Texas Instruments ADS868 Series, Manual

Page: 9 / 67

ADS8684, ADS8688
www.ti.com SBAS582C – JULY 2014 – REVISED APRIL 2015
Electrical Characteristics (continued)
Minimum and maximum specifications are at T
A
= –40°C to 125°C. Typical specifications are at T
A
= 25°C.
AVDD = 5 V, DVDD = 3 V, V
REF
= 4.096 V (internal), and f
SAMPLE
= 500 kSPS, unless otherwise noted.
TEST
(1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
LEVEL
DYNAMIC CHARACTERISTICS
Input range = ±2.5 × V
REF
90 92 dB A
Input range = ±1.25 × V
REF
89 91 dB A
Signal-to-noise ratio
SNR Input range = ±0.625 × V
REF
87.5 89 dB A
(V
IN
– 0.5 dBFS at 1 kHz)
Input range = 2.5 × V
REF
88.5 90.5 dB A
Input range = 1.25 × V
REF
87.5 89 dB A
Total harmonic distortion
(6)
THD All input ranges –102 dB B
(V
IN
– 0.5 dBFS at 1 kHz)
Input range = ±2.5 × V
REF
89 91.5 dB A
Input range = ±1.25 × V
REF
88.5 91 dB A
Signal-to-noise ratio
SINAD Input range = ±0.625 × V
REF
87 89 dB A
(V
IN
– 0.5 dBFS at 1 kHz)
Input range = 2.5 × V
REF
87.5 90.5 dB A
Input range = 1.25 × V
REF
87 89 dB A
Spurious-free dynamic range
SFDR All input ranges 103 dB B
(V
IN
– 0.5 dBFS at 1 kHz)
Aggressor channel input is
Crosstalk isolation
(7)
overdriven to 2 × maximum input 110 dB B
voltage
Aggressor channel input is
Crosstalk memory
(8)
overdriven to 2 × maximum input 90 dB B
voltage
BW
(–3 dB)
Small-signal bandwidth, –3 dB At T
A
= 25°C, all input ranges 15 kHz B
BW
(–0.1 dB)
Small-signal bandwidth, –0.1 dB At T
A
= 25°C, all input ranges 2.5 kHz B
AUXILIARY CHANNEL
Resolution 16 Bits A
V
(AUX_IN)
AUX_IN voltage range (AUX_IN – AUX_GND) 0 V
REF
V A
AUX_IN 0 V
REF
V A
Operating input range
AUX_GND 0 V A
During sampling 75 pF C
C
i
Input capacitance
During conversion 5 pF C
I
Ikg(in)
Input leakage current 100 nA A
DNL Differential nonlinearity –0.99 ±0.6 1.5 LSB A
INL Integral nonlinearity –4 ±1.5 4 LSB A
E
G(AUX)
Gain error At T
A
= 25°C ±0.02 ±0.2 % FSR A
E
O(AUX)
Offset error At T
A
= 25°C –10 10 mV A
SNR Signal-to-noise ratio V
(AUX_IN)
= –0.5 dBFS at 1 kHz 87 89 dB A
THD Total harmonic distortion
(6)
V
(AUX_IN)
= –0.5 dBFS at 1 kHz –102 dB B
SINAD Signal-to-noise + distortion V
(AUX_IN)
= –0.5 dBFS at 1 kHz 86 88.5 dB A
SFDR Spurious-free dynamic range V
(AUX_IN)
= –0.5 dBFS at 1 kHz 103 dB B
(6) Calculated on the first nine harmonics of the input frequency.
(7) Isolation crosstalk is measured by applying a full-scale sinusoidal signal up to 10 kHz to a channel, not selected in the multiplexing
sequence, and measuring its effect on the output of any selected channel.
(8) Memory crosstalk is measured by applying a full-scale sinusoidal signal up to 10 kHz to a channel, which is selected in the multiplexing
sequence, and measuring its effect on the output of the next selected channel, for all combinations of input channels.
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