Rainbow Electronics DS1558Y User Manual
Ds1558 watchdog clock with nv ram control, Features, Ordering information

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072402
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FEATURES
§ Integrated real-time clock (RTC), power-fail
control circuit, and NV RAM controller
§ Clock registers are accessed identically to the
static RAM; these registers are resident in the
16 top RAM locations
§ Century register
§ Greater than 10 years of timekeeping and data
retention in the absence of power with small
lithium coin cell(s) and low- leakage SRAM
§ Precision power-on reset
§ Programmable watchdog timer and RTC
alarm
§ BCD-coded year, month, date, day, hours,
minutes, and seconds with automatic leap-
year compensation valid up to the year 2100
§ Battery voltage-level indicator flag
§ Power-fail write protection allows for
±
10%
V
CC
power-supply tolerance
§ Underwriters Laboratory (UL) recognized
ORDERING INFORMATION
PART
PIN-
PACKAGE
V
CC
(V)
TOP
MARK
DS1558Y
48 TQFP
5
DS1558B
DS1558W
48 TQFP
3.3
DS1558D
PIN ASSIGNMENT (Top View)
Package Dimension Information
PIN DESCRIPTION
A0–A18
- Address Input
DQ0–DQ7
- Data Input/Outputs
IRQ
\FT
- Interrupt, Frequency- Test
Output (Open Drain)
RST
- Power-On Reset Output
(Open Drain)
CE
- Chip- Enable Input
CER
- Chip- Enable RAM
OE
- Output-Enable Input
OER
- Output-Enable RAM
WE
- Write Enable
V
CC
- Power-Supply Input
V
CCO
- V
CC
Out to RAM
GND
- Ground
N.C.
- No Connection
X1, X2
- Crystal Connection
V
BAT1
- +3V Battery Input
V
BAT2
- +3V Battery Input
DS1558
Watchdog Clock with
NV RAM Control
www.maxim-ic.com
www.maxim-ic.com
A18
A16
A12
A6
A4
A3
A2
A1
A5
A7
A14
N.C.
VCCO
1
2
3
4
5
6
7
8
10
12
35
36
VCC
N.C.
A16
GND
RST
NC
N.C.
DQ0
DQ1
DQ
2
DQ6
VBAT1
WE
IRQ/FT
A8
OE
A10
CE
X1
GND
VBAT
2
A15
A13
OER
A9
A11
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
11
9
48
47
46
45
44
43
42
41
40
39
38
37
CER
DQ7
DQ5
DQ4
DQ3
GND
A0
DS1558
X2
N.C.