AD7782BRUZ-REEL7 Analog Devices Inc, AD7782BRUZ-REEL7 Datasheet - Page 7

• Manufacturer Part Number: AD7782BRUZ-REEL7
• Description: 2 Chnl Non-writeable 24-bit ADC
• Manufacturer: Analog Devices Inc

Specifications of AD7782BRUZ-REEL7

• Number Of Bits: 24
• Sampling Rate (per Second): 19.79
• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 3.9mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP (0.173", 4.40mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Typical Performance Characteristics
ADC CIRCUIT INFORMATION
Overview
The AD7782 incorporates an analog multiplexer with a Σ-∆ ADC
channel, on-chip programmable gain amplifier, and on-chip digital
filtering intended for the measurement of wide dynamic range,
low-frequency signals such as those in weigh-scale, strain-gage,
pressure transducer, or temperature measurement applications.
This ADC input is buffered and can be programmed to have an
input voltage range of ± 160 mV or ± 2.56 V. The input channels
are configured as two fully differential inputs. Buffering the input
channels means that the part can accommodate significant source
impedances on the analog inputs and that R, C filtering (for
noise rejection or RFI reduction) can be placed on the analog
inputs if required. The device requires an external reference of
+2.5 V nominal. Figure 3 shows the basic connections required
to operate the part.
OUT–
SUPPLY
POWER
IN+
IN–
5
4
3
1
9
8
7
6
2
0
10 F
OUT+
10k
6k
0.1 F
AIN1(+)
AIN1(–)
AIN2(+)
AIN2(–)
REFIN(+)
REFIN(–)
AD7782
GND
V
DD
DOUT/RDY
XTAL1
XTAL2
SCLK
CS
32.768kHz
CRYSTAL
CONTROLLER
The output rate of the AD7782 (f
while the settling time equals:
Normal-mode rejection is the major function of the digital filter on
the AD7782. Simultaneous 50 Hz and 60 Hz rejection of better
than 60 dB is achieved as notches are placed at both 50 Hz and
60 Hz. Figure 4 shows the filter rejection.
–100
–120
–140
–160
–20
–40
–60
–80
3.0
2.5
2.0
1.5
1.0
0.5
0
0
1.0
0
OUTPUT DATA RATE = 19.8Hz
INPUT BANDWIDTH = 4.74Hz
50Hz REJECTION = –66dB, 50Hz
60Hz REJECTION = –117dB, 60Hz
V
V
T
DD
REF
A
10
= 25 C
f
1.5
= 5V
ADC
= 2.5V
t
SETTLE
20
=
2.0
2.56V RANGE
32 768 10
30
.
=
2.5



FREQUENCY – Hz
40
f
×
ADC
V
2
REF
3.0
50
ADC
3

 = ×

– V
/
1Hz REJECTION = –60dB
) equals:
1Hz REJECTION = –94dB
(
60
2
69
3.5
160mV RANGE
× ×
t
70
ADC
8 3
4.0
80
AD7782
)
4.5
90
100
5.0