Datasheet
STARTING A CONVERSION
Convert ConvertAcquire Acquire
MODE
BUSY
CONV
t
3
t
2
t
1
t
5
t
4
t
7
t
6
t
8
t
10
t
11
t
9
ADS8513
SLAS486C – JUNE 2007 – REVISED JANUARY 2009 ......................................................................................................................................................
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If a conversion is not currently in progress, a falling edge on the CONV input places the sample-and-hold into the
hold mode and begins a conversion, as shown in Figure 36 according to the timing shown in Table 2 . During the
conversion, the CONV input is ignored. Starting a conversion does not depend on the state of CS. A conversion
can be started once every 25 µ s (40kSPS maximum conversion rate). There is no minimum conversion rate.
Figure 36. Basic Conversion Timing
Table 2. Conversion and Data Timing, T
A
= – 40 ° C to +85 ° C
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
1
Conversion plus acquisition time 25 µ s
t
2
CONV low to all digital inputs stable 19 µ s
t
3
CONV low to initiate a conversion 0.04 12 µ s
t
4
BUSY rising to any digital input active 5 ns
t
5
CONV high prior to start of conversion ( CONV high time) 15 ns
t
6
BUSY low 18 20 µ s
t
7
CONV low to BUSY low 12 20 ns
t
8
Aperture delay ( CONV falling edge to actual conversion start) 5 ns
t
9
Conversion time 18 20 µ s
t
10
Conversion complete to BUSY rising 90 ns
t
11
Acquisition time 7 µ s
t
12
CONV low to rising edge of first internal DATACLK 2.0 µ s
t
13
Internal DATACLK high 300 410 425 ns
t
14
Internal DATACLK low 300 410 425 ns
t
15
Internal DATACLK period 0.6 0.82 0.85 µ s
t
16
DATA valid to internal DATACLK rising 150 204 ns
t
17
Internal DATACLK falling to DATA not valid 150 208 ns
t
18
Falling edge of last DATACLK to BUSY rising 4.4 5 µ s
t
19
External DATACLK rising to DATA not valid 4 14 ns
t
20
External DATACLK rising to DATA valid 2 12 20 ns
t
21
External DATACLK high 15 ns
t
22
External DATACLK low 15 ns
t
23
External DATACLK period 35 ns
t
24
CONV low to external DATACLK active 15 ns
t
25
External DATACLK low or CS high to BUSY rising 5 µ s
t
26
CS low to digital outputs enabled 15 ns
t
27
CS high to digital outputs disabled 15 ns
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