DS2704 Maxim Integrated Products, DS2704 Datasheet - Page 4

• Manufacturer Part Number: DS2704
• Description: 1280-Bit EEPROM
• Manufacturer: Maxim Integrated Products

PIN DESCRIPTION
Figure 1. Block Diagram
DETAILED DESCRIPTION
The DS2704 is comprised of an EEPROM memory array and SHA-1 Authentication function that are accessed via
a 1-Wire interface. The 1-Wire interface controls access by a host system to the 64-bit Net Address (ROM ID),
SHA-1 Authentication, 1280-bit EEPROM memory and EEPROM Status.
The DS2704 operates in one of four modes: standby, communication, computation and programming. Standby
mode is the default mode of operation. Whenever any task has been completed, the IC will automatically return to
standby mode. Standby mode is also directly entered if DQ is low for a period of t
been entered, DQ can be returned to logic high and standby mode is retained. Most operations are performed in
communication mode, with the host system addressing the DS2704 using Net Address commands and then
retrieving EEPROM and Status data using memory function commands or setting up an authentication exchange
and retrieving the results. The supply current, I
selection of Standard or Overdrive bus timing.
In SHA-1 computation mode, the supply current increases to I
current occurs after the last bit of one of the Compute MAC function commands is sent.
2, 3, 4
PIN
6
5
1
SYMBOL
VSS
DQ
VDD
VSS
DQ
NC
1-Wire Interface
Memory Control
Serial interface data I/O pin. Bi-directional data transmit and receive at 16KBPS
or 143KBPS
Supply GND and reference for serial communication. Attach VSS to battery
pack negative terminal
Supply input. Bypass to VSS with 0.01mF typical
No Connection
CRC Generator
64 bit ROM ID
Dout’
Din
DD1
, varies depending on bus activity, communication direction, and
4 of 18
FUNCTION
W15, A-E Registers
Constants and W0-
EEPROM STATUS
EEPROM Memory
SHA-1 Algorithm,
5 page x 32 byte
DD2
64 bit Secret
Charge Pump
Data Field
Data Field
(1280 bit)
Multi-Stage
for a period of t
SHA
Vpp
RSTL
. The computation mode load
. Once standby mode has
VDD