MLX90313KDF ETC [List of Unclassifed Manufacturers], MLX90313KDF Datasheet - Page 12

• Manufacturer Part Number: MLX90313KDF
• Description: Programmable IR Sensor Interface
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Digital-to-Analog Converter (DAC)
A 8 bit digital to analog converter can be used to output the data for the linearised Tobject- and Tambient
signals. The DAC can work with a internal programmable reference voltage, as well as with an external
one. In case the internal reference voltage is used, this voltage can be monitored on the VREFP pin. If
one wants to use his own reference voltage, this can be done by applying this voltage to the VREFP pin,
and setting the appropriate configuration bit.
The result from D/A conversion is stored on hold capacitors and buffered. The signals are available at
IROUT and TEMPOUT respectively, if the appropriate bits are set in the configuration register (EEPROM
address 04h).
The reference value for the D/A can be programmed with 3 bits: SELDR[2:0] (register Irgain2) according
to the table below:
For reference voltages higher than 3V the ENDREFDIV bit must be set. In this case the ASIC will divide
internally the reference by 2 to provide proper input common mode for the output buffer amplifiers at pins
IROUT and TEMPOUT. In this case the result of the D/A conversion result will be amplified times 2 by the
output amplifiers, which will ensure the requested signal swing.
Melexis can rescale the DAC reference and eeprom table for the linearisation unit to provide absolute
analog output. This way, at maximum calibrated temperature, the voltage of IROUT or TEMPOUT pin will
always correspond to the requested D/A reference voltage.
The regulator for the VREFP voltage can be stopped and an external reference voltage can be forced and
used from the D/A. The regulator for DAC reference voltage can also be stopped (bit ENDACREF=0)
when DAC is not in use. This will save some supply current.
MLX90313 Programmable IR sensor Interface
3901090313
SELDR2
0
0
0
0
1
1
Temp-chain out
IR-chain out
SELDR1
TINP pin
TINN pin
VRefir
VReft
0
0
1
1
0
0
ADC reference configuration
SELDR0
Page 12
x3
x3
0
1
0
1
0
1
Programmable IR Sensor Interface
Irgain register: [RSEL4:RSEL0]
Config register 1: BYPTEMP
-Vrefp
-Vrefp
Vrefp
Vrefp
ADC
ADC
ENDREFDIV
12
12
Linearisation
0
0
0
1
1
1
Unit
MLX90313
Rev 1.0 21-July-2001
VREFP
2.5
3.5
4.5
2
3
4