W27C512-45 Winbond Electronics, W27C512-45 Datasheet - Page 6

• Manufacturer Part Number: W27C512-45
• Manufacturer: Winbond Electronics

Specifications of W27C512-45

• Density: 512Kb
• Interface Type: Parallel
• Organization: 64Kx8
• Access Time (max): 45ns
• Write Protection: No
• Operating Supply Voltage (typ): 5V
• Package Type: PDIP
• Operating Temp Range: 0C to 70C
• Supply Current: 30mA
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (max): 5.25V
• Operating Temperature Classification: Commercial
• Mounting: Through Hole
• Pin Count: 28
• Lead Free Status / Rohs Status: Not Compliant

W27C512
Standby Mode
The standby mode significantly reduces V
current. This mode is entered when CE high. In standby
CC
mode, all outputs are in a high impedance state, independent of OE /V
.
PP
Two-line Output Control
Since EPROMs are often used in large memory arrays, the W27C512 provides two control inputs for
multiple memory connections. Two-line control provides for lowest possible memory power dissipation
and ensures that data bus contention will not occur.
System Considerations
An EPROM's power switching characteristics require careful device decoupling. System designers are
interested in three supply current issues: standby current levels (I
), active current levels (I
), and
SB
CC
transient current peaks produced by the falling and rising edges of CE . Transient current magnitudes
depend on the device output's capacitive and inductive loading. Two-line control and proper
decoupling capacitor selection will suppress transient voltage peaks. Each device should have a 0.1 μ
F ceramic capacitor connected between its V
and GND. This high frequency, low inherent-
CC
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 V
and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
CC
inductances.
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