NXP Semiconductors MC9S12G - Page 383

S12 Clock, Reset and Power Management Unit (S12CPMU)
MC9S12G Family Reference Manual Rev.1.27
NXP Semiconductors 385
Figure 10-26. Influence of TCTRIM[4:0] on the Temperature Coefficient
NOTE
The frequency is not necessarily linear with the temperature (in most cases
it will not be). The above diagram is meant only to give the direction
(positive or negative) of the variation of the TC, relative to the nominal TC.
Setting TCTRIM[4:0] to 0b00000 or 0b10000 does not mean that the
temperature coefficient will be zero. These two combinations basically
switch off the TC compensation module, which results in the nominal TC of
the IRC1M.
TCTRIM[4:0]
IRC1M indicative
relative TC variation
IRC1M indicative frequency drift
for relative TC variation
00000 0 (nominal TC of the IRC) 0%
00001 -0.27% -0.5%
00010 -0.54% -0.9%
00011 -0.81% -1.3%
00100 -1.08% -1.7%
00101 -1.35% -2.0%
00110 -1.63% -2.2%
frequency
temperature
T
C
T
R
IM
[
4
:
0
]
=
0
b
1
1
1
1
1
T
C
T
R
I
M
[
4
:
0
]
=
0
b
0
1
1
1
1
- 40C
150C
TCTRIM[4:0] = 0b10000 or 0b00000 (nominal TC)
0b00001
0b00010
0b00011
0b00100
0b00101
...
0b01111
0b11111
...
0b10101
0b10100
0b10011
0b10010
0b10001
TC increases
TC decreases