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  • LM26420 双路 2A 高效同步直流/直流转换器

    • ZHCSI81L February   2009  – May 2018 LM26420

      PRODUCTION DATA.  

  • CONTENTS
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  • LM26420 双路 2A 高效同步直流/直流转换器
  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      LM26420 双路降压直流/直流转换器
      2.      LM26420 效率（高达 93%）
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: 16-Pin WQFN
    2.     Pin Functions 20-Pin HTSSOP
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings (LM26420X/Y)
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics Per Buck
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Soft Start
      2. 7.3.2 Power Good
      3. 7.3.3 Precision Enable
    4. 7.4 Device Functional Modes
      1. 7.4.1 Output Overvoltage Protection
      2. 7.4.2 Undervoltage Lockout
      3. 7.4.3 Current Limit
      4. 7.4.4 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Programming Output Voltage
      2. 8.1.2 VINC Filtering Components
      3. 8.1.3 Using Precision Enable and Power Good
      4. 8.1.4 Overcurrent Protection
    2. 8.2 Typical Applications
      1. 8.2.1 LM26420X 2.2-MHz, 0.8-V Typical High-Efficiency Application Circuit
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2 Inductor Selection
          3. 8.2.1.2.3 Input Capacitor Selection
          4. 8.2.1.2.4 Output Capacitor
          5. 8.2.1.2.5 Calculating Efficiency and Junction Temperature
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM26420X 2.2-MHz, 1.8-V Typical High-Efficiency Application Circuit
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LM26420X 2.2-MHz, 2.5-V Typical High-Efficiency Application Circuit
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
      4. 8.2.4 LM26420Y 550 kHz, 0.8-V Typical High-Efficiency Application Circuit
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
      5. 8.2.5 LM26420Y 550-kHz, 1.8-V Typical High-Efficiency Application Circuit
        1. 8.2.5.1 Design Requirements
        2. 8.2.5.2 Detailed Design Procedure
        3. 8.2.5.3 Application Curves
      6. 8.2.6 LM26420Y 550-kHz, 2.5-V Typical High-Efficiency Application Circuit
        1. 8.2.6.1 Design Requirements
        2. 8.2.6.2 Detailed Design Procedure
        3. 8.2.6.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
      1. 10.3.1 Method 1: Silicon Junction Temperature Determination
      2. 10.3.2 Thermal Shutdown Temperature Determination
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 第三方产品免责声明
      2. 11.1.2 使用 WEBENCH® 工具创建定制设计方案
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 接收文档更新通知
    4. 11.4 社区资源
    5. 11.5 商标
    6. 11.6 静电放电警告
    7. 11.7 术语表
  12. 12机械、封装和可订购信息
  13. 重要声明
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DATA SHEET

LM26420 双路 2A 高效同步直流/直流转换器

本资源的原文使用英文撰写。 为方便起见，TI 提供了译文；由于翻译过程中可能使用了自动化工具，TI 不保证译文的准确性。 为确认准确性，请务必访问 ti.com 参考最新的英文版本（控制文档）。

1 特性

  • 符合 CISPR25 5 类传导发射标准
  • 输入电压范围：3V 至 5.5V
  • 输出电压范围：0.8V 至 4.5V
  • 每稳压器 2A 输出电流
  • 高开关频率：2.2MHz (LM26420X)
       0.55MHz (LM26420Y)
  • 0.8V 1.5% 内部电压基准
  • 内部软启动
  • 针对每个输出的独立电源正常和精密使能功能
  • 电流模式、PWM 运行
  • 热关断
  • 过压保护
  • 启动至预偏置输出负载
  • 稳压器为 180° 异相
  • 使用 LM26420 及其 WEBENCH® 电源设计器创建定制设计

2 应用

  • FPGA 的局部 5V 到 Vcore
  • HDD 和机顶盒的内核电源
  • USB 用电设备
  • CPU 和 ASIC 的内核供电和 I/O 电压

    • 空白

3 说明

LM26420 稳压器是一款单片高效双路 PWM 降压直流/直流转换器。该器件可使用一流的 BICMOS 技术通过内部 75mΩ PMOS 顶部开关和内部 50mΩ NMOS 底部开关驱动两个 2A 负载，实现最佳的功率密度。世界级控制电路可实现低至 30ns 的接通时间，从而在整个 3V 至 5.5V 输入工作范围内支持低至 0.8V 的最小输出电压的出色高频转换。

尽管运行频率很高，但仍可以轻松实现高达 93% 的效率。具备外部关断功能，因此具有超低的待机电流。LM26420 可利用电流模式控制和内部补偿在各种运行条件下提供高性能调节。

器件信息(1)

器件型号 封装 封装尺寸（标称值）
LM26420 HTSSOP (20) 6.50mm x 4.40mm
WQFN (16) 4.00mm × 4.00mm
  1. 如需了解所有可用封装，请参阅产品说明书末尾的可订购产品附录。

Device Images

LM26420 双路降压直流/直流转换器

LM26420 Typical dual Buck DC/DC Converter LM26420 LM26420_Typical_Dual_Buck_DCDC_Converter.gif

