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  • LM2676 SIMPLE SWITCHER® 电源转换器、3A、高效降压稳压器

    • ZHCSRY0M april   2000  – may 2023 LM2676

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  • LM2676 SIMPLE SWITCHER® 电源转换器、3A、高效降压稳压器
  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: LM2676 – 3.3 V
    6. 6.6  Electrical Characteristics: LM2676 – 5 V
    7. 6.7  Electrical Characteristics: LM2676 – 12 B
    8. 6.8  Electrical Characteristics: LM2676 – Adjustable
    9. 6.9  Electrical Characteristics – All Output Voltage Versions
    10. 6.10 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Switch Output
      2. 7.3.2 Input
      3. 7.3.3 C Boost
      4. 7.3.4 Ground
      5. 7.3.5 Feedback
      6. 7.3.6 ON/OFF
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Design Considerations
      2. 8.1.2 Inductor
      3. 8.1.3 Output Capacitor
      4. 8.1.4 Input Capacitor
      5. 8.1.5 Catch Diode
      6. 8.1.6 Boost Capacitor
      7. 8.1.7 Additional Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Application for All Output Voltage Versions
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Capacitor Selection Guides
          2. 8.2.1.2.2 Inductor Selection Guides
      2. 8.2.2 Application Curves
      3. 8.2.3 Fixed Output Voltage Application
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
          1. 8.2.3.2.1 Capacitor Selection
      4. 8.2.4 Adjustable Output Voltage Application
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
          1. 8.2.4.2.1 Capacitor Selection
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 接收文档更新通知
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 DAP (VSON Package)
  12. 重要声明

封装选项

机械数据 (封装 | 引脚)
  • KTW|7
    • MPSF015
  • NDZ|7
    • MMSF005
  • NHM|14
    • MPDS422
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散热焊盘机械数据 (封装 | 引脚)
  • KTW|7
    • PPTD278
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Data Sheet

LM2676 SIMPLE SWITCHER® 电源转换器、3A、高效降压稳压器

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

  • 推出的新产品：
    • LMR51430 4.5V 至 36V、3A、500kHz 至 1.1MHz 同步转换器
  • 用于加快上市速度：
    • TLVM13630 3V 至 36V、3A、200kHz 至 2.2MHz 电源模块
  • 效率高达 94%
  • 实现便捷设计（使用现成的外部元件）
  • 150mΩ DMOS 输出开关
  • 3.3V、5V、12V 固定输出和可调节
    （1.2V 至 37V）版本
  • 关断时的待机电流为 50µA
  • 在所有线路和负载条件下具有 ±2% 的最大输出容差
  • 宽输入电压范围：8V 至 40V
  • 260kHz 固定频率内部振荡器
  • -40°C 至 125°C 的工作结温范围

2 应用

  • 通信模块
  • 电表
  • 呼叫按钮操作面板
  • 电机驱动器

3 说明

LM2676 系列稳压器是为降压开关稳压器提供全部所示功能的单片集成电路，能够驱动高达 3A 的负载，并且拥有出色的线路和负载调节特性。使用低导通电阻 DMOS 电源开关可获得高效率 (>90%)。该系列包含 3.3V、5V 和 12V 固定输出电压和可调节输出版本。

SIMPLE SWITCHER® 电源转换器概念使用超少的外部元件即可提供完整设计。高固定频率振荡器 (260kHz) 允许使用物理尺寸更小的元件。多家制造商提供了一系列可与 LM2676 搭配使用的标准电感器，可极大地简化设计过程。

LM2676 系列还具有内置热关断、电流限制和开关控制输入，可将稳压器下电至 50µA 的低静态电流待机状态。可确保输出电压容差为 ±2%。时钟频率控制在 ±11% 的容差范围内。

封装信息
器件型号 封装(1) 封装尺寸（标称值）
LM2676 KTW（TO-263，7） 10.10mm × 8.89mm
NDZ（TO-220，7） 14.986mm × 10.16mm
NHM（VSON，14） 6.00mm × 5.00mm
(1) 如需了解所有可用封装，请参阅数据表末尾的可订购产品附录。
GUID-6D048107-31CA-40B6-8A70-0C31E472ACE6-low.png典型应用

4 Revision History

Changes from Revision L (June 2020) to Revision M (May 2023)

  • 删除了与 LMR33630 相关的信息，并在 #GUID-FE9117BE-B1C0-432E-A514-EC7AC622735D/TITLE-SNVS031SNVS0310036 中添加了 LMR51430 和 TLVM13630 产品文件夹的链接Go
  • 更新了整个文档中的表格、图和交叉参考的编号格式Go
  • 更新的商标信息Go

Changes from Revision K (June 2016) to Revision L (June 2020)

  • 添加了有关 LMR33630 的信息Go

Changes from Revision J (April 2013) to Revision K (June 2016)

