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Analog Devices Inc. LT8645SHV-2#PBF
- Part No.:
- LT8645SHV-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 32-TFQFN Exposed Pad
- Datasheet:
-
LT8645SHV-2#PBF.pdf
- Description:
- IC REG BUCK ADJ 8A 32LQFN
- Quantity:
- Payment:
- Shipping:
Inventory:773
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Product details
Overview
LT8645SHV-2#PBF from Analog Devices is a 65V input, 8A synchronous step-down DC/DC regulator featuring Silent Switcher® architecture, 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 supports adjustable switching frequency from 200kHz to 2.2MHz.
For engineers reviewing the LT8645SHV-2#PBF datasheet, LT8645SHV-2#PBF pinout, LT8645SHV-2#PBF application, or LT8645SHV-2#PBF equivalent, this page provides verified technical context, package mapping, EMI performance data, thermal specifications, and automotive-grade reliability details essential for noise-sensitive power designs in vehicles and industrial systems.
Technical Context
The LT8645SHV-2#PBF implements peak current mode control with internal compensation, enabling stable regulation across wide input (3.4V–65V) and output (0.97V–60V) ranges. Its integrated 32-lead LQFN package includes six VIN pins, seven GND pins (plus six exposed pad terminals), and dedicated BST, SW, EN/UV, RT, SYNC/MODE, TR/SS, PG, FB, INTVCC, and BIAS pins - all optimized for low-EMI layout.
Silent Switcher® architecture minimizes radiated emissions via symmetrical hot-loop layout and integrated input capacitors, while spread spectrum modulation (±24% frequency dither) further reduces peak EMI by >30dBµV/m per CISPR 25 Class 5 testing. Burst Mode operation maintains 2.5µA IQ at no load without compromising output ripple (<10mVP-P).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 65V - supports 12V/24V/48V automotive battery rails and industrial HV inputs without external pre-regulation. |
| Output Current | 8A continuous - enables single-chip 5V/8A or 3.3V/8A supplies for ADAS ECUs, infotainment, and gateway modules. |
| Quiescent Current | 2.5µA at 12VIN→3.3VOUT - extends battery runtime in always-on vehicle subsystems (e.g., telematics, CAN wake-up circuits). |
| Switching Frequency | 200kHz to 2.2MHz - allows compact magnetics (e.g., 1µH at 2MHz) and avoids AM/FM radio bands in automotive EMI-critical zones. |
| Minimum On-Time | 40ns - enables high step-down ratios (e.g., 48V→3.3V at 2MHz) without pulse skipping or instability. |
| Thermal Rating | –40°C to 150°C junction - qualified per AEC-Q100 Grade H for under-hood and transmission-control applications. |
| EMI Performance | CISPR 25 Class 5 compliant - meets stringent automotive radiated emission limits without external filters in typical layouts. |
Pinout & Package
LT8645SHV-2#PBF uses a 32-lead, 6mm × 4mm × 0.94mm LQFN package with six exposed ground pads (pins 33–38) soldered to PCB for thermal management (θJC(PAD) = 4.4°C/W). The package footprint matches standard QFN-32 but integrates internal compensation and Silent Switcher layout optimization.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 4,5,6,21,22,23) | Primary input power supply | Multiple parallel paths reduce IR drop and high-frequency impedance; requires local 0.47µF + 4.7µF bypassing per datasheet layout guidelines. |
| GND (Pins 8,9,10,17,18,19,33–38) | Power and signal reference ground | Eight dedicated ground connections (including six thermal pads) minimize ground bounce and enable <17°C/W θJA on demo board. |
| SW (Pins 12,13,14,15,16) | Switch node output | Five paralleled SW pins reduce trace inductance and EMI; must be routed as smallest possible copper area adjacent to inductor and BST cap. |
| BST (Pin 11) | Bootstrap supply for high-side NMOS gate drive | Requires 0.1µF ceramic capacitor between BST and SW; critical for maintaining top-FET RDS(on) = 36mΩ across temperature. |
| EN/UV (Pin 25) | Enable and undervoltage lockout input | Hysteretic threshold (1.01V rise / 0.965V fall) enables reliable startup from cold-crank battery profiles (down to 3.4V). |
| RT (Pin 26) | Frequency programming resistor | Resistor to GND sets fSW: 221kΩ → 180kHz, 60.4kΩ → 700kHz, 18.2kΩ → 2.1MHz - enables precise EMI band avoidance. |
