ADS8381

SLAS364D − APRIL 2002 − REVISED FEBRUARY 2005

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7

TIMING CHARACTERISTICS

All specifications typical at −40

°C to 85°C, +VA = 5 V, +VBD = 3 V (see Notes 1, 2, and 3)

PARAMETER

MIN

TYP

MAX

UNIT

tCONV

Conversion time

1.4

µs

tACQ

Acquisition time

0.3

µs

tHOLD

Sampling capacitor hold time

25

ns

tpd1

CONVST low to conversion started (BUSY high)

50

ns

tpd2

Propagation delay time, end of conversion to BUSY low

25

ns

tpd3

Propagation delay time, from start of conversion (internal state) to rising edge of BUSY

25

ns

tw1

Pulse duration, CONVST low

40

600

ns

tsu1

Setup time, CS low to CONVST low

20

ns

tw2

Pulse duration, CONVST high

20

ns

CONