AD7940 Analog Devices, AD7940 Datasheet - Page 9

• Manufacturer Part Number: AD7940
• Description: 3 mW, 100 kSPS, 14-Bit ADC in 6-Lead SOT-23
• Manufacturer: Analog Devices

Specifications of AD7940

• Resolution (bits): 14bit
• # Chan: 1
• Sample Rate: 100kSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Uni
• Ain Range: Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SOP,SOT

TYPICAL PERFORMANCE CHARACTERISTICS
Figure 5 shows a typical FFT plot for the AD7940 at 100 kSPS
sample rate and 10 kHz input frequency. Figure 6 shows the
signal-to-(noise + distortion) ratio performance versus the
input frequency for various supply voltages while sampling at
100 kSPS with an SCLK of 2.5 MHz.
–100
–120
–140
–160
–20
–40
–60
–80
90
85
80
75
0
10
0
Figure 5. AD7940 Dynamic Performance at 100 kSPS
Figure 6. AD7940 SINAD vs. Analog Input Frequency
F
T
SAMPLE
A
= 25
for Various Supply Voltages at 100 kSPS
°
C
= 100kSPS
10k
V
DD
INPUT FREQUENCY (kHz)
= 5.25V
FREQUENCY (kHz)
20k
V
DD
= 2.5V
V
DD
= 4.75V
30k
V
F
F
SNR = 84.48dB
SINAD = 84.35dB
THD = –98.97dB
SFDR = –100.84dB
DD
SAMPLE
IN
= 10kHz
= 4.75V
40k
V
V
V
V
= 100kSPS
DD
DD
DD
DD
= 4.3V
= 3.6V
= 3V
= 2.7V
100
50k
Rev. A | Page 9 of 20
Figure 7 shows a graph of the total harmonic distortion versus
the analog input frequency for various supply voltages, while
Figure 8 shows a graph of the total harmonic distortion versus
the analog input frequency for various source impedances (see
the Analog Input section). Figure 9 and Figure 10 show the
typical INL and DNL plots for the AD7940.
110
105
100
110
105
100
95
90
85
80
95
90
85
80
75
70
10
10
V
F
T
F
T
V
V
Figure 7. AD7940 THD vs. Analog Input Frequency
Figure 8. AD7940 THD vs. Analog Input Frequency
DD
SAMPLE
A
SAMPLE
A
DD
DD
= 25
= 25
= 5.25V
= 4.75V
V
= 3V
DD
for Various Supply Voltages at 100 kSPS
°
°
C
C
= 100kSPS
= 100kSPS
= 4.75V
for Various Source Impedances
V
DD
= 3.6V
INPUT FREQUENCY (kHz)
INPUT FREQUENCY (kHz)
V
DD
= 2.5V
V
V
DD
DD
= 2.7V
= 4.3V
R
R
R
R
IN
IN
IN
IN
= 10Ω
= 50Ω
= 100Ω
= 1000Ω
AD7940
100
100