Maximum Ratings
Operating Temperature….0oC to 70oC
Storage Temperature…….0oC to 70oC
Soldering Temperature
And Time………………….260oC for 10 sec
Supply Voltage…………….0V to 7.0V
Input Voltage………………-0.5V to 7.0V
Input/ Output Voltage…….-0.5V to Vcc + 0.3V
Power Dissipation…………1.0W
Parameter Symbol Min. Typ Max. Unit
Supply Voltage Vcc 4.5 5.0 5.5 V
Gnd 0 - 0 V
Input Voltage VIH 2.2 3.5 Vcc
+0.3 V
VIL 0 - 0.8 V
Recommended D.C. Operating Conditions
DATA RETENTION
The IM 1245Y-100 provides full functional ca-
pability for Vcc greater than 4.5V and write protects at
4.25V. Data is retained in the absence of Vcc without
any additional support circuitry. The SRAM constantly
monitors Vcc. The moment Vcc decays, the RAM au-
tomatically write protects itself. All inputs to the RAM
become “don’t care” and all outputs are in high imped-
ance-state. As Vcc falls below approximately 3.0V the
power switching circuit connects the lithium energy
source to RAM to retain data. During power-on, when
Vcc rises above approximately 3.0V the power switch-
ing circuit connects external Vcc to the RAM and dis-
connects the lithium energy source. Normal RAM op-
eration can resume after Vcc becomes greater than
4.5V.
READ MODE
The IM 1245Y-100 performs a read cycle when-
ever WE high and CE low. The unique address speci-
fied by the 17 address inputs A0-A16 defines which of
the 131,072 bytes of data is to be accessed. Valid data
will be available to the eight data output drivers within
access time tACC after the last address input is stable,
provided that CE and OE access times are satisfied. If
OE or CE access times are not satisfied, data access
will be measured from the limiting parameter (tCO or tOE),
rather than address. The state of the eight data I/O
lines is controlled by the OE and CE control signals.
The data lines may be in an indeterminate state be-
tween tOH and tAA but the data lines will always have
valid data at tAA.
WRITE MODE
The IM 1245Y-100 is in the write mode whenever CE
and WE inputs are held low . The latter occurring falling
edge of either CE or WE determines the start of a write
cycle. A write is terminated by the earlier rising edge of
CE or WE. The address must be held valid throughout
the write cycle. WE must return to the high state for a
minimum recovery time (tWR) before another Read or
Write cycle can be initiated. CE or WE is high during
power on to perfect memory after Vcc reaches Vcc (min)
but before the processor stabilizes
.
FRESHNESS SEAL AND SHIPPING
The IM1245Y - 100 is shipped from INNOVATIVE
MICROTECHONOLOGY INC. with the lithium energy
source disconnected , guaranteeing full energy capac-
ity. When Vcc is first applied at a level of greater than
4.5 volts, the lithium energy source is enabled for bat-
tery back-up operation.
INNOVATIVE IM1245Y-100
128K X 8 NO POWER SRAM