AD7898AR-10 Analog Devices Inc, AD7898AR-10 Datasheet - Page 7

• Manufacturer Part Number: AD7898AR-10
• Description: A/D Converter (A-D) IC
• Manufacturer: Analog Devices Inc

Specifications of AD7898AR-10

• No. Of Bits: 12 Bit
• Mounting Type: Surface Mount
• No. Of Channels: 1
• Interface Type: Serial
• Package / Case: 8-SOIC
• Rohs Status: RoHS non-compliant
• Number Of Bits: 12
• Sampling Rate (per Second): 220k
• Data Interface: Serial
• Number Of Converters: 1
• Power Dissipation (max): 22.5mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C

PERFORMANCE CURVES
TPC 1 shows a typical FFT plot for the AD7898 at 220 kSPS
sampling rate with a 30 kHz input frequency while operating in
Mode 0.
TPC 2 shows a typical FFT plot for the AD7898 at 220 kSPS
sampling rate with a 30 kHz input frequency while operating in
Mode 1.
TPC 3 shows the Power Supply Rejection Ratio versus supply
frequency for the AD7898. The power supply rejection ratio is
defined as the ratio of the power in the ADC output at full-scale
frequency f, to the power of a 100 mV sine wave applied to the
ADC V
Pf = Power at frequency f in ADC output, Pfs = power at fre-
quency fs coupled on to the ADC V
100 mV peak-to-peak sine wave is coupled onto the V
100 nF decoupling was used on the supply.
REV. A
–115
–115
DD
–15
–35
–55
–75
–95
–15
–35
–55
–75
–95
5
5
supply of frequency f
0
0
TPC 1. Mode 0 Dynamic Performance
TPC 2. Mode 1 Dynamic Performance
20
20
PSRR (dB) = 10 log (Pf/Pfs)
40
FREQUENCY – kHz
40
FREQUENCY – kHz
S
.
DD
60
60
supply input. Here a
8192 POINT FFT
f
f
SINAD = 71.823dB
THD = –90.28dB
SFDR = –91.467dB
8192 POINT FFT
f
f
SINAD = 71.779dB
THD = –88.337dB
SFDR = –89.639dB
SAMPLE
IN
SAMPLE
IN
= 30kHz
= 30kHz
80
80
= 220kSPS
= 220kSPS
100
100
DD
Typical Performance Characteristics–AD7898
supply.
–7–
TPC 4 shows a graph of effective number of bits versus input
frequency while sampling at 220 kSPS.
The effective number of bits for a device can be calculated from
its measured Signal to (Noise + Distortion) Ratio (see Termi-
nology section). TPC 4 shows a typical plot of effective number
of bits versus frequency for the AD7898 from dc to f
The sampling frequency is 220 kSPS.
The formula for Signal to (Noise + Distortion) Ratio is related
to the resolution or number of bits in the converter. Rewriting
the formula, below, gives a measure of performance expressed in
effective number of bits (N):
where SNR is Signal to (Noise + Distortion) Ratio.
TPC 4. Effective Number of Bits vs. Input Frequency at
220 kSPS
11.9
11.8
11.7
11.6
11.5
11.4
11.3
11.2
–20
–30
–40
–50
–60
–70
–80
TPC 3. PSRR vs. Supply Ripple Frequency
0
0
10
20
N = (SNR – 1.76)/6.02
20
INPUT FREQUENCY – kHz
INPUT FREQUENCY – kHz
30
40
40
50
60
60
80
70
SAMPLE/2
80
100
.