Electrical Specifications
Memory Characteristics
MC68HC08MR4/MC68HC908MR8 — Rev. 2.0
Technical Data
MOTOROLA
Electrical Specifications
351
21.7 Memory Characteristics
Characteristic
Symbol
Min
Typ
Max
Unit
RAM data retention voltage
VRDR
1.3
——
V
FLASH program bus clock frequency
—
1
——
MHz
FLASH read bus clock frequency
fRead
(1)
1. fRead is defined as the frequency range for which the FLASH memory can be read.
32k
—
8.4M
Hz
FLASH page erase time
tErase
(2)
2. If the page erase time is longer than tErase (Min), there is no erase-disturb, but it reduces the endurance of the FLASH
memory.
1
——
ms
FLASH mass erase time
tMErase
(3)
3. If the mass erase time is longer than tMErase (Min), there is no erase-disturb, but it reduces the endurance of the FLASH
memory.
4
——
ms
FLASH PGM/ERASE to HVEN set up time
tnvs
10
——
s
FLASH high-voltage hold time
tnvh
5
——
s
FLASH high-voltage hold time (mass erase)
tnvhl
100
——
s
FLASH program hold time
tpgs
5
——
s
FLASH program time
tPROG
30
—
40
s
FLASH return to read time
trcv
(4)
4. trcv is defined as the time it needs before the FLASH can be read after turning off the high voltage charge pump, by clearing
HVEN to logic 0.
1
——
s
FLASH cumulative program HV period
tHV
(5)
5.
tHV is defined as the cumulative high voltage programming time to the same row before next erase.
tHV must satisfy this condition: tnvs + tnvh + tpgs + (tPROG × 64) ≤ tHV max.
——
4ms
FLASH row erase endurance(6)
6. The minimum row endurance value specifies each row of the FLASH memory is guaranteed to work for at
least this many erase / program cycles.
—
10k
100k(7)
7. FLASH endurance is a function of the temperature at which erasure occurs. Typical endurance degrades when the tem-
perature while erasing is less than 25
°C.
—
Cycles
FLASH row program endurance(8)
8. The minimum row endurance value specifies each row of the FLASH memory is guaranteed to work for at
least this many erase / program cycles.
—
10k
100k(7)
—
Cycles
FLASH data retention time(9)
9. The FLASH is guaranteed to retain data over the entire operating temperature range for at least the minimum
time specified.
—
10
100(10)
10. Motorola performs reliability testing for data retention. These tests are based on samples tested at elevated temperatures.
Due to the higher activation energy of the elevated test temperature, calculated life tests correspond to more than 100
years of operation/storage at 55
°C
—
Years
Notes: