aduc7062 Analog Devices, Inc., aduc7062 Datasheet - Page 31

• Manufacturer Part Number: aduc7062
• Description: Low-power, Precision Analog Microcontroller, Dual ?-? Adcs, Flash/ee, Arm7tdmi
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
Table 29. Primary ADC: Typical Output RMS noise in Normal Mode
ADC
Register
(Chop
On)
(Chop
Off)
(Chop
Off)
(Chop
Off)
Table 30. Auxillary ADC: Typical Output RMS Noise
ADC Register
Chop On
Chop On
Chop Off
Chop Off
Reference Sources
Both the primary and secondary ADCs have the option of using
the internal reference voltage or, one of two external differential
reference sources. The first external reference is applied to the
VREF+/VREF− pins. The second external reference is applied
to the ADC4 (EXT_VREF2+) and ADC5 (EXT_VREF2−) pins.
By default, each ADC uses the internal 1.2 V reference source.
For details on how to configure the external reference source for
the primary ADC, see the description of the ADC0REF[1:0]
bits in the ADC0 control register, ADC0CON.
For details on how to configure the external reference source for
the auxiliary ADC, see the description of the ADC1REF[2:0]
bits in the ADC1 control register, ADC1CON.
If an external reference source of greater than 1.35 V is needed
for ADC0, the HIGHEXTREF0 bit must be set in ADC0CON.
Similarly, if an external reference source of greater than 1.35 V
is used for ADC1, set the HIGHEXTREF1 bit in ADC1CON.
Data
Update
Rate
4 Hz
50 Hz
1 kHz
8 kHz
Data Update
Rate
4 Hz
10 Hz
1 kHz
8 kHz
±2.34 mV
(512)
0.033 μV
0.098 μV
0.52 μV
0.909 μV
±4.68 mV
(256)
0.032 μV
0.098 μV
0.56 μV
0.915 μV
0.633
0.810
RMS value
7.4
54.18
μ
V
μ
μ
μ
±9.375 mV
(128)
0.0338 μV
0.12 μV
0.55 μV
1.75 μV
V
V
V
±18.75 mV
(64)
0.032 μV
0.123 μV
0.53 μV
1.71 μV
Rev. PrA | Page 31 of 100
±37.5 mV
(32)
0.041 μV
0.147 μV
0.658 μV
2.5 μV
Note, if an external reference source of greater than 1.35 V is
used for ADC0, the HIGHEXTREF0 bit must be set in
ADC0CON. Similarly, an external reference source of greater
than 1.35 V is used for ADC1, the HIGHEXTREF1 bit must be
set in ADC1CON.
Diagnostic Current Sources
To detect a connection failure to an external sensor, the
ADuC706x incorporates 50 μA constant current sources on the
selected analog input channels to both the primary and
auxiliary ADCs.
The diagnostic current sources for the primary ADC analog
inputs are controlled by the ADC0DIAG[1:0] bits in the
ADC0CON register.
Similarly, the diagnostic current sources for the auxiliary ADC
analog inputs are controlled by the ADC1DIAG[1:0] bits in the
ADC0CON register.
Figure 10. Example Circuit Using Diagnostic Current Sources
AVDD
±75 mV
(16)
0.077 μV
0.27 μV
1.17 μV
4.59 μV
ADuC7060/ADuC7061/ADuC7062
A
A
R1
R2
±150 mV
(8)
0.109 μV
0.38 μV
1.6 μV
7.88 μV
B
B
AIN0 (+)
AIN1 (–)
±300 mV
(4)
0.175μV
0.570 μV
2.55 μV
14.30 μV
±600 mV
(2)
0.648 μV
1.89 μV
8.4 μV
55.54 μV
VIN =
AIN0,
AIN1
±1.2 V
(1)
0.62 μV
1.97 μV
8.54 μV
54.97 μV