Rainbow Electronics DS1644P - Manual

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FEATURES
Integrated NV SRAM, real time clock,
crystal, power-fail control circuit and lithium
energy source
Clock registers are accessed identically to the
static RAM. These registers are resident in
the eight top RAM locations.
Totally nonvolatile with over 10 years of
operation in the absence of power
BCD coded year, month, date, day, hours,
minutes, and seconds with leap year
compensation valid up to 2100
Power-fail write protection allows for ±10%
V
CC
power supply tolerance
DS1644 only (DIP Module)
−
Upward compatible with the DS1643
Timekeeping RAM to achieve higher RAM
density
−
Standard JEDEC bytewide 32k x 8 static
RAM pinout
DS1644P only (PowerCap
®
Module Board)
−
Surface mountable package for direct
connection to PowerCap containing battery
and crystal
−
Replaceable battery (PowerCap)
−
Power-fail output
−
Pin-for-pin compatible with other densities
of DS164XP Timekeeping RAM
PIN ASSIGNMENT
PIN DESCRIPTION
A0-A14 - Address Input
CE - Chip Enable
OE - Output Enable
WE - Write Enable
V
CC
- +5V
GND - Ground
DQ0-DQ7 - Data Input/Output
NC - No Connection
PFO - Power-fail Output
(DS1644P only)
X1, X2 - Crystal Connection
V
BAT
- Battery Connection
15
DS1644/DS1644P
Nonvolatile Timekeeping RAM
www.dalsemi.com
13
27
28-Pin Encapsulated Package (720-mil
Extended)
A7
A5
A3
A2
A1
A0
DQ0
DQ1
GND
DQ2
VCC
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ3
DQ4
1
2
3
4
5
6
7
8
9
10
11
12
14
28
26
25
24
23
22
21
20
19
18
17
16
A12
A6
A4
A14
1 NC
2
3 NC
NC
PFO
V
CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
4
5
6
7
8
9
10
11
12
13
14
15
16
17
NC
A14 33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
34 NC
X1 GND V
BAT
X2
34-Pin PowerCap Module Board
(Uses DS9034PCX PowerCap)
A12