DS1685/DS1687 3V/5V Real-Time Clocks
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RTC AC TIMING CHARACTERISTICS
(
VCC = 3.0V±10%, TA = 0°C to +70°C, TA = -40°C to +85°C)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
NOTES
Cycle Time
4B
tCYC
260
DC
ns
Pulse Width, RD/WR Low
5B
PWRWL
100
ns
Pulse Width, RD/WR High
PWRWH
100
ns
Input Rise and Fall Time
tR, tF
30
ns
Chip-Select Setup Time
Before WR or RD
tCS
20
ns
Chip-Select Hold Time
tCH
0
ns
Read-Data Hold Time
tDHR
10
50
ns
Write-Data Hold Time
tDHW
0
ns
Muxed Address Valid Time to
ALE Fall
tASL
30
ns
Muxed Address Hold Time
from ALE Fall
tAHL
15
ns
RD
or WR High Setup to ALE
Rise
tASD
30
ns
Pulse-Width ALE High
PWASH
80
ns
ALE Low Setup to RD or WR
Fall
tASED
30
ns
Output-Data Delay Time from
RD
tDDR
20
80
ns
6
Data Setup Time
tDSW
60
ns
IRQ
Release from RD
tIRD
2
s
AC TEST CONDITIONS
Output Load: 50pF
Input Pulse Levels: 0 to 3.0V
Timing Measurement Reference Levels
Input : 1.5V
Output: 1.5V
Input Pulse Rise and Fall Times: 5ns