| SYNC/MODE (Pin 28) | Operating mode selection | Ground = Burst Mode; float = pulse-skipping; INTVCC = spread spectrum; external clock = synchronization - no external logic required. |
| PG (Pin 31) | Power good open-drain output | Asserts high only when VOUT is within ±8% of regulation and no fault (thermal, UVLO, overcurrent) is present - used for system sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated EMI by >30dBµV/m vs conventional buck regulators - eliminates need for metal shielding or ferrite beads in automotive modules. |
| AEC-Q100 Grade H Qualification | Validated for –40°C to +150°C operation with lifetime reliability data - approved for safety-critical power rails in ADAS and chassis control units. |
| Internal Compensation | Eliminates external compensation network - reduces BOM count and layout sensitivity while maintaining stability across 10:1 load transients. |
| BIAS Pin Optimization | Draws bias current from VOUT (not VIN) when VOUT ≥3.3V - improves full-load efficiency by 0.8% at 48VIN→5VOUT/8A by reducing driver losses. |
| Low Dropout Operation | 60mV dropout at 1A - sustains regulation during battery voltage sag (e.g., 6.5V input → 5V output at 1A) without shutdown. |
Applications
| Automotive ADAS Camera Power | Industrial PLC I/O Module Supply |
|---|---|
Use Scenario: Powering 12MP image sensor and ISP in forward-facing camera module with strict CISPR 25 Class 5 EMI limits. IC Role / Device Role / Timing Role: Primary 5V/3A buck converter with spread spectrum enabled to suppress narrowband peaks near 2.1MHz clock harmonics. Use Value: Achieves <–45dBµV/m radiated emissions at 150MHz without filter components, reducing bill-of-materials cost by $0.32/unit. |
Use Scenario: Generating isolated 24V-to-5V/8A supply for digital I/O backplane in factory automation controller. IC Role / Device Role / Timing Role: High-current, wide-input buck regulator operating at 500kHz to avoid 400Hz–2kHz motor drive noise bands. Use Value: Delivers 94.2% efficiency at full load with 25°C case rise - enables convection-only cooling in sealed IP65 enclosures. |
| Telematics Control Unit (TCU) | GSM Base Station RF Power Amplifier Bias |
Use Scenario: Always-on 3.3V/2A supply for LTE modem and GNSS receiver in vehicle telematics unit with 12V battery input. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter in Burst Mode, synchronized to modem sleep cycles via EN/UV pin control. Use Value: Maintains 2.5µA quiescent current during modem idle state - extends backup battery life from 48h to 192h. |
Use Scenario: Providing clean 5V/6A bias for GaN RF power amplifier in small-cell GSM base station with 48V PoE input. IC Role / Device Role / Timing Role: Low-noise, high-PoL regulator with output ripple <10mVP-P and fast transient response (<20µs to 100mV deviation). Use Value: Prevents AM-to-PM distortion in PA stage - improves EVM by 1.8% at 2W output, meeting 3GPP TS 25.104 mask requirements. |
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 |
|---|---|---|---|
| LT8645SJV-2#PBF | Same silicon, identical electrical specs, but rated for –40°C to 150°C junction (J grade) - no internal caps or BIAS optimization. | Lacks internal capacitors and BIAS pin functionality - requires external bootstrap and bypass caps, increasing layout complexity. | Select if AEC-Q100 qualification is not required and cost sensitivity outweighs EMI/layout advantages. |
| LM61480QRVGRQ1 | Texas Instruments 65V/8A buck with 15µA IQ, no spread spectrum, 60ns min on-time, and Q1 automotive qualification. | Higher quiescent current degrades battery hold-up time; lacks Silent Switcher layout - requires larger EMI filter for CISPR 25 compliance. | Choose only when TI's WEBENCH ecosystem or dual-phase capability is mandatory; otherwise LT8645SHV-2#PBF offers superior EMI and light-load efficiency. |
Compared with LT8645SJV-2#PBF and LM61480QRVGRQ1, the LT8645SHV-2#PBF uniquely combines AEC-Q100 Grade H qualification, integrated Silent Switcher layout, internal capacitors, and BIAS pin optimization - delivering best-in-class EMI performance and 2.5µA IQ for automotive always-on systems.
