DS1558W Maxim Integrated Products, DS1558W Datasheet - Page 2

• Manufacturer Part Number: DS1558W
• Description: IC RTC W/NV RAM 3.3V 48-LQFP
• Manufacturer: Maxim Integrated Products
• Type: Watchdog Timer/NVSRAMr

Specifications of DS1558W

• Time Format: HH:MM:SS (24 hr)
• Date Format: YY-MM-DD-dd
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Memory Size: -

PIN DESCRIPTION
1, 13, 39
18, 45,
41, 43
PIN
10
11
12
14
27
29
30
31
32
36
44
15
16
17
19
20
21
22
23
48
24
25
26
28
33
34
2
3
4
5
6
7
8
9
IRQ/FT
NAME
GND
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
CER
OER
N.C.
A18
A16
A14
A12
A10
A11
A13
A15
A17
WE
OE
A7
A6
A5
A4
A3
A2
A1
A0
A9
A8
CE
Address Inputs fo
whether or not a
RTC registers.
Data Input/Outputs. Data input/output pins for the RTC registers.
Active-Low Chip-Enable RAM. CE is passed through to CER, with an added
propagation delay. When the signals on A0–A18 match an RTC address, CER is held
high, disabling the SRAM. If OE is also low, the RTC outputs data on DQ0–DQ7.
Active-Low Output-Enable RAM. OE is passed through to OER, with an added
propagation delay. When the signals on A0–A18 match an RTC address, CER is held
high, disabling the SRAM. If CE is also low, the RTC outputs data on DQ0–DQ7.
Active-Low Chip-Enable Input. Used to access the RTC and the external SRAM.
Active-Low Output-Enable Input. Used to access the RTC and the external SRAM.
Active-Low Interrupt/Frequency-Test Output. This pin is used to output the alarm
interrupt or the frequency test signal. It is open drain and requires an external pullup
resistor.
Active-Low Write Enable. Used to write data to the RTC registers.
No Connection
Ground
read o write cycle should
r Ad ess Decode. T e
dr
r
2 of 18
FUNCTION
h DS1558 uses the address
be dire
cted to the attached SRAM or to the
inputs to determine