LT8640SEV-2#PBF - 42V, 6A Synchronous Step-Down Silent Switcher | ADI
料号： LT8640SEV-2#PBF ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $15.84 | $15.84 |
| 10 | $14.85 | $148.50 |
| 100 | $12.5 | $1,250.00 |
| 500 | $10.75 | $5,375.00 |
| 1,000 | $9.2 | $9,200.00 |
LT8640SEV-2#PBF 概述
What is a Silent Switcher buck regulator? A synchronous buck converter is a switch-mode DC-DC topology that steps down a higher input voltage to a lower regulated output using a pair of MOSFET switches and an LC output filter; it replaces a traditional buck diode with a synchronous MOSFET to reduce conduction loss. The Silent Switcher 2 architecture further minimizes EMI by splitting the input hot loop into symmetrical parallel paths, enabling the LT8640SEV-2 to meet CISPR 25 / CISPR 32 Class 5 radiated and conducted EMI limits with minimal filtering, which is essential for noise-sensitive automotive and industrial designs.
Key specifications include a 30 ns minimum on-time that supports high step-down ratios even at 2 MHz switching frequency, 96% peak efficiency, 2.5 uA quiescent current in Burst Mode operation, and 200 kHz to 3 MHz programmable switching frequency. The device supports spread-spectrum frequency modulation, external clock synchronization, pulse-skipping, and forced continuous modes through the SYNC/MODE pin, and includes internal loop compensation to simplify PCB design. The 24-LQFN exposed pad provides low thermal resistance for sustained 6 A operation.
The peak current-mode control architecture with 30 ns minimum top switch on-time enables high VIN-to-low-VOUT conversion at high switching frequencies (e.g., 24 V to 1.0 V at 2 MHz). Internal MOSFETs are optimized for both high efficiency and thermal performance, supporting up to 6 A continuous load with no external heatsink required when VIN-VOUT differential is moderate.
Typical applications include automotive infotainment and ADAS power rails, industrial 24 V bus to point-of-load conversion, battery-powered systems (12 V / 24 V / 36 V Li-ion stacks), GPS / telematics modules, and low-EMI communications infrastructure. The 2.5 uA quiescent current also makes it suitable for always-on bias supplies.
Design trade-off: the -2 variant is specified for tighter EMI compliance but is otherwise equivalent to the LT8640SEV; the standard -1 (LT8640S/LT8640SA) and non-EMI -2 variants coexist on the same datasheet for design flexibility. Always place input ceramics directly at the VIN and PGND pins to maximize the benefit of Silent Switcher 2.
This page synthesizes distributor pricing, verified drop-in alternatives from the LT8640S / LT8643S-2 family, and practical design notes not duplicated in the manufacturer datasheet, providing an engineer-ready decision matrix for selecting the right synchronous buck for low-EMI applications.
直接替换替代料： LT8640SEV-2#PBF ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： LT8640SEV-2#PBF （相同外形与封装尺寸） ——差异在于 Output Voltage Range, Architecture, MSL Level, Operating Junction Temperature, Package.
快速对比工具——选择替代料号进行并排对比：
LT8643SEV-2#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8640SEV#PBF
✅ 直接替换✓ 有现货
$6.93 / 个
查看数据手册 →LT8640SHV-2#WPBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8640SIV#PBF
✅ 直接替换✓ 有现货
$4.95 / 个
查看数据手册 →LT8642SIV#PBF
✅ 直接替换📋 参考替代料（不在目录中）
LT8640SEV-2#PBF 最大额定值与电气特性
| 拓扑 | Synchronous Step-Down (Buck) |
| 输入电压范围 | 3.4 V to 42 V |
| 输出电压范围 | 0.97 V to 41.58 V (adjustable) |
| 最大输出电流 | 6 A |
| Switching Frequency Range | 200 kHz to 3 MHz |
| Minimum Switch On-Time | 30 ns |
| Peak Efficiency | 96% |
| Quiescent Current (Burst Mode) | 2.5 uA |
| Architecture | Silent Switcher 2 (ultra-low EMI) |
| Control Mode | Peak Current-Mode |
| Synchronization | External clock, SYNC/MODE pin (spread spectrum, pulse-skipping, forced continuous) |
| 封装 | 24-LQFN-EP (4 mm x 6 mm) |
| 工作结温 | -40C to +125C |
| 安装类型 | Surface Mount |
| MSL 等级 | 3 |
| RoHS 状态 | Compliant |
| EMI Compliance | CISPR 25 / CISPR 32 Class 5 (with minimal filtering) |
LT8640SEV-2#PBF 引脚配置
| 引脚 1 | VIN — Input supply voltage |
| 引脚 2 | VIN — Input supply voltage |
| 引脚 3 | PGND — Power ground |
| 引脚 4 | PGND — Power ground |
| 引脚 5 | SW — Switch node (output to inductor) |
| 引脚 6 | SW — Switch node (output to inductor) |
| 引脚 7 | SW — Switch node (output to inductor) |
| 引脚 8 | SW — Switch node (output to inductor) |
