LTC2494IUHF#PBF Linear Technology, LTC2494IUHF#PBF Datasheet - Page 21

• Manufacturer Part Number: LTC2494IUHF#PBF
• Description: IC ADC 16BIT W/PGA 38-QFN
• Manufacturer: Linear Technology

Specifications of LTC2494IUHF#PBF

• Number Of Bits: 16
• Sampling Rate (per Second): 15
• Data Interface: MICROWIRE™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 480µW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 38-WFQFN, Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

applications inForMation
Table 5a. Performance vs Gain in Normal Speed Mode (V
GAIN
Input Span
LSB
Noise Free Resolution*
Gain Error
Offset Error
Table 5b. Performance vs Gain in 2x Speed Mode (V
GAIN
Input Span
LSB
Noise Free Resolution*
Gain Error
Offset Error
*The resolution in counts is calculated as the FS divided by LSB or the RMS noise value, whichever is larger.
GAIN (GS2, GS1, GS0)
The input referred gain of the LTC2494 is adjustable
from 1 to 256 (see Tables 5a and 5b). With a gain of 1,
the differential input range is ±V
mode input range is rail-to-rail. As the gain is increased,
the differential input range is reduced to ±0.5 • V
but the common mode input range remains rail-to-rail.
As the differential gain is increased, low level voltages
are digitized with greater resolution. At a gain of 256, the
LTC2494 digitizes an input signal range of ±9.76mV with
over 16,000 counts.
Temperature Sensor
The LTC2494 includes an integrated temperature sensor.
The temperature sensor is selected by setting IM = 1.
During temperature readings, MUXOUTN/MUXOUTP
remains connected to the selected input channel. The
ADC internally connects to the temperature sensor and
performs a conversion.
The digital output is proportional to the absolute tem-
perature of the device. This feature allows the converter
to perform cold junction compensation for external
thermocouples or continuously remove the temperature
effects of external sensors.
65536
65536
±2.5
38.1
±2.5
38.1
200
0.5
1
5
1
5
REF
±0.625
65536
65536
±1.25
9.54
19.1
200
0.5
/2 and the common
4
5
2
5
CC
±0.312
±0.625
65536
65536
4.77
9.54
200
0.5
8
5
= 5V, V
4
5
REF
CC
/Gain
= 5V, V
REF
±0.156
±0.312
65536
65536
= 5V)
2.38
4.77
200
0.5
16
REF
5
8
5
The internal temperature sensor output is 28mV at 27°C
(300°K), with a slope of 93.5µV/°C independent of V
Slope calibration is not required if the reference voltage
(V
LSBs
code (where DATAOUT
the 16-bit result) for a 5V reference using the following
formula:
If a different value of V
is:
If the value of V
measuring the temperature sensor at a known temperature
T
This value of slope can be used to calculate further tem-
perature readings using:
All Kelvin temperature readings can be converted to T
(°C) using the fundamental equation:
= 5V)
N
REF
T
T
SLOPE = DATAOUT
T
T
(in °K) and using the following formula:
K
K
K
C
16
) is known. A 5V reference has a slope of 2.45
= DATAOUT
= DATAOUT
= DATAOUT
= T
±0.156
65536
65536
±78m
1.19
2.38
/°C. The temperature is calculated from the output
200
0.5
32
16
5
5
K
– 273
REF
65536
65536
±39m
0.596
±78m
16
16
16
1.19
200
is not known, the slope is determined by
0.5
64
32
5
5
/2.45 in Kelvin
/SLOPE
• V
REF
16
16
REF
/T
is the decimal representation of
is used, the temperature output
N
/12.25 in Kelvin
±19.5m
32768
45875
0.298
±39m
0.596
128
200
0.5
64
5
5
±9.76m
±19.5m
16384
22937
0.149
0.298
256
128
200
LTC2494
0.5
8
5
ppm of FS
ppm of FS

Counts
Counts
UNIT
UNIT
2494fd
REF
µV
µV
µV
µV
V
V
C
.