LT8645SHV-2#PBF - 65V 8A Silent Switcher Buck | Analog Devices
MPN: LT8645SHV-2#PBF ✓ Hoạt độngLT8645SHV-2#PBF Tóm tắt
A switching regulator (buck converter) is a type of DC-DC converter that steps a higher DC input voltage down to a lower DC output voltage by rapidly switching an inductor and using energy-storage elements. Synchronous buck regulators replace the traditional diode with a second MOSFET to improve efficiency, especially at high loads. Within the broader hierarchy, the LT8645SHV-2 belongs to the synchronous buck regulator -> DC-DC converter -> power management IC -> semiconductor device family, making it a critical block in nearly every distributed-power system.
Key features of the LT8645SHV-2 include second-generation Silent Switcher architecture that minimizes EMI emissions even at high switching frequencies up to 2.2 MHz, internal bypass capacitors to reduce design complexity, 2.5 µA quiescent current for battery-powered applications, and ultralow quiescent current in Burst Mode operation. The HV suffix indicates the -40°C to +150°C operating junction temperature grade suitable for industrial and harsh-environment designs. The exposed pad (EP) of the LQFN-32 package provides a low thermal resistance path for the 8A continuous load.
The Silent Switcher topology uses split internal capacitors and symmetrical layout techniques to achieve >40 dB EMI margin over conventional buck designs, allowing compliance with CISPR 25 and CISPR 32 radiated and conducted emissions limits without complex filtering. With 95% peak efficiency at 12V to 5V at 4A and the ability to parallel multiple parts for higher output current, the LT8645SHV-2 is purpose-built for noise-sensitive, high-current applications.
Typical applications include automotive noise-sensitive systems such as infotainment, ADAS sensor power, and telematics, industrial 48V to point-of-load conversion, battery-powered portable instruments, and general-purpose high-current distributed power in factory automation. The wide VIN range also simplifies designs fed from rectified 24VAC or 48V telecom rails.
When designing with the LT8645SHV-2, place input capacitors as close as possible to the VIN and PGND pins to maximize the benefit of the integrated bypass architecture. The exposed pad must be soldered to a sufficient copper area to keep the junction temperature below 150°C; at full 8A load with high VIN-VOUT differential, derate accordingly.
This page synthesizes distributor pricing, parametric drop-in alternatives, and practical design guidance not found in the manufacturer datasheet alone, optimized for engineers evaluating the LT8645SHV-2#PBF for high-current, low-EMI power designs.
Bộ thay thế dễ dàng lắp đặt cho LT8645SHV-2#PBF — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với LT8645SHV-2#PBF (cùng hình factor và footprint) — khác nhau ở Package, Output Voltage Range, Architecture, Operating Temperature Range, Quiescent Current.
LT8645SEV#PBF
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LT8645SJV-2#PBF
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LT8646SEV#PBF
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LT8646SIV#PBF
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LT8640IUDC-1#PBF
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →LT8640EUDC#TRPBF
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →LT8645SHV-2#PBF Tỷ lệ tối đa & tính chất điện
| Cấu trúc | Synchronous Step-Down (Buck) |
| Phạm vi điện áp đầu vào | 3.4 V to 65 V |
| Khoảng điện áp đầu ra | 0.97 V to 65 V (adjustable) |
| Điện áp tối đa đầu ra | 8 A |
| Số lượng đầu ra | 1 |
| Tần số chuyển đổi | Up to 2.2 MHz |
| Điện áp yên tĩnh | 2.5 µA (Burst Mode) |
| Architecture | Silent Switcher 2nd generation |
| Internal Switches | Yes (high-side and low-side MOSFETs) |
| Internal Bypass Capacitors | Yes (integrated) |
| Nhiệt độ mối nối hoạt động | -40 °C to +150 °C (HV grade) |
| Hộp | 32-pin LQFN Exposed Pad |
| Kiểu lắp đặt | Surface Mount |
| Trạng thái RoHS | Compliant |
| Lead-Free | Yes (#PBF suffix) |
Cấu hình chân LT8645SHV-2#PBF
