Datasheet
ADS6445, ADS6444
ADS6443, ADS6442
www.ti.com
SLAS531B –MAY 2007–REVISED DECEMBER 2009
OUTPUT TIMINGS AT LOWER SAMPLING FREQUENCIES
Setup, hold, and other timing parameters are specified across sampling frequencies and for each type of output
interface in the following tables.
Table 28 to Table 31: Typical values are at 25°C, min and max values are across the full temperature range T
MIN
= –40°C to T
MAX
= 85°C, AVDD = LVDD = 3.3 V, C
L
= 5 pF, I
O
= 3.5 mA, R
L
= 100 Ω, no internal termination,
unless otherwise noted.
Timing parameters are ensured by design and characterization and not tested in production.
Ts = 1/ Sampling frequency = 1/Fs
Table 27. Clock Propagation Delay for Different Interface Options
SERIALIZER LATENCY
(1)
INTERFACE SERIALIZATION CLOCK PROPAGATION DELAY, t
pd_clk
clock cycles
14x t
pd_clk
= 0.428xT
s
+ t
delay
1-Wire with DDR bit clock 0
16x t
pd_clk
= 0.375xT
s
+ t
delay
2
(when t
pd_clk
≥ T
s
)
2-Wire with DDR bit clock t
pd_clk
= 0.857xT
s
+ t
delay
14x 1
(when t
pd_clk
< T
s
)
2-Wire with SDR bit clock t
pd_clk
= 0.428xT
s
+ t
delay
0
1
(when t
pd_clk
≥ T
s
)
2-Wire with DDR bit clock t
pd_clk
= 0.75xT
s
+ t
delay
16x 0
(when t
pd_clk
< T
s
)
2-Wire with SDR bit clock t
pd_clk
= 0.375xT
s
+ t
delay
0
(1) Note that the total latency = ADC latency + internal serializer latency. The ADC latency is 12 clock cycles.
Table 28. Timings for 1-Wire Interface
DATA SETUP TIME, t
su
DATA HOLD TIME, t
h
t
delay
SAMPLING
ns ns ns
SERIALIZATION FREQUENCY
MSPS
MIN TYP MAX MIN TYP MAX MIN TYP MAX
65 0.3 0.5 0.4 0.6 F
s
≥ 40 MSPS
40 0.65 0.85 0.7 0.9 3 4 5
14×
20 1.3 1.65 1.6 1.9 F
s
< 40 MSPS
10 3.2 3.5 3.2 3.6 3 4.5 6
65 0.22 0.42 0.35 0.55 F
s
≥ 40 MSPS
3 4 5
16×
F
s
< 40 MSPS
3 4.5 6
Table 29. Timings for 2-Wire Interface, DDR Bit Clock
DATA SETUP TIME, t
su
DATA HOLD TIME, t
h
t
delay
SAMPLING
ns ns ns
SERIALIZATION FREQUENCY
MSPS
MIN TYP MAX MIN TYP MAX MIN TYP MAX
105 0.45 0.65 0.5 0.7 F
s
≥ 45 MSPS
92 0.55 0.75 0.6 0.8
3.4 4.4 5.4
14× 80 0.65 0.85 0.7 0.9
65 0.8 1.1 0.8 1.1 F
s
< 45 MSPS
40 1.4 1.7 1.5 1.9 3.7 5.2 6.7
105 0.35 0.55 0.4 0.6 F
s
≥ 45 MSPS
92 0.45 0.65 0.5 0.7
3.4 4.4 5.4
16× 80 0.55 0.75 0.6 0.8
65 0.6 0.9 0.7 1 F
s
< 45 MSPS
40 1.1 1.4 1.3 1.7 3.7 5.2 6.7
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