  • 删除了对计算机设计软件 LM267X Made Simple （6.0 版）的所有引用Go
  • 添加了 ESD 等级 表、特性说明 部分、器件功能模式、应用和实现 部分、电源相关建议 部分、布局 部分、器件和文档支持 部分以及机械、封装和可订购信息 部分Go
  • 删除了对计算机设计软件 LM267X Made Simple （6.0 版）的所有引用Go

Changes from Revision I (April 2013) to Revision J (April 2013)

  • Changed layout of National Data Sheet to TI formatGo

5 Pin Configuration and Functions

GUID-BD212C52-C19A-4B7C-8154-9706B185E18B-low.svgFigure 5-1 KTW Package7-Pin TO-263Top View
GUID-4D04A7B0-95DE-4896-984B-A14998D5FD01-low.svg
DAP connect to pin 9
Figure 5-3 NHM Package14-Pin VSONTop View
GUID-545AEFD9-020B-42AF-AD64-9B15E4CCC4B0-low.svgFigure 5-2 NDZ Package7-Pin TO-220Top View
Table 5-1 Pin Functions
PIN I/O DESCRIPTION
NAME TO-263,
TO-220		 VSON
Switch output 1 12, 13, 14 O Source pin of the internal high-side FET. This is a switching node. Attached this pin to an inductor and the cathode of the external diode.
Input 2 2, 3 I Supply input pin to collector pin of high-side FET. Connect to power supply and input bypass capacitors CIN. Path from VIN pin to high frequency bypass CIN and GND must be as short as possible.
CB 3 4 I Boot-strap capacitor connection for high-side driver. Connect a high-quality 100-nF capacitor from CB to VSW Pin.
GND 4 9 — Power ground pins. Connect to system ground. Ground pins of CIN and COUT. Path to CIN must be as short as possible.
FB 6 7 I Feedback sense input pin. Connect to the midpoint of feedback divider to set VOUT for ADJ version or connect this pin directly to the output capacitor for a fixed output version.
ON/ OFF 7 8 I Enable input to the voltage regulator. High = ON and low = OFF. Pull this pin high or float to enable the regulator.
NC 5 1, 5, 6, 10, 11 — No connect pins

6 Specifications

6.1 Absolute Maximum Ratings

see (1)(2)
MINMAXUNIT
Input supply voltage45V
Soft-start pin voltage–0.16V
Switch voltage to ground(3)–1VINV
Boost pin voltageVSW + 8V
Feedback pin voltage–0.314V
Power dissipationInternally Limited
Soldering temperatureWave, 4 s260°C
Infrared, 10 s240
Vapor phase, 75 s219
Storage temperature, Tstg–65150°C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications.
(3) The absolute maximum specification of the Switch Voltage to Ground applies to DC voltage. An extended negative voltage limit of –10 V applies to a pulse of up to 20 ns, –6 V of 60 ns and –3 V of up to 100 ns.

6.2 ESD Ratings

VALUEUNIT
V(ESD)Electrostatic dischargeHuman-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)(2)±2000V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) ESD was applied using the human-body model, a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin.

6.3 Recommended Operating Conditions

MINMAXUNIT
Supply voltage840V
Junction temperature (TJ)–40125°C

6.4 Thermal Information

THERMAL METRIC(1)LM2678UNIT
NDZ (TO-220)KTW (TO-263)NHM (VSON)
7 PINS7 PINS14 PINS
RθJAJunction-to-ambient thermal resistanceSee (2)65——°C/W
See (3)45——
See (4)—56—
See (5)—35—
See (6)—26—
See (7)——55
See (8)——29
RθJC(top)Junction-to-case (top) thermal resistance22—°C/W
(1) For more information about traditional and new thermal metrics, see theSemiconductor and IC Package Thermal Metrics application report, SPRA953.
(2) Junction to ambient thermal resistance (no external heat sink) for the 7-lead TO-220 package mounted vertically, with 0.5 in leads in a socket, or on a PCB with minimum copper area.
(3) Junction to ambient thermal resistance (no external heat sink) for the 7-lead TO-220 package mounted vertically, with 0.5 in leads soldered to a PCB containing approximately 4 square inches of (1 oz) copper area surrounding the leads.
(4) Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB area of 0.136 square inches (the same size as the DDPAK package) of 1 oz (0.0014 in thick) copper.
(5) Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB area of 0.4896 square inches (3.6 times the area of the DDPAK package) of 1 oz (0.0014 in thick) copper.
(6) Junction to ambient thermal resistance for the 7-lead DDPAK mounted horizontally against a PCB copper area of 1.0064 square inches (7.4 times the area of the DDPAK 3 package) of 1 oz (0.0014 in thick) copper. Additional copper area reduces thermal resistance further.
(7) Junction to ambient thermal resistance for the 14-lead VSON mounted on a PCB copper area equal to the die attach paddle.
(8) Junction to ambient thermal resistance for the 14-lead VSON mounted on a PCB copper area using 12 vias to a second layer of copper equal to die attach paddle. Additional copper area reduces thermal resistance further. For layout recommendations, see the AN-1187 Leadless Leadfram Package (LLP) application report.

