LTC2984 datasheet(60/78 Pages) AD

60 / 78 page

LTC2984

2984fb

For more information www.linear.com/LTC2984

Typical Application RTD and Thermistor Measurements

The LTC2984 includes 20 fully configurable analog input

channels. Each input channel can be configured to accept

any sensor type. Figure 35 shows a typical application

digitizing multiple RTDs and thermistors. Each RTD/

thermistor requires a sense resistor which can be shared

with multiple sensors. RTDs can be configured as 2, 3,

or 4-wire topologies. For example, a single sense resistor

APPLICATIONS INFORMATION

Figure 35. Typical RTD/Thermistor Application

CH2

CH3

CH4

CH5

CH6

CH7

CH8

CH9

CH11

CH12

CH13

CH14

CH15

CH10

CH1

VDD

RSENSE

SDI

SDO

SCK

VREFOUT

VREFP

2, 4, 6, 8, 45

2.85V TO 5.25V

4-WIRE

RTD

2-WIRE

RTD

3-WIRE

RTD

3-WIRE

RTD

4-WIRE

RTD

2984 F35

CH16

CH17

CH18

CH19

CH20

COM

0.1µF

10µF

1µF

VREF_BYP

1µF

LDO

10µF

(OPTIONAL, DRIVE

LOW TO RESET)

SPI INTERFACE

1, 3, 5, 7, 9, 12, 15, 44

RESET

INTERRUPT

GND

(CH1, CH2) is shared between a 4-wire RTD (CH4, CH3), a

2-wire RTD (CH7, CH6), two 3-wire RTDs (CH9, CH8 and

CH11, CH10) and a thermistor (CH13, CH12). This can

be mixed with diode sensors (CH15) and thermocouples

(CH14). Sense resistors (CH17, CH16) can also be dedi-

cated to specific sensors, in this case a 4-wire RTD (CH19,

CH18). Current is applied through both the sense resistor

and RTD/Thermistor, the resulting voltages are simultane-

ously measured and the results are output in °C or °F.

LTC2984 Datasheet(PDF) 60 Page - Analog Devices

LTC2984 Datasheet(HTML) 60 Page - Analog Devices

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