Datasheet

–2–
REV. 0
AD7895–SPECIFICATIONS
Parameter A Versions
l
B Versions Units Test Conditions/Comments
DYNAMIC PERFORMANCE
2
Signal to (Noise + Distortion) Ratio
3
@ +25°C 70 70 dB min f
IN
= 50 kHz Sine Wave, f
SAMPLE
= 200 kHz
T
MIN
to T
MAX
70 70 dB min
Total Harmonic Distortion (THD)
3
–78 –78 dB max f
IN
= 50 kHz Sine Wave, f
SAMPLE
= 200 kHz,
Typically –87 dB
Peak Harmonic or Spurious Noise
3
–89 –89 dB typ f
IN
= 50 kHz Sine Wave, f
SAMPLE
= 200 kHz
Intermodulation Distortion (IMD)
3
fa = 9 kHz, fb = 9.5 kHz, f
SAMPLE
= 200 kHz
2nd Order Terms –87 –87 dB typ
3rd Order Terms –87 –87 dB typ
DC ACCURACY
Resolution 12 12 Bits
Minimum Resolution for which
No Missing Codes are Guaranteed 12 12 Bits
Relative Accuracy
3
±1 ±1 LSB max Typically 0.4 LSB
Differential Nonlinearity
3
±1 ±1 LSB max
Positive Full-Scale Error
3
±3 ±2 LSB max
AD7895-2
Unipolar Offset Error ±3 ±2 LSB max
AD7895-10, AD7895-3 Only
Negative Full-Scale Error
3
±3 ±2 LSB max
Bipolar Zero Error ±4 ±3 LSB max
ANALOG INPUT
AD7895-10
Input Voltage Range ±10 ±10 Volts
Input Resistance 24 24 kΩ min
AD7895-3
Input Voltage Range ±2.5 ±2.5 Volts
Input Resistance 9 9 kΩ min
AD7895-2
Input Voltage Range 0 to +2.5 0 to +2.5 Volts
Input Current 500 500 nA max
REFERENCE INPUT
REF IN Input Voltage Range 2.375/2.625 2.375/2.625 V min/V max 2.5 V ± 5%
Input Current 1 1 µA max
Input Capacitance
3
10 10 pF max
LOGIC INPUTS
Input High Voltage, V
INH
2.4 2.4 V min V
DD
= 5 V ± 5%
Input Low Voltage, V
INL
0.8 0.8 V max V
DD
= 5 V ± 5%
Input Current, I
IN
±10 ±10 µA max V
IN
= 0 V to V
DD
Input Capacitance, C
IN
4
10 10 pF ax
LOGIC OUTPUTS
Output High Voltage, V
OH
4.0 4.0 V min I
SOURCE
= 200 µA
Output Low Voltage, V
OL
0.4 0.4 V max I
SINK
= 1.6 mA
Output Coding
AD7895-10, AD7895-3 2s Complement
AD7895-2 Straight (Natural) Binary
CONVERSION RATE
Conversion Time
Mode 1 Operation 3.8 3.8 µs max
Mode 2 Operation
5
9.8 9.8 µs max
Track/Hold Acquisition Time
3
0.5 0.5 µs max
POWER REQUIREMENTS
V
DD
+5 +5 V nom ±5% for Specified Performance
I
DD
4 4 mA max Digital Inputs @ V
DD
, V
DD
= 5 V ± 5%
Power Dissipation 20 20 mW max Typically 16 mW
Power-Down Mode
I
DD
@ +25°C55µA max Digital Inputs @ GND, V
DD
= 5 V ± 5%
T
MIN
to T
MAX
10 10 µA max Digital Inputs @ GND, V
DD
= 5 V ± 5%
Power Dissipation @ +25°C2525 µW max
NOTES
1
Temperature ranges are as follows: A, B Versions: –40°C to +85°C.
2
Applies to Mode 1 operation. See section on “Operating Modes.”
3
See Terminology.
4
Sample tested @ +25°C to ensure compliance.
5
This 9.8 µs includes the “wake-up” time from standby. This “wake-up” time is timed from the rising edge of CONVST, whereas conversion is timed from the falling edge of CONVST, for
narrow
CONVST pulse width the conversion time is effectively the “wake-up” time plus conversion time hence 9.8 µs. This can be seen from Figure 3. Note that if the CONVST pulse width
is greater than 6 µs then the effective conversion time will increase beyond 9.8 µs.
Specifications subject to change without notice.
(V
DD
= +5 V, GND = 0 V, REF IN = +2.5 V.
All specifications T
MIN
to T
MAX
unless otherwise noted)