AMC7832 Datasheet, PDF (57/70 Pages) Texas Instruments – AMC7832 12-Bit Analog Monitor and Control Solution with Multi-Channel ADC, Bipolar DACs, Temperature Sensor and GPIO Ports

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AMC7832
SLAS836 – MARCH 2014
To reduce DC error in sampling, it is recommended to decrease the ADC input impedance and reduce any input
capacitance to ground. Increasing the input capacitance essentially increases C_IN, and therefore increases the
required amount of input current (I_IN).
In applications where the signal source has high impedance, it is recommended that the analog input is buffered
before applying to the ADC channel.
Special care must be taken when biasing the two input classes, as both classes have different voltages – with
respect to GND – that they cannot exceed. These voltage values are located in Absolute Maximum Ratings.
9.2.3.2 DAC Output Range Selection
The AMC7832 contains 12 DACs that are arranged by different DAC banks, where each channel within a bank
shares a common programmable voltage range. Each DAC bank is fully programmable with up to three different
voltage ranges: -10 to 0-V, 0 to +10-V, and 0 to +5-V. The VRANGE terminals combined with the DAC
configuration register sets the different DAC voltage ranges.
The output buffer is capable of generating rail-to rail voltages on its output, giving an output range of AVSS to
AV_CC. The maximum source and sink capability of this internal amplifier is listed in the Electrical Characteristics
DAC Output Characteristics.
The graphs listed in the Application plots section illustrate the relationship of both stability and settling time with
different capacitive and resistive loading structures.
9.2.3.3 Temperature Sensing Applications
The AMC7832 contains one local temperature and 5 low-voltage unipolar channels that are easily configurable to
remote temperature sensor circuits. The integrated temperature sensor and analog input registers automatically
update with every conversion. An example of a remote temperature sensor connection is displayed in Figure 59.
The temperature sensor described is a LM50, a high precision integrated-circuit temperature sensor that can
sense a -40°C to +125°C temperature range using a single positive supply. The full-scale output of the
temperature sensor ranges from +100mV to +1.75V for a -40°C to +125°C temperature range. In an extremely
noisy environment it may be necessary to add some filtering to minimize noise pickup. A typical recommended
value for the bypass capacitor is 0.1µF from V+ to GND. A high-quality ceramic type NP0 or X7R is
recommended for its optimal performance across temperature, and very low dissipation factor.
DV_DD
0.12F
LM50
4 _V+
VO ³
1
NC
GND
25
LV_ADC15
Figure 59. External Remote Temperature IC (LM50) Connected to AMC7832 (LV_ADC15) Input Pin
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