U634H256
PowerStore and Automatic Power Up RECALL
VCAP
5.0 V
VSWITCH
t
PowerStore
p
tPDSTORE
Power Up
(24)
(24)
RECALL
tRESTOR
tRESTORE
E
W
p
tDELAY
DQi
BROWN OUT
BROWN OUT
POWER UP
RECALL
NO STORE
(NO SRAM WRITES)
PowerStore
Hardware Controlled STORE
q
tw(H)S
(28)
HSB
DQi
t
en(H)S (27)
tdis(H)S
(26)
High Impedance
Previous Data Valid
Data Valid
Output
td(H)S
(25)
Symbol
25
35
45
Software Controlled STORE/RECALL
Cycle
No.
Unit
Alt.
tAVAV
tELQZ
IEC
Min. Max. Min. Max. Min. Max.
29 STORE/RECALL Initiation Time
30 Chip Enable to Output Inactives
31 STORE Cycle Time
tcR
25
35
45
ns
ns
ms
µs
ns
ns
ns
tdis(E)SR
td(E)S
600
10
600
10
600
10
tELQXS
tELQXR
tAVELN
tELEHN
tEHAXN
32 RECALL Cycle Timer
td(E)R
20
20
20
33 Address Setup to Chip Enablet
34 Chip Enable Pulse Widths, t
35 Chip Disable to Address Changet
tsu(A)SR
tw(E)SR
th(A)SR
0
20
0
0
25
0
0
30
0
p: tPDSTORE approximate td(E)S or td(H)S; tDELAY approximate tdis(H)S
.
q: After tw(H)S HSB is hold down internal by STORE operation.
r: An automatic RECALL also takes place at power up, starting when VCC exceeds VSWITCH and takes tRESTORE. VCC must not drop below
V
SWITCH once it has been exceeded for the RECALL to function properly.
s: Once the software controlled STORE or RECALL cycle is initiated, it completes automatically, ignoring all inputs.
t: Noise on the E pin may trigger multiple READ cycles from the same address and abort the address sequence.
8
April 21, 2004
ZMD [ Zentrum Mikroelektronik Dresden AG ]
