DS28EC20
20Kb 1-Wire EEPROM
www.maxim-ic.com
GENERAL DESCRIPTION
FEATURES
The DS28EC20 is a 20480-bit, 1-Wire® EEPROM
organized as 80 memory pages of 256 bits each. An
additional page is set aside for control functions.
Data is written to a 32-byte scratchpad, verified, and
then copied to the EEPROM memory. As a special
feature, blocks of eight memory pages can be write
protected or put in EPROM-Emulation mode, where
bits can only be changed from a 1 to a 0 state. The
DS28EC20 communicates over the single-conductor
1-Wire bus. The communication follows the standard
1-Wire protocol. Each device has its own unalterable
and unique 64-bit ROM registration number that is
factory lasered into the chip. The registration number
is used to address the device in a multidrop 1-Wire
net environment.
20480 Bits of Nonvolatile (NV) EEPROM
Partitioned into Eighty 256-Bit Pages
Individual 8-Page Groups of Memory Pages
(Blocks) can be Permanently Write Protected or
Put in OTP EPROM-Emulation Mode ("Write to
0")
Read and Write Access Highly Backward-
Compatible to Legacy Devices (e.g., DS2433)
256-Bit Scratchpad with Strict Read/Write
Protocols Ensures Integrity of Data Transfer
200k Write/Erase Cycle Endurance at +25°C
Unique Factory-Programmed 64-Bit Registration
Number Ensures Error-Free Device Selection
and Absolute Part Identity
Switchpoint Hysteresis and Filtering to Optimize
Performance in the Presence of Noise
Communicates to Host at 15.4kbps or 125kbps
Using 1-Wire Protocol
APPLICATIONS
Device Authentication
IEEE 1451.4 Sensor TEDS
Ink/Toner Cartridges
Medical Sensors
Low-Cost TO-92 Package
Operating Range: 5V ±5%, -40°C to +85°C
Operating Range: 3.3V ±5%, 0°C to +70°C
(Standard Speed only)
PCB Identification
Wireless Base Stations
IEC 1000-4-2 Level 4 ESD Protection (8kV
Contact, 15kV Air, Typical) for I/O Pin
ORDERING INFORMATION
PART
TEMP RANGE PIN-PACKAGE
PIN CONFIGURATION
DS28EC20+
DS28EC20+T
DS28EC20P+
DS28EC20P+T
3 TO-92
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
3 TO-92, T&R
6 TSOC
DALLAS
28EC20
TO-92
PIN 1 ---------- GND
PIN 2 ---------- I/O
PIN 3 ---------- N.C.
6 TSOC, T&R
+ Denotes a lead-free package.
T = tape and reel
FOR TAPE-AND-
REEL THE LEADS
ARE FORMED TO
100 MILS (2.54mm)
SPACING VERSUS
50 MILS (1.27mm)
FOR BULK.
TYPICAL OPERATING CIRCUIT
VCC
RPUP (300Ω
to 2.2kΩ)
1
2
3
PX.Y
I/O
BOTTOM VIEW
1
2
3
DS28EC20
GND
µC
TSOC, Top View
PIN 1 ---------- N.C.
PIN 2 ---------- I/O
PIN 3 ---------- GND
PIN 4, 5, 6 ---- N.C.
1
2
3
6
5
4
Commands, bytes, and modes are capitalized for clarity.
1-Wire is a registered trademark of Maxim Integrated Products, Inc.
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REV: 040109