DS2502:1Kb Add-Only Memory

The DS2502 1Kb 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 1Kb of EPROM which is user-programmable. The power to program and read the DS2502 is derived entirely from the 1-Wire® communication line. 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 A provision is also included for indicating that a certain page or pages of data are no longer valid and have been replaced with new or updated data that is now residing at an alternate page address.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.

Key Features
  • Easily Add Traceability and Relevant Information to Any Individual System
    • 1k-Bit EPROM with Page-Level Write Protection and Guaranteed Unique 64-Bit ROM ID Chip for Absolute Traceability
    • 1024 Bits Electrically Programmable Read Only Memory (EPROM)
    • Unique, Factory-Lasered and Tested 64-Bit Registration Number (8-Bit Family Code + 48-Bit Serial Number + 8-Bit CRC Tester)
    • EPROM Partitioned into Four 256-Bit Pages for Randomly Accessing Packetized Data
    • Each Memory Page Can Be Permanently Write- Protected to Prevent Tampering
    • Device is an Add Only Memory Where Additional Data Can Be Programmed into EPROM Without Disturbing Existing Data
    • Architecture Allows Software to Patch Data by Superseding an Old Page in Favor of a Newly Programmed Page
    • 8-Bit Family Code Specifies DS2502 Communications Requirements to Reader
  • Minimalist 1-Wire Interface Lowers Cost and Interface Complexity
    • Reduces Control, Address, Data, Power, and Programming Signals to a Single Data Pin
    • Directly Connects to a Single Port Pin of a Microprocessor and Communicates at up to 16.3kb Per Second
    • Built-In Multidrop Controller Ensures Compatibility with Other 1-Wire Net Products o Presence Pulse Acknowledges When the Reader First Applies Voltage
    • Low Cost TO-92, SFN, or 8-Pin SO, SOT-23 (3 Pin), TSOC and WLP Surface Mount Package
  • Wide Voltage and Temperature Operating Ranges Provide Robust System Performance
    • Reads Over Voltage Range of 2.8V to 6.0V at -40°C to +85°C
    • Zero Standby Power Required
    • Programs at 11.5V to 12.0V from -40°C to +50°C
DS2502: Block Diagram
DS2502: Block Diagram
titleDownload file
DS2502 Data SheetDS2502.pdf
Part NumberMemory TypeMemory SizeBus TypeVSUPPLY
minmaxSee Notes
DS2502EPROM1K x 11-Wire2.86SFN/2
$1.04 @1k
Design kits & evaluation modules
Quality and Environmental Data
Additional Resources
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS2502No Longer AvailableDS2502+TO92,;3 pin;19.5 mm²-40°C to +85°CNo
DS2502+ActiveTO92,;3 pin;19.5 mm²-40°C to +85°CLead Free
DS2502+T&RActiveTO92,;3 pin;27.6 mm²-40°C to +85°CLead Free
DS2502/T&RNo Longer AvailableDS2502+T&RTO92,;3 pin;27.6 mm²-40°C to +85°CNo
DS2502/T&R/SLNo Longer AvailableTO92,;3 pin;19.5 mm²-40°C to +85°CNo
DS2502G+T&RActiveSFN,;2 pin;37.2 mm²-40°C to +85°CLead Free
DS2502G+UActiveSFN,;2 pin;37.2 mm²-40°C to +85°CLead Free
DS2502PNo Longer AvailableDS2502P+TSOC,;6 pin;17.8 mm²-40°C to +85°CNo
DS2502P+ActiveTSOC,;6 pin;17.8 mm²-40°C to +85°CLead Free
DS2502P+T&RActiveTSOC,;6 pin;17.8 mm²-40°C to +85°CLead Free
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS2502P/T&RNo Longer AvailableDS2502P+T&RTSOC,;6 pin;17.8 mm²-40°C to +85°CNo
DS2502R+T&RActiveSOT,;3 pin;8 mm²-40°C to +85°CLead Free
DS2502R-01C+T&RActiveSOT,;3 pin;8 mm²-40°C to +85°CLead Free
DS2502R/T&RNo Longer AvailableDS2502R+T&RSOT,;3 pin;8 mm²-40°C to +85°CNo
DS2502SNo Longer AvailableDS2502S+SOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
DS2502S+ActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS2502S+T&RActiveSOIC(N),;8 pin;30.9 mm²-40°C to +85°CLead Free
DS2502S/T&RNo Longer AvailableDS2502S+T&RSOIC(N),;8 pin;30.9 mm²-40°C to +85°CNo
DS2502X1+ActiveWLP,;4 pin;THIN W;-40°C to +85°CLead Free
DS2502X1+UActiveWLP,;4 pin;THIN W;-40°C to +85°CLead Free
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