PCF2129T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF2129T' PDF : 73 Pages View PDF
NXP Semiconductors
PCF2129T
Accurate RTC with integrated quartz crystal for industrial
8.4 Register Aging_offset
Table 12. Aging_offset - crystal aging offset register (address 19h) bit description
Bit Symbol
Value
Description
7 to 4 -
-
unused
3 to 0 AO[3:0]
see Table 13 aging offset value
8.4.1 Crystal aging correction
The PCF2129T has an offset register Aging_offset to correct the crystal aging effects2.
The accuracy of the frequency of a quartz crystal depends on its aging. The aging offset
adds an adjustment, positive or negative, in the temperature compensation circuit which
allows correcting the aging effect.
At 25 C, the aging offset bits allow a frequency correction of typically 1 ppm per AO[3:0]
value, from 7 ppm to +8 ppm.
Table 13.
AO[3:0]
Decimal
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Frequency correction at 25C, typical
Binary
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
ppm
+8
+7
+6
+5
+4
+3
+2
+1
[1]
0
1
2
3
4
5
6
7
[1] Default value.
2. For further information, refer to the application note Ref. 3 “AN11186”.
PCF2129T
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 3 — 12 February 2013
© NXP B.V. 2013. All rights reserved.
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