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AD7871/AD7872
–3–
REV. D
TIMNGCHARACTERISTICS
1, 2
Limit at T
MIN
, T
MAX
(J, K, A, B Versions)
Limit at T
MIN
, T
MAX
(T Version)
Parameter
Units
Conditions/Comments
t
1
t
2
t
3
t
4
t
5
t
63
t
74
50
0
60
0
70
57
5
50
0
0
100
440
155
140
20
4
100
60
120
200
0
0
0
50
0
75
0
70
70
5
50
0
0
100
440
155
150
20
4
100
60
120
200
0
0
0
ns min
ns min
ns min
ns min
ns min
ns max
ns min
ns max
ns min
ns min
ns min
ns min
ns max
ns max
ns min
ns min
ns max
ns min
ns max
ns min
ns min
ns min
ns min
CONVST
Pulse Width
CS
to
RD
Setup T ime (Mode 1)
RD
Pulse Width
CS
to
RD
Hold T ime (Mode 1)
RD
to
INT
Delay
Data Access T ime after
RD
Bus Relinquish T ime after
RD
t
8
t
9
t
t
10
t
126
t
13
HBEN to
RD
Setup T ime
HBEN to
RD
Hold T ime
SSTRB
to SCLK Falling
Edge Setup T ime
SCLK Cycle T ime
SCLK to Valid Data Delay. C
L
= 35 pF
SCLK Rising Edge to
SSTRB
t
14
Bus Relinquish T ime after SCLK
t
15
t
t
16
t
18
t
19
t
20
CS
to
RD
Setup T ime (Mode 2)
CS
to
BUSY
Propagation Delay
Data Setup T ime Prior to BUSY
CS
to
RD
Hold T ime (Mode 2)
HBEN to
CS
Setup T ime
HBEN to
CS
Hold T ime
NOT ES
1
T iming Specifications in
bold print
are 100% production tested. All other times are sample tested at +25
°
C to ensure compliance. All input signals are specified with
tr = tf = 5 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V.
2
Serial timing is measured with a 4.7 k
pull-up resistor on SDAT A and
SSTRB
and a 2 k
pull-up resistor on SCLK . T he capacitance on all three outputs is 35 pF.
3
t
6
and t
are measured with the load circuits of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V.
4
t
is derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 2. T he measured number is then extrapolated
back to remove the effects of charging or discharging the 50 pF capacitor. T his means that the time, t
7
, quoted in the T iming Characteristics is the true bus relinquish
time of the part and is independent of bus loading.
5
SCLK mark/space ratio (measured from a voltage level of 1.6 V) is 40/60 to 60/40.
6
SDAT A will drive higher capacitive loads, but this will add to t
12
since it increases the external RC time constant (4.7 k
//C
L
) and hence the time to reach 2.4 V.
Specifications subject to change without notice.
ABSOLUT E MAX IMUM RAT INGS*
V
DD
to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
V
SS
to AGND . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to –7 V
AGND to DGND . . . . . . . . . . . . . . . . –0.3 V to V
DD
+ 0.3 V
V
IN
to AGND . . . . . . . . . . . . . . . . V
SS
–0.3 V to V
DD
+ 0.3 V
REF OUT , C
REF
to AGND . . . . . . . . . . . . . . . . . . 0 V to V
DD
Digital Inputs to DGND . . . . . . . . . . . –0.3 V to V
DD
+ 0.3 V
Digital Outputs to DGND . . . . . . . . . . –0.3 V to V
DD
+ 0.3 V
Operating T emperature Range
Commercial (J, K Versions) . . . . . . . . . . . . . . 0
°
C to +70
°
C
Industrial (A, B Versions) . . . . . . . . . . . . . –40
°
C to +85
°
C
Extended (T Version) . . . . . . . . . . . . . . . –55
°
C to +125
°
C
Storage T emperature Range . . . . . . . . . . . . –65
°
C to +150
°
C
Lead T emperature (Soldering, 10 sec) . . . . . . . . . . . . +300
°
C
Power Dissipation (Any Package) to +75
°
C . . . . . . . . 450 mW
Derates above +75
°
C by . . . . . . . . . . . . . . . . . . . . . 6 mW/
°
C
*Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. T his is a stress rating only; functional operation
of the device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
WARNING!
ESD SENSITIVE DEVICE
C AUT ION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD7871/AD7872 features proprietary ESD protection circuitry, permanent dam-
age may occur on devices subjected to high energy electrostatic discharges. T herefore, proper
ESD precautions are recommended to avoid performance degradation or loss of functionality.
Figure 1. Load Circuit for Access Time
Figure 2. Load Circuit for Output Float Delay
(V
DD
= +5 V
6
5%, V
SS
= –5 V
6
5%, AGND = DGND = OV. See Figures 9, 10, 11 and 12.)