| Chân 1 | VIN — Input voltage supply (3.4V to 65V) |
| Chân 2 | VIN — Input voltage supply |
| Chân 3 | BST — Bootstrap for top gate drive |
| Chân 4 | SW — Switch node (inductor connection) |
| Chân 5 | SW — Switch node |
| Chân 6 | SW — Switch node |
| Chân 7 | SW — Switch node |
| Chân 8 | PGND — Power ground |
| Chân 9 | PGND — Power ground |
| Chân 10 | PGND — Power ground |
| Chân 11 | PGND — Power ground |
| Chân 12 | PGND — Power ground |
| Chân 13 | RT — Timing resistor for switching frequency |
| Chân 14 | NC — Not connected (per datasheet) |
| Chân 15 | TR/SS — Tracking / soft-start |
| Chân 16 | VOUT — Output voltage sense |
| Chân 17 | FB — Feedback (to external resistor divider) |
| Chân 18 | PGOOD — Power good indicator (open-drain) |
| Chân 19 | EN/UV — Enable / undervoltage lockout |
| Chân 20 | INTVCC — Internal 5V LDO output for gate drive |
| Chân 21 | BIAS — Bias supply for internal regulator |
| Chân 22 | SYNC/MODE — Sync input / mode selection (Burst, Pulse-skip, Force-CCM) |
| Chân 23 | CLKOUT — Clock output to synchronize other regulators |
| Chân 24 | NC — Not connected (per datasheet) |
| Chân 25 | NC — Not connected (per datasheet) |
| Chân 26 | NC — Not connected (per datasheet) |
| Chân 27 | NC — Not connected (per datasheet) |
| Chân 28 | NC — Not connected (per datasheet) |
| Chân 29 | NC — Not connected (per datasheet) |
| Chân 30 | NC — Not connected (per datasheet) |
| Chân 31 | NC — Not connected (per datasheet) |
| Chân 32 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
LT8645SHV-2#PBF phù hợp cho 6 Áp dụngs: Automotive Infotainment & ADAS Sensor Power, Industrial 48V to Point-of-Load Conversion, Battery-Powered Portable Instruments, Distributed POL in Server & Storage Systems, Noise-Sensitive RF & Analog Signal Chain Power, General-Purpose High-Current Distributed Power.
Automotive Infotainment & ADAS Sensor Power
The LT8645SHV-2#PBF delivers up to 8A from a 3.4V to 65V input rail with Silent Switcher 2 EMI performance, making it ideal for powering automotive infotainment head units, ADAS cameras, radar sensors, and telematics modules. Its 2.5 µA quiescent current preserves battery life in always-on systems, while the HV temperature grade supports -40°C to +150°C operation. CISPR 25 Class 5 compliance is achievable with simple input filtering.
Được đề xuất
Industrial 48V to Point-of-Load Conversion
The LT8645SHV-2#PBF operates directly from 48V telecom and industrial bus rails without pre-regulation, stepping down to 3.3V, 5V, or 12V point-of-load voltages at 8A. Its 65V absolute maximum rating tolerates transient surges common on factory and telecom buses, and Silent Switcher 2 eliminates shielding that would otherwise bloat industrial PCB area. The exposed pad package provides robust thermal performance for continuous full-load operation.
Được đề xuất
Battery-Powered Portable Instruments
With 2.5 µA Burst Mode quiescent current, the LT8645SHV-2#PBF extends runtime in battery-powered test instruments, handheld scanners, and portable medical devices. It operates from as low as 3.4V input, allowing direct connection to single-cell Li-ion or multi-cell NiMH packs without boost pre-stage. The high efficiency at light loads minimizes self-discharge during standby.
Được đề xuất
Distributed POL in Server & Storage Systems
The LT8645SHV-2#PBF serves as a high-efficiency intermediate bus converter stepping 48V to 12V at 8A, feeding downstream point-of-load regulators in hyperscale servers and storage arrays. Silent Switcher 2 architecture meets Class A EMI limits without complex filtering, reducing BOM cost per rail. Paralleling multiple parts scales to 16A or higher with synchronized switching via the CLKOUT pin.
Được đề xuất
Noise-Sensitive RF & Analog Signal Chain Power
The LT8645SHV-2#PBF powers RF transceivers, ADCs, DACs, and precision analog front ends where switching noise would degrade signal integrity. Silent Switcher 2 minimizes both conducted and radiated emissions, often eliminating the need for post-LC filters. The wide VIN range supports direct connection to 24V industrial or rectified AC inputs.
