Packages – Rainbow Electronics DS1554 User Manual
Page 3
DS1554
3 of 20
The DS1554 also contains its own power-fail circuitry, which automatically deselects the device when the
V
CC
supply enters an out of tolerance condition. This feature provides a high degree of data security
during unpredictable system operation brought on by low V
CC
levels.
PACKAGES
The DS1554 is available in two packages (32-pin DIP and 34-pin PowerCap module). The 32-pin DIP
style module integrates the crystal, lithium energy source, and silicon all in one package. The 34-pin
PowerCap module board is designed with contacts for connection to a separate PowerCap (DS9034PCX)
that contains the crystal and battery. This design allows the PowerCap to be mounted on top of the
DS1554P after the completion of the surface mount process. Mounting the PowerCap after the surface
mount process prevents damage to the crystal and battery due to the high temperatures required for solder
reflow. The PowerCap is keyed to prevent reverse insertion. The PowerCap Module board and PowerCap
are ordered separately and shipped in separate containers. The part number for the PowerCap is
DS9034PCX.
DS1554 BLOCK DIAGRAM Figure 1
DS1554 OPERATING MODES Table 1
V
CC
CE
OE
WE
DQ0-DQ7
MODE
POWER
V
IH
X
X
HIGH-Z
DESELECT
STANDBY
V
IL
X
V
IL
D
IN
WRITE
ACTIVE
V
IL
V
IL
V
IH
D
OUT
READ
ACTIVE
V
CC
> V
PF
V
IL
V
IH
V
IH
HIGH-Z
READ
ACTIVE
V
SO
< V
CC
<V
PF
X
X
X
HIGH-Z
DESELECT
CMOS STANDBY
V
CC
<V
SO
< V
PF
X
X
X
HIGH-Z
DATA
RETENTION
BATTERY
CURRENT