AD7450ARMZ Analog Devices Inc, AD7450ARMZ Datasheet - Page 11

IC ADC 12BIT DIFF IN 1MSPS 8MSOP

AD7450ARMZ

Manufacturer Part Number
AD7450ARMZ
Description
IC ADC 12BIT DIFF IN 1MSPS 8MSOP
Manufacturer
Analog Devices Inc
Datasheet

Specifications of AD7450ARMZ

Data Interface
DSP, MICROWIRE™, QSPI™, Serial, SPI™
Number Of Bits
12
Sampling Rate (per Second)
1M
Number Of Converters
1
Power Dissipation (max)
9.25mW
Voltage Supply Source
Single Supply
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Resolution (bits)
12bit
Input Channel Type
Differential
Supply Voltage Range - Analogue
2.7V To 3.3V, 4.75V To 5.25V
Supply Current
1.8mA
No. Of Pins
8
Operating
RoHS Compliant
Sampling Rate
1MSPS
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
EVAL-AD7450CBZ - BOARD EVALUATION FOR AD7450
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD7450ARMZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
THE ANALOG INPUT
The analog input of the AD7450 is fully differential. Differential
signals have a number of benefits over single-ended signals,
including noise immunity based on the device’s common-mode
rejection, improvements in distortion performance, doubling of
the device’s available dynamic range, and flexibility in input ranges
and bias points.
Figure 7 defines the fully differential analog input of the AD7450.
The amplitude of the differential signal is the difference between
the signals applied to the V
V
amplitude V
the differential signal is therefore –V
(i.e., 2
The common mode is the average of the two signals, i.e.,
(V
are centered on. This results in the span of each input being
CM ± V
range varies with V
mon-mode range decreases. When driving the inputs with an
amplifier, the actual common-mode range will be determined
by the amplifier’s output voltage swing.
REV. 0
V
V
IN+
REF
REF
IN+
and V
p-p
p-p
*CM = COMMON-MODE VOLTAGE
+ V
COMMON-MODE
REF
V
IN–
Figure 6. Typical Connection Diagram
IN–
REF
/2. This voltage has to be set up externally and its
Figure 7. Differential Input Definition
VOLTAGE
REF
)/2, and is therefore the voltage that the two inputs
are simultaneously driven by two signals each of
). This is regardless of the common mode (CM).
that are 180° out of phase. The amplitude of
CM*
CM*
REF
. As the value of V
V
V
V
V
REF
DD
IN+
IN–
0.1 F
IN+
V
V
0.1 F
REF
REF
AD7450
1.25V/2.5V
and V
V
p-p
p-p
REF
IN–
10 F
SDATA
REF
SCLK
pins (i.e., V
GND
REF
CS
3V/5V
SUPPLY
V
to +V
V
IN+
IN–
increases, the com-
SERIAL
INTERFACE
AD7450
REF
IN+
p-p
– V
C/ P
IN–
).
–11–
Figures 8 and 9 show how the common-mode range typically
varies with V
common mode must be in this range to guarantee the
functionality of the AD7450.
For ease of use, the common mode can be set up to be equal to
V
on V
rejected resulting in a virtually noise free signal of amplitude
–V
Figure 9. Input Common-Mode Range vs. V
and V
Figure 10 shows examples of the inputs to V
different values of V
mum and minimum common-mode voltages for each reference
value according to Figure 8.
REF
REF
, resulting in the differential signal being ± V
REF
Figure 8. Input Common-Mode Range vs. V
(V
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
REF
to +V
3.0
2.5
2.0
1.5
1.0
0.5
0
. When a conversion takes place, the common mode is
0.25
DD
0
0.25
(Max) = 2.2 V)
= 5 V and V
REF
REF
0.50
0.75
corresponding to the digital codes of 0 to 4095.
for both a 5 V and a 3 V power supply. The
0.75
REF
1.25
COMMON-MODE RANGE
COMMON-MODE RANGE
REF
for V
1.00
(Max) = 3.5 V)
1.75
DD
V
REF
V
1.25
= 5 V. It also gives the maxi-
REF
2.25
1.50
2.75
1.75
IN+
AD7450
and V
REF
REF
2.00
3.25 3.50
(V
centered
DD
IN–
REF
2.20
3.25V
1.75V
= 3 V
2V
1V
for

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