Rainbow Electronics DS1558Y User Manual
Ds1558 watchdog clock with nv ram control, Features, Ordering information
1 of 18
072402
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here:
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.