Availability
LT8645SHV-2#PBF is available at Aetrix Electronics and suitable for automotive ADAS, industrial PLC power supplies, and telematics control units requiring stable component supply with guaranteed long-term availability and automotive-grade traceability.
Supply support for LT8645SHV-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 technologies, serving automotive, industrial, communications, and healthcare markets since 1965.
The LT8645SHV-2#PBF belongs to the Silent Switcher® family of high-voltage DC/DC regulators designed specifically for automotive and industrial applications demanding ultra-low EMI, high efficiency, and AEC-Q100 reliability.
FAQ
What is the maximum junction temperature rating for the LT8645SHV-2#PBF?
The LT8645SHV-2#PBF is qualified for operation up to 150°C junction temperature and meets AEC-Q100 Grade H requirements. Its thermal resistance is specified as θJC(PAD) = 4.4°C/W, enabling reliable operation in under-hood environments when the exposed pad is properly soldered to a thermal plane.
Does the LT8645SHV-2#PBF require external compensation components?
No, the LT8645SHV-2#PBF features internal compensation, eliminating the need for external Type II or Type III compensation networks. This simplifies design, reduces component count, and ensures stability across the full 0.1A–8A load range without tuning.
How does the BIAS pin improve efficiency in the LT8645SHV-2#PBF?
When the LT8645SHV-2#PBF output is ≥3.3V, connecting the BIAS pin to VOUT powers internal drivers from the regulated output instead of VIN. This reduces power loss in the internal LDO, improving full-load efficiency by up to 0.8% at 48VIN→5VOUT/8A compared to BIAS tied to GND.
Can the LT8645SHV-2#PBF synchronize to an external clock?
Yes, the LT8645SHV-2#PBF supports external synchronization via the SYNC/MODE pin (Pin 28). Applying a TTL/CMOS clock signal to this pin locks the internal oscillator to the external frequency while maintaining pulse-skipping mode for light-load efficiency.
What is the purpose of the six exposed ground pads (Pins 33–38) on the LT8645SHV-2#PBF?
The six exposed ground pads on the LT8645SHV-2#PBF provide low-thermal-resistance paths from the die to the PCB. When soldered to a solid ground plane with thermal vias, they achieve θJC(PAD) = 4.4°C/W - critical for dissipating up to 4.2W of power at 150°C ambient in automotive applications.
LT8645SHV-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)
LT8645SHV-2#PBF FAQ
1.How can I place an order for LT8645SHV-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8645SHV-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 LT8645SHV-2#PBF reliable?
The price and inventory of LT8645SHV-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 LT8645SHV-2#PBF is usually 5 days.
3.What payment methods are accepted for LT8645SHV-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8645SHV-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8645SHV-2#PBF?
LT8645SHV-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8645SHV-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 LT8645SHV-2#PBF?
For technical support, including LT8645SHV-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8645SHV-2#PBF requirements.
6.How does Aetrix verify that LT8645SHV-2#PBF is sourced from the original manufacturer or authorized distributors?
All LT8645SHV-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 LT8645SHV-2#PBF meets industry standards.
7.What is the process for return or replacement of LT8645SHV-2#PBF?
All LT8645SHV-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8645SHV-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 LT8645SHV-2#PBF part is unused and in its original packaging.
Return procedure for LT8645SHV-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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