JAJSGG5D November   2018  – March 2021 TPS3703-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Timing Diagrams
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 VDD
      2. 8.3.2 SENSE
      3. 8.3.3 RESET
      4. 8.3.4 Capacitor Time (CT)
      5. 8.3.5 Manual Reset ( MR)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal Operation (VDD > VDD(MIN))
      2. 8.4.2 Undervoltage Lockout (VPOR < VDD < UVLO)
      3. 8.4.3 Power-On Reset (VDD < VPOR)
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Voltage Threshold Accuracy
      2. 9.1.2 CT Reset Time Delay
        1. 9.1.2.1 Factory-Programmed Reset Delay Timing
        2. 9.1.2.2 Programmable Reset Delay-Timing
      3. 9.1.3 RESET Latch Mode
      4. 9.1.4 Adjustable Voltage Thresholds
      5. 9.1.5 Immunity to SENSE Pin Voltage Transients
        1. 9.1.5.1 Hysteresis
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1: Multi-Rail Window Monitoring for Microcontroller Power Rails
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Design 2: RESET Latch Mode
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Guidelines
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Evaluation Module
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 サポート・リソース
    5. 12.5 Trademarks
    6. 12.6 静電気放電に関する注意事項
    7. 12.7 用語集
  13. 13Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

9.1.4 Adjustable Voltage Thresholds

The TPS3703-Q1 0.7% maximum accuracy allows for adjustable voltage thresholds using external resistors without adding major inaccuracies to the device. In case that the desired monitored voltage is not available, external resistor dividers can be used to set the desired voltage thresholds. Figure 9-4 illustrates an example of how to adjust the voltage threshold with external resistor dividers. The resistors can be calculated depending on the desired voltage threshold and device part number. TI recommends using the 0.8V voltage threshold device such as the TPS3703B3080 because of the bypass mode of internal resistor ladder.

For example, consider a 2.0 V rail being monitored (VMON) using the TPS3703B3080 variant. Using Equation 4, R1 = 15 kΩ given that R2 = 10 kΩ, VMON = 2 V , and VSENSE = 0.8 V. This device is typically meant to monitor a 0.8 V rail with ±3% voltage thresholds. This means that the device undervoltage threshold (VIT-(UV)) and overvoltage threshold (VIT-(OV)) is 0.776 V and 0.824 V respectively. Using Equation 4 , VMON = 1.94 V when VSENSE = VIT-(UV). This can be denoted as VMON-, the monitored undervoltage threshold where the device will assert a reset signal. Using Equation 4 again, the monitored overvoltage threshold (VMON+) = 2.06 V when VSENSE = VIT+(OV). If a wider tolerance or UV only threshold is desired, use a device variant shown on Table 7 to determine what device part number matches your application.

Equation 4. VSENSE = VMON × (R2 ÷ (R1 + R2))

There are inaccuracies that must be taken into consideration while adjusting voltage thresholds. Aside from the tolerance of the resistor divider, there is an internal resistance of the SENSE pin that may affect the accuracy of the resistor divider. Although expected to be very high impedance, users are recommended to calculate the values for design specifications. The internal sense resistance (RSENSE) can be calculated by the sense voltage (VSENSE) divided by the sense current (ISENSE) as shown in Equation 6. VSENSE can be calculated using Equation 4 depending on the resistor divider and monitored voltage. ISENSE can be calculated using Equation 5.

Equation 5. ISENSE = (VMON – VSENSE) ÷ R1 – (VSENSE ÷ R2)
Equation 6. RSENSE = VSENSE ÷ ISENSE
GUID-74D1475A-E29A-4C9B-9806-0A4F54296E65-low.gifFigure 9-4 Adjustable Voltage Threshold with External Resistor Dividers