SLAA334B September   2006  – August 2018 MSP430BT5190 , MSP430F1101 , MSP430F1101A , MSP430F1111A , MSP430F112 , MSP430F1121 , MSP430F1121A , MSP430F1122 , MSP430F1132 , MSP430F122 , MSP430F1222 , MSP430F123 , MSP430F1232 , MSP430F133 , MSP430F135 , MSP430F147 , MSP430F1471 , MSP430F148 , MSP430F1481 , MSP430F149 , MSP430F1491 , MSP430F155 , MSP430F156 , MSP430F157 , MSP430F1610 , MSP430F1611 , MSP430F1612 , MSP430F167 , MSP430F168 , MSP430F169 , MSP430F2001 , MSP430F2002 , MSP430F2003 , MSP430F2011 , MSP430F2012 , MSP430F2013 , MSP430F2013-EP , MSP430F2101 , MSP430F2111 , MSP430F2112 , MSP430F2121 , MSP430F2122 , MSP430F2131 , MSP430F2132 , MSP430F2232 , MSP430F2234 , MSP430F2252 , MSP430F2252-Q1 , MSP430F2254 , MSP430F2272 , MSP430F2272-Q1 , MSP430F2274 , MSP430F233 , MSP430F2330 , MSP430F235 , MSP430F2350 , MSP430F2370 , MSP430F2410 , MSP430F2416 , MSP430F2417 , MSP430F2418 , MSP430F2419 , MSP430F247 , MSP430F2471 , MSP430F248 , MSP430F2481 , MSP430F249 , MSP430F2491 , MSP430F2616 , MSP430F2617 , MSP430F2618 , MSP430F2619 , MSP430F412 , MSP430F413 , MSP430F4132 , MSP430F415 , MSP430F4152 , MSP430F417 , MSP430F423 , MSP430F423A , MSP430F425 , MSP430F4250 , MSP430F425A , MSP430F4260 , MSP430F427 , MSP430F4270 , MSP430F427A , MSP430F435 , MSP430F4351 , MSP430F436 , MSP430F4361 , MSP430F437 , MSP430F4371 , MSP430F438 , MSP430F439 , MSP430F447 , MSP430F448 , MSP430F4481 , MSP430F449 , MSP430F4491 , MSP430F4616 , MSP430F46161 , MSP430F4617 , MSP430F46171 , MSP430F4618 , MSP430F46181 , MSP430F4619 , MSP430F46191 , MSP430F47126 , MSP430F47127 , MSP430F47163 , MSP430F47166 , MSP430F47167 , MSP430F47173 , MSP430F47176 , MSP430F47177 , MSP430F47183 , MSP430F47186 , MSP430F47187 , MSP430F47193 , MSP430F47196 , MSP430F47197 , MSP430F477 , MSP430F478 , MSP430F4783 , MSP430F4784 , MSP430F479 , MSP430F4793 , MSP430F4794 , MSP430F5131 , MSP430F5132 , MSP430F5151 , MSP430F5152 , MSP430F5171 , MSP430F5172 , MSP430F5304 , MSP430F5308 , MSP430F5309 , MSP430F5310 , MSP430F5324 , MSP430F5325 , MSP430F5326 , MSP430F5327 , MSP430F5328 , MSP430F5329 , MSP430F5333 , MSP430F5336 , MSP430F5338 , MSP430F5340 , MSP430F5341 , MSP430F5342 , MSP430F5418 , MSP430F5418A , MSP430F5419 , MSP430F5419A , MSP430F5435 , MSP430F5435A , MSP430F5436 , MSP430F5436A , MSP430F5437 , MSP430F5437A , MSP430F5438 , MSP430F5438A , MSP430F5500 , MSP430F5501 , MSP430F5502 , MSP430F5503 , MSP430F5504 , MSP430F5505 , MSP430F5506 , MSP430F5507 , MSP430F5508 , MSP430F5509 , MSP430F5510 , MSP430F5630 , MSP430F5631 , MSP430F5632 , MSP430F5633 , MSP430F5634 , MSP430F5635 , MSP430F5636 , MSP430F5637 , MSP430F5638 , MSP430F6433 , MSP430F6435 , MSP430F6436 , MSP430F6438 , MSP430F6630 , MSP430F6631 , MSP430F6632 , MSP430F6633 , MSP430F6634 , MSP430F6635 , MSP430F6636 , MSP430F6637 , MSP430F6638 , MSP430FE423 , MSP430FE4232 , MSP430FE423A , MSP430FE4242 , MSP430FE425 , MSP430FE4252 , MSP430FE425A , MSP430FE427 , MSP430FE4272 , MSP430FE427A , MSP430FG4250 , MSP430FG4260 , MSP430FG4270 , MSP430FG437 , MSP430FG438 , MSP430FG439 , MSP430FG4616 , MSP430FG4617 , MSP430FG4618 , MSP430FG4619 , MSP430FG477 , MSP430FG478 , MSP430FG479 , MSP430FW423 , MSP430FW425 , MSP430FW427 , MSP430G2001 , MSP430G2101 , MSP430G2102 , MSP430G2111 , MSP430G2112 , MSP430G2121 , MSP430G2131 , MSP430G2132 , MSP430G2152 , MSP430G2201 , MSP430G2201-Q1 , MSP430G2211 , MSP430G2212 , MSP430G2221 , MSP430G2231 , MSP430G2231-Q1 , MSP430G2232 , MSP430G2252 , MSP430G2302 , MSP430G2312 , MSP430G2332 , MSP430G2352 , MSP430G2402 , MSP430G2432 , MSP430G2452 , MSP430L092

