LT8643S/
LT8643SA

推荐用于新设计

42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current

数据手册 (Rev. D) 产品选型表
产品技术资料帮助

ADI公司所提供的资料均视为准确、可靠。但本公司不为用户在应用过程中侵犯任何专利权或第三方权利承担任何责任。技术指标的修改不再另行通知。本公司既没有含蓄的允许，也不允许借用ADI公司的专利或专利权的名义。本文出现的商标和注册商标所有权分别属于相应的公司。
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概述

  • Silent Switcher ®2 Architecture
    • Ultralow EMI Emissions on Any PCB
    • Eliminates PCB Layout Sensitivity
    • Internal Bypass Capacitors Reduce Radiated EMI
    • Optional Spread Spectrum Modulation
  • High Efficiency at High Frequency
    • Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
    • Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
  • Wide Input Voltage Range: 3.4V to 42V
  • Output Voltage Range: 0.97V to 10V(LT8640S/LT8643S); 0.97V to (VIN – 0.5V) (LT8640SA/LT8643SA)
  • 6A Maximum Continuous, 7A Peak Output
  • Ultralow Quiescent Current Burst Mode® Operation
    • 2.5µA IQ Regulating 12VIN to 3.3VOUT (LT8640S/LT8640SA)
    • Output Ripple < 10mVP-P
  • External Compensation: Fast Transient Response and Current Sharing (LT8643S)
  • Robust High VOUT Operation (LT8640SA/LT8643SA)
    • Safely Tolerates High Reverse Current
  • Fast Minimum Switch On-Time: 30ns
  • Low Dropout Under All Conditions: 100mV at 1A
  • Forced Continuous Mode
  • Adjustable and Synchronizable: 200kHz to 3MHz
  • Output Soft-Start and Tracking
  • Small 24-Lead 4mm × 4mm LQFN Package
  • AEC-Q100 Qualified for Automotive Applications

The LT®8640S/LT8643S/LT8640SA/LT8643SA synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by reducing layout sensitivity. This performance makes the LT8640S/LT8643S/LT8640SA/LT8643SA ideal for noise-sensitive applications and environments.

Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S/LT8643SA has external compensation to enable current sharing and fast transient response at high switching frequencies.

Burst Mode operation enables ultralow standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread
spectrum operation can further reduce EMI emissions.

Applications

  • Automotive and Industrial Supplies
LT8643S/
LT8643SA
42V, 6A Synchronous Step-Down Silent Switcher 2 with 2.5μA Quiescent Current
LT8640S/LT8643S Application Circuit LT8640S/LT8643S Performance Graph LT8640S/LT8643S Pin Configuration LT8640S/LT8643S Pin Configuration
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参考资料

数据手册 1

用户手册 2

设计笔记 2

评估设计文件 1

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硬件生态系统

部分模型 产品周期 描述
保护开关和控制器 2
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工具及仿真模型

LTpowerCAD 1

LTpowerCAD中提供以下器件的设计工具：

  • LT8643SA
LTspice

LTspice®是一款强大高效的免费仿真软件、原理图采集和波形观测器，为改善模拟电路的仿真提供增强功能和模型。

LTpowerCAD

LTpowerCAD®是一种电源设计程序，它选择功率级元件，提供详细效率信息，显示快速环路波特图稳定性和负载瞬态分析，并可导出至LTspice进行仿真。

评估套件

eval board
schematic 1
schematic 2
schematic 3
schematic 4
DC2658A

LT8643S演示板 | VIN = 5.8V至42V（VOUT = 5V，6A (2MHz)）

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产品详情

演示电路2658A是一款具有展频(SSFM)功能的42V、6A同步降压型第二代SILENT SWITCHER，内置LT8643S。该演示板设计提供5V输出和5.8V至42V的输入。宽输入范围支持各种输入源，如汽车电池和工业电源。LT8643S是一款紧凑型、超低辐射、高效率和高速同步单芯片降压型开关稳压器。集成旁路电容可优化快速电流环路，并通过降低布局敏感度更轻松地将EMI/EMC辐射降至较低。可选展频模式可以进一步改善EMI/EMC性能。30ns的最短快速导通时间在高频率下可从高电平VIN转换为低电平VOUT。

eval board
schematic 5
schematic 6
schematic 7
EVAL-LT8643SA-AZ

LT8643SA| 42V, 6A Synchronous Step-Down Silent Switcher 2

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产品详情

The demonstration circuit EVAL-LT8643SA-AZ is a 42V, 6A micropower synchronous step-down second generation Silent Switcher® with spread spectrum frequency modulation featuring the LT8643SA. The demo board is designed for 5V output from a 5.8V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8643SA is a compact, ultra-low emission, high efficiency, and high speed synchronous monolithic step-down switching regulator. The integrated bypass capacitors optimize all the fast current loops and make it easier to minimize EMI/EMC emissions by reducing layout sensitivity. Selectable spread spectrum mode can further improve EMI/EMC performance. Ultra-low quiescent current in Burst Mode® operation achieves high efficiency at very light loads. Fast minimum on-time of 30ns enables high VIN to low VOUT conversion at high frequency.

Please see user guide for the full description.
DC2658A
LT8643S演示板 | VIN = 5.8V至42V（VOUT = 5V，6A (2MHz)）
DC2658A Evaluation Board DC2658A Evaluation Board - Top View DC2658A Evaluation Board - Bottom View DC2658A
EVAL-LT8643SA-AZ
LT8643SA| 42V, 6A Synchronous Step-Down Silent Switcher 2
EVAL-LT8643SA-AZ Board Photo Angle View EVAL-LT8643SA-AZ Board Photo Top View EVAL-LT8643SA-AZ Board Photo Bottom View

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