SLAA423A December   2009  – November 2018 MSP430F4132 , MSP430F4152 , MSP430F47126 , MSP430F47127 , MSP430F47163 , MSP430F47166 , MSP430F47167 , MSP430F47173 , MSP430F47176 , MSP430F47177 , MSP430F47183 , MSP430F47186 , MSP430F47187 , MSP430F47193 , MSP430F47196 , MSP430FG4616 , MSP430FG4617 , MSP430FG4618

 

  1.   XOSC8 Guidance
    1.     Trademarks
    2. 1 Introduction
    3. 2 Contribution of ESR, Load Capacitance, VCC, and Temperature
      1. 2.1 Crystal ESR
        1. 2.1.1 ESR and Start-up Reliability
        2. 2.1.2 ESR Specification
      2. 2.2 Load Capacitance
      3. 2.3 Temperature and VCC
    4. 3 Using a Shunt Resistor From XIN to GND
    5. 4 Failsafe Mechanisms
      1. 4.1 2xx Family
      2. 4.2 4xx Family
    6. 5 Summary
    7. 6 References
  2.   Revision History

5 Summary

The occurrence of XOSC8 can be controlled with VCC, temperature, load capacitance, ESR, and impedance. However, only ESR and impedance adjustments provide solutions over the entire VCC and temperature range. It is recommended to use the highest amount of load capacitance possible, regardless of the workaround chosen. Using too little or no load capacitance is not recommended. The first workaround is the workaround found in the XOSC8 erratum: use a crystal with an ESR greater than 40 kΩ. The second workaround is to use a shunt or load resistor from XIN to ground (AVSS).

The workarounds and descriptions in this application report are based upon good design practices for low-frequency crystal oscillator circuits found in MSP430 32-kHz Crystal Oscillators. While disregarding good practices can actually mitigate the occurrence of XOSC8 (forcing the oscillator to work harder), doing so makes the impedance and capacitance values discussed in this report inapplicable.