3
REV. 2.0, AUG. 27, 2003
P/N: PM0708
MX27C2000A
is the output control and should be used to gate data to
the output pins, independent of device selection.
Assuming that addresses are stable, address access
time (tACC) is equal to the delay from CE to output (tCE).
Data is available at the outputs tOE after the falling edge
of OE, assuming that CE has been LOW and addresses
have been stable for at least tACC - tOE.
STANDBY MODE
The MX27C2000A has a CMOS standby mode which
reduces the maximum VCC current to 100 uA. It is
placed in CMOS standby when CE is at VCC
±
0.3 V. The
MX27C2000A also has a TTL-standby mode which
reduces the maximum VCC current to 1.5 mA. It is
placed in TTL-standby when CE is at VIH. When in
standby mode, the outputs are in a high-impedance
state, independent of the OE input.
TWO-LINE OUTPUT CONTROL FUNCTION
To accommodate multiple memory connections, a two-
line control function is provided to allow for:
1. Low memory power dissipation,
2. Assurance that output bus contention will not
occur.
It is recommended that CE be decoded and used as the
primary device-selecting function, while OE be made a
common connection to all devices in the array and
connected to the READ line from the system control bus.
This assures that all deselected memory devices are in
their low-power standby mode and that the output pins
are only active when data is desired from a particular
memory device.
SYSTEM CONSIDERATIONS
During the switch between active and standby
conditions, transient current peaks are produced on the
rising and falling edges of Chip Enable. The magnitude
of these transient current peaks is dependent on the
output capacitance loading of the device. At a minimum,
a 0.1 uF ceramic capacitor (high frequency, low inherent
inductance) should be used on each device between Vcc
and GND to minimize transient effects. In addition, to
overcome the voltage drop caused by the inductive
effects of the printed circuit board traces on EPROM
arrays, a 4.7 uF bulk electrolytic capacitor should be
used between VCC and GND for each eight devices. The
location of the capacitor should be close to where the
power supply is connected to the array.
NOTES:
1.VH = 12.0 V
±
0.5 V
2.X = Either VIH or VIL
3.A1 - A8 = A10 - A17 = VIL(For auto select)
4.See DC Programming Characteristics for VPP voltage during programming.
MODE SELECT TABLE
PINS
A0
X
X
X
X
X
X
X
VIL
VIH
MODE
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Manufacturer Code(3)
Device Code(3)
CE
VIL
VIL
VIH
VCC
±
0.3V
VIL
VIL
VIH
VIL
VIL
OE
VIL
VIH
X
X
VIH
VIL
X
VIL
VIL
PGM
X
X
X
X
VIL
VIH
X
X
X
A9
X
X
X
X
X
X
X
VH
VH
VPP
VCC
VCC
VCC
VCC
VPP
VPP
VPP
VCC
VCC
OUTPUTS
DOUT
High Z
High Z
High Z
DIN
DOUT
High Z
C2H
C3H