AVAILABLE
Functional Diagrams
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and
ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
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 sin-
gle data lead and a ground return. Every DS1990A is
factory lasered with a guaranteed unique 64-bit regis-
tration 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 easily by human operators. Accessories
enable the DS1990A iButton to be mounted on almost
any object, including containers, pallets, and bags.
Applications
Access Control
Work-In-Progress Tracking
Tool Management
Inventory Control
Features
Can Be Read in Less Than 5ms
Operating Range: 2.8V to 6.0V, -40°C to +85°C
Common iButton Features
Unique Factory-Lasered 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
Serial Number i
Button
Pin Configurations
Ordering Information
Rev: 10/08
PART TEMP RANGE PIN-PACKAGE
DS1990A-F5+ -40°C to +85°C F5 i
Button
DS1990A-F3+ -40°C to +85°C F3 iButton
Examples of Accessories
PART ACCESSORY
DS9096P Self-Stick Adhesive Pad
DS9101 Multipurpose Clip
DS9093RA Mounting Lock Ring
DS9093A Snap-In Fob
DS9092 iButton Probe
16.25mm
5.89mm
0.51mm
3.10mm
0.51mm
17.35mm
BRANDING
F5 SIZE
GND
GND
IOIO
F3 SIZE
89 01
000000FBC52B
1-Wire
®
®
i
B
u
t
t
o
n
®
.
c
o
m
Y
Y
W
W
Z
Z
Z
D
S
1
9
9
0
A
+
F
5
iButton and 1-Wire are registered trademarks of Maxim
Integrated Products, Inc.
+
Denotes a lead(Pb)-free/RoHS-compliant package.
DS1990A
0SEFSJOH*OGPSNBUJPO
Serial Number i
Button
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(T
A
= -40°C to +85°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1: All voltages are referenced to ground.
Note 2: External pullup voltage. See Figure 4.
Note 3: System requirement.
Note 4: Full R
PUP
range is guaranteed by design and simulation and not production tested. Production testing performed at a
fixed R
PUP
value. Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-
Wire recovery times. The specified value here applies to systems with only one device and with the minimum 1-Wire recov-
ery times. For more heavily loaded systems, an active pullup such as that found in the DS2480B may be required.
Note 5: Capacitance on the IO pin could be 800pF when power is first applied. If a 5kΩ resistor is used to pull up the IO line to
V
PUP
, 5µs after power has been applied the parasite capacitance will not affect normal communications.
Note 6: Guaranteed by design, simulation only. Not production tested.
Note 7: Input load is to ground.
IO Voltage Range to GND .....................................-0.5V to +6.0V
IO Sink Current....................................................................20mA
Junction Temperature......................................................+125°C
Storage Temperature Range .............................-55°C to +125°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IO PIN: GENERAL DATA
1-Wire Pullup Voltage V
PUP
(Notes 1, 2) 2.8 6.0 V
1-Wire Pullup Resistance R
PUP
(Notes 3, 4) 0.6 5 k
Input Capacitance C
IO
(Notes 5, 6) 100 800 pF
Input Load Current I
L
(Note 7) 0.25 μA
Input Low Voltage V
IL
(Notes 1, 3, 8) 0.3 V
Input High Voltage V
IH
(Notes 1, 9) 2.2 V
Output Low Voltage at 4mA V
OL
(Note 1) 0.4 V
Operating Charge Q
OP
(Notes 6, 10) 30 nC
Recovery Time t
REC
(Note 3) 1 μs
Time Slot Duration t
SLOT
(Note 3) 61 μs
IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE
Reset Low Time t
RSTL
(Notes 3, 11) 480 μs
Reset High Time t
RSTH
(Notes 3, 12) 480 μs
Presence-Detect High Time t
PDH
15 60 μs
Presence-Detect Low Time t
PDL
(Note 13) 60 240 μs
Presence-Detect Sample Time t
MSP
(Note 3) 60 75 μs
IO PIN: 1-Wire WRITE
Write-Zero Low Time t
W0L
(Notes 3, 14) 60 120 μs
Write-One Low Time t
W1L
(Notes 3, 14) 1 15 μs
IO PIN: 1-Wire READ
Read Low Time t
RL
(Notes 3, 15) 1 15 - μs
Read Sample Time t
MSR
(Notes 3, 15) t
RL
+ 15 μs
DS1990A
Maxim Integrated
Serial Number i
Button
Note 8: The voltage on IO must be less than or equal to V
ILMAX
whenever the master drives the line low.
Note 9: V
IH
is a function of the internal supply voltage.
Note 10: 30nC per 72 time slots at 5.0V pullup voltage with a 5kΩ pullup resistor and t
SLOT
120µs.
Note 11: The reset low time (t
RSTL
) should be restricted to a maximum of 960µs to allow interrupt signaling. A longer duration could
mask or conceal interrupt pulses if this device is used in parallel with a DS1994.
Note 12: An additional reset or communication sequence cannot begin until the reset high time has expired.
Note 13: Presence pulse is guaranteed only after a preceding reset pulse (t
RSTL
).
Note 14: ε in Figure 7 represents the time required for the pullup circuitry to pull the voltage on IO up from V
IL
to V
IH
. The actual
maximum duration for the master to pull the line low is t
W1LMAX
+ t
F
- ε and t
W0LMAX
+ t
F
- ε, respectively.
Note 15: δ in Figure 7 represents the time required for the pullup circuitry to pull the voltage on IO up from V
IL
to the input-high
threshold of the bus master. The actual maximum duration for the master to pull the line low is t
RLMAX
+ t
F
.
iButton CAN PHYSICAL SPECIFICATION
SIZE See the Package Information section.
WEIGHT (DS1990A) Ca. 2.5 grams
Detailed Description
The block diagram in Figure 1 shows the major function
blocks of the device. The DS1990A takes the energy it
needs to operate from the IO line, as indicated by the
parasite power block. The ROM function control unit
includes the 1-Wire interface and the logic to implement
the ROM function commands, which access 64 bits of
lasered ROM.
DS1990A
PARASITE POWER
ROM
FUNCTION CONTROL
IO
64-BIT
LASERED ROM
Figure 1. Block Diagram
DS1990A
Maxim Integrated
3

DS1990A-F3+

Mfr. #:
Manufacturer:
Maxim Integrated
Description:
Security ICs / Authentication ICs Serial Number iButton
Lifecycle:
New from this manufacturer.
Delivery:
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