| 引脚 9 | BOOST — Bootstrap capacitor for top gate drive |
| 引脚 10 | BIAS — Internal LDO bias supply decoupling |
| 引脚 11 | EN/UVLO — Enable / undervoltage lockout threshold |
| 引脚 12 | RT — Timing resistor to program switching frequency |
| 引脚 13 | SYNC/MODE — Sync input / mode selection (spread spectrum, pulse-skipping, forced continuous) |
| 引脚 14 | FB — Voltage feedback for adjustable output |
| 引脚 15 | PGND — Power ground (signal) |
| 引脚 16 | PGND — Power ground |
| 引脚 17 | PGND — Power ground |
| 引脚 18 | PGND — Power ground |
| 引脚 19 | VIN — Input supply voltage |
| 引脚 20 | VIN — Input supply voltage |
| 引脚 21 | NC — Not connected (per datasheet) |
| 引脚 22 | NC — Not connected (per datasheet) |
| 引脚 23 | NC — Not connected (per datasheet) |
| 引脚 24 | NC — Not connected (per datasheet) |
| 引脚 EP | EP — Exposed thermal pad - solder to PGND copper pour for heatsinking |
典型应用
LT8640SEV-2#PBF 适用于 7 应用s: Automotive Infotainment Power Rail, Industrial 24 V Bus Point-of-Load Conversion, Battery-Powered Portable Equipment, GPS and Telematics Modules, ADAS Sensor Power (Radar / Camera), Low-EMI Communications Infrastructure, Always-On Bias Supply for IoT Edge Nodes.
Automotive Infotainment Power Rail
The LT8640SEV-2#PBF powers 3.3 V / 5 V rails in head units, instrument clusters, and telematics modules from a 12 V / 24 V automotive battery bus. Its Silent Switcher 2 architecture and 30 ns minimum on-time let the part meet CISPR 25 Class 5 radiated/conducted EMI limits with only two small input ceramic capacitors, eliminating the bulky input pi-filters that conventional buck regulators require. Peak efficiency of 96% keeps dissipation under 2 W at typical infotainment loads (1-2 A), and the 2.5 uA Burst-Mode quiescent current preserves battery life during parked/standby states. The 42 V absolute input rating provides margin against 24 V truck-bus load-dump transients.
推荐
Industrial 24 V Bus Point-of-Load Conversion
The LT8640SEV-2#PBF steps down a 24 V industrial bus (18-32 V typical) to logic rails of 3.3 V, 5 V, or 12 V for PLCs, factory sensors, motor-control boards, and HMI panels. Its 42 V max input tolerates 24 V bus transients and 28 V MIL-STD surges, while the 3.4 V minimum VIN supports cold-start scenarios. Programmable switching frequency up to 3 MHz allows engineers to place the switching harmonics away from sensitive sensor bands; spread-spectrum mode further reduces EMI in dense multi-rail designs. The exposed thermal pad plus a 1 oz copper pour sustains full 6 A at 24 V-to-5 V conversion without external heatsinking.
推荐
Battery-Powered Portable Equipment
The LT8640SEV-2#PBF operates from 3.4 V to 42 V and consumes only 2.5 uA in Burst Mode, making it well-suited for battery stacks from 4S Li-ion (12-16.8 V) through 8S (28-33.6 V). Portable medical devices, test instruments, and field-deployed IoT gateways benefit from its high efficiency (>94% at 12 V-to-3.3 V) and low standby drain, which extends runtime directly. External clock synchronization allows multiple LT8640SEV-2 converters to operate 180 degrees out of phase, reducing input ripple and allowing smaller input capacitors in space-constrained portable designs.
推荐
GPS and Telematics Modules
The LT8640SEV-2#PBF provides clean 3.3 V / 1.8 V rails for GPS receivers, GNSS modules, and cellular telematics units from an automotive or asset-tracking battery. Silent Switcher 2 architecture prevents converter switching noise from desensitizing the GPS L1/L5 front end or causing phase error in GNSS positioning. The 30 ns minimum on-time supports 12 V-to-1.8 V conversion at 2 MHz with a small 1 uH inductor, reducing both BOM cost and PCB area. The 2.5 uA quiescent current is ideal for asset trackers that spend most of their life in sleep mode.
推荐
ADAS Sensor Power (Radar / Camera)
The LT8640SEV-2#PBF powers low-voltage rails for 77 GHz radar MMICs, forward-facing camera SoCs, and LiDAR sensor front ends from a 12 V or 24 V automotive supply. CISPR 25 Class 5 EMI compliance prevents the buck converter from raising the noise floor of sensitive analog front ends and high-speed ADCs. Synchronization to an external clock avoids beat-frequency interference with radar chirp or camera pixel clocks. Combined with the LT8640SHV-2#WPBF automotive-grade variant, the part supports AEC-Q100 designs for safety-critical ADAS functions.
