DS1825UTR datasheet(2/21 Pages) MAXIM

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DS1825 Programmable Resolution 1-Wire Digital Thermometer With 4-Bit ID

2 of 21

DESCRIPTION (cont.)

Each DS1825 has a unique 64-bit serial code, which allows multiple DS1825s to function on the same 1-Wire bus;

thus, it is simple to use one microprocessor to control many DS1825s distributed over a large area. In addition, the

4-bit location address can be used to identify specific temperature sensors in the system without requiring a wide

lookup table. Applications that can benefit from this feature include HVAC environmental controls, temperature

monitoring systems inside buildings, equipment or machinery, and process monitoring and control systems.

ABSOLUTE MAXIMUM RATINGS*

Voltage on Any Pin Relative to Ground

-0.5V to +6.0V

Operating Temperature Range

-55°C to +125

°C

Storage Temperature Range

-55°C to +125°C

Solder Dip Temperature (10s)

+260°C

Reflow Oven Temperature

+220°C

These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation

sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

DC ELECTRICAL CHARACTERISTICS

(-55°C to +125°C; VDD= 3.0V to 3.7V)

PARAMETER

SYMBOL

CONDITION

MIN

TYP

MAX

UNITS

NOTES

Supply Voltage

VDD

Local Power

+3.0

+3.7

Parasite Power

+3.0

+3.7

Pullup Supply Voltage

VPU

Local Power

+3.0

VDD

1, 2

-10°C to +85°C

±0.5

°C

Thermometer Error

tERR

-55°C to +125°C

±2

°C

Programming

Resistor: AD0-AD3

RPGM

DQ Input Logic Low

VIL(DQ)

-0.3

+0.7

1, 4, 5

Local Power

+2.2

DQ Input Logic High

VIH(DQ)

Parasite Power

+3.0

The lower of

3.7

VDD + 0.3

1, 6

Sink Current

VI/O = 0.4V

4.0

Standby Current

IDDS

500

1000

7, 8

Active Current

IDD

VDD = 3.7V

0.65

1.5

DQ Input Current

IDQ

µA

Drift

±0.2

°C

NOTES:

All voltages are referenced to ground.

The Pullup Supply Voltage specification assumes that the pullup device is ideal, and therefore the high level of the pullup is equal to VPU.

In order to meet the VIH spec of the DS1825, the actual supply rail for the strong pullup transistor must include margin for the voltage drop

across the transistor when it is turned on; thus: VPU_ACTUAL = VPU_IDEAL + VTRANSISTOR.

See typical performance curve in Figure 18

Logic low voltages are specified at a sink current of 4mA.

To guarantee a presence pulse under low voltage parasite power conditions, VILMAX may have to be reduced to as low as 0.5V.

Logic high voltages are specified at a source current of 1mA.

Standby current specified up to 70

°C. Standby current typically is 3mA at 125°C.

To minimize IDDS, DQ should be within the following ranges: GND

£ DQ £ GND + 0.3V or VDD - 0.3V £ DQ £ VDD.

Active current refers to supply current during active temperature conversions or EEPROM writes.

10.

DQ line is high (“hi-Z” state).

11.

Drift data is based on a 1000 hour stress test at 125°C.

12.

Inputs AD0-AD3 must be tied either High or Low. A "Low" is a connection to the GND terminal. A "High" connection varies with usage of

the DS1825. When connected as a parasite powered sensor, a connection to DQ is considered a High. When powered through the VDD

pin, a connection to VDD is a High. If left floating, the input values are indeterminate and may be either logical "0" or logical "1." See

Figures 20 and 21 for details. When optional programming resistors are used, their maximum values are 10,000

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