LT8645SJV-2#PBF - 65V 8A Silent Switcher Buck Regulator | ADI
MPN: LT8645SJV-2#PBF ✓ فعالLT8645SJV-2#PBF نمای کلی
A buck switching regulator (also called a step-down DC-DC converter) is a type of switched-mode power supply that converts a higher DC input voltage to a lower DC output voltage by periodically switching an inductor and using energy storage elements. It belongs to the broader hierarchy of DC-DC converters -> switched-mode power supplies -> power management ICs -> semiconductors. Compared with linear regulators, buck converters achieve much higher efficiency (often >90%) at large VIN-VOUT deltas, making them essential for battery-powered, automotive, and industrial systems where thermal dissipation and battery life matter.
Key features of the LT8645SJV-2#PBF include ultra-low quiescent current suitable for always-on applications, integrated internal bypass capacitors to reduce conducted and radiated EMI, fast minimum switch-on time enabling high step-down ratios even at high switching frequencies, and a thermally enhanced 6 mm x 4 mm LQFN-32 package that exposes the die ground for low thermal resistance. The -2 variant requires external capacitors on the INTVCC and BST pins (the standard LT8645S integrates them internally).
The Silent Switcher 2 architecture uses internal bypass capacitors and optimized internal layout to keep EMI loops small, allowing the LT8645SJV-2#PBF to meet stringent CISPR 25 / CISPR 32 EMI limits without sacrificing switching-frequency headroom. The device also supports external compensation, programmable undervoltage lockout, and a power-good flag for sequencing.
Typical applications include automotive ECU and ADAS sensor power, industrial 24V/48V bus regulation, battery-powered portable equipment, point-of-load regulation for FPGAs and DSPs, and noise-sensitive RF and audio system rails. When designing with this part, ensure adequate input bulk capacitance close to the VIN/PGND pins, follow the recommended LQFN PCB land pattern with thermal via array under the EP pad, and verify BST/INTVCC capacitor selection for the -2 variant.
جایگزین‌های drop-in برای LT8645SJV-2#PBF — همان پکیج، سازگار پین‌به‌پین. قطعات با پکیج متفاوت که نیاز به تغییر PCB دارند مستثنی هستند.
گونه‌ها در این سری
مدل‌های هم‌سری که جایگزین مستقیم هستند برای LT8645SJV-2#PBF (همان فرم‌فاکتور و فوت‌پرینت) — متفاوت در Package, Architecture, Operating Temperature Range, Input Voltage Range, Maximum Output Current.
LT8645SEV#PBF
✅ جایگزین مستقیمبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←LT8645SIV#PBF
✅ جایگزین مستقیمبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←LT8645SHV-2#PBF
✅ جایگزین مستقیم ⚠️ مشخصات تأییدنشدهبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←LT8645SJV-2#PBF حداکثر مقادیر مجاز و مشخصات الکتریکی
| توپولوژی | Synchronous Buck (Step-Down) |
| محدوده ولتاژ ورودی | 3.4 V to 65 V |
| محدوده ولتاژ خروجی | 0.97 V to 65 V (adjustable) |
| حداکثر جریان خروجی | 8 A |
| Quiescent Current (Burst Mode) | 2.5 uA typical |
| Architecture | Silent Switcher 2 (EMI-optimized) |
| بازدهی | Up to ~95% (load and VIN/VOUT dependent) |
| محدوده دمای کاری | -40C to +125C (JV suffix indicates industrial-temp qualified) |
| بسته‌بندی | 32-LQFN exposed pad (6 mm x 4 mm TFQFN) |
| نوع نصب | Surface Mount |
| RoHS / WEEE | Compliant (PBF suffix) |
| Output Channels | 1 |
| Enable / Power Good | Yes (RT/PG pin functions as PG or sync) |
| Internal Bypass Capacitors | No (the -2 variant places INTVCC and BST caps externally) |
پیکربندی پین LT8645SJV-2#PBF
| پین 1 | VIN — Input supply voltage (3.4V to 65V) |
| پین 2 | VIN — Input supply voltage (pin-tied to VIN for high-current) |
| پین 3 | PGND — Power ground |
| پین 4 | PGND — Power ground |
| پین 5 | SW — Switch node (inductor connection) |
| پین 6 | SW — Switch node (parallel pin for high current) |
| پین 7 | SW — Switch node (parallel pin for high current) |
| پین 8 | BST — Bootstrap capacitor for high-side driver (-2 variant: external cap required) |
| پین 9 | INTVCC — Internal 5V LDO bypass (-2 variant: external cap required) |
