W27C520 Datasheet, PDF (3/16 Pages) Winbond – 64K X 8 ELECTRICALLY ERASABLE EPROM

Preliminary W27C520
System Considerations
An EPROM's power switching characteristics require careful device decoupling. System designers are
interested in three supply current issues: standby current levels (ISB), active current levels (IDD), 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 µF ceramic capacitor connected between its VDD 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 µF electrolytic capacitor should be placed at the array's power supply connection
between VDD and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
inductances.
TABLE OF OPERATING MODES
(VPP = 13V, VPE = 13V, VHH = 12V, VDP = 6.5V, VDE = 6.5V, VDD = 3.3V or 5.0V, VDI = 5.0V, X = VIH or VIL)
MODE
PIN
ALE _{OE /VPP}
OTHER ADDRESS
VDD
Address Latch Enable
VIH
VIH
AIN
VDD
Read
VIL
VIL
AIN
VDD
Output Disable
VIL/
VIH
VIH
X
VDD
Standby
VIH
VIH
X
VDD
Program
VIH
VPP
AIN
VDP
Erase 1
VIH
VPE
A8&A11 = VIL, A9 = VPE,
VDE
A10 = VIH, Others = X
Erase 2
VIH
VPE
First command:
VDE
Addr. = 5555 (hex)
Second command:
VDE
Addr. = 2AAA (hex)
Product Identifier-
manufacturer
VIL
VIL
A8 = VIL, A9 = VHH, Others = X VDI
Product Identifier-device VIL
VIL
A8 = VIH, A9 = VHH, Others = X VDI
AD[7:0]
A[7:0]
DOUT
High Z
A[7:0]
DIN
X
AA(hex)
10(hex)
DA(Hex)
1F(Hex)
Publication Release Date: October 2000
-3-
Revision A1