M48T512Y-85PM1 STMICROELECTRONICS [STMicroelectronics], M48T512Y-85PM1 Datasheet - Page 13

• Manufacturer Part Number: M48T512Y-85PM1
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M48T512Y, M48T512V
Figure 7.
Figure 8.
NORMAL
POSITIVE
CALIBRATION
NEGATIVE
CALIBRATION
Frequency (ppm)
–100
–120
–140
–160
–20
–40
–60
–80
20
One method for ascertaining how much calibration a given M48T512Y/V may require
involves setting the clock, letting it run for a month and comparing it to a known accurate
reference and recording deviation over a fixed period of time.
Calibration values, including the number of seconds lost or gained in a given period, can be
found in STMicroelectronics’ application note AN934, “TIMEKEEPER
allows the designer to give the end user the ability to calibrate the clock as the environment
requires, even if the final product is packaged in a non-user serviceable enclosure. The
designer could provide a simple utility that accesses the calibration bits. For more
information on calibration see application note AN934, “TIMEKEEPER
ST website.
Crystal accuracy across temperature
Calibration waveform
0
–40
–30
–20
–10
0
Doc ID 5747 Rev 6
10
Temperature °C
ΔF = -0.038
F
20
T
30
0
ppm
= 25 °C
C
2
(T - T
40
0
)
2
50
± 10%
60
70
®
®
calibration.” This
calibration” on the
Clock operations
80
AI00594B
AI00999
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