JAJSGL5C December   2018  – August 2019 TPS3840

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション回路
      2.      TPS3840 の標準的な消費電流
  4. 4 改訂履歴
  5. 5 概要 (続き)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Input Voltage (VDD)
        1. 9.3.1.1 VDD Hysteresis
        2. 9.3.1.2 VDD Transient Immunity
      2. 9.3.2 User-Programmable Reset Time Delay
      3. 9.3.3 Manual Reset (MR) Input
      4. 9.3.4 Output Logic
        1. 9.3.4.1 RESET Output, Active-Low
        2. 9.3.4.2 RESET Output, Active-High
    4. 9.4 Device Functional Modes
      1. 9.4.1 Normal Operation (VDD > VDD(min))
      2. 9.4.2 VDD Between VPOR and VDD(min)
      3. 9.4.3 Below Power-On-Reset (VDD < VPOR)
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design 1: Dual Rail Monitoring with Power-Up Sequencing
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Design 2: Battery Voltage and Temperature Monitor
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
      3. 10.2.3 Design 3: Fast Start Undervoltage Supervisor with Level-shifted Input
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
      4. 10.2.4 Design 4: Voltage Monitor with Back-up Battery Switchover
        1. 10.2.4.1 Design Requirements
        2. 10.2.4.2 Detailed Design Procedure
      5. 10.2.5 Application Curve: TPS3840EVM
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13デバイスおよびドキュメントのサポート
    1. 13.1 デバイスの項目表記
    2. 13.2 コミュニティ・リソース
    3. 13.3 商標
    4. 13.4 静電気放電に関する注意事項
    5. 13.5 Glossary
  14. 14メカニカル、パッケージ、および注文情報

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

10.2.2.2 Detailed Design Procedure

The primary constraint for this application is choosing the correct device to monitor the battery supply voltage. The TPS3840 can monitor any voltage between 1.6 V and 10 V and is available in 0.1 V increments. Depending on how far away from the nominal voltage rail the user wants the voltage supervisor to trigger determines the correct voltage supervisor variant to choose. In this design example, the TPS3840DL30 is chosen for both the undervoltage and overvoltage monitoring. For undervoltage monitoring, the undervoltage fault occurs when the 3.3-V rail falls to 3 V and for the overvoltage monitoring, the overvoltage fault occurs when the 2.8-V rail rises above the 3-V threshold (VIT-) plus 100mV hysteresis (VHYS). It's important to note that in the undervoltage application, the TPS3840 RESET output is logic high during normal conditions whereas in the overvoltage application, the TPS3840 RESET output is logic low during normal conditions which is the reason a single device can be used for either type of monitoring depending on the logic required at the output. The opposite RESET output logic is offered in the push-pull, active-high device TPS3840PH noted with the RESET output. The secondary constraint for this application is the battery temperature monitoring accomplished by the TMP303A. Typical Lithium Ion battery discharge temperature range is 0°C to 60°C which is accomplished by the 'A' variante of TMP303A. The TMP303A triggers a fault to the MR pin of the TPS3840 or directly to the battery charger whenever the temperature is outside of the temperature range. The TMP303A offers 1°C resolution to meet the high resolution requirement. Because the undervoltage monitor design uses TMP303A, a push-pull active-high output device, an additional inverter is required before the MR pin because during normal operation, the TMP303 output is low but the MR pin must be logic high during normal operation. If using two TPS3840 devices for both undervoltage and overvoltage monitoring on the same battery, only one single temperature monitoring device is required. The last constraint is the RESET/RESET time delay set by CCT. For applications with ambient temperatures ranging from –40°C to +125°C, CCT can be calculated using RCT and solving for CCT in Equation 2. By choosing a standard 10% capacitor value of 10 µF ensures the RESET/RESET time delay will be at least 6 seconds. Note: active-low devices use the output label RESET and active-high devices use the output label RESET.

A 0.1-µF decoupling capacitor is connected to the VDD pin as a good analog design practice. The pull-up resistor is only required for the Open-Drain device variants and is calculated to maintain the RESET current within the ±5 mA limit found in the Recommended Operating Conditions: RPull-up = VPull-up ÷ 5 mA. For this design, a 1-MΩ pull-up resistor is selected to minimize current draw when RESET is asserted and to prevent the battery from unnecessary discharge. Keep in mind the lowering the pull-up resistor, increases VOL and IOUT. The MR pin is used for a second fault condition provided by the temperature switch.