CLOCK

CONVST

10ns

Cyc e

l 1

Cyc e

l 2

A

B

C

10ns

5ns

5ns

ADS7863

SBAS383E – JUNE 2007 – REVISED JANUARY 2011

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TIMING CHARACTERISTICS (continued)

NOTE: All CONVST commands that occur more than 10ns before the rising edge of cycle ‘1’ of the external clock

(Region ‘A’) initiate a conversion on the rising edge of cycle ‘1’. All CONVST commands that occur 5ns after the rising

edge of cycle ‘1’ or 10ns before the rising edge of cycle 2 (Region ‘B’) initiate a conversion on the rising edge of cycle

‘2’. All CONVST commands that occur 5ns after the rising edge of cycle ‘2’ (Region ‘C’) initiate a conversion on the

rising edge of the next clock period.

The CONVST pin should never be switched from LOW to HIGH in the region 10ns prior to the rising edge of the

CLOCK and 5ns after the rising edge (gray areas). If CONVST is toggled in this gray area, the conversion could begin

on either the same rising edge of the CLOCK or the following edge.

Figure 2. CONVST Timing

TIMING REQUIREMENTS

(1)

otherwise noted.

ADS7863

SYMBOL

PARAMETER

COMMENTS

MIN

MAX

UNIT

Conversion time

406.25

ns

Acquisition time

62.5

ns

CLOCK frequency

See Figure 1

1

32

MHz

CLOCK period

See Figure 1

31.25

1000

ns

CLOCK low time

See Figure 1

9.4

ns

CLOCK high time

See Figure 1

9.4

ns

CONVST high time

See Figure 1

20

ns

SDI setup time to CLOCK falling edge

See Figure 1

10

ns

SDI hold time to CLOCK falling edge

See Figure 1

5

ns

RD high setup time to CLOCK falling edge

See Figure 1

10

ns

RD high hold time to CLOCK falling edge

See Figure 1

5

ns

CONVST low time

See Figure 1

1

RD low time relative to CLOCK falling edge

See Figure 1

1

CS low to SDOx valid

See Figure 1

13

ns

See Figure 1,

4

11

ns

CLOCK rising edge to DATA valid delay

2.7V

(MIN = minimum hold time of current data;

See Figure 1,

MAX = maximum delay to new data valid)

3

9

ns

4.5V

See Figure 1

3

ns

CLOCK rising edge to BUSY low delay

See Figure 1

3

ns

CS low to RD high delay

See Figure 1

10

ns

(1)

(2)

Not applicable in auto-NAP power-down mode.

8

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