推荐
Low-EMI Communications Infrastructure
The LT8640SEV-2#PBF powers base-station RF chains, small-cell radios, and PoE-powered network equipment where switching-noise-induced phase jitter and spurious emissions must be minimized. Silent Switcher 2 architecture with spread-spectrum modulation distributes noise energy across a wide band, simplifying system-level EMI compliance to EN 55032 Class B. The 200 kHz to 3 MHz programmable switching range allows the fundamental switching tone to be placed in guard bands between sensitive radio bands. Internal compensation eliminates external loop components, reducing PCB complexity in dense RF designs.
推荐
Always-On Bias Supply for IoT Edge Nodes
The LT8640SEV-2#PBF serves as the always-on bias supply in solar-powered IoT edge nodes, building-automation controllers, and remote sensor gateways. Burst Mode operation at 2.5 uA quiescent current keeps idle drain negligible while still providing fast load-step response for periodic sensor wake events. The wide 3.4 V to 42 V input range accepts direct connection to 12 V lead-acid, 24 V solar battery stacks, or rectified 24 VAC building-bus supplies without front-end regulation. Synchronization to a low-power 32.768 kHz-derived clock minimizes harmonics in the GNSS band.
推荐
推荐产品汇总
工程参考数据： LT8640SEV-2#PBF ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | LT8643SEV-2#PBF | LT8640SEV#PBF | LT8640SHV-2#WPBF | LT8640SIV#PBF | LT8642SIV#PBF |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 24-LQFN-EP (4x6 mm) | 24-LQFN-EP (4x6 mm) - same | 24-LQFN-EP (4x6 mm) - same | 24-LQFN-EP (4x6 mm) - same | 24-LQFN-EP (4x6 mm) - same | 24-LQFN-EP (4x6 mm) - same |
| Input Voltage Range | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.0 V to 42 V |
| Maximum Output Current | 6 A | 8.5 A (+42%) | 6 A | 6 A | 6 A | 10 A (+67%) |
| Silent Switcher Architecture | Silent Switcher 2 (ultra-low EMI) | Silent Switcher 2 (same) | Silent Switcher 1 (higher EMI) | Silent Switcher 2 (same) | Silent Switcher 1 (higher EMI) | Silent Switcher 1 (higher EMI) |
| AEC-Q100 Automotive Grade | No (industrial) | No (industrial) | No (industrial) | Yes (AEC-Q100) | No (industrial) | No (industrial) |
| Minimum Switch On-Time | 30 ns | 30 ns | 30 ns | 30 ns | 30 ns | 30 ns |
| Approx. 1ku List Price (USD) | $6.93 (LT8640S family starting price) | Higher (8.5 A upgrade) | Comparable | Higher (automotive grade) | Comparable | Higher (10 A upgrade) |
关键差异点
- Silent Switcher 2 architecture delivers CISPR 25 Class 5 EMI with minimal filtering （对比 LT8640SEV#PBF)
- Pin-compatible 8.5 A upgrade path without PCB redesign （对比 LT8643SEV-2#PBF)
- AEC-Q100 automotive-qualified drop-in variant available （对比 LT8640SHV-2#WPBF)
设计说明
Place two small input ceramic capacitors (e.g., 1 uF + 0.1 uF X7R) directly at the VIN and PGND pins as close as physically possible - this is critical for realizing the full Silent Switcher 2 EMI benefit. Use multiple vias from the LQFN exposed pad to a large PGND copper pour on inner/outer layers to keep junction temperature below 125C at full 6 A load. Estimated: at VIN=24V, VOUT=5V, IOUT=6A, power dissipation is approximately 1.8W, requiring ~1 sq.in. of 1-oz copper for safe operation.
Keep the SW node traces short and narrow to minimize radiated EMI from the high-dV/dt switching node. Place the output inductor away from noise-sensitive analog traces; if possible, shield the inductor with a grounded copper pour. Route the feedback (FB) trace away from the SW node and use a ground guard ring to prevent switching noise from coupling into the regulation loop. For multi-converter designs, synchronize all LT8640SEV-2 ICs 180 degrees out of phase via the SYNC/MODE pin to reduce input ripple.
Do not omit the BOOST capacitor (typically 0.1 uF) between BOOST and SW pins - without it, the top-side gate driver will fail and the converter will not start. Ensure RT resistor is within the 200 kHz to 3 MHz programming range; values outside this range can cause subharmonic instability. For automotive load-dump transients, verify the input TVS clamp limits transients below 42 V - the part's absolute maximum VIN is 42 V continuous with limited transient tolerance above. Do not exceed 6 A continuous without sufficient PCB thermal relief.
合规信息
RoHS and lead-free compliant per Analog Devices product page (#PBF suffix). LT8640SEV-2#PBF is industrial grade; for AEC-Q100 automotive use choose LT8640SHV-2#WPBF. Halogen-free status not explicitly stated in distributor data.