 

  1.   MSP430 Flash Memory Characteristics
    1.     Trademarks
    2. 1 Flash Memory
    3. 2 Simplified Flash Memory Cell
    4. 3 Flash Memory Parameters
      1. 3.1 Data Retention
        1. 3.1.1 Leakage Mechanism
        2. 3.1.2 Data Retention Time
      2. 3.2 Flash Endurance
      3. 3.3 Cumulative Program Time
    5. 4 Flash Enhancements With Software
      1. 4.1 EEPROM Emulation With Flash
      2. 4.2 Enhancing Flash Data Retention Time With Flash Refresh
      3. 4.3 Verify Flash Data With a Checksum or CRC
    6. 5 Conclusion
    7. 6 References
  2.   Revision History

3.1.2 Data Retention Time

A common concern with nonvolatile erasable memories is data retention. As explained in Section 3.1.1, over time, the floating gate charge is reduced due to leakage introduced by oxide defects. With higher temperatures, leakage current increases and, thus, the charge on the floating gate is reduced more quickly than at lower temperatures. This temperatures dependence follows the Arrhenius equation (see Equation 1):

Equation 1. AF = e – Ea k 1 T1 – 1 T2

    where

  • AF = Acceleration factor
  • Ea = 0.6 eV = Activation energy
  • k = 86.17 × 10–6 = Speed constant
  • T1 = Temperature 1 (K)
  • T2 = Temperature 2 (K)

The Arrhenius equation gives an acceleration factor (AF) for data retention based on a temperature difference. Because it would take too long to measure a data-retention time at 25°C, these measurements are done at a much higher temperature to accelerate the process. In the data sheets of MSP430 devices, data retention is specified to exceed 100 years at 25°C (see Table 1). This value is industry accepted and all vendors specify 100 years as the flash data retention duration at 25°C, despite it being extremely conservative.

Table 1. Data Retention Over Recommended Operating Temperature in Data Sheets

PARAMETER TEST CONDITIONS MIN MAX UNIT
tRetention Data retention duration TJ = 25°C 100 years

Further tests show the exact number of years at 25°C is 1324 years.[6]

Equation 2 is an example of using the Arrhenius equation to calculate data retention for any ambient temperature:

T1 = 50°C = 323K
T2 = 25°C = 298K (data-sheet specification)

Equation 2. AF = e – Ea k 1 T1 – 1 T2 = e – 0 .6 eV 86 .17 ×10 –6 1 323 K – 1 298 K ≈6

Stored data ages six times faster at 50°C than it ages at 25°C.

In an application operating at 50°C, 24 hours per day, 7 days per week, the data retention time (specified in Understanding MSP430 Flash Data Retention) is reduced from 1324 years to 1324/6 ≈ 220 years.

If the application is running 5 hours per day at 50°C and the rest of the day at 25°C, the data retention is calculated as shown here:

5 hours/day at 50°C is equivalent to data aging at 25°C for 5 hours × 6 = 30 hours

19 hours/day at 25°C is equivalent to data aging at 25°C for 19 hours

Total data aging per day is 30 hours + 19 hours = 49 hours ≈ 2 days at 25°C

In this scenario, data retention is 662 years.

Erased MSP430 flash memory bits have fully charged floating gates and read as logical 1s. Therefore, single-bit failures due to leakage currents show erroneous 0s that should be 1s. These single-bit failures based on leakage currents can never read an erroneous 1, instead of expected 0s.