
40 MHz (Continued)
AC Electrical Characteristics (Continued)
See Notes 1 and 4 and
Figure 1 thru Figure 5 ) VCC e 50V g10% unless otherwise specified TA e 25 C one wait state
Symbol
Parameter
Min
Max
Units
EXTERNAL HOLD
tSALE e 075 tC a 40
HLD Falling Edge before ALE Rising Edge
775
ns
tHWP e 075 tC a 35
HLD Pulse Width
725
ns
tHAE e 075 tC a 100
HLDA Falling Edge after HLD Falling Edge (Note 3)
1375
ns
tHAD e 075 tC a 85
HLDA Rising Edge after HLD Rising Edge
1225
ns
tBF
Bus TRI-Stated after HLDA Falling Edge (Note 5)
70
ns
tBE e 075 tC a 30
Bus Enable after HLDA Rising Edge
675
ns
NATIVE BUS TIMING ADDRESS CYCLE
tLL e 05 tC b10
ALE Pulse Width
15
ns
t1ALR
ALE Rising Edge after CK1 Rising Edge (Note 2)
0
35
ns
t1ALF
ALE Falling Edge after CK1 Falling Edge (Note 2)
0
35
ns
t2ALR e 025 tC a 20
ALE Rising Edge after CK2 Rising Edge
325
ns
t2ALF 025 tC a 20
ALE Falling Edge after CK2 Falling Edge
325
ns
tST e 025 tC b 9
Address Valid to ALE Falling Edge
35
ns
tVP e 05 tC b 10
Address Hold after ALE Falling Edge
15
ns
READ CYCLE
tRW e 025 tC a WS b 15
RD Pulse Width
475
ns
tARD e 075 tC b 20
Address Valid to RD Falling Edge
175
ns
tARR e 05 tC b 20
ALE Falling Edge to RD Falling Edge
5
ns
tRD e 025 tC a WS b 20
RD Falling Edge to Input Data Valid
425
ns
tDR
Data Hold after RD Rising Edge
0
50
ns
tACC e tC a WS b 20
Address Valid to Input Data Valid
80
ns
WRITE CYCLE
tWW e 075 tC a WS b 15
WR Pulse Width
725
ns
tV e 05 tC a WS b 20
Data Valid before WR Rising Edge
55
ns
tHW e 05 tC b 10
Data Hold after WR Rising Edge
15
ns
tAWR e 075 tC b 20
Address Valid to WR Falling Edge
175
ns
READY INPUT
tRDYS
RDY Falling Edge before CK2 Falling Edge
45
ns
tRDYH
RDY Rising Edge after CK2 Falling Edge
0
ns
tRDYV e WS a 025 tC b 30
RDY Falling Edge after RD or WR Falling Edge
325
ns
CHIP SELECT NATIVE BUS TIMING
tCS30RD e 075 tC b 30
CS3 CS0 Valid to RD Falling Edge
75
ns
tACCS30 e tC a WS b 30
CS3 CS0 Valid to Input Data Valid
70
ns
tCS21RD e 075 tC b 35
CS2 CS1 Valid to RD Falling Edge
25
ns
tACCS21 e tC a WS b 35
CS2 CS1 Valid to Input Data Valid
65
ns
tCSHR e tC b 15
Chip Select Hold after RD Rising Edge
35
ns
tCS30WR e 075 tC b 30
CS3 CS0 Valid to WR Falling Edge
75
ns
tCS21WR e 075 tC b 35
CS2 CS1 Valid to WR Falling Edge
25
ns
tCSHW e 05 tC b 15
Chip Select Hold after WR Rising Edge
10
ns
4