6.5 Electrical Characteristics: LM2676 – 3.3 V

Specifications apply for TA = TJ = 25°C unless otherwise noted. RADJ = 5.6 kΩ.
PARAMETERTEST CONDITIONSMIN(1)TYP(2)MAX(1)UNIT
VOUTOutput voltageVIN = 8 V to 40 V,
100 mA ≤ IOUT ≤ 5 A		3.2343.33.366V
over the entire junction temperature range of operation –40°C to 125°C3.2013.399
ηEfficiencyVIN = 12 V, ILOAD = 5 A86%
(1) All room temperature limits are 100% tested during production with TA = TJ = 25°C. All limits at temperature extremes are specified through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical values are determined with TA = TJ = 25°C and represent the most likely norm.

6.6 Electrical Characteristics: LM2676 – 5 V

Specifications apply for TA = TJ = 25°C unless otherwise noted. RADJ = 5.6 kΩ.
PARAMETERTEST CONDITIONSMIN(1)TYP(2)MAX(1)UNIT
VOUTOutput voltageVIN = 8 V to 40 V,
100 mA ≤ IOUT ≤ 5 A		4.955.1V
over the entire junction temperature range of operation –40°C to 125°C4.855.15
ηEfficiencyVIN = 12 V, ILOAD = 5 A88%
(1) All room temperature limits are 100% tested during production with TA = TJ = 25°C. All limits at temperature extremes are specified through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical values are determined with TA = TJ = 25°C and represent the most likely norm.

6.7 Electrical Characteristics: LM2676 – 12 B

Specifications apply for TA = TJ = 25°C unless otherwise noted. RADJ = 5.6 kΩ.
PARAMETERTEST CONDITIONSMIN(1)TYP(2)MAX(1)UNIT
VOUTOutput voltageVIN = 15 V to 40 V,
100 mA ≤ IOUT ≤ 5 A		11.761212.24V
over the entire junction temperature range of operation –40°C to 125°C11.6412.36
ηEfficiencyVIN = 24 V, ILOAD = 5 A94%
(1) All room temperature limits are 100% tested during production with TA = TJ = 25°C. All limits at temperature extremes are specified through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical values are determined with TA = TJ = 25°C and represent the most likely norm.

6.8 Electrical Characteristics: LM2676 – Adjustable

PARAMETERTEST CONDITIONSMIN(1)TYP(2)MAX(1)UNIT
VFBFeedback voltageVIN = 8 V to 40 V,
100 mA ≤ IOUT ≤ 5 A,
VOUT programmed for 5 V		1.1861.211.234V
over the entire junction temperature range of operation –40°C to 125°C1.1741.246
ηEfficiencyVIN = 12 V, ILOAD = 5 A88%
(1) All room temperature limits are 100% tested during production with TA = TJ = 25°C. All limits at temperature extremes are specified through correlation using standard Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical values are determined with TA = TJ = 25°C and represent the most likely norm.

6.9 Electrical Characteristics – All Output Voltage Versions

Specifications are for TA = TJ = 25°C unless otherwise specified. Unless otherwise specified VIN = 12 V for the 3.3-V, 5-V, and Adjustable versions and VIN = 24 V for the 12-V version.
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
DEVICE PARAMETERS
IQQuiescent currentVFEEDBACK = 8 V for 3.3-V, 5-V, and ADJ versions,
VFEEDBACK = 15 V for 12-V versions		4.26mA
ISTBYStandby quiescent currentON/ OFF pin = 0 V50100µA
over the entire junction temperature range of operation –40°C to 125°C150
ICLCurrent limit3.84.55.25A
over the entire junction temperature range of operation –40°C to 125°C3.65.4
ILOutput leakage currentVIN = 40 V,
soft-start pin = 0 V		VSWITCH = 0V200µA
VSWITCH = –1V1615mA
RDS(ON)Switch ON-resistanceISWITCH = 5 A0.150.17Ω
over the entire junction temperature range of operation –40°C to 125°C0.29
fOOscillator frequencyMeasured at
switch pin		260kHz
over the entire junction temperature range of operation –40°C to 125°C225280
DDuty cycleMaximum duty cycle91%
Minimum duty cycle0%
IBIASFeedback bias
current		VFEEDBACK = 1.3 V
ADJ version only		85nA
VON/OFFON/OFF threshold voltage1.4V
over the entire junction temperature range of operation –40°C to 125°C0.82
ION/OFFON/OFF input currentON/ OFF pin = 0 V20µA
over the entire junction temperature range of operation –40°C to 125°C45

