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Analog Devices Inc. LT8645SJV-2#PBF
- Part No.:
- LT8645SJV-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 32-TFQFN Exposed Pad
- Datasheet:
-
LT8645SJV-2#PBF.pdf
- Description:
- IC REG BUCK ADJ 8A 32LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:114
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Product details
Overview
LT8645SJV-2#PBF from Analog Devices is a 65V, 8A synchronous step-down Silent Switcher regulator with 2.5µA quiescent current in Burst Mode, 40ns minimum on-time, and AEC-Q100 qualification for automotive applications. It delivers up to 95% efficiency at 1MHz (12VIN→5VOUT) and features integrated power MOSFETs in a 32-lead 6mm × 4mm LQFN package.
For engineers reviewing the LT8645SJV-2#PBF datasheet, LT8645SJV-2#PBF pinout, LT8645SJV-2#PBF application, or LT8645SJV-2#PBF equivalent, key selection criteria include ultralow EMI performance, wide 3.4V–65V input range, spread spectrum modulation support, and junction temperature operation up to 150°C.
Technical Context
The LT8645SJV-2#PBF uses peak current mode control with frequency programmable from 200kHz to 2.2MHz via an external RT resistor. Its Silent Switcher architecture minimizes radiated EMI through symmetrical layout and internal thermal/EMI optimization, enabling compliance with CISPR 25 Class 5 limits without external filters.
It supports four operating modes via the SYNC/MODE pin: Burst Mode (ultralow IQ), pulse-skipping (full-frequency light-load operation), spread spectrum (±20% frequency modulation), and external synchronization. Internal compensation eliminates need for external loop components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 65V - supports 12V, 24V, 36V, and 48V automotive and industrial rails with headroom for transients. |
| Output Current | 8A continuous - enables single-chip 5V/8A or 3.3V/8A conversion without external power stages. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT - sustains battery-powered systems for years in standby. |
| Switching Frequency | 200kHz–2.2MHz - allows optimization of size (high fSW) vs. efficiency (low fSW) and EMI filtering requirements. |
| Min On-Time | 40ns - enables high step-down ratios (e.g., 48V→3.3V) at 2MHz without pulse skipping. |
| Feedback Reference | 0.97V ±0.006V - tight tolerance enables accurate output regulation across temperature and load. |
| Thermal Rating | Junction temp up to 150°C - qualified per AEC-Q100 Grade 1 (–40°C to +150°C), suitable for under-hood automotive use. |
Pinout & Package
LT8645SJV-2#PBF is housed in a 32-lead 6mm × 4mm × 0.94mm LQFN package with exposed thermal pad (pins 33–38). The package footprint matches standard 6mm × 4mm QFN layouts and requires soldering the exposed pad to PCB ground for optimal thermal performance (θJC(PAD) = 4.4°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 4,5,6,21,22,23) | Main input power supply | Multiple parallel pins reduce IR drop and thermal stress; must be bypassed with dual 0.47µF + 4.7µF ceramic capacitors. |
| GND (Pins 8,9,10,17,18,19,33–38) | Power and signal reference | Exposes 6 dedicated GND pins plus 6-pad thermal pad-requires low-inductance connection to solid ground plane. |
| SW (Pins 12–16) | Switch node | Five paralleled SW outputs minimize conduction loss and EMI; must be routed as compact, low-area copper island. |
| BST (Pin 11) | Bootstrap supply | Drives high-side NMOS gate; requires 0.1µF ceramic capacitor placed adjacent to IC with minimal trace length. |
| EN/UV (Pin 25) | Enable / undervoltage lockout | Hysteretic threshold (1.01V rise / 0.965V fall) enables VIN brownout protection and controlled startup sequencing. |
| RT (Pin 26) | Frequency programming | Resistor-to-ground sets switching frequency; e.g., 60.4kΩ yields ~700kHz, 221kΩ yields ~210kHz. |
| SYNC/MODE (Pin 28) | Operating mode control | Ground = Burst Mode; float = pulse-skipping; INTVCC = spread spectrum; external clock = sync-no external logic required. |
