Datasheet

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ELECTRICAL CHARACTERISTICS: +V
CC
= +2.7V
ADS7822
SBAS062C – JANUARY 1996 – REVISED AUGUST 2007
At – 40 ° C to +85 ° C, +V
CC
= +2.7V, V
REF
= +2.5V, f
SAMPLE
= 75kHz, and f
CLK
= 16 × f
SAMPLE
, unless otherwise noted.
ADS7822 ADS7822B ADS7822C
PARAMETER TEST CONDITIONS UNIT
MIN TYP MAX MIN TYP MAX MIN TYP MAX
ANALOG INPUT
Full-scale input span +In – ( – In) 0 V
REF
0 V
REF
0 V
REF
V
+In – GND – 0.2 V
CC
+ 0.2 – 0.2 V
CC
+ 0.2 – 0.2 V
CC
+ 0.2 V
Absolute input range
– In – GND – 0.2 +1.0 – 0.2 +1.0 – 0.2 +1.0 V
Capacitance 25 25 25 pF
Leakage current ± 1 ± 1 ± 1 μ A
SYSTEM PERFORMANCE
Resolution 12 12 12 Bits
No missing codes 11 12 11 Bits
Integral linearity error – 2 ± 0.5 +2 – 1 ± 0.5 +1 – 0.75 ± 0.25 +0.75 LSB
(1)
Differential linearity error – 2 ± 0.5 +2 – 1 ± 0.5 +1 – 0.75 ± 0.25 +0.75 LSB
Offset error – 3 +3 – 3 +3 – 1 +1 LSB
Gain error – 3 +3 – 3 +3 – 1 +1 LSB
Noise 33 33 33 μ Vrms
Power-supply rejection 82 82 82 dB
SAMPLING DYNAMICS
Conversion time 12 12 12 Clk Cycles
Acquisition time 1.5 1.5 1.5 Clk Cycles
Throughput rate 75 75 75 kHz
DYNAMIC CHARACTERISTICS
Total harmonic distortion V
IN
= 2.5V
PP
at 1kHz – 82 – 82 – 82 dB
SINAD V
IN
= 2.5V
PP
at 1kHz 71 71 71 dB
Spurious-free dynamic range V
IN
= 2.5V
PP
at 1kHz 86 86 86 dB
REFERENCE OUTPUT
Voltage range 0.05 V
CC
0.05 V
CC
0.05 V
CC
V
CS = GND, f
SAMPLE
= 0Hz 5 5 5 G Ω
Resistance
CS = V
CC
5 5 5 G Ω
At code 710h 8 40 8 40 8 40 μ A
Current drain f
SAMPLE
= 7.5kHz 0.8 0.8 0.8 μ A
CS = V
CC
0.001 3 0.001 3 0.001 3 μ A
DIGITAL INPUT/OUTPUT
Logic family CMOS CMOS CMOS
V
IH
I
IH
= +5 μ A 2.0 5.5 2.0 5.5 2.0 5.5 V
V
IL
I
IL
= +5 μ A – 0.3 0.8 – 0.3 0.8 – 0.3 0.8 V
Logic levels
V
OH
I
OH
= – 250 μ A 2.1 2.1 2.1 V
V
OL
I
OL
= 250 μ A 0.4 0.4 0.4 V
Data format Straight Binary Straight Binary Straight Binary
POWER-SUPPLY REQUIREMENTS
Specified performance 2.7 3.6 2.7 3.6 2.7 3.6 V
V
CC
See Notes
(2)
and
(3)
2.0 2.7 2.0 2.7 2.0 2.7 V
See Note
(3)
2.7 3.6 2.7 3.6 2.7 3.6 V
f
SAMPLE
= 7.5kHz
(4) (5)
20 20 20 μ A
Quienscent current
f
SAMPLE
= 75kHz
(5)
200 325 200 325 200 325 μ A
Power down CS = V
CC
3 3 3 μ A
TEMPERATURE RANGE
Specified performance – 40 +85 – 40 +85 – 40 +85 ° C
(1) LSB means least significant bit. With V
REF
equal to +2.5V, one LSB is 0.61mV.
(2) The maximum clock rate of the ADS7822 is less than 1.2MHz in this power-supply range.
(3) See the Typical Characteristics for more information.
(4) f
CLK
= 1.2MHz, CS = V
CC
for 145 clock cycles out of every 160.
(5) See the Power Dissipation section for more information regarding lower sample rates.
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