MCP3901EV-MCU16 Microchip Technology, MCP3901EV-MCU16 Datasheet - Page 23

• Manufacturer Part Number: MCP3901EV-MCU16
• Description: BOARD EVAL FOR 2CH ADC MCP3901
• Manufacturer: Microchip Technology

Specifications of MCP3901EV-MCU16

• Number Of Adc's: 2
• Number Of Bits: 24
• Data Interface: SPI™
• Inputs Per Adc: 1 Differential
• Input Range: ±1 V
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: MCP3901
• Silicon Manufacturer: Microchip
• Application Sub Type: ADC
• Kit Application Type: Data Converter
• Silicon Core Number: MCP3901, PIC24F, PIC24H, DsPIC33, PIC18F86J55
• Kit Contents: Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.16
The crosstalk is defined as the perturbation caused by
one ADC channel on the other ADC channel. It is a
measurement of the isolation between the two ADCs
present in the chip.
This measurement is a two-step procedure:
1.
2.
The crosstalk is then the ratio between the output
power of the ADC when the perturbation is present and
when it is not divided by the power of the perturbation
signal.
A higher crosstalk value implies more independence
and isolation between the two channels.
The measurement of this signal is performed under the
following conditions:
• GAIN = 1,
• PRESCALE = 1,
• OSR = 256,
• MCLK = 4 MHz
Step 1
• CH0+ = CH0- = AGND
• CH1+ = CH1- = AGND
Step 2
• CH0+ = CH0- = AGND
• CH1+ – CH1- = 1 V
The crosstalk is then calculated with the following
formula:
EQUATION 4-10:
4.17
This is the ratio between a change in the power supply
voltage and the ADC output codes. It measures the
influence of the power supply voltage on the ADC
outputs.
The PSRR specification can be DC (the power supply
is taking multiple DC values) or AC (the power supply
is a sinewave at a certain frequency with a certain
common-mode). In AC, the amplitude of the sinewave
is representing the change in the power supply.
© 2010 Microchip Technology Inc.
sine wave)
Measure one ADC input with no perturbation on
the other ADC (ADC inputs shorted).
Measure
perturbation sine wave signal on the other ADC
at a certain predefined frequency.
CTalk dB
Crosstalk
PSRR
(
the
)
=
same
P-P
10
log
@ 50/60 Hz (full-scale
⎛
⎝
Δ
-------------------------------- -
Δ
ADC
CH0Power
CH1Power
input
⎞
⎠
with
a
It is defined as:
EQUATION 4-11:
Where V
output code translates to with the ADC transfer
function. In the MCP3901 specification, AV
from 4.5V to 5.5V, and for AC PSRR, a 50/60 Hz
sinewave is chosen, centered around 5V with a
maximum 500 mV amplitude. The PSRR specification
is measured with AV
4.18
This is the ratio between a change in the
common-mode input voltage and the ADC output
codes. It measures the influence of the common-mode
input voltage on the ADC outputs.
The
common-mode input voltage is taking multiple DC
values) or AC (the common-mode input voltage is a
sinewave at a certain frequency with a certain
common-mode). In AC, the amplitude of the sinewave
is representing the change in the power supply.
It is defined as:
EQUATION 4-12:
Where V
input voltage and V
the output code is translated to the ADC transfer
function. In the MCP3901 specification, VCM varies
from -1V to +1V, and for the AC specification, a 50/
60 Hz sinewave is chosen, centered around 0V, with a
500 mV amplitude.
4.19
ADC Reset mode (also called Soft Reset mode) can
only be entered through setting the RESET<1:0> bits
high in the Configuration register. This mode is defined
as the condition where the converters are active, but
their output is forced to ‘0’.
The registers are not affected in this Reset mode and
retain their values.
The ADCs can immediately output meaningful codes
after leaving Reset mode (and after the sinc filter set-
tling time of 3/DRCLK). This mode is both entered and
exited through the setting of bits in the Configuration
register.
CMRR
CM
CMRR
ADC Reset Mode
OUT
CMRR dB
PSRR dB
= (CHn+ + CHn-)/2 is the common-mode
is the equivalent input voltage that the
specification
(
(
OUT
DD
)
)
=
=
= DV
is the equivalent input voltage,
20
20
log
log
DD
MCP3901
⎛
⎝
.
⎛
⎝
------------------ -
Δ
Δ
can
Δ
-----------------
Δ
AV
V
V
V
OUT
OUT
CM
DD
DS22192C-page 23
be
⎞
⎠
⎞
⎠
DC
DD
varies
(the