Rainbow Electronics DS1687 - Manual (Page 31)

DS1685/DS1687
31 of 38
RTC AC TIMING CHARACTERISTICS
(V
CC
= 5.0V±10%, 0°C to +70°C, -40°C to 85°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Cycle Time t
CYC
195 DC ns
Pulse Width, RD / WR Low PW
RWL
75 ns
Pulse Width, RD / WR High PW
RWH
75 ns
Input Rise and Fall Time t
R
, t
F
30 ns
Chip-Select Setup Time
Before
WR , or RD
t
CS
20 ns
Chip-Select Hold Time t
CH
0 ns
Read-Data Hold Time t
DHR
10 50 ns
Write-Data Hold Time t
DHW
0 ns
Muxed Address Valid Time
to ALE Fall
t
ASL
30 ns
Muxed Address Hold Time
from ALE Fall
t
AHL
15 ns
RD or WR High Setup to
ALE Rise
t
ASD
25 ns
Pulse-Width ALE High PW
ASH
40 ns
ALE Low Setup to RD or
WR Fall
t
ASED
30 ns
Output-Data Delay Time
from
RD
t
DDR
20 60 ns 7
Data Setup Time t
DSW
60 ns
IRQ Release from RD
t
IRD
2 ms
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