50 pcs/lot (10pcs red,10pcs green,10pcs blue,10pcs black,10pcs yellow)
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.
|PARAMETER||SYMBOL||CONDITIONS||MIN TYP MAX||UNITS|
|IO PIN: GENERAL DATA|
|1-Wire Pul lup Voltage||VPUP||(Notes 1, 2)||2.8 6.0||V|
|1-Wire Pullup Resistance||RPUP||(Notes 3, 4)||0.6 5||kΩ|
|Input Capacitance||CIO||(Notes 5, 6)||100 800||pF|
|Input Load Current||IL||(Note 7)||0.25||μA|
|Input Low Voltage||VIL||(Notes 1, 3, 8)||0.3||V|
|Input High Voltage||VIH||(Notes 1, 9)||2.2||V|
|Output Low Voltage at 4mA||VOL||(Note 1)||0.4||V|
|Operating Charge||QOP||(Notes 6, 10)||30||nC|
|Recovery Time||tREC||(Note 3)||1||μs|
|Time Slot Duration||tSLOT||(Note 3)||61||μs|
|IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE|
|Reset Low Time||tRSTL||(Notes 3, 11)||480||μs|
|Reset High Time||tRSTH||(Notes 3, 12)||480||μs|
|Presence-Detect High Time||tPDH||15 60||μs|
|Presence-Detect Low Time||tPDL||Note 13)||60 240||μs|
|Presence-Detect Sample Time||tMSP||(Note 3)||60 75||μs|
|IO PIN: 1-Wire WRITE|
|Write-Zero Low Time||tW0L||(Notes 3, 14)||60 120||μs|
|Write-One Low Time||tW1L||(Notes 3, 14)||1 15||μs|
|IO PIN: 1-Wire READ|
|Read Low Time||tRL||(Notes 3, 15)||1 15 – &||μs|
|Read Sample Time||tMSR||(Notes 3, 15)||tRL + & 15||μs|
|Note 1: All voltages are referenced to ground.|
|Note 2: External pullup voltage. See Figure 4.|
|Note 3: System requirement.|
Note 4: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.
Note 5: Capacitance on the IO pin could be 800pF when power is first
after power has been applied the parasite capacitance will not affect
|Note 6: Guaranteed by design, simulation only. Not production tested.|
|Note 7: Input load is to ground.|
|Note 8: The voltage on IO must be less than or equal to VILMAX whenever
the master drives the line low.
|Note 9: VIH 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 tSLOT ≤ 120µs.
Note 11: The reset low time (tRSTL) should be restricted to a maximum of
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
Note 14: ε in Figure 7 represents the time required for the pullup
tW0LMAX + tF – ε, respectively.
Note 15: δ in Figure 7 represents the time required for the pullup circuitry to
pull the voltage on IO up from VIL to the inputhigh threshold of the bus master.
The actual maximum duration for the master to pull the line low is tRLMAX + tF.
So called “Economy Int’l Shipping” means China post air mail(Generally delivery in 45 days,
if you are from Brazil or Russia Federation,maybe up to 3 months), If you’re hurry to get it，
please choose“Expedited int’l shipping” ,that is DHL/UPS/Fedex(delivery in 1 week)