DS1990 DALLAS [Dallas Semiconductor], DS1990 Datasheet - Page 10

• Manufacturer Part Number: DS1990
• Description: Serial Number iButton
• Manufacturer: DALLAS [Dallas Semiconductor]

NOTES:
1. All voltages are referenced to ground.
2. V
3. Input load is to ground.
4. An additional reset or communication sequence cannot begin until the reset high time has expired.
5. Read data setup time refers to the time the host must pull the 1-Wire bus low to read a bit. Data is
6. V
7. 30 nanocoulombs per 72 time slots @ 5.0V.
8. At V
9. Capacitance on the I/O pin could be 800 pF when power is first applied. If a 5 k resistor is used to
10. The reset low time (t
guaranteed to be valid within 1 s of this falling edge and will remain valid for 14 s minimum. (15
pull up the I/O line to V
normal communications.
otherwise, it could mask or conceal interrupt pulses if this device is used in parallel with a DS1994.
s total from falling edge on 1-Wire bus.)
PUP
IH
is a function of the external pullup resistor and the V
CC
= external pullup voltage.
=5.0V with a 5 k pullup to V
RSTL
CC
) should be restricted to a maximum of 960 s, to allow interrupt signaling,
, 5 s after power has been applied the parasite capacitance will not affect
CC
and a maximum time slot of 120 s.
10 of 10
CC
supply.
DS1990A