JAJS499J June   2010  – January 2018 TPS7A80

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      標準アプリケーション回路
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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
    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 Internal Current Limit
      2. 7.3.2 Shutdown
      3. 7.3.3 Start-Up
      4. 7.3.4 Undervoltage Lockout (UVLO)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Dropout Voltage
        2. 8.2.1.2 Minimum Load
        3. 8.2.1.3 Input and Output Capacitor Requirements
        4. 8.2.1.4 Transient Response
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Output Noise
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Board Layout Recommendations to Improve PSRR and Noise Performance
      2. 10.1.2 Thermal Considerations
      3. 10.1.3 Power Dissipation
      4. 10.1.4 Estimating Junction Temperature
    2. 10.2 Layout Example
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 ドキュメントのサポート
      1. 11.1.1 関連資料
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 コミュニティ・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 Glossary
  12. 12メカニカル、パッケージ、および注文情報

8.2.2 Detailed Design Procedure

The voltage on the FB pin sets the output voltage and is determined by the values of R1 and R2. The values of R1 and R2 can be calculated for any voltage using the formula given in Equation 2:

Equation 2. TPS7A80 q_vout_bvs135.gif

Sample resistor values for common output voltages are shown in Table 1. In Table 1, E96 series resistors are used, and all values meet 1% of the target VOUT, assuming resistors with zero error. For the actual design, pay attention to any resistor error factors. Using lower values for R1 and R2 reduces the noise injected from the FB pin.

Table 1. Sample 1% Resistor Values for Common Output Voltages

VOUT R1 R2
0.8 V 0 Ω (Short) Do not populate
1 V 2.49 kΩ 10 kΩ
1.2 V 4.99 kΩ 10 kΩ
1.5 V 8.87 kΩ 10 kΩ
1.8 V 12.5 kΩ 10 kΩ
2.5 V 21 kΩ 10 kΩ
3.3 V 30.9 kΩ 10 kΩ
5 V 52.3 kΩ 10 kΩ