ADuCM310 Hardware Reference Manual
UG-549
Rev. C | Page 19 of 192
ADC CIRCUIT
ADC CIRCUIT FEATURES
The
incorporates a fast, multichannel, 16-bit ADC. The ADC is specified to be 14-bit no missing codes.
The flexible input multiplexer supports 10 external inputs and 14 internal channels. The internal channels include the following:
•
Temperature sensor channel
•
Internal 2.505 V reference
•
External reference
•
BUF_BREF2.5A and BUF_BREF2.5B
•
Six IDAC channels. These are the voltage at each of the IDAC output pins
•
PVDD_IDAC2 supply voltage
•
IOV
DD
/2 supply voltage.
•
AV
DD
/2 supply voltage
The input buffer can be selected for any channel to allow very low input current/input leakage specifications on these input channels. It is
recommended to use the input buffer for the AV
DD
/2, IOV
DD
/2, and temperature sensor channels.
The ADC features a high precision, low drift internal 2.505 V reference source.
An external reference can also be connected to the ADC_CAPP and ADC_CAPN pins.
The programmable ADC update rate is from 19.55 kSPS to 800 kSPS.
There is an internal digital comparator for the AIN4 channel. An interrupt can be generated if the digital comparator detects an ADC
result above/below a user defined threshold.
Each channel has its own distinct data register for its conversion result. For example, when AIN0 is selected, the result appears in
ADCDAT0; if AIN7 is selected, the result appears in ADCDAT7. For a differential measurement, the result always appears in the data
register of the positive channel.
ADC CIRCUIT BLOCK DIAGRAM
COMP
CONTROL
LOGIC
SWITCHES CONTROL
BUSY
OUTPUT CODE
CNV
C
C
2C
65,536C
4C
131,072C
LSB
SW+
MSB
LSB
SW–
MSB
C
C
2C
65,536C
4C
131,072C
AIN+
V
REF
AGND
AIN–
1
1461-
004
Figure 4. ADC Circuit Block Diagram
ADC CIRCUIT OVERVIEW
The
incorporates a fast, multichannel, 16-bit ADC. The ADC is specified to be 14-bit no missing codes. The ADC can
operate from a 2.9 V to 3.6 V supply and is capable of providing a throughput of up to 800 kSPS. This ADC block provides the user with a
multichannel multiplexer, input buffer for high impedance input channels, on-chip reference, and SAR ADC.
The SAR ADC circuit is implemented on the low voltage analog die. The ARM Cortex-M3 processor interfaces to the ADC via an
internal parallel die-to-die interface.
Depending on the input signal configuration, the ADC can operate in one of the following two modes:
•
Differential mode, to measure the difference between two signals.
•
Single-ended mode, to measure any signal relative to AGND.
The converter accepts an analog input range of 0 to V
REF
when operating in single-ended mode. In fully differential mode, the
measurement range is ±V
REF
while each signal must be between the range of AGND to AV
DD
.