REV. B
–4–
AD7858/AD7858L
Limit at TMIN, TMAX
(A, B Versions)
Parameter
5 V
3 V
Units
Description
fCLKIN
2
500
kHz min
Master Clock Frequency
4
MHz max
1.8
MHz max
L Version, 0
°C to +70°C, B Grade Only
1
MHz max
L Version, –40
°C to +85°C
fSCLK
4
MHz max
t1
3
100
ns min
CONVST Pulsewidth
t2
50
90
ns max
CONVST
↓ to BUSY↑ Propagation Delay
tCONVERT
4.6
s max
Conversion Time = 18 tCLKIN
10 (18)
s max
L Version 1.8 (1) MHz CLKIN. Conversion Time = 18 tCLKIN
t3
–0.4 tSCLK
ns min
SYNC
↓ to SCLK↓ Setup Time (Noncontinuous SCLK Input)
0.4 tSCLK
ns min/max
SYNC
↓ to SCLK↓ Setup Time (Continuous SCLK Input)
t4
4
50
90
ns max
Delay from
SYNC
↓ Until DOUT Three-State Disabled
t5
4
50
90
ns max
Delay from
SYNC
↓ Until DIN Three-State Disabled
t6
4
75
115
ns max
Data Access Time After SCLK
↓
t7
40
60
ns min
Data Setup Time Prior to SCLK
↑
t8
20
30
ns min
Data Valid to SCLK Hold Time
t9
0.4 tSCLK
ns min
SCLK High Pulsewidth
t10
0.4 tSCLK
ns min
SCLK Low Pulsewidth
t11
30
50
ns min
SCLK
↑ to SYNC↑ Hold Time (Noncontinuous SCLK)
30/0.4 tSCLK
50/0.4 tSCLK
ns min/max
(Continuous SCLK)
t12
5
50
ns max
Delay from
SYNC
↑ Until DOUT Three-State Enabled
t13
90
130
ns max
Delay from SCLK
↑ to DIN Being Configured as Output
t14
6
50
90
ns max
Delay from SCLK
↑ to DIN Being Configured as Input
t15
2.5 tCLKIN
ns max
CAL
↑ to BUSY↑ Delay
t16
2.5 tCLKIN
ns max
CONVST
↓ to BUSY↑ Delay in Calibration Sequence
tCAL
7
31.25
ms typ
Full Self-Calibration Time, Master Clock Dependent
(125013 tCLKIN)
tCAL1
7
27.78
ms typ
Internal DAC Plus System Full-Scale Calibration Time, Master
Clock Dependent (111114 tCLKIN)
tCAL2
7
3.47
ms typ
System Offset Calibration Time, Master Clock Dependent
(13899 tCLKIN)
NOTES
1Sample 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.
2Mark/Space ratio for the master clock input is 40/60 to 60/40.
3The
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).
4Measured 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.
5t
12 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 i s 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.
6t
14 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.
7The 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.
TIMING SPECIFICATIONS1
(AVDD = DVDD = +3.0 V to +5.5 V; fCLKIN = 4 MHz for AD7858 and 1.8/1 MHz for AD7858L;
TA = TMIN to TMAX , unless otherwise noted)