Number iButton. DS1990A Datasheet

DS1990A Datasheet PDF, Equivalent


Part Number

DS1990A

Description

Serial Number iButton

Manufacture

Dallas Semiconductor

Total Page 10 Pages
PDF Download
Download DS1990A Datasheet PDF


DS1990A Datasheet
DS1990A
Serial Number iButtonTM
www.dalsemi.com
DS1990A SPECIAL FEATURES
§ Upgrade of DS1990 allows multiple Serial
F3 MICROCANTM
Number iButtons to reside on a common bus
§ Unique 48–bit serial number
§ Low-cost electronic key for access control
www.DataSh§eet48U-.bcoimt CRC for checking data integrity
§ Can be read in less than 5 ms
§ Operating temperature range of -40°C to
0.36
3.10
0.51
c 1993
16.25
YYWW REGISTERED RR
66 01
000000FBC52B
17.35
+85°C
COMMON iButton FEATURES
§ Unique, factory-lasered and tested 64-bit
registration number (8-bit family code + 48-
DATA
GROUND
F5 MICROCANTM
bit serial number + 8-bit CRC tester) assures
absolute traceability because no two parts are
alike
§ Multidrop controller for MicroLAN
§ Digital identification by momentary contact
§ Chip-based data carrier compactly stores
information
§ Data can be accessed while affixed to an
0.36
5.89
0.51
c 1993
YYWW REGISTERED RR
E6 01
000000FBD8B3
16.25
17.35
object
§ Economically communicates to bus master
with a single digital signal at 16.3k bits per
DATA
GROUND
second
§ Standard 16 mm diameter and 1-WireTM
All dimensions shown in millimeters
protocol ensure compatibility with iButton
family
§ 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
§ Presence detector acknowledges when reader
ORDERING INFORMATION
DS1990A-F3
F3 MicroCan
DS1990A-F5
F5 MicroCan
EXAMPLES OF ACCESSORIES
DS9096P
Self-Stick Adhesive Pad
DS9101
Multi-Purpose Clip
DS9093RA
Mounting Lock Ring
DS9093F
Snap-In Fob
DS9092
iButton Probe
first applies voltage
§ Meets UL#913 (4th Edit.); Intrinsically Safe
Apparatus, Approved under Entity Concept
for use in Class 1, Division 1, Group A, B, C
and D locations
1 of 10
081999

DS1990A Datasheet
DS1990A
iButton DESCRIPTION
The DS1990A Serial Number iButton is a rugged data carrier that acts as an electronic registration
number for automatic identification. The DS1990A consists of a factory-lasered, 64-bit ROM that
includes an unique 48-bit serial number, an 8-bit CRC and an 8-bit Family Code (01h). Data is transferred
serially via the 1-Wire protocol which requires only a single data lead and a ground return. The DS1990A
is fully compatible with the DS1990 Serial Number iButton but provides the additional 1-Wire protocol
capability that allows the Search ROM command to be interpreted by the DS1990A and therefore allows
multiple DS1990A devices to reside on a single data line.
The durable MicroCan package is highly resistant 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 easily by human operators. Accessories permit the DS1990A to be mounted on plastic key tabs,
www.DataShpeheot4tUo.cIoDm badges, printed circuit boards or any smooth surface of an object. Applications include access
control, work-in-progress tracking, tool management and inventory control.
OPERATION
The DS1990A’s internal ROM is accessed via a single data line. The 48-bit serial number, 8-bit family
code and 8-bit CRC are retrieved using the Dallas 1-Wire protocol. This protocol defines bus transactions
in terms of the bus state during specified time slots that are initiated on the falling edge of sync pulses
from the bus master. All data is read and written least significant bit first.
1-WIRE BUS SYSTEM
The 1-Wire bus is a system which has a single bus master system and one or more slaves. In all instances,
the DS1990A is a slave device. The bus master is typically a microcontroller. The discussion of this bus
system is broken down into three topics: hardware configuration, transaction sequence, and 1-Wire
signaling (signal type and timing). For a more detailed protocol description, refer to Chapter 4 of the
Book of DS19xx iButton Standards.
Hardware Configuration
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 an
open drain connection or 3-state outputs. The DS1990A is an open drain part with an internal circuit
equivalent to that shown in Figure 2. The bus master can be the same equivalent circuit. If a bidirectional
pin is not available, separate output and input pins can be tied together. The bus master requires a pullup
resistor at the master end of the bus, with the bus master circuit equivalent to the one shown in Figure 3.
The value of the pullup resistor should be approximately 5 kfor short line lengths. A multidrop bus
consists of a 1-Wire bus with multiple slaves attached. The 1-Wire bus has a maximum data rate of 16.3k
bits per second.
The idle state for the 1-Wire bus is high. If, for any reason, a transaction needs to be suspended, the bus
MUST be left in the idle state if the transaction is to resume. If this does not occur and the bus is left low
for more than 120 µs, one or more of the devices on the bus may be reset.
2 of 10


Features Datasheet pdf DS1990A Serial Number iButtonTM www.dals emi.com DS1990A SPECIAL FEATURES Upgra de of DS1990 allows multiple Serial Num ber iButtons to reside on a common bus § Unique 48–bit serial number § Low -cost electronic key for access control www.DataSheet4U.com § 8-bit CRC for c hecking data integrity § Can be read i n less than 5 ms § Operating temperatu re range of -40°C to +85°C § F3 MIC ROCANTM 3.10 0.36 0.51 c 1993 16.25 Y YWW REGISTERED RR 66 01 17.35 00000 0FBC52B DATA COMMON iButton FEATURES § Unique, factory-lasered and tested 6 4-bit registration number (8-bit family code + 48bit serial number + 8-bit CRC tester) assures absolute traceability because no two parts are alike Multidro p controller for MicroLAN Digital ident ification by momentary contact Chip-bas ed data carrier compactly stores inform ation Data can be accessed while affixe d to an object Economically communicate s to bus master with a single digital s ignal at 16.3k bits per second Standard 16 mm diameter and 1-WireTM protoc.
Keywords DS1990A, datasheet, pdf, Dallas Semiconductor, Serial, Number, iButton, S1990A, 1990A, 990A, DS1990, DS199, DS19, Equivalent, stock, pinout, distributor, price, schematic, inventory, databook, Electronic, Components, Parameters, parts, cross reference, chip, Semiconductor, circuit, Electric, manual, substitute




@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site (Privacy Policy & Contact)