LM26420 效率（高达 93%）

LM26420, Efficiency Up to 93% LM26420 LM26420_Efficiency_Up_to_93_Percent.png

4 修订历史记录

Changes from K Revision (April 2016) to L Revision

  • 将汽车产品说明书拆分为单独的文档 (SNVSB35) 并从 SNVS579 中删除了特定于汽车的内容Go
  • Added WEBENCH 链接Go

Changes from J Revision (September 2015) to K Revision

  • Changed RθJA value from 35°C/W to 38.5°C/W for PWP package and from 40°C/W to 36.2°C/W; replaced RθJC values with 2 new rows (and new values); added additional thermal valuesGo
  • Changed "C1" to "C2" on Figure 42Go
  • Changed "C1" to "C2" on Figure 51Go
  • Deleted "C7" and "C8" from Table 6 Go

Changes from I Revision (June 2015) to J Revision

  • fixed error in WQFN Pin Functions - shifted "Description" column down one row and added back description for VIND1 pinGo
  • Changed reference from "Typical Applications" to "Table 1". Go
  • Deleted definition for RDS (not part of equation 15) Go

Changes from H Revision (August 2014) to I Revision

  • Changed 在标题中将“频率”更改为“高效”；添加新的“特性”项目（关于 CISPR25）Go
  • Changed moved Storage temperature to Absolute Maximum Ratings tableGo
  • Changed figure 36 caption Go
  • Added part number to caption wordingGo
  • Added application note Go
  • Changed title of Thermal Guidelines to Thermal Considerations and moved the section to the correct location.Go
  • Added 相关文档 和社区资源 两个小节Go

Changes from G Revision (July 2014) to H Revision

  • Changed percent sign to suffix Go

Changes from F Revision (March 2013) to G Revision

  • Changed 格式，以匹配新的 TI 产品说明书指导准则；添加了器件信息 表、处理额定值 表、布局 部分和器件和文档支持 部分；将功能 说明 更改为详细 说明 且将 应用 更改为应用 和实施 部分Go
  • Changed to new equationGo

5 Pin Configuration and Functions

RUM Package
16-Pin WQFN
Top View
LM26420 30069601.gif
PWP Package
20-Pin HTSSOP
Top View
LM26420 30069602.gif

Pin Functions: 16-Pin WQFN

PIN TYPE DESCRIPTION
NUMBER NAME
1,2 VIND1 P Power input supply for Buck 1.
3 SW1 P Output switch for Buck 1. Connect to the inductor.
4 PGND1 G Power ground pin for Buck 1.
5 FB1 A Feedback pin for Buck 1. Connect to external resistor divider to set output voltage.
6 PG1 G Power Good Indicator for Buck 1. Pin is connected through a resistor to an external supply (open drain output).
7 PG2 G Power Good Indicator for Buck 2. Pin is connected through a resistor to an external supply (open drain output).
8 FB2 A Feedback pin for Buck 2. Connect to external resistor divider to set output voltage.
9 PGND2 G Power ground pin for Buck 2.
10 SW2 P Output switch for Buck 2. Connect to the inductor.
11, 12 VIND2 A Power Input supply for Buck 2.
13 EN2 A Enable control input. Logic high enable operation for Buck 2. Do not allow this pin to float or be greater than VIN + 0.3 V.
14 AGND G Signal ground pin. Place the bottom resistor of the feedback network as close as possible to pin.
15 VINC A Input supply for control circuitry.
16 EN1 A Enable control input. Logic high enable operation for Buck 1. Do not allow this pin to float or be greater than VIN + 0.3 V.
DAP Die Attach Pad — Connect to system ground for low thermal impedance and as a primary electrical GND connection.

Pin Functions 20-Pin HTSSOP

PIN TYPE DESCRIPTION
NUMBER NAME
1 VINC A Input supply for control circuitry.
2 EN1 A Enable control input. Logic high enable operation for Buck 1. Do not allow this pin to float or be greater than VIN + 0.3 V.
3, 4 VIND1 A Power Input supply for Buck 1.
5 SW1 P Output switch for Buck 1. Connect to the inductor.
6,7 PGND1 G Power ground pin for Buck 1.
8 FB1 A Feedback pin for Buck 1. Connect to external resistor divider to set output voltage.
9 PG1 G Power Good Indicator for Buck 1. Pin is connected through a resistor to an external supply (open drain output).
10, 11, DAP Die Attach Pad — Connect to system ground for low thermal impedance, but it cannot be used as a primary GND connection.
12 PG2 G Power Good Indicator for Buck 2. Pin is connected through a resistor to an external supply (open drain output).
13 FB2 A Feedback pin for Buck 2. Connect to external resistor divider to set output voltage.
14, 15 PGND2 G Power ground pin for Buck 2.
16 SW2 P Output switch for Buck 2. Connect to the inductor.
17, 18 VIND2 A Power Input supply for Buck 2.
19 EN2 A Enable control input. Logic high enable operation for Buck 2. Do not allow this pin to float or be greater than VIN + 0.3 V.
20 AGND G Signal ground pin. Place the bottom resistor of the feedback network as close as possible to pin.

 
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