DS2404
EconoRAM Time Chip
www.maxim-ic.com
FEATURES
PIN ASSIGNMENT
4096 bits of nonvolatile dual-port memory
including real time clock/calendar in binary
format, programmable interval timer, and
programmable power-on cycle counter
1-Wire® interface for MicroLAN
communication at 16.3kbits/s
VCC
IRQ
RST
DQ
1
2
3
4
5
6
16
15
14
13
12
11
VCC
X1
X2
GND
NC
I/O
3-wire host interface for high-speed data
communications at 2Mb/s
CLK
1HZ
NC
7
8
10
9
VBATO
VBATB
Unique, factory-lasered and tested 64-bit
registration number (8-bit family code +
48-bit serial number + 8-bit CRC tester)
assures absolute traceability because no two
parts are alike
GND
16-PIN DIP (300 MIL)
16-PIN SO (300 MIL)
16-PIN SSOP (208 MIL)
See Mechanical Drawings Section
Memory partitioned into 16 pages of 256-bits
for packetizing data
PIN DESCRIPTION
VCC
IRQ
RST
DQ
I/O
CLK
NC
GND
VBATB
VBATO
1Hz
256-bit scratchpad with strict read/write
protocols ensures integrity of data transfer
Programmable alarms can be set to generate
interrupts for interval timer, real time clock,
and/or cycle counter
16-pin DIP, SO, and SSOP packages
Operating temperature range from -40°C to
+85°C
– 2.8 to 5.5V
– Interrupt Output
– 3-Wire Reset Input
– 3-Wire Input/Output
– 1-Wire Input/Output
– 3-Wire Clock Input
– No Connection
– Ground
Operating voltage range from 2.8V to 5.5V
– Battery Backup Input
– Battery Operate Input
– 1Hz Output
ORDERING INFORMATION
DS2404-001
DS2404S-001
DS2404B
16-pin DIP
16-pin SO
16-pin SSOP
X1, X2
– Crystal Connections
DS2404S-001/T&R Tape and Reel of S2404S-001
DS2404B/T&R
Tape and Reel of DS2404B
DESCRIPTION
The DS2404 EconoRAM Time Chip offers a simple solution for storing and retrieving vital data and time
information with minimal hardware. The DS2404 contains a unique lasered ROM, real-time
clock/calendar, interval timer, cycle counter, programmable interrupts, and 4096-bits of SRAM. Two
separate ports are provided for communication: 1-Wire and 3-wire. Using the 1-Wire port, only one pin is
required for communication, and the lasered-ROM can be read even when the DS2404 is without power.
The 3-wire port provides high-speed communication using the traditional Dallas Semiconductor 3-wire
interface. With either interface, a strict protocol for accessing the DS2404 ensures data integrity. Utilizing
backup energy sources, the data is nonvolatile (NV) and allows for stand-alone operation.
1-Wire is a registered trademark of Dallas Semiconductor.
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