DS2502 Maxim Integrated Products, DS2502 Datasheet - Page 2

• Manufacturer Part Number: DS2502
• Description: EPROM
• Manufacturer: Maxim Integrated Products

ORDERING INFORMATION
Standard
DS2502
DS2502/T&R
DS2502R/T&R
DS2502P
DS2502P/T&R
DS2502S
DS2502S/T&R
DS2502X1
+ Indicates lead-free compliance.
DESCRIPTION
The DS2502 1 kbit Add-Only Memory identifies and stores relevant information about the product to
which it is associated. This lot- or product-specific information can be accessed with minimal interface-
for example, a single port pin of a microcontroller. The DS2502 consists of a factory-lasered registration
number that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-bit Family Code (09h) plus 1
kbit of EPROM which is user-programmable. The power to program and read the DS2502 is derived
entirely from the 1-Wire
Data is transferred serially via the 1-Wire protocol which requires only a single data lead and a ground
return. The entire device can be programmed and then write-protected if desired. Alternatively, the part
may be programmed multiple times with new data being appended to, but not overwriting, existing data
with each subsequent programming of the device. Note: Individual bits can be changed only from a
logical 1 to a logical 0, never from a logical 0 to a logical 1. A provision is also included for indicating
that a certain page or pages of data are no longer valid and have been replaced with new or updated data
that is now residing at an alternate page address. This page address redirection allows software to patch
data and enhance the flexibility of the device as a stand-alone database. The 48-bit serial number that is
factory-lasered into each DS2502 provides a guaranteed unique identity which allows for absolute
traceability. The familiar TO-92 or SOIC or TSOC packages provide a compact enclosure that allows
standard assembly equipment to handle the device easily for attachment to printed circuit boards or
wiring. Typical applications include storage of calibration constants, maintenance records, asset tracking,
product revision status, and access codes.
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of
the DS2502. The DS2502 has three main data components: 1) 64-bit lasered ROM, 2) 1024-bit EPROM,
and 3) EPROM Status Bytes. The device derives its power for read operations entirely from the 1-Wire
communication line by storing energy on an internal capacitor during periods of time when the signal line
is high and continues to operate off of this “parasite” power source during the low times of the 1-Wire
line until it returns high to replenish the parasite (capacitor) supply. During programming, 1-Wire
communication occurs at normal voltage levels and then is pulsed momentarily to the programming
voltage to cause the selected EPROM bits to be programmed. The 1-Wire line must be able to provide 12
volts and 10 milliamperes to adequately program the EPROM portions of the part. Whenever
programming voltages are present on the 1-Wire line a special high voltage detect circuit within the
DS2502 generates an internal logic signal to indicate this condition. The hierarchical structure of the 1-
Wire protocol is shown in Figure 2. The bus master must first provide one of the six ROM Function
Commands, 1) Read ROM, 2) Match ROM, 3) Search ROM, 4) Skip ROM. These commands operate on
the 64-bit lasered ROM portion of each device and can singulate a specific device if many are present on
1-Wire is a registered trademark of Dallas Semiconductor.
Lead-Free
DS2502+
DS2502+T&R
DS2502R+T&R
DS2502P+
DS2502P+T&R
DS2502S+
DS2502S+T&R
®
communication line.
Description
TO-92 Package
TO-92 Package, 2k Tape & Reel
3-pin SOT-23 Package, 3k Tape & Reel
6-pin TSOC Package
TSOC Package, 4k Tape & Reel
8-pin SO Package
SO Package, 2.5k Tape & Reel
Flip Chip, 10k Tape & Reel
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