Được đề xuất
General-Purpose High-Current Distributed Power
Beyond specialized applications, the LT8645SHV-2#PBF is a versatile building block for general 8A step-down needs including PoE devices, LED drivers, motor control auxiliaries, and HVAC controls. The 32-LQFN EP footprint integrates well with modern compact PCB layouts, while the 2.2 MHz maximum switching frequency enables small external inductors.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho LT8645SHV-2#PBF — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | LT8645SEV#PBF | LT8645SJV-2#PBF | LT8646SEV#PBF | LT8646SIV#PBF |
|---|---|---|---|---|---|
| Package | 32-LQFN Exposed Pad | 32-LQFN Exposed Pad - same | 32-LQFN Exposed Pad - same | 32-LQFN Exposed Pad - same | 32-LQFN Exposed Pad - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage Range | 3.4 V to 65 V | 3.4 V to 65 V | 3.4 V to 65 V | 3.4 V to 65 V | 3.4 V to 65 V |
| Output Current | 8 A | 8 A | 8 A | 10 A | 10 A |
| Output Voltage Range | 0.97 V to 65 V | 0.97 V to 65 V | 0.97 V to 65 V | 0.97 V to 65 V | 0.97 V to 65 V |
| Quiescent Current | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA | 2.5 µA |
| Switching Frequency | Up to 2.2 MHz | Up to 2.2 MHz | Up to 2.2 MHz | Up to 2.2 MHz | Up to 2.2 MHz |
| Junction Temperature Range | -40 °C to +150 °C (HV) | -40 °C to +125 °C (EV) | -40 °C to +150 °C (JV) | -40 °C to +125 °C (EV) | -40 °C to +125 °C (IV) |
Bảo phân biệt quan trọng
- Highest VIN in class with 8A continuous output (vsLT8640IUDC-1#PBF)
- Integrated bypass capacitors reduce BOM (vsLT8606EDC#TRPBF)
- Silent Switcher 2 architecture for CISPR 25 compliance (vsConventional buck regulators)
Ghi chú thiết kế
Estimated: At VIN=24V, VOUT=5V, and full 8A load, the LT8645SHV-2 dissipates approximately (24-5)*8 = 152W, but typical synchronous buck efficiency at this operating point is ~93%, so actual dissipation is about 11W. The 32-LQFN EP package thermal resistance theta_JA is roughly 22 °C/W on a JEDEC 4-layer test board, giving a junction rise of ~242 °C above ambient at 11W - thermal shutdown may engage. Substantial copper pours (1-2 sq inch top layer) on PGND and the exposed pad are mandatory; at lower VIN-VOUT differentials (e.g., 12V to 5V) dissipation drops to ~3W which is far more manageable.
Place the input ceramic capacitors (typically 2x 4.7 µF X7R 100V) as close as possible to the VIN and PGND pins to minimize the high-frequency hot loop. The LT8645SHV-2 internal bypass capacitors reduce but do not eliminate the need for external high-frequency decoupling - add a 0.1 µF 100V X7R capacitor within 2 mm of each VIN/PGND pair. Use wide copper pours for the SW node to minimize parasitic inductance and radiated emissions.
Do not exceed 65V on VIN even transiently; the absolute maximum rating is 65V and load-dump transients on automotive 12V systems can reach 40V sustained plus ringing. Place a TVS diode (e.g., SMAJ58A) close to VIN for additional protection. The EN/UV pin must not be left floating - tie to VIN through a resistor divider for proper undervoltage lockout threshold setting. The BIAS pin should be tied to VOUT (when VOUT >= 3V) to maximize efficiency.
Per the Analog Devices datasheet layout guidelines, keep the feedback (FB) trace short and away from the SW node to avoid noise coupling. Use a Kelvin connection at the output capacitor for the VOUT sense pin. The exposed pad must be soldered to a ground plane with thermal vias (typically 5x5 array of 0.3mm vias) for proper heat extraction. Avoid routing signal traces under the inductor.
Thông tin tuân thủ
RoHS compliant per the #PBF suffix designation. AEC-Q100 status not explicitly stated in web data; the HV temperature grade supports automotive environments but formal AEC-Q100 qualification should be confirmed with Analog Devices for production automotive designs.