6.10 Typical Characteristics

GUID-DA1878C0-EBDE-4149-9BD0-85742F6FB1D8-low.pngFigure 6-1 Normalized Output Voltage
GUID-1ED70F45-0F7C-43E5-8ABD-96CE1F2C5408-low.pngFigure 6-3 Efficiency versus Input Voltage
GUID-7C4BAA2C-40AE-4E73-9076-19E63EE76AE4-low.pngFigure 6-5 Switch Current Limit
GUID-E482B4E7-A939-4B12-B367-6818F7D0CA60-low.pngFigure 6-7 Standby Quiescent Current
GUID-23C6D7C9-80D9-41AF-9ACF-4EF6DE93685B-low.pngFigure 6-9 ON/ OFF Pin Current (Sourcing)
GUID-A3D6A518-93DC-437A-A18F-9DCE0A0969C5-low.png
Figure 6-11 Feedback Pin Bias Current
GUID-3D70ED98-E6BE-4B60-83D9-8F462527DC07-low.png
Discontinuous Mode Switching Waveforms VIN = 20 V, VOUT = 5 V, ILOAD = 500 mA L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
A: VSW Pin Voltage, 10 V/div.
B: Inductor Current, 1 A/div
C: Output Ripple Voltage, 20 mV/div AC-Coupled
Figure 6-13 Horizontal Time Base: 1 µs/div
GUID-B6AA216E-4BFC-46F5-A8EC-18061921DB9A-low.png
Load Transient Response for Discontinuous Mode VIN = 20 V, VOUT = 5 V, L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
A: Output Voltage, 100 mV/div, AC-Coupled
B: Load Current: 200-mA to 3-A Load Pulse
Figure 6-15 Horizontal Time Base: 200 µs/div
GUID-C0C71B75-1119-4C11-88AE-56DF2F39EE67-low.pngFigure 6-2 Line Regulation
GUID-F4FF5762-B696-441B-9B7E-242FE504EECA-low.pngFigure 6-4 Efficiency versus ILOAD
GUID-ACDA1AC0-5E43-43C8-90AC-E8DE4DE3CC73-low.pngFigure 6-6 Operating Quiescent Current
GUID-98E09850-05CF-4125-BF8D-82B136557510-low.pngFigure 6-8 ON/OFF Threshold Voltage
GUID-C7F32CB7-9C91-4155-AF39-50F0536C6288-low.pngFigure 6-10 Switching Frequency
GUID-CF75C78F-7EC6-4E51-BDEF-C38D80B70AA3-low.png
Continuous Mode Switching Waveforms VIN = 20 V, VOUT = 5 V, ILOAD = 3 A L = 33 µH, COUT = 200 µF, COUTESR = 26 mΩ
A: VSW Pin Voltage, 10 V/div.
B: Inductor Current, 1 A/div
C: Output Ripple Voltage, 20 mV/div AC-Coupled
Figure 6-12 Horizontal Time Base: 1 µs/div
GUID-E0B8DDDE-8141-42C3-9AC0-4DD5F7DC65D5-low.png
Load Transient Response for Continuous Mode VIN = 20 V, VOUT = 5 V L = 33 µH, COUT = 200 µF, COUTESR = 26 mΩ
A: Output Voltage, 100 mV//div, AC-Coupled.
B: Load Current: 500-mA to 3-A Load Pulse
Figure 6-14 Horizontal Time Base: 100 µs/div

7 Detailed Description

7.1 Overview

The LM2676 provides all of the active functions required for a step-down (buck) switching regulator. The internal power switch is a DMOS-power MOSFET to provide power supply designs with high current capability, up to 3 A, and highly efficient operation.

The design support WEBENCH can also be used to provide instant component selection, circuit performance calculations for evaluation, a bill of materials component list, and a circuit schematic for LM2676.

7.2 Functional Block Diagram

GUID-87FECF62-4EFD-4D22-8B6A-D4A99142F0A0-low.png
* Active Inductor Patent Number 5,514,947 † Active Capacitor Patent Number 5,382,918

7.3 Feature Description

7.3.1 Switch Output

This is the output of a power MOSFET switch connected directly to the input voltage. The switch provides energy to an inductor, an output capacitor, and the load circuitry under control of an internal pulse-width-modulator (PWM). The PWM controller is internally clocked by a fixed 260-kHz oscillator. In a standard step-down application, the duty cycle (Time ON/Time OFF) of the power switch is proportional to the ratio of the power supply output voltage to the input voltage. The voltage on pin 1 switches between VIN (switch ON) and below ground by the voltage drop of the external Schottky diode (switch OFF).

 
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