LTC1392CS8 Linear Technology, LTC1392CS8 Datasheet - Page 9

• Manufacturer Part Number: LTC1392CS8
• Description: IC DATA ACQ SYSTEM 10BIT 8-SOIC
• Manufacturer: Linear Technology
• Type: Data Acquisition System (DAS)r

Specifications of LTC1392CS8

• Resolution (bits): 10 b
• Sampling Rate (per Second): 25k
• Data Interface: Serial
• Voltage Supply Source: Single Supply
• Voltage - Supply: 4.5 V ~ 6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
Differential Voltage Conversion
The LTC1392 measures the differential input voltage
through pins + V
full scale are available for differential voltage measure-
ment with resolutions of 10 bits. Tables 4a and 4b describe
the exact relationship of output data to measured differen-
tial input voltage in the 1V and 0.5V input range. Equations
(3) and (4) can be used to calculate the differential voltage
in the 1V and 0.5V input voltage range respectively. The
output code is in unipolar format.
Table 4a. Codes for 1V Differential Voltage Range
Table 4b. Codes for 0.5V Differential Voltage Range
1111111111
1111111110
0000000001
0000000000
1111111111
1111111110
0000000001
0000000000
Differential Voltage = 1V • (10-bit code)/1024
Differential Voltage = 0.5V • (10-bit code)/1024
OUTPUT
OUTPUT
CODE
CODE
...
...
0.5V – 1LSB
0.5V – 2LSB
1V – 1LSB
1V – 2LSB
VOLTAGE
VOLTAGE
IN
INPUT
INPUT
1LSB
0LSB
1LSB
0LSB
...
...
and – V
U
INFORMATION
U
IN
RANGE = 0.5V
RANGE = 1V
. Input ranges of 0.5V or 1V
999.0mV
998.0mV
0.977mV
499.5mV
499.0mV
0.488mV
0.00mV
0.00mV
INPUT
INPUT
...
...
W
1LSB = 0.5/1024
1LSB = 1/1024
REMARKS
REMARKS
U
(3)
(4)
Thermal Coupling/Airflow
The supply current of the LTC1392 is 700 A typically
when running at the maximum conversion rate. The equiva-
lent power dissipation of 3.5mW causes a temperature
rise of 0.455 C in the SO8 and 0.35 C in PDIP packages
due to self-heating effects. At sampling rates less than 400
samples per second, less than 20 A current is drawn from
the supply (see Typical Performance Characteristics) and
the die self-heating effect is negligible. This LTC1392 can
be attached to a surface (such as microprocessor chip or
a heat sink) for precision temperature monitoring. The
package leads are the principal path to carry the heat into
the device; thus any wiring leaving the device should be
held at the same temperature as the surface. The easiest
way to do this is to cover up the wires with a bead of epoxy
which will ensure that the leads and wires are at the same
temperature as the surface. The thermal time constant of
the LTC1392 in still air is about 22 seconds (see the graph
in the Typical Performance Charateristics section). At-
taching an LTC1392 to a small metal fin (which also
provides a small thermal mass) will help reduce thermal
time constant, speed up the response and give the steadi-
est reading in slow moving air.
LTC1392
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