M27C801-100B1 Ver la hoja de datos (PDF) - STMicroelectronics
Número de pieza
componentes Descripción
Fabricante
M27C801-100B1 Datasheet PDF : 24 Pages
| |||
Device description
2
Device description
M27C801
The operating modes of the M27C801 are listed in the Operating Modes table. A single
power supply is required in Read mode. All inputs are TTL levels except for GVPP and 12V
on A9 for Electronic Signature and Margin Mode Set or Reset.
Table 2. Operating modes (1)
Mode
E
Read
Output Disable
Program
Program Inhibit
Standby
Electronic signature
1. X = VIH or VIL, VID = 12 V ± 0.5 V.
VIL
VIL
VIL Pulse
VIH
VIH
VIL
GVpp
VIL
VIH
VPP
VPP
X
VIL
A9
Q7-Q0
X
Data Out
X
Hi-Z
X
Data In
X
Hi-Z
X
Hi-Z
VID
Codes
2.1
Read mode
The M27C801 has two control functions, both of which must be logically active in order to
obtain data at the outputs. Chip Enable (E) is the power control and should be used for
device selection. Output Enable (G) is the output control and should be used to gate data to
the output pins, independent of device selection. Assuming that the addresses are stable,
the address access time (tAVQV) is equal to the delay from E to output (tELQV). Data is
available at the output after a delay of tGLQV from the falling edge of G, assuming that E has
been low and the addresses have been stable for at least tAVQV-tGLQV.
2.2
Standby mode
The M27C801 has a standby mode which reduces the supply current from 35mA to 100µA.
The M27C801 is placed in the standby mode by applying a CMOS high signal to the E input.
When in the standby mode, the outputs are in a high impedance state, independent of the
GVPP input.
2.3
Two-line output control
Because EPROMs are usually used in larger memory arrays, the product features a 2 line
control function which accommodates the use of multiple memory connection. The two line
control function allows:
● the lowest possible memory power dissipation,
● complete assurance that output bus contention will not occur.
For the most efficient use of these two control lines, E should be decoded and used as the
primary device selecting function, while G should be made a common connection to all
devices in the array and connected to the READ line from the system control bus. This
8/24
Share Link: 