Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsDS28CM00R-A00+T

1 of 9

REV: 072406

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device

may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata

GENERAL DESCRIPTION

The DS28CM00 is a low-cost, electronic registration

number to provide an absolutely unique identity that

can be determined with the industry standard I²C and

SMBus interface. The registration number is a

factory-lasered, 64-bit ROM that includes a unique

48-bit serial number, an 8-bit CRC, and an 8-bit

family code (70h). In SMBus mode, the DS28CM00

resets its communication interface if it detects a bus

fault condition.

APPLICATIONS

Printed Circuit Board Unique Serialization

Accessory and Peripheral Identification

Equipment Registration and License Management

Network Node Identification

TYPICAL OPERATING CIRCUIT

SCL

µC

GND

SDA

SCL

DS28CM00

GND

FEATURES

 Unique, Factory-Lasered and Tested 64-bit

Registration Number (8-bit Family Code + 48-bit

Serial Number + 8-bit CRC)

 SMBus-Compatible I²C Serial Interface

 Supports 100kHz and 400kHz Communication

Speeds

 5V Tolerant Interface Pins

 Operating Range: 1.8V ±10% to 5V ±5%, -40°C

to +85°C

 5-Pin SOT23 Package

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS28CM00R-A00+T

-40°C to +85°C

SOT23-5

Tape-and-Reel

+Denotes lead-free package.

PIN CONFIGURATION

5SCL

GND

SDA

VCC

DS28CM00

I²C/SMBus Silicon Serial Numbe

www.maxim-ic.com

SOT23

Summary of content (9 pages)

PAGE 1
DS28CM00 I²C/SMBus Silicon Serial Number www.maxim-ic.com GENERAL DESCRIPTION FEATURES The DS28CM00 is a low-cost, electronic registration number to provide an absolutely unique identity that can be determined with the industry standard I²C and SMBus interface. The registration number is a factory-lasered, 64-bit ROM that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-bit family code (70h). In SMBus mode, the DS28CM00 resets its communication interface if it detects a bus fault condition.
PAGE 2
DS28CM00: I²C/SMBus Silicon Serial Number ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground Maximum Current Into Any Pin Operating Temperature Range Junction Temperature Storage Temperature Range Soldering Temperature -0.5V, +6V ±20mA -40°C to +85°C +150°C -55°C to +125°C See IPC/JEDEC J-STD-020 Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
PAGE 3
DS28CM00: I²C/SMBus Silicon Serial Number PARAMETER SYMBOL 0.3 0.3 0.3 100 0.6 tBUF (Note 8) 1.3 Cb (Notes 4, 8) tHD:DAT Data Setup Time Setup Time for STOP Condition Bus Free Time Between a STOP and START Condition Capacitive Load for Each Bus Line tSU:DAT tSU:STO Note 6: Note 7: Note 8: Note 9: Note 10: Note 11: MIN VCC ≥ 2.7V VCC ≥ 2.0V VCC < 2.0V (Notes 8, 11) (Note 8) Data Hold Time (Notes 9, 10) Note 1: Note 2: Note 3: Note 4: Note 5: CONDITIONS TYP MAX UNITS 0.9 1.1 1.
PAGE 4
DS28CM00: I²C/SMBus Silicon Serial Number Figure 1. Block Diagram VCC SCL ROM Registration Number SDA Serial Interface Control Register GND Figure 2.
PAGE 5
DS28CM00: I²C/SMBus Silicon Serial Number DEVICE OPERATION Typically, the DS28CM00 is accessed after power-up to read the 64-bit Registration number, which may serve to identify the object that the device is embedded in. Write access exists only to the Control Register. Read and write access are controlled through the I²C/SMBus serial interface. See section Read and Write for details.
PAGE 6
DS28CM00: I²C/SMBus Silicon Serial Number Figure 4. I²C/SMBus Protocol Overview R/W MS-bit ACK bit ACK bit SDA Slave Address Acknowledgment from Receiver SCL 1 Idle START Condition 2 6 7 8 9 ACK Repeated if more bytes are transferred 1 2 8 9 ACK STOP Condition Repeated START Condition Bus Idle or Not Busy Both, SDA and SCL, are inactive, i. e., in their logic HIGH states. START Condition To initiate communication with a slave, the master has to generate a START condition.
PAGE 7
DS28CM00: I²C/SMBus Silicon Serial Number Not Acknowledged by Slave A slave device may be unable to receive or transmit data, e.g., because it is busy. As a SMBus-compatible device, the DS28CM00 will always acknowledge its slave address. However, some time later the slave may refuse to accept data, e.g., because of an invalid memory address or access mode, e. g. attempting to write to a ROM byte. In this case the slave device will not acknowledge any of the bytes that it refuses and will leave SDA HIGH.
PAGE 8
DS28CM00: I²C/SMBus Silicon Serial Number I²C Communication⎯Legend SYMBOL S DESCRIPTION SYMBOL DESCRIPTION START Condition A Acknowledged AD,0 Select DS28CM00 for Write Access A\ Not Acknowledged AD,1 Select DS28CM00 for Read Access Transfer of One Byte Sr Repeated START Condition VMA Valid Memory Address (00h to 08h) P STOP Condition IMA Invalid Memory Address Command-Specific Communication⎯Color-Codes Master-to-Slave Slave-to-Master Communication Examples Write to Control
PAGE 9
DS28CM00: I²C/SMBus Silicon Serial Number Figure 6. Application Schematic VCC RP RP VCC To additional devices SDA SCL VCC SDA SCL DS28CM00 GND µC GND For I²C systems, the rise time and fall time are measured from 30% to 70% of the pullup voltage. The maximum bus capacitance CB is 400pF. The maximum rise time must not exceed 300ns. Assuming maximum rise time, the maximum resistor value at any given capacitance CB is calculated as: RPMAX = 300ns/(CB*ln(7/3)).