Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)64 kBit

General Description

The DS1990A serial number iButton

is a rugged data

carrier that serves as an electronic registration number for

automatic identification. Data is transferred serially through

the 1-Wire

protocol, which requires only a single data lead

and a ground return. Every DS1990A has a unique 64-bit

registration number that allows for absolute traceability.

The durable stainless-steel iButton package is highly resis-

tant to environmental hazards such as dirt, moisture, and

shock. Its compact coin-shaped profile is self-aligning with

mating receptacles, allowing the DS1990A to be used eas-

ily by human operators. Accessories enable the DS1990A

iButton to be mounted on almost any object, including con-

tainers, pallets, and bags.

Applications

● Access Control

● Work-in-Progress Tracking

● Tool Management

● Inventory Control

Features

● Can Be Read in Less Than 5ms

Common iButton Features

● Unique 64-Bit Registration Number Ensures Error-

Free Device Selection and Absolute Traceability

Because No Two Parts are Alike

● Built-In Multidrop Controller for 1-Wire Net

● Digital Identification by Momentary Contact

● Data Can Be Accessed While Affixed to Object

● Economically Communicates to Bus Master with a

Single Digital Signal at 16.3kbps

● Button Shape is Self-Aligning with Cup-Shaped

Probes

● Durable Stainless-Steel Case Engraved with

Registration Number Withstands Harsh Environments

● Easily Affixed with Self-Stick Adhesive Backing,

Latched by its Flange, or Locked with a Ring

Pressed Onto its Rim

iButton and 1-Wire are registered trademarks of Maxim

Integrated Products, Inc.

19-8145; Rev: 11/21

+Denotes a lead(Pb)-free/RoHS-compliant package.

PART TEMP RANGE PIN-PACKAGE

DS1990A-F5+ -40°C to +85°C

F5 iButton

DS1990A-F3+ -40°C to +85°C

F3 iButton

DS1990AA-F5+ -40°C to +85°C

F5 iButton

DS1990AA-F3+ -40°C to +85°C

F3 iButton

PART ACCESSORY

DS9096P Self-Stick Adhesive Pad

DS9101 Multipurpose Clip

DS9093RA Mounting Lock Ring

DS9093A Snap-In Fob

DS9092

iButton Probe

Serial Number iButton

DS1990A

Design

Resources

Support

Click here to ask an associate for production status of specific part numbers.

Pin Congurations

Examples of Accessories

16.25mm

5.89mm

0.51mm

3.10mm

0.51mm

17.35mm

BRANDING

F5 SIZE

GNDGND

IOIO

F3 SIZE

89 01

000000FBC52B

1-Wire

16 .25m m

5.8 9mm

0.5 1mm

17 .35m m

BRAND ING

F5 SI ZE

GND

3.1 0mm

0.5 1mm

F3 SI ZE

GND

89 01

1-Wire

000000FBC52B

Ordering Information

Summary of content (10 pages)

PAGE 1
Design Resources Support Click here to ask an associate for production status of specific part numbers. DS1990A Serial Number iButton General Description The DS1990A serial number iButton® is a rugged data carrier that serves as an electronic registration number for automatic identification. Data is transferred serially through the 1-Wire® protocol, which requires only a single data lead and a ground return. Every DS1990A has a unique 64-bit registration number that allows for absolute traceability.
PAGE 2
DS1990A Serial Number iButton Absolute Maximum Ratings Junction Temperature.......................................................+125°C Storage Temperature Range............................. -55°C to +125°C IO Voltage Range to GND.....................................-0.5V to +6.0V IO Sink Current DS1990A...................................................20mA IO Sink Current DS1990AA...............................................
PAGE 3
DS1990A Serial Number iButton Electrical Characteristics (continued) (Limits are 100% production tested at TA = +25°C and/or TA = +85°C. Limits over the operating temperature range and relevant supply voltage range are guaranteed by design and characterization. Typical values at +25°C.) Note 3: Capacitance on the IO pin could be 800pF when power is first applied.
PAGE 4
DS1990A Serial Number iButton 1-Wire Bus System 64-Bit Unique ROM Each DS1990A contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code. The next 48 bits are a unique serial number. The last 8 bits are a CRC of the first 56 bits. See Figure 2 for details. The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and XOR gates as shown in Figure 3. The polynomial is X8 + X5 + X4 + 1.
PAGE 5
DS1990A Serial Number iButton Hardware Configuration Transaction Sequence The 1-Wire bus has only a single line by definition; it is important that each device on the bus be able to drive it at the appropriate time. To facilitate this, each device attached to the 1-Wire bus must have open-drain or threestate outputs. The 1-Wire port of the DS1990A is open drain with an internal circuit equivalent to that shown in Figure 4. A multidrop bus consists of a 1-Wire bus with multiple slaves attached.
PAGE 6
DS1990A Serial Number iButton 1-Wire ROM Function Commands Once the bus master has detected a presence, it can issue one of the ROM function commands the DS1990A supports. All ROM function commands are 8 bits long. A list of these commands follows. (See Figure 5 for a flowchart.
PAGE 7
DS1990A Serial Number iButton 1-Wire Signaling pulse by pulling the line low for tPDL. To detect a presence pulse, the master must test the logical state of the 1-Wire line at tMSP. The DS1990A requires strict protocols to ensure data integrity. The protocol consists of four types of signaling on one line: reset sequence with reset pulse and presence pulse, write-zero, write-one, and read-data. Except for the presence pulse, the bus master initiates all these signals.
PAGE 8
DS1990A Serial Number iButton WRITE-ONE TIME SLOT tW1L VPUP VIHMASTER VIHMIN VILMAX 0V ε tF tSLOT RESISTOR MASTER WRITE-ZERO TIME SLOT tW0L VPUP VIHMASTER VIHMIN VILMAX 0V ε tF tSLOT RESISTOR READ-DATA TIME SLOT tRL VPUP VIHMASTER VIHMIN VILMAX 0V tREC MASTER tMSR MASTER SAMPLING WINDOW δ tF tSLOT RESISTOR MASTER tREC DS1990A Figure 7. Read/Write Timing Diagram www.analog.
PAGE 9
DS1990A Serial Number iButton Slave-to-Master A read-data time slot begins like a write-one time slot. The voltage on the data line must remain below VILMAX until the read low time tRL is expired. During the tRL window, when responding with a 0, the DS1990A starts pulling the data line low; its internal timing generator determines when this pulldown ends and the voltage starts rising again.
PAGE 10
DS1990A Serial Number iButton Revision History REVISION DATE DESCRIPTION PAGES CHANGED 033005 Redid the formatting based on newer template style. Also deleted the 0F Read ROM command and added a note about presence pulse criteria. 1–8 Created newer template-style data sheet. All Updated Ordering Information with lead-free part numbers.