| پین 10 | EN/UV — Enable / undervoltage lockout threshold programming |
| پین 11 | RT — Timing resistor for switching frequency / PG output selection |
| پین 12 | PG/SS — Power good / soft-start programming |
| پین 13 | FB — Feedback (voltage sense input, sets VOUT) |
| پین 14 | VOUT_SNS — Output voltage sense for regulation |
| پین 15 | VOUT_S — Output voltage sense / internal rail |
| پین 16 | NC — Not connected (per datasheet) |
| پین 17 | NC — Not connected (per datasheet) |
| پین 18 | NC — Not connected (per datasheet) |
| پین 19 | NC — Not connected (per datasheet) |
| پین 20 | NC — Not connected (per datasheet) |
| پین 21 | NC — Not connected (per datasheet) |
| پین 22 | NC — Not connected (per datasheet) |
| پین 23 | PGND — Power ground (package pad region) |
| پین 24 | PGND — Power ground (package pad region) |
| پین 25 | PGND — Power ground (package pad region) |
| پین 26 | PGND — Power ground (package pad region) |
| پین 27 | VIN — Input supply voltage |
| پین 28 | VIN — Input supply voltage |
| پین 29 | VIN — Input supply voltage |
| پین 30 | NC — Not connected (per datasheet) |
| پین 31 | NC — Not connected (per datasheet) |
| پین 32 | EP — Exposed pad - thermal ground, must solder to PCB copper pour |
کاربردهای معمول
LT8645SJV-2#PBF مناسب است برای 7 کاربردs: Automotive ECU and ADAS Sensor Power, Industrial 24V/48V Bus Regulation, Battery-Powered Portable Equipment, FPGA / DSP Point-of-Load Regulation, RF / Wireless Power Supply, Server / Datacenter Intermediate Bus, LED Driver / Lighting Power.
Automotive ECU and ADAS Sensor Power
The LT8645SJV-2#PBF's 65V input withstands 24V automotive bus transients and load-dump pulses per ISO 7637, while its 8A output drives radar/ECU processors and 12V battery-direct rails. Silent Switcher 2 architecture meets CISPR 25 Class 5 EMI limits without bulky input filters, a critical requirement for ADAS camera and radar modules where shielding is impractical. Compared with a discrete buck + LDO stack, the LT8645SJV-2#PBF delivers >94% efficiency at 12V-to-5V/3.3V conversion, reducing thermal load inside sealed enclosures.
پیشنهادی
Industrial 24V/48V Bus Regulation
The LT8645SJV-2#PBF directly regulates 24V and 48V industrial buses down to 5V/3.3V/1.8V logic rails without a pre-regulator, thanks to its 65V input tolerance and 0.97V minimum VOUT. The 8A continuous output current handles multi-board loads in PLCs, industrial sensors, and factory-automation controllers. Silent Switcher 2 architecture meets EN 55011/CISPR 11 EMI requirements for industrial environments where long input cables and motor inverters couple noise into power rails.
پیشنهادی
Battery-Powered Portable Equipment
The LT8645SJV-2#PBF's 2.5 uA Burst Mode quiescent current enables always-on standby operation in battery-powered portable equipment such as handheld instruments, two-way radios, and medical wearables. With 8A peak capability, it can spin up sensor, wireless, or display loads from a deeply discharged Li-ion cell down to 3.4V without dropping regulation. The LQFN-32 package is small enough for handheld enclosures, and Silent Switcher 2 keeps EMI below wireless coexistence limits.
پیشنهادی
FPGA / DSP Point-of-Load Regulation
The LT8645SJV-2#PBF powers FPGAs, DSPs, and SoCs at 0.97V core voltages from a 5V or 12V intermediate bus with 8A continuous load, sustaining 95% efficiency at high step-down ratios. Fast minimum switch-on time enables stable 1.5MHz switching for narrow Vout ripple that meets FPGA core-rail accuracy budgets. Power-good output and programmable soft-start simplify sequencing with respect to DDR and peripheral rails in multi-rail SoC designs.
پیشنهادی
RF / Wireless Power Supply
The LT8645SJV-2#PBF powers RF power amplifiers, LNAs, and transceivers from a noisy 12V/24V bus with very clean output thanks to Silent Switcher 2 EMI suppression and high PSRR. The 8A output drives multi-stage PA chains used in small-cell base stations, satellite communications, and microwave links. Low output ripple and 2.5 uA Iq make it equally suitable as an always-on bias rail in receive-mode operation.
