IO Voltage Range to GND....................................-0.5V to +6.0V

IO Sink Current DS1990A ..................................................20mA

IO Sink Current DS1990AA..............................................±10mA

Junction Temperature......................................................+125°C

Storage Temperature Range............................ -55°C to +125°C

(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.)

Electrical Characteristics

Note 1: System requirement.

Note 2: Full RPUP range is guaranteed by design and simulation and not production tested. Production testing performed at a fixed

RPUP 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 recovery

times. For more heavily loaded systems, an active pullup such as that found in the DS2480B may be required.

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

IO PIN: GENERAL DATA

1-Wire Pullup Voltage

VPUP

DS1990A (Note 1)

2.8

6.0

V

DS1990AA (Note 1)

3.0

5.25

V

1-Wire Pullup Resistance

RPUP

DS1990A (Notes 1 and 2)

0.6

5

kΩ

DS1990AA (Notes 1 and 2)

0.3

2.2

kΩ

Input Capacitance

CIO

DS1990A (Notes 3, 4, and 5)

100

800

pF

DS1990AA (Notes 4 and 5)

1000

pF

Input Load Current

IL

DS1990A (Note 6)

0.25

µA

DS1990AA IO pin at VPUP (Note 6)

0.05

1.75

6.7

µA

Input Low Voltage

VIL

(Notes 1 and 7)

0.3

V

Input High Voltage

VIH

DS1990A (Notes 4 and 8)

2.2

V

DS1990AA (Notes 4 and 8)

0.75 x

VPUP

Output Low Voltage

VOL

IOL = 4mA

0.4

V

Recovery Time

tREC

DS1990A (Note 1)

1

µs

DS1990AA (Note 1)

5

µs

Time Slot Duration

tSLOT

DS1990A (Note 1)

61

µs

DS1990AA (Note 1)

65

µs

IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE

Reset Low Time

tRSTL

DS1990A (Notes 1 and 9)

480

µs

DS1990AA (Note 1)

480

640

µs

Reset High Time

tRSTH

(Notes 1 and 10)

480

µs

Presence-Detect High Time

tPDH

15

60

µs

Presence-Detect Low Time

tPDL

(Note 11)

60

240

µs

Presence-Detect Sample Time

tMSP

(Note 1)

60

75

µs

IO PIN: 1-Wire WRITE

Write-Zero Low Time

tW0L

(Notes 1 and 12)

60

120

µs

Write-One Low Time

tW1L

(Notes 1 and 12)

1

15

µs

IO PIN: 1-Wire READ

Read Low Time

tRL

(Notes 1 and 13)

1

15 - d

µs

Read Sample Time

tMSR

(Notes 1 and 13)

tRL + d

15

µs

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Analog Devices │ 2

DS1990A

Serial Number iButton

Absolute Maximum Ratings

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.