Linear Technology LTC2983 - Page 53

LTC2983
53
2983fc
For more information www.linear.com/LTC2983
APPLICATIONS INFORMATION
Typical Application Thermocouple Measurements
The LTC2983 includes 20 fully configurable analog input
channels. Each input channel can be configured to accept
any sensor type. Figure 31 shows a typical application
digitizing multiple thermocouples. Each thermocouple
requires a cold junction sensor and each cold junction
sensor can be shared amongst multiple thermocouples.
For example, the thermocouple tied to CH1 can use the
diode tied to CH2 as a cold junction sensor. However, any
thermocouple (CH1, CH3, CH5, CH6, CH9, CH10, or CH16)
can use any diode (CH2, CH4, or CH7), RTD (CH13, CH14),
or Thermistor (CH19, CH20) as its cold junction compen-
sation. The LTC2983 simultaneously measures both the
thermocouple and cold junction sensor and outputs the
results in °C or °F.
Figure 31. Typical Thermocouple Application
CH2
CH3
CH4
CH5
CH6
CH7
CH8
CH9
CH11
CH12
CH13
CH14
CH15
CH10
CH1 V
DD
Q1
Q2
Q3
CS
SDI
SDO
SCK
V
REFOUT
V
REFP
16
48
47
46
13
14
11
43
42
41
40
39
38
37
2, 4, 6, 8, 45
2.85V TO 5.25V
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
2983 F31
CH16
CH17
CH18
CH19
CH20
COM
0.1µF
10µF
10µF
1µF
V
REF_BYP
1µF
LDO
10µF
(OPTIONAL, DRIVE
LOW TO RESET)
SPI INTERFACE
1, 3, 5, 7, 9, 12, 15, 44
RESET
INTERRUPT
GND
R
SENSE
R
SENSE
4-WIRE
RTD