Rainbow Electronics DS17487 - Manual (Page 28)

DS17485/DS17487
28 of 38
RTC AC TIMING CHARACTERISTICS Over the operating range (5V)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Cycle Time t
CYC
240 DC ns
Pulse-Width, RD / WR Low PW
RWL
120 ns
Pulse-Width, RD / WR High PW
RWH
80 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
20 ns
Muxed Address Hold Time to
ALE fall
t
AHL
10 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
20 120 ns 6
Data Setup Time t
DSW
30 ns
IRQ Release from RD
t
IRD
2 ms
AC TEST CONDITIONS
Output Load: 50pF
Input Pulse Levels: 0V to 3.0V
Timing Measurement Reference Levels
Input:
1.5V
Output: 1.5V
Input Pulse Rise and Fall Times: 5ns