MAX6901 View Datasheet(PDF) - Maxim Integrated
Part Name
Description
Manufacturer
MAX6901 Datasheet PDF : 18 Pages
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3-Wire Serial RTC in a TDFN
CS
tCC
SCLK
tCDH
tDC
I/O
0
1
tCCZ
tCDD
tCDD
7
0
tCDZ
1
READ ADDRESS/COMMAND BYTE
Figure 4. 3-Wire Read Data Transfer Serial Timing Diagram
CS
tCC
SCLK
tCDH
tDC
I/O
0
tCL
tR
tCDH
1
7
READ DATA BIT
tCWH
tCCH
tF
0
WRITE ADDRESS/COMMAND BYTE
Figure 5. 3-Wire Write Data Transfer Serial Timing Diagram
WRITE DATA BIT
∆ttotal = ∆tdrift + ∆tinitial
∆ttotal = 0.00002+0.000025=0.000045s/s
After 1 month, that translates to:
( ) ∆t =
31days
×
24
hr
day
×
60
min
hr
×
60
s
min
×
(0.00045s /s) = 120.528s
Total worst-case timekeeping error at the end of 1
month at +45°C is about 120s or 2 min (assumes negli-
gible parasitic layout capacitance).
Oscillator Start Time
The MAX6901 oscillator typically takes 5s to 10s to
begin oscillating. To ensure the oscillator is operating
correctly, the software should validate proper time-
keeping. This is accomplished by reading the Seconds
register. Any reading of 1s or more from the POR value
of zero is a validation of proper startup.
Power-On Reset
The MAX6901 contains an integral POR circuit that
ensures all registers are reset to a known state on
power-up. Once V CC rises above 1.6V (typ), the POR
circuit releases the registers for normal operation. When
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