Rainbow Electronics DS1957 - Manual (Page 25)

DS1957
25 of 25
AC ELECTRICAL CHARACTERISTICS
OVERDRIVE SPEED
(V
PUP
=4.0V to 5.5V; -20°C to +70°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Time Slot t
SLOT
6 16 µs
Write 1 Low Time t
LOW1
1 2 µs
Write 0 Low Time t
LOW0
6 16 µs
Read Low Time t
LOWR
1 2 µs
Read Data Valid t
RDV
exactly 2 µs
Release Time t
RELEASE
0 1.5 4 µs
Read Data Setup t
SU
1 µs 5
Recovery Time t
REC
1 µs
Reset Time High t
RSTH
48 µs 4
Reset Time Low t
RSTL
48 80 µs
Presence Detect High t
PDHIGH
2 6 µs
Presence Detect Low t
PDLOW
8 24 µs
NOTES:
1. All voltages are referenced to ground.
2. V
PUP
= external pull-up voltage.
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
guaranteed to be valid within 1 µs of this falling edge.
6. Capacitance on the data pin could be 150 nF when power is first applied. If a 1.5 kΩ resistor is used
to pull up the data line to V
CC
, 500 µs after power has been applied, the parasite capacitance will not
affect normal communications.
7. The reset low time (t
RSTL
) should be restricted to a maximum of 960 µs, to allow interrupt signaling,
otherwise, it could mask or conceal interrupt pulses.