CC2480 Datasheet, PDF (25/44 Pages) Texas Instruments – Z-Accel 2.4 GHz ZigBee® Processor

CC2480
9.3 ADC
9.3.1 ADC Introduction
The ADC supports up to 12-bit analog-to-
digital conversion. The ADC includes an
analog multiplexer with up to two individually
configurable channels and reference voltage
generator.
The main features of the ADC are as follows:
A1
A0
VDD/3
TMP_SENSOR
input
mux
Sigma-delta
modulator
• Selectable decimation rates which also
sets the resolution (7 to 12 bits).
• Two individual input channels, single-
ended or differential
• Internal voltage reference
• Temperature sensor input
• Battery measurement capability
Decimation
filter
Int 1.25V
Clock generation and
control
Figure 7: ADC block diagram.
9.3.2 ADC Operation
This section describes the general setup and
operation of the ADC.
9.3.2.1 ADC Core
The ADC includes an ADC capable of
converting an analog input into a digital
representation with up to 12 bits resolution.
9.3.2.2 ADC Inputs
The signals from input pins A0 and A1 are
used as single-ended ADC inputs. The ADC
automatically performs a sequence of
conversions when the SYS_ADC_READ
command is issued.
In addition to the input pins A0-1, the output of
an on-chip temperature sensor can be
9.3.2.3 ADC conversion sequences
The CC2480 has two ADC channels that are
connected to external pins. Additionally, the
ADC can measure the chip voltage and
temperature.
The ADC conversions are done channel by
channel incrementally.
The two external pin inputs A0 and A1 can be
used as single-ended or differential inputs.
The ADC uses a selectable positive reference
voltage.
selected as an input to the ADC for
temperature measurements.
It is also possible to select a voltage
corresponding to AVDD_SOC/3 as an ADC
input. This input allows the implementation of
e.g. a battery monitor in applications where
this
feature
is
required.
In the case where differential inputs are
selected, the differential inputs consist of the
input pair A0-1. Note that no negative supply
can be applied to these pins, nor a supply
larger than VDD (unregulated power). It is the
difference between the pairs that are
converted in differential mode.
CC2480 Data Sheet SWRS074
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