Datasheet

REV. A
–2–
AD7776/AD7777/AD7778–SPECIFICATIONS
CLKIN = 8 MHz; RTN = O V; C
REFIN
= 10 nF; all specifications T
MIN
to T
MAX
unless otherwise noted.)
Parameter A Versions
1
Units Conditions/Comments
DC ACCURACY
Resolution
2
10 Bits
Relative Accuracy ± 1 LSB max See Terminology
Differential Nonlinearity ± 1 LSB max No Missing Codes; See Terminology
Bias Offset Error ± 12 LSB max See Terminology
Bias Offset Error Match 10 LSB max Between Channels, AD7777/AD7778 Only; See Terminology
Plus or Minus Full-Scale Error ± 12 LSB max See Terminology
Plus or Minus Full-Scale Error Match 10 LSB max Between Channels, AD7777/AD7778 Only; See Terminology
ANALOG INPUTS
Input Voltage Range
All Inputs V
BIAS
± V
SWING
V min/V max
Input Current +200 µA max V
IN
= V
BIAS
± V
SWING
; Any Channel
REFERENCE INPUT
REFIN 1.9/2.1 V min/V max For Specified Performance
REFIN Input Current +200 µA max
REFERENCE OUTPUT
REFOUT 1.9/2.1 V min/V max Nominal REFOUT = 2.0 V
DC Output Impedance 5 Ω typ
Reference Load Change ± 2 mV max For Reference Load Current Change of 0 to ± 500 µA
± 5 mV max For Reference Load Current Change of 0 to ± 1 mA
Reference Load Should Not Change During Conversion
Short Circuit Current
3
20 mA max See Terminology
LOGIC OUTPUTS
DB0–DB9, BUSY/INT
V
OL
, Output Low Voltage 0.4 V max I
SINK
= 1.6 mA
V
OH
, Output High Voltage 4.0 V min I
SOURCE
= 200 µA
Floating State Leakage Current ± 10 µA max
Floating State Capacitance
3
10 pF max
ADC Output Coding Twos Complement
LOGIC INPUTS
DB0–DB9, CS, WR, RD, CLKIN
Input Low Voltage, V
INL
0.8 V max
Input High Voltage, V
INH
2.4 V min
Input Leakage Current 10 µA max
Input Capacitance
3
10 pF max
CONVERSION TIMING
Acquisition Time 4.5 t
CLKIN
ns min See Terminology
5.5 t
CLKIN
+ 70 ns max
Single Conversion 14 t
CLKIN
ns max
Double Conversion 28 t
CLKIN
ns max
t
CLKIN
125/500 ns min/ns max Period of Input Clock CLKIN
t
CLKIN
High 50 ns min Minimum High Time for CLKIN
t
CLKIN
Low 40 ns min Minimum Low Time for CLKIN
POWER REQUIREMENTS
V
CC
Range 4.75/5.25 V min/V max For Specified Performance
I
CC
, Normal Mode 15 mA max CS = RD = +5 V, CR8 = 0
I
CC
, Power-Down Mode 1.5 mA max CR8 = 1. All Linear Circuitry OFF
Power-Up Time to Operational
Specifications 500 µs max From Power-Down Mode
DYNAMIC PERFORMANCE See Terminology
Signal to Noise and Distortion
S/(N+D) Ratio –56 dB min V
IN
= 99.88 kHz Full-Scale Sine Wave with f
SAMPLING
= 380.95 kHz
Total Harmonic Distortion (THD) –60 dB min V
IN
= 99.88 kHz Full-Scale Sine Wave with f
SAMPLING
= 380.95 kHz
Intermodulation Distortion (IMD) –75 dB typ fa = 103.2 kHz, fb = 96.5 kHz with f
SAMPLING
= 380.95 kHz. Both
Signals Are Sine Waves at Half-Scale Amplitude
Channel-to-Channel Isolation –90 dB typ V
IN
= 100 kHz Full-Scale Sine Wave with f
SAMPLING
= 380.95 kHz
NOTES
1
Temperature range as follows: A = –40°C to +85°C.
2
1 LSB = (2 × V
SWING
)/1024 = 1.95 mV for V
SWING
= 1.0 V.
3
Guaranteed by design, not production tested.
Specifications subject to change without notice.
(V
CC
= +5 V ⴞ 5%; AGND = DGND = O V;