AMC7836_15 Datasheet, PDF (74/87 Pages) Texas Instruments – AMC7836 High-Density, 12-Bit Analog Monitor and Control Solution With Multichannel ADC, Bipolar DACs, Temperature Sensor, and GPIO Ports

AMC7836
SLAS986B – NOVEMBER 2014 – REVISED FEBRUARY 2015
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Typical Application (continued)
8.2.1 Design Requirements
The AMC7836 example schematic uses the majority of the design parameters listed in Table 63.
DESIGN PARAMETER
AV_CC
AV_EE
IOV_DD
DV_DD
AV_DD
AV_SS banks
ADC bipolar inputs
ADC unipolar inputs
DAC outputs
Remote temperature sensing
Table 63. Design Parameters
EXAMPLE VALUE
5V
–12 V
3.3 V
5V
5V
AV_EE
ADC[0-15]: –12.5 to 12.5 V input range
LV_ADC[16-20]: 0 to 5 V range
Sixteen Monotonic 12-bit DACs
Selectable ranges: 0 to 5 V, 0 to 10 V, –10 to 0 V or –5 to 0 V
IC temperature sensor (LM50) or thermistor
8.2.2 Detailed Design Procedure
Use the following parameters to facilitate the design process:
• AV_CC and AV_EE voltage values
• ADC input voltage range
• DAC Output voltage Ranges
8.2.2.1 ADC Input Conditioning
The AMC7836 device has an ADC with 21 analog inputs for external voltage sensing. Sixteen of these inputs are
bipolar and the other five are unipolar. The bipolar inputs (ADC_0 through ADC_15) range is –12.5 to 12.5 V,
and the unipolar analog inputs (LV_ADC16 through LV_ADC20) range is 0 to 2 × V_ref. The ADC operates from
an internal 2.5 V reference (V_ref, measured at the REF_CMP pin). For additional noise filtering, a 4.7-µF
capacitor should be connected between the REF_CMP and AGND2 pins. A high-quality ceramic type NP0 or
X7R is recommended because of the optimal performance of the capacitor across temperature and very-low
dissipation factor.
The ADC timing signals are driven from an on-chip temperature compensated 4 MHz oscillator. The on-chip
oscillator is primarily responsible for the sampling frequency of the ADC. The sampling frequency of the ADC is
dynamic and dependent on the acquisition and conversion time of each channel. Table 64 lists the relationship
between the total update time and the internal oscillator frequency.
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