
–5–
REV. D
AD7701
TIMNGCHARACTERISTICS
1, 2
Limit at T
MIN
, T
MAX
(A, B Versions)
Limit at T
MIN
, T
MAX
(S, T Versions)
Parameter
Units
Conditions/Comments
f
CLK IN3, 4
200
5
200
5
50
50
0
50
1000
200
5
200
5
50
50
0
50
1000
kHz min
MHz max
kHz min
MHz max
ns max
ns max
ns min
ns min
ns min
Master Clock Frequency: Internal Gate Oscillator
T ypically 4.096 MHz
Master Clock Frequency: Externally Supplied
t
r5
t
f5
t
1
t
2
t
36
Digital Output Rise T ime. T ypically 20 ns
Digital Output Fall T ime. T ypically 20 ns
SC1, SC2 to CAL High Setup T ime
SC1, SC2 Hold T ime After CAL Goes High
SLEEP
High to CLK IN High Setup T ime
SSC Mode
t
47
t
5
t
6
t
7
t
8
t
98
t
108, 9
3/f
CLK IN
100
250
300
790
l/f
CLK IN
+200
(4/f
CLK IN
) +200
3/f
CLK IN
100
250
300
790
l/f
CLK IN
+200
(4/f
CLK IN
) +200
ns max
ns max
ns min
ns max
ns max
ns max
ns max
Data Access T ime (
CS
Low to Data Valid)
SCLK Falling Edge to Data Valid Delay (25 ns typ)
MSB Data Setup T ime. T ypically 380 ns
SCLK High Pulse Width. T ypically 240 ns
SCLK Low Pulse Width. T ypically 730 ns
SCLK Rising Edge to Hi-Z Delay (l/f
CLK IN
+ 100 ns typ)
CS
High to Hi-Z Delay
SEC Mode
f
SCLK
t
11
t
12
t
137, 10
t
1411
t
158
t
168
5
35
160
160
150
250
200
5
35
160
160
150
250
200
MHz
ns min
ns min
ns max
ns max
ns max
ns max
Serial Clock Input Frequency
SCLK Input High Pulse Width
SCLK Low Pulse Width
Data Access T ime (
CS
Low to Data Valid). T ypically 80 ns
SCLK Falling Edge to Data Valid Delay. T ypically 75 ns
CS
High to Hi-Z Delay
SCLK Falling Edge to Hi-Z Delay. T ypically 100 ns
AC Mode
t
17
t
18
t
19
40
180
200
40
180
200
ns min
ns max
ns max
CS
Setup T ime. T ypically 20 ns
Data Delay T ime. T ypically 90 ns
SCLK Falling Edge to Hi-Z Delay. T ypically 100 ns
NOT ES
1
1
Sample tested at +25
°
C to ensure compliance. All input signals are specified with t
r
= t
f
= 5 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V.
1
2
See Figures 1 to 6.
1
3
CLK IN Duty Cycle range is 20% to 80%. CLK IN must be supplied whenever the AD7701 is not in SLEEP mode. If no clock is present in this case, the device can
draw higher current than specified and possibly become uncalibrated.
1
4
T he AD7701 is production tested with f
CLK IN
at 4.096 MHz. It is guaranteed by characterization to operate at 200 kHz.
1
5
Specified using 10% and 90% points on waveform of interest.
1
6
In order to synchronize several AD7701s together using the
SLEEP
pin, this specification is met.
1
7
t
4
and t
13
are measured with the load circuit of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V.
1
8
t
9
, t
10
, t
15
and t
16
are derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. T he measured number is
then extrapolated back to remove the effects of charging or discharging the 100 pF capacitor. T his means that the time quoted in the T iming Characteristics is the
true bus relinquish time of the part and as such as independent of external bus loading capacitance.
1
9
If
CS
is returned high before all 16 bits are output, the SDAT A and SCLK outputs will complete the current data bit and then go to high impedance.
10
If
CS
is activated asynchronously to
DRDY
,
CS
will not be recognized if it occurs when
DRDY
is high for four clock cycles. T he propagation delay time may be as
great as 4 CLK IN cycles plus 160 ns. T o guarantee proper clocking of SDAT A when using asynchronous
CS
, the SCLK input should not be taken high sooner than
4 CLK IN cycles plus 160 ns after
CS
goes low.
11
SDAT A is clocked out on the falling edge of the SCLK input.
(AV
DD
= DV
DD
= +5 V
6
10%; AV
SS
= DV
SS
= –5 V
6
10%; AGND= DGND= OV;
f
CLKIN
= 4.096 MHz; Input Levels: Logic O= OV, Logic 1 = DV
DD
)