| TR/SS (Pin 29) | Soft-start / tracking | Internal 2µA current source enables capacitor-programmed ramp rate; supports output voltage tracking during power-up. |
| PG (Pin 31) | Power good indicator | Open-drain output asserts high when FB is within ±8% of 0.97V reference and no fault (thermal, UVLO, overcurrent) exists. |
| FB (Pin 32) | Feedback input | Regulates to 0.97V; connects to resistor divider tap; requires 1–10pF phase-lead capacitor between FB and VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated EMI by >30dB vs. conventional buck regulators-enables Class 5 CISPR 25 compliance without ferrite beads or shielding cans. |
| Ultralow Quiescent Current | 2.5µA IQ in regulation enables >10-year battery life in always-on automotive modules (e.g., telematics, ADAS sensors). |
| Integrated Power Stages | Top NMOS (36mΩ) and bottom NMOS (25mΩ) eliminate external FETs and drivers-reduces BOM count and layout complexity. |
| Spread Spectrum Modulation | ±20% triangular frequency dither reduces peak EMI amplitude-critical for meeting stringent automotive EMC requirements. |
| AEC-Q100 Qualified | Grade 1 (–40°C to +150°C) qualification ensures reliability in engine bay, transmission control, and ADAS applications. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module Supply |
|---|---|
Use Scenario: Powering 5V/3A SoC, display interface, and audio codec in head unit with strict CISPR 25 radiated emissions limits. IC Role / Device Role / Timing Role: Primary 48V→5V DC/DC converter delivering clean, low-noise power with EMI suppression enabled. Use Value: Eliminates need for external EMI filters and shielding, reducing board area by 35% and system cost by $1.20/unit. | Use Scenario: Generating 3.3V/5A for microcontroller, CAN transceiver, and analog sensor front-end in DIN-rail mounted controller. IC Role / Device Role / Timing Role: High-reliability, wide-input buck regulator supporting 24V nominal with 60V surge tolerance. Use Value: Maintains regulation during 100ms 60V transients while delivering full 5A output-no brownouts or resets. |
| GSM Base Station RF Power Amp Bias | Medical Imaging Sensor Interface |
Use Scenario: Providing 5V/4A bias supply to GaN RF power amplifier in small-cell base station with dense component layout. IC Role / Device Role / Timing Role: High-efficiency, low-EMI point-of-load regulator operating at 2MHz to avoid sensitive IF bands. Use Value: Achieves 94% efficiency at 2MHz (12VIN→5VOUT) with <10mVP-P ripple-prevents RF desensitization. | Use Scenario: Powering low-noise 24-bit ADC, precision op-amps, and FPGA in portable ultrasound probe requiring ultra-low noise and long battery life. IC Role / Device Role / Timing Role: Battery-supplied 12V→3.3V regulator with Burst Mode for sub-µA sleep current and fast wake-up. Use Value: Extends battery runtime to 14 days in standby (2.5µA IQ) while maintaining <20µV RMS output noise. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8645SEV-2#PBF | Same silicon, rated for –40°C to +125°C junction temperature; lacks 150°C qualification. | Not suitable for under-hood automotive locations exceeding 125°C ambient. | Select LT8645SJV-2#PBF for AEC-Q100 Grade 1 environments; choose LT8645SEV-2#PBF only for commercial/industrial chassis-mount use. |
| LT8646S#PBF | Requires external compensation network; no internal caps; higher 3.5µA IQ in Burst Mode. | Lacks integrated compensation-increases design time and risk of instability with non-standard output caps. | Choose LT8645SJV-2#PBF for faster time-to-market and guaranteed stability; select LT8646S#PBF only when custom loop response tuning is required. |
Compared with LT8645SEV-2#PBF and LT8646S#PBF, the LT8645SJV-2#PBF uniquely combines AEC-Q100 Grade 1 qualification, internal compensation, and lowest 2.5µA quiescent current-making it the only choice for production automotive power supplies needing zero-layout-risk deployment.
