Table of operating modes – Rainbow Electronics W27E520 User Manual
Page 3
Advance Information W27E520
Publication Release Date: 4/26/2000
- 3 -
Revision A1
An EPROM's power switching characteristics require careful device decoupling. System designers are
interested in three supply current issues: standby current levels (I
SB
), active current levels (I
DD
), and
transient current peaks produced by the falling and rising edges of ALE Transient current magnitudes
depend on the device output's capacitive and inductive loading. Proper decoupling capacitor selection
will suppress transient voltage peaks. Each device should have a
0.1
µ
F ceramic capacitor connected between its V
DD
and GND. This high frequency, low inherent-
inductance capacitor should be placed as close as possible to the device. Additionally, for every eight
devices, a 4.7
µ
F electrolytic capacitor should be placed at the array's power supply connection
between V
DD
and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
inductances.
TABLE OF OPERATING MODES
(V
PP
= 13V, V
PE
= 13V, V
HH
= 12V, V
DP
= 6.5V, V
DE
= 6.5V, V
DD
= 5.0V, V
DI
= 5.0V, X = V
IH
or V
IL
)
MODE
PIN
ALE
OE /V
PP
OTHER ADDRESS
V
DD
AD[7:0]
Address Latch Enable
V
IH
V
IH
X
V
DD
A[7:0]
Read
V
IL
V
IL
A
IN
V
DD
D
OUT
Output Disable
V
IL
V
IH
X
V
DD
High Z
Standby
V
IH
V
IH
A
IN
V
DD
A[7:0]
Program
V
IH
V
PP
A
IN
V
DP
D
IN
Erase 1
V
IH
V
PE
A8&A11 = V
IL
, A9 = V
PE
,
A10 = V
IH
, Others = X
V
DE
X
Erase 2
V
IH
V
PE
First command:
Addr. = 5555 (hex)
V
DE
AA(hex)
Secon command:
Addr. = 2AAA (hex)
V
DE
10(hex)
Product Identifier-
manufacturer
V
IL
V
IL
A8 = V
IL
, A9 = V
HH
, Others = X
V
DI
DA(Hex)
Product Identifier-device
V
IL
V
IL
A8 = V
IH
, A9 = V
HH
, Others = X
V
DI
1F(Hex)