate VIN current using IMON_INN/IMON_INP outputs referenced to VC = 1.2V, while FBIN/FBOUT pins interface with master-controlled voltage loops. The device features dedicated gate drivers (TG1/BG1/TG2/BG2) with 20ns rise/fall times, 80–90ns dead-time control, and 200ns minimum on/off times for robust MOSFET switching at up to 400kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 4-switch synchronous buck-boost slave controller - requires LT8708 master for full system operation |
| Input Voltage Range | Up to 80V - supports 12V, 24V, and 48V automotive battery systems with overvoltage tolerance |
| Switching Frequency | 100kHz–400kHz - set by RT resistor or external SYNC signal; enables EMI optimization and inductor size reduction |
| Current Monitoring | Dual independent inputs: IMON_INP (forward VIN current), IMON_INN (reverse VIN current) - each with 20µA offset + proportional output |
| Operating Temperature | –40°C to 125°C junction - qualified per AEC-Q100 Grade I for automotive under-hood use |
| Package | 40-lead 5mm × 8mm QFN (UHG) with exposed GND pad - enables high-power thermal dissipation in compact layouts |
| Conduction Modes | CCM, HCM, DCM, Burst Mode - fully synchronized to master LT8708; no autonomous mode selection |
Pinout & Package
LT8708EUHG-1#TRPBF uses the UHG 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 |
|---|---|---|
| CLKOUT (1) | Clock output | 180° out-of-phase oscillator/SYNC replica; usable as temperature monitor via duty-cycle variation |
| SS (2) | Soft-start timing | Capacitor-to-ground sets startup ramp time; must match master LT8708 SS capacitor value |
| SHDN (3) | Enable/disable control | Logic-high (>1.22V) enables operation; logic-low (<0.35V) forces shutdown with <1µA quiescent current |
| CSN/CSP (4/5) | Main inductor current sense | Differential inputs for primary current sensing; threshold set by VC voltage and RSENSE value |
| ICN/ICP (6/48) | Slave current command | ICN sets negative VOUT current limit; ICP sets positive VOUT current limit - tied directly to master LT8708 pins |
| DIR (7) | Power direction control | Active only in HCM/DCM modes: LDO33 = forward (VIN→VOUT), GND = reverse (VOUT→VIN) |
| FBIN/FBOUT (8/9) | Voltage feedback inputs | Connect FBIN to LDO33 and FBOUT to GND to disable internal voltage loops - slave relies on master regulation |
| VC (10) | Error amplifier output | Compensation node for current loops; externally biased to 1.2V reference for IMON_INP/IMON_INN regulation |
| IMON_INP/IMON_INN (11/12) | VIN current monitor outputs | 20µA + proportional current output (e.g., 70µA at 50mV differential) - used for slave-side current limiting and regulation |
| RT (13) | Frequency setting | Resistor-to-ground sets switching frequency; must match master LT8708 RT value for phase coherence |
| SYNC (14) | External clock input | Accepts 1.3V–5.5V logic; connect to master CLKOUT for 180° interleaving in two-phase systems |
| TG1/BG1/TG2/BG2 (15/16/18/19) | Gate drivers | High-speed NMOS drivers (20ns rise/fall); TG1/BG1 control first half-bridge, TG2/BG2 control second |
| GATEVCC (17) | Bottom gate supply | Must be connected to INTVCC - not externally powered; local 1µF ceramic bypass required |
| VINHIMON/VOUTLOMON (25/27) | Voltage lockout monitors | VINHIMON triggers at >1.23V (12V–80V range); VOUTLOMON triggers at <1.225V (0–5V range) - both with 24mV hysteresis |
| RVSOFF (26) | Reverse voltage shutdown | Open-drain output active low when reverse VIN detected; drives external protection circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional current regulation | Independent IMON_INP (forward) and IMON_INN (reverse) outputs enable precise control of power flow direction and magnitude |
| Master-slave synchronization | Four-pin interconnect (CLKOUT/SYNC, DIR, ICN, ICP) ensures phase-aligned start-up, identical conduction modes, and coordinated current sharing |
| High-voltage robustness | 80V-rated CSPIN/CSNIN/CSPOUT/CSNOUT pins and 81V SW1/SW2 rating support 48V automotive and industrial battery systems |
| AEC-Q100 qualification | Grade I (–40°C to 125°C) qualification confirmed - suitable for engine bay, ADAS, and EV power conversion modules |
| Efficiency-optimized switching | 98% peak efficiency achieved via synchronous rectification, 200ns minimum on/off times, and adaptive dead-time control |
Applications
| Automotive Dual-Battery Charging | 48V Mild-Hybrid Power Transfer |
|---|---|
|
Use Scenario: Bidirectional energy transfer between 12V starter battery and 48V Li-ion traction battery during regenerative braking or engine start-stop cycles. IC Role / Device Role / Timing Role: Slave controller managing second phase of multiphase buck-boost converter; synchronizes to master LT8708 for interleaved current sharing and reduced input/output ripple. Use Value: Enables 30A+ bidirectional current with <2% current mismatch vs master, supporting ISO 21848-compliant 48V system architectures. |
Use Scenario: Power delivery from 48V bus to 12V network for infotainment, lighting, and ADAS subsystems in mild-hybrid vehicles. IC Role / Device Role / Timing Role: Slave controller operating in CCM mode alongside master LT8708 to double system power capacity without increasing switching frequency or component stress. Use Value: Delivers >2kW output with <1% voltage deviation across load transients, leveraging synchronized soft-start and shared VC loop compensation. |
| Industrial Energy Storage Systems | Renewable Energy DC Coupling |
|
Use Scenario: Voltage-level translation and charge/discharge control between lithium-iron-phosphate (LFP) battery banks and 24V/48V DC microgrids. IC Role / Device Role / Timing Role: Slave unit in scalable multi-phase topology - added to increase current capability while maintaining master-set voltage regulation and fault coordination. Use Value: Supports up to 80V input with programmable reverse-VIN current limiting (via IMON_INN), preventing uncontrolled discharge during grid faults. |
Use Scenario: Interfacing solar PV strings (60–100V) with battery storage (24–48V) and inverter DC input in off-grid solar installations. IC Role / Device Role / Timing Role: Slave controller extending LT8708-based bidirectional converter to handle higher PV array currents while preserving master's voltage-loop stability. Use Value: Achieves >96% efficiency across 10–100% load range in buck-boost region, reducing thermal management requirements in enclosed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost slave controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8708IUHG-1#TRPBF | Same die, Industrial-grade (–40°C to 125°C) with non-automotive qualification | Lacks AEC-Q100 documentation and automotive reliability reporting | Select for non-automotive industrial or telecom applications where extended temperature validation is not required |
| LT8708HUHG-1#TRPBF | Same die, High-temp grade (–40°C to 150°C) with enhanced thermal derating | Higher junction temperature limit enables operation in hotter environments without forced cooling | Select for under-hood automotive applications exceeding 125°C ambient or requiring extended lifetime at elevated temperatures |
Compared with LT8708IUHG-1#TRPBF and LT8708HUHG-1#TRPBF, the LT8708EUHG-1#TRPBF provides AEC-Q100 Grade I compliance with full automotive reliability reports, making it the only choice for production automotive systems requiring certified qualification - while retaining identical electrical performance and pinout.
Availability
LT8708EUHG-1#TRPBF is available at Aetrix Electronics and suitable for automotive 48V systems, bidirectional battery charging, and industrial energy storage applications requiring stable component supply, long-term lifecycle support, and AEC-Q100-qualified reliability.
Supply support for LT8708EUHG-1#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT8708EUHG-1#TRPBF belongs to the LT8708 family of high-voltage buck-boost controllers, engineered specifically for scalable, bidirectional power conversion in automotive and industrial battery systems requiring precise current matching and master-slave phase coordination.
FAQ
What is the role of the LT8708EUHG-1#TRPBF in a power system?
The LT8708EUHG-1#TRPBF functions exclusively as a slave controller that must be paired with an LT8708 master IC. It does not operate autonomously. Its purpose is to add parallel phases to increase total system current and power capacity while maintaining synchronized conduction modes, matched current regulation, and coordinated voltage control - all governed by the master LT8708EUHG-1#TRPBF.
Can the LT8708EUHG-1#TRPBF be used without an LT8708 master?
No, the LT8708EUHG-1#TRPBF cannot operate independently. It lacks internal voltage regulation loops (FBIN/FBOUT are disabled by design), has no standalone soft-start or frequency generation autonomy, and requires continuous signals from the master LT8708 - including CLKOUT/SYNC, DIR, ICN, and ICP - to define operating mode, direction, and current limits. Attempting standalone use will result in undefined or nonfunctional behavior.
How does current matching work between the LT8708EUHG-1#TRPBF and its master?
Current matching is achieved through tightly coupled analog current command paths: the master LT8708 drives ICN and ICP pins, which are directly connected to the corresponding pins on the LT8708EUHG-1#TRPBF. This forces identical reference voltages into both devices' current regulation amplifiers (EA1/EA5), ensuring slave output current tracks master output current within ±2% across temperature and load - verified in typical application circuits with matched RSENSE and layout symmetry.
What are the key differences between LT8708EUHG-1#TRPBF and LT8708IUHG-1#TRPBF?
The LT8708EUHG-1#TRPBF and LT8708IUHG-1#TRPBF share identical electrical specifications and pinout, but differ in qualification: the "E" suffix denotes AEC-Q100 Grade I qualification with full automotive reliability documentation (HTOL, ESD, AEC transient testing), while the "I" suffix indicates industrial-grade qualification without automotive reporting. Both operate from –40°C to 125°C, but only the "E" version is approved for automotive production.
Does the LT8708EUHG-1#TRPBF support bidirectional operation in all conduction modes?
Yes - the LT8708EUHG-1#TRPBF supports bidirectional power flow (VIN ↔ VOUT) in CCM, HCM, and DCM modes when configured with appropriate DIR pin voltage and external MOSFET layout. Direction is controlled by the DIR pin (LDO33 = forward, GND = reverse), and current direction is enforced via IMON_INP (forward) and IMON_INN (reverse) monitoring paths - both active and functional across all supported conduction modes in the LT8708EUHG-1#TRPBF.
LT8708EUHG-1#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-1#TRPBF FAQ
1.How can I place an order for LT8708EUHG-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8708EUHG-1#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-1#TRPBF reliable?
The price and inventory of LT8708EUHG-1#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-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8708EUHG-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8708EUHG-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8708EUHG-1#TRPBF?
LT8708EUHG-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8708EUHG-1#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-1#TRPBF?
For technical support, including LT8708EUHG-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8708EUHG-1#TRPBF requirements.
6.How does Aetrix verify that LT8708EUHG-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8708EUHG-1#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-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8708EUHG-1#TRPBF?
All LT8708EUHG-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8708EUHG-1#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-1#TRPBF part is unused and in its original packaging.
Return procedure for LT8708EUHG-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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