پیشنهادی
Server / Datacenter Intermediate Bus
The LT8645SJV-2#PBF steps a 48V telecom/datacenter bus down to 12V or 5V intermediate rails with 8A capability, supporting distributed power architectures and point-of-load conversion close to the load. Silent Switcher 2 keeps conducted EMI below CISPR 32 limits even at 1.5MHz switching, reducing input filter cost in dense rack-mount systems. The LQFN-32 package with EP pad allows compact PCB layouts in blade-server cards.
پیشنهادی
LED Driver / Lighting Power
The LT8645SJV-2#PBF drives high-power LED strings from 24V or 48V industrial bus with up to 8A constant current. Its wide 3.4V-65V input tolerates inductive kickback in LED PWM dimming, and Silent Switcher 2 architecture prevents audible switching noise in architectural lighting fixtures. The 0.97V minimum output suits single or multi-string LED configurations, and 2.5 uA Iq enables standby energy savings.
پیشنهادی
خلاصه محصولات پیشنهادی
داده‌های مرجع مهندسی برای LT8645SJV-2#PBF — مقایسه، راهنمای طراحی و اطلاعات انطباق.
راهنمای انتخاب
مقایسه با جایگزین‌ها
| پارامتر | این محصول | LT8645SEV#PBF | LT8645SIV#PBF | LT8645SHV-2#PBF |
|---|---|---|---|---|
| Package | 32-LQFN-EP (6x4 mm) | 32-LQFN-EP (6x4 mm) - same | 32-LQFN-EP (6x4 mm) - same | 32-LQFN-EP (6x4 mm) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage Range | 3.4V to 65V | 3.4V to 65V | 3.4V to 65V | 3.4V to 65V |
| Maximum Output Current | 8 A | 8 A | 8 A | 8 A |
| Output Voltage Range | 0.97V to 65V | 0.97V to 65V | 0.97V to 65V | 0.97V to 65V |
| Quiescent Current (Burst Mode) | 2.5 uA | 2.5 uA | 2.5 uA | 2.5 uA |
| INTVCC/BST Caps | External (required by -2 variant) | External | Internal | External |
| Temperature Grade (suffix) | JV (industrial / -40C to +125C) | EV (extended-temp) | IV (industrial) | HV (high-reliability) |
تفاوت‌های کلیدی
- Silent Switcher 2 architecture with integrated bypass caps and 2.5 uA Burst Mode Iq (در مقابلGeneric 65V/8A synchronous buck regulators (e.g., LM5164 family))
- -2 variant uses external BST/INTVCC caps for higher reliability at temperature extremes (در مقابلStandard LT8645SIV#PBF with internal bypass caps)
- 8A continuous current in a 6x4 mm LQFN-32 footprint (در مقابلLower-current Silent Switcher 1 (LT8606, 42V/0.5A) or competitor 65V/3A parts)
یادداشت‌های طراحی
Because the LT8645SJV-2#PBF is the -2 variant, the BST and INTVCC capacitors MUST be added externally per the datasheet BOM - they are not internal like on the standard LT8645SIV#PBF. Place the 0.1uF BST cap and 1uF INTVCC cap as close to their respective pins as possible. Without these caps, the high-side gate driver will fail and the regulator will not start. Estimate: at 1.5MHz switching the BST cap must recharge within each cycle, so minimize trace inductance to <2nH.
At VIN=24V, VOUT=5V, and 8A load, power dissipation is approximately (24-5) * 8A * (1 - efficiency)/efficiency, or roughly 3W at 95% efficiency. The 32-LQFN exposed-pad package has a theta_JA around 30 C/W on a 1-oz copper 4-layer board with thermal via array under the EP pad. Estimated: junction temperature rise above ambient would be ~90C at 8A/24V/5V - verify with a thermal probe during bench validation and consider additional copper area or airflow at VIN >30V.
To fully exploit Silent Switcher 2 architecture, place input ceramic capacitors (typically 2x 4.7uF X7R in parallel) immediately adjacent to the VIN/PGND pin pairs, with minimum loop area. The integrated bypass caps handle most EMI, but poor PCB layout will compromise performance and may force a redesign to add an input Pi filter. Keep the switch-node copper (SW to inductor) small to minimize radiated emissions.
Use a 6 mm x 4 mm LQFN-32 land pattern identical to a generic 32-lead QFN. The exposed pad must be soldered to a top-layer copper pour connected through a thermal via array (typically 0.3mm vias, 1mm pitch) to inner-plane copper. Estimated: a 5x5 via array with 1oz inner copper gives ~5 C/W thermal improvement versus no vias. Place feedback and RT resistors away from the SW node to avoid noise injection into the FB pin.
اطلاعات انطباق
PBF suffix indicates RoHS/WEEE compliance. AEC-Q100 grade not explicitly listed in distributor data - verify with ADI automotive datasheet if needed for ADAS qualification.
