
REV. B
–4–
AD7858/AD7858L
TIMING SPECIFICATIONS
1
(AV
DD
= DV
DD
= +3.0 V to +5.5 V; f
CLKIN
= 4 MHz for AD7858 and 1.8/1 MHz for AD7858L;
T
A
= T
MIN
to T
MAX
, unless otherwise noted)
5 V
Limit at T
MIN
, T
MAX
(A, B Versions)
Parameter
f
CLKIN2
3 V
Units
Description
500
4
1.8
1
4
100
50
4.6
10 (18)
–0.4 t
SCLK
0.4 t
SCLK
50
50
75
40
20
0.4 t
SCLK
0.4 t
SCLK
30
30/0.4 t
SCLK
50
90
50
2.5 t
CLKIN
2.5 t
CLKIN
31.25
500
4
1.8
1
4
100
90
4.6
10 (18)
–0.4 t
SCLK
0.4 t
SCLK
90
90
115
60
30
0.4 t
SCLK
0.4 t
SCLK
50
50/0.4 t
SCLK
50
130
90
2.5 t
CLKIN
2.5 t
CLKIN
31.25
kHz min
MHz max
MHz max
MHz max
MHz max
ns min
ns max
μ
s max
μ
s max
ns min
ns min/max
ns max
ns max
ns max
ns min
ns min
ns min
ns min
ns min
ns min/max
ns max
ns max
ns max
ns max
ns max
ms typ
Master Clock Frequency
L Version, 0
°
C to +70
°
C, B Grade Only
L Version, –40
°
C to +85
°
C
f
SCLK
t
13
t
2
t
CONVERT
CONVST
Pulsewidth
CONVST
↓
to BUSY
↑
Propagation Delay
Conversion Time = 18 t
CLKIN
L Version 1.8 (1) MHz CLKIN. Conversion Time = 18 t
CLKIN
SYNC
↓
to SCLK
↓
Setup Time (Noncontinuous SCLK Input)
SYNC
↓
to SCLK
↓
Setup Time (Continuous SCLK Input)
Delay from
SYNC
↓
Until DOUT Three-State Disabled
Delay from
SYNC
↓
Until DIN Three-State Disabled
Data Access Time After SCLK
↓
Data Setup Time Prior to SCLK
↑
Data Valid to SCLK Hold Time
SCLK High Pulsewidth
SCLK Low Pulsewidth
SCLK
↑
to
SYNC
↑
Hold Time (Noncontinuous SCLK)
(Continuous SCLK)
Delay from
SYNC
↑
Until DOUT Three-State Enabled
Delay from SCLK
↑
to DIN Being Configured as Output
Delay from SCLK
↑
to DIN Being Configured as Input
CAL
↑
to BUSY
↑
Delay
CONVST
↓
to BUSY
↑
Delay in Calibration Sequence
Full Self-Calibration Time, Master Clock Dependent
(125013 t
CLKIN
)
Internal DAC Plus System Full-Scale Calibration Time, Master
Clock Dependent (111114 t
CLKIN
)
System Offset Calibration Time, Master Clock Dependent
(13899 t
CLKIN
)
t
3
t
44
t
54
t
64
t
7
t
8
t
9
t
10
t
11
t
125
t
13
t
146
t
15
t
16
t
CAL7
t
CAL17
27.78
27.78
ms typ
t
CAL27
3.47
3.47
ms typ
NOTES
1
Sample tested at +25
°
C to ensure compliance. All input signals are specified with tr = tf = 5 ns (10% to 90% of V
DD
) and timed from a voltage level of 1.6 V.
See Table XI and timing diagrams for different interface modes and Calibration.
2
Mark/Space ratio for the master clock input is 40/60 to 60/40.
3
The
CONVST
pulsewidth will apply here only for normal operation. When the part is in power-down mode, a different
CONVST
pulsewidth will apply
(see Power-Down section).
4
Measured with the load circuit of Figure 1 and defined as the time required for the output to cross 0.8 V or 2.4 V.
5
t
is derived form the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then extrapolated
back to remove the effects of charging or discharging the 100 pF capacitor. This means that the time, t
12
, quoted in the timing characteristics is the true bus
relinquish time of the part and is independent of the bus loading.
6
t
is derived form the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then
extrapolated back to remove the effects of charging or discharging the 100 pF capacitor. This means that the time quoted in the Timing Characteristics is the
true delay of the part in turning off the output drivers and configuring the DIN line as an input. Once this time has elapsed the user can drive the DIN line
knowing that a bus conflict will not occur.
7
The typical time specified for the calibration times is for a master clock of 4 MHz. For the L version the calibration times will be longer than those quoted here due to
the 1.8/1 MHz master clock.
Specifications subject to change without notice.