Availability
LT8645SJV-2#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLCs, medical imaging devices, and telecom RF power supplies requiring stable component supply, long-term lifecycle support, and AEC-Q100 compliance.
Supply support for LT8645SJV-2#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT8645S-2 product line delivers high-efficiency, ultralow-EMI synchronous buck regulators optimized for noise-sensitive automotive and industrial applications where reliability, small solution size, and regulatory compliance are critical.
FAQ
What is the maximum junction temperature rating for the LT8645SJV-2#PBF?
The LT8645SJV-2#PBF is rated for operation up to +150°C junction temperature and is qualified per AEC-Q100 Grade 1 (–40°C to +150°C). This makes it suitable for under-hood automotive applications where ambient temperatures exceed 125°C. Thermal derating above 125°C is required per Analog Devices' lifetime models.
Does the LT8645SJV-2#PBF require external compensation components?
No, the LT8645SJV-2#PBF features internal compensation and does not require external compensation components. Its fully integrated error amplifier and VC node eliminate the need for external type-II or type-III networks-reducing BOM count, layout area, and design validation effort compared to alternatives like the LT8646S#PBF.
How does the LT8645SJV-2#PBF achieve ultralow EMI performance?
The LT8645SJV-2#PBF achieves ultralow EMI through its patented Silent Switcher® architecture, which includes symmetrical internal power stage layout, integrated bootstrap capacitor, and optimized pinout to minimize hot-loop area. When combined with proper PCB layout (small SW/BST nodes, ground plane under IC), it meets CISPR 25 Class 5 radiated emission limits without external filters.
What are the operating modes supported by the SYNC/MODE pin on the LT8645SJV-2#PBF?
The SYNC/MODE pin on the LT8645SJV-2#PBF supports four distinct modes: (1) Ground = Burst Mode (2.5µA IQ), (2) Float = pulse-skipping mode (full-frequency down to light loads), (3) Tied to INTVCC = spread spectrum + pulse-skipping, and (4) Driven by external clock = synchronization. No external logic is needed to configure any mode.
Can the LT8645SJV-2#PBF be used with a 48V input to generate 3.3V at 8A?
Yes, the LT8645SJV-2#PBF supports 48V input and can deliver 3.3V at 8A using its 40ns minimum on-time and peak current mode control. At 2MHz switching frequency, it maintains >92% efficiency (per typical curves) and regulates stably with appropriate output capacitance and thermal management-validated in Analog Devices' DC2468A demo board.
LT8645SJV-2#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®2
- Package/Case:
- 32-TFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.4V
- Voltage - Input (Max):
- 65V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 65V
- Current - Output:
- 8A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-LQFN (6x4)
LT8645SJV-2#PBF FAQ
1.How can I place an order for LT8645SJV-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8645SJV-2#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 LT8645SJV-2#PBF reliable?
The price and inventory of LT8645SJV-2#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8645SJV-2#PBF is usually 5 days.
3.What payment methods are accepted for LT8645SJV-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8645SJV-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8645SJV-2#PBF?
LT8645SJV-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8645SJV-2#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 LT8645SJV-2#PBF?
For technical support, including LT8645SJV-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8645SJV-2#PBF requirements.
6.How does Aetrix verify that LT8645SJV-2#PBF is sourced from the original manufacturer or authorized distributors?
All LT8645SJV-2#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 LT8645SJV-2#PBF meets industry standards.
7.What is the process for return or replacement of LT8645SJV-2#PBF?
All LT8645SJV-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8645SJV-2#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 LT8645SJV-2#PBF part is unused and in its original packaging.
Return procedure for LT8645SJV-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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