DS2770

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ELECTRICAL CHARACTERISTICS:

1-WIRE INTERFACE

(-20

PARAMETER

SYMBOL CONDITION

MIN

TYP

MAX

UNITS NOTES

Time Slot

60

120

ms

Recovery Time

1

ms

Write 0 Low Time

60

120

ms

Write 1 Low Time

115

ms

Read Data Valid

15

ms

Reset Time High

480

ms

Reset Time Low

480

960

ms

Presence Detect High

15

60

ms

Presence Detect Low

60

240

ms

DQ Capacitance

25

pF

NOTES

1) All voltages are referenced to ground.

2) Self-heating due to output pin loading; sense resistor power dissipation will alter the reading from

ambient conditions.

3) Using the internal current-sense resistor.

4) Using an external current-sense resistor.

value.

7) This specification includes the effects of temperature on the sense resistor. The DS2770 compensates

for the internal sense resistor’s temperature coefficient of 3700ppm/°C to an accuracy of

±500ppm/°C. The DS2770 does not attempt to compensate for the characteristics of an external sense

resistor. Error terms arising from the use of an external sense resistor should be taken into account

when calculating total current measurement error.

8) Four-year data retention at +70°C.

11) The UV and CC pins are driven low with respect to the SNS pin. Current flow into UV or CC is

returned to SNS and therefore is not included in the current measurement.

12) Current full-scale rating limits input saturation and nonlinear conversion under high average current

signal levels of either polarity. Transient currents up to 1.5 times the current full-scale rating are

measured to specified accuracy if the RC filter formed by the internal resistors and external capacitor

at the IS1 and IS2 pins limits the average signal level to the Current Full-Scale rating.

13) This value deviates proportionally to gain error.