DS1920

21 of 22

AC ELECTRICAL CHARACTERISTICS:

1-WIRE INTERFACE

PARAMETER

SYMBOL

MIN

TYP

MAX

UNITS

NOTES

Time Slot

60

120

µs

Write 1 Low Time

1

15

µs

Write 0 Low Time

60

120

µs

Read Data Valid

exactly 15

µs

Release Time

0

15

45

µs

Read Data Setup

1

µs

8

Recovery Time

1

µs

Reset Time High

480

µs

Reset Time Low

480

4800

µs

6,7

Presence Detect High

15

60

µs

Presence Detect Low

60

240

µs

NOTES:

2. All voltages are referenced to ground.

4. Active current refers to temperature conversion.

5. Writing to EEPROM consumes approximately 200

µA.

µs. With longer times, the result of temperature conversion may get lost.

7. The reset low time should be restricted to a maximum of 960 ms, to allow interrupt signaling,

otherwise it could mask or conceal interrupt pulses.

8. 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 and will remain valid for 14 µs minimum. (15

µs total from falling edge on 1-Wire bus.)

9. Capacitance on the data contact could be 800 pF when power is first applied. If a 5k

Ω resistor is used

µs after power has been applied, the parasite capacitance will not

affect normal communications.

guarantee a presence pulse.

11. See Typical Curve for specification limits outside the 0°C to 70°C range. Thermometer error reflects

sensor accuracy as tested during calibration.