Preliminary W27LE520
Publication Release Date: June 2000
- 3 -
Revision A1
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
F 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
F 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
AD[7:0]
Address Latch Enable
VIH
X
VDD
A[7:0]
Read
VIL
AIN
VDD
DOUT
Output Disable
VIL
VIH
X
VDD
High Z
Standby
VIH
AIN
VDD
A[7:0]
Program
VIH
VPP
AIN
VDP
DIN
Erase 1
VIH
VPE
A8&A11 = VIL, A9 = VPE,
A10 = VIH, Others = X
VDE
X
Erase 2
VIH
VPE
First command:
Addr. = 5555 (hex)
VDE
AA(hex)
Secon command:
Addr. = 2AAA (hex)
VDE
10(hex)
Product Identifier-
manufacturer
VIL
A8 = VIL, A9 = VHH, Others = X
VDI
DA(Hex)
Product Identifier-device
VIL
A8 = VIH, A9 = VHH, Others = X
VDI
1F(Hex)