W27C512 Datasheet, PDF (3/15 Pages) Winbond – 64K X 8 ELECTRICALLY ERASABLE EPROM

W27C512
Standby Mode
The standby mode significantly reduces VCC current. This mode is entered when CE high. In standby
mode, all outputs are in a high impedance state, independent of OE /VPP.
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 (ISB), active current levels (ICC), and
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 VCC 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 VCC and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
inductances.
TABLE OF OPERATING MODES
(VPP = 12V, VPE = 14V, VHH = 12V, VCP = 5V, VCE = 5V, X = VIH or VIL)
MODE
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Erase
Erase Verify
Erase Inhibit
Product Identifier-manufacturer
Product Identifier-device
CE
VIL
VIL
VIH
VCC ±0.3V
VIL
VIL
VIH
VIL
VIL
VIH
VIL
VIL
OE /VPP
VIL
VIH
X
X
VPP
VIL
VPP
VPE
VIL
VPE
VIL
VIL
PINS
A0 A9
X
X
X
X
X
X
X
X
X
X
X
X
X
X
VIL VPE
X
X
X
X
VIL VHH
VIH VHH
VCC OUTPUTS
VCC DOUT
VCC High Z
VCC High Z
VCC High Z
VCP DIN
VCC
VCP
VCE
DOUT
High Z
DIH
3.75 DOUT
VCE High Z
VCC DA (Hex)
VCC 08 (Hex)
Publication Release Date: November 1999
-3-
Revision A4