m41t81 STMicroelectronics, m41t81 Datasheet - Page 16

• Manufacturer Part Number: m41t81
• Description: Serial Access Real-time Clock With Alarms
• Manufacturer: STMicroelectronics

Clock operation
16/30
The IRQ/FT/OUT/SQW pin is an open drain output which requires a pull-up resistor to V
for proper operation. A 500-10k resistor is recommended in order to control the rise time.
The FT Bit is cleared on power-down.
Figure 10. Crystal accuracy across temperature
Figure 11. Clock calibration
Frequency (ppm)
NORMAL
POSITIVE
CALIBRATION
NEGATIVE
CALIBRATION
–100
–120
–140
–160
–20
–40
–60
–80
20
0
–40
–30
–20
–10
0
10
Temperature °C
∆F = K x (T – T
F
K
= –0.036 ppm/°C
20
T
30
O
= 25°C ± 5°C
O
)
2
40
2
± 0.006 ppm/°C
50
60
2
70
80
AI07888
M41T81
AI00594B
CC