Datasheet

Electrical Specifications
MC68HC908QB8 Data Sheet, Rev. 3
226 Freescale Semiconductor
18.17 Memory Characteristics
Characteristic Symbol Min
Typ
(1)
1. Typical values are for reference only and are not tested in production.
Max Unit
RAM data retention voltage
(2)
2. Values are based on characterization results, not tested in production.
V
RDR
1.3 — — V
FLASH program bus clock frequency — 1 — — MHz
FLASH PGM/ERASE supply voltage (V
DD
)V
PGM/ERASE
2.7 — 5.5 V
FLASH read bus clock frequency f
Read
(3)
3. f
Read
is defined as the frequency range for which the FLASH memory can be read.
0—8 MHz
FLASH page erase time
<1 K cycles
>1 K cycles
t
Erase
0.9
3.6
1
4
1.1
5.5
ms
FLASH mass erase time t
MErase
4——ms
FLASH PGM/ERASE to HVEN setup time t
NVS
10 — — μs
FLASH high-voltage hold time t
NVH
5——μs
FLASH high-voltage hold time (mass erase) t
NVHL
100 — — μs
FLASH program hold time t
PGS
5——μs
FLASH program time t
PROG
30 — 40 μs
FLASH return to read time t
RCV
(4)
4. t
RCV
is defined as the time it needs before the FLASH can be read after turning off the high voltage charge pump, by clear-
ing HVEN to 0.
1——μs
FLASH cumulative program HV period t
HV
(5)
5. t
HV
is defined as the cumulative high voltage programming time to the same row before next erase.
t
HV
must satisfy this condition: t
NVS
+ t
NVH
+ t
PGS
+ (t
PROG
x 32) ≤ t
HV
maximum.
—— 4ms
FLASH endurance
(6)
6. Typical endurance was evaluated for this product family. For additional information on how Freescale Semiconductor
defines Typical Endurance, please refer to Engineering Bulletin EB619.
— 10 k 100 k — Cycles
FLASH data retention time
(7)
7. Typical data retention values are based on intrinsic capability of the technology measured at high temperature and de-rated
to 25•C using the Arrhenius equation. For additional information on how Freescale Semiconductor defines Typical Data
Retention, please refer to Engineering Bulletin EB618.
— 15 100 — Years