Epson RTC-72421 A Clock User Manual


 
RTC - 72421 / 72423
Page - 5 MQ - 162 - 03
Switching characteristics (AC characteristics)
1. When ALE is used
Write mode ( V
DD
=5 V
±
0.5 V, RTC-72421;Ta=
10
°
C to +70
°
C, RTC-72423;Ta=
40
°
C to +85
°
C )
Item Symbol Condition Min. Max. Unit
CS1 set-up time t
SU
(CS1) 1000
Address set-up time before ALE t
SU
(A-ALE) 50
Address hold time after ALE th(ALE-A) 50
ALE pulse width tw(ALE) 80
ALE set-up time before write t
SU
(ALE-W) 0
Write pulse width tw(W) 120 ns
ALE set-up time after write t
SU
(W-ALE) 50
Data input set-up time before write t
SU
(D-W) 80
Data input hold time after write th(W-D) 10
CS1 hold time th(CS1) 1000
Write recovery time trec(W) 200
Read mode ( V
DD
=5 V
±
0.5 V, RTC-72421;Ta=
10
°
C to +70
°
C, RTC-72423;Ta=
40
°
C to +85
°
C )
Item Symbol Condition Min. Max. Unit
CS1 set-up time t
SU
(CS1) 1000
Address set-up time before ALE t
SU
(A-ALE) 50
Address hold time after ALE th(ALE-A) 50
ALE pulse width tw(ALE) 80
ALE set-up time before read t
SU
(ALE-R) 0 ns
ALE set-up time after read t
SU
(R-ALE) 50
Data output transfer time after read t
PZV
(R-Q) C
L
=150 pF 120
Data output floating transfer time after read t
PVZ
(R-Q) 0 70
CS1 hold time th(CS1) 1000
Read recovery time trec(W) 200
(1) Write mode
VIH2
tsu(CS1)
tsu(A-ALE)
tw(ALE)
th(ALE-A)
tsu(ALE-W) tw(W)
VIH1
VIL1
VIH1
VIL1
VIH1
VIL1
VIH1
VIH1
VIL1 VIL1
VIH1
VIL1
tsu(W-ALE)
VIH1
VIL1
VIH1
VIL1
tsu(D-W)
th(W-D)
th(CS1)
VIH2
CS1
A0 to A3
CS0
ALE
D0 to D3
WR
(Input)
(2) Read mode
VIH2
tsu(CS1)
tsu(A-ALE)
tw(ALE)
th(ALE-A)
tsu(ALE-R)
VIH1
VIL1
VIH1
VIL1
VIH1
VIL1
VIH1
VIH1
VIL1 VIL1
VIH1
VIL1
tsu(R-ALE)
VIH1
VIL1
VIH1
VIL1
tpzv(R-Q)
)
tpvz(R-Q)
th(CS1)
VIH2
CS1
A0 to A3
CS0
ALE
D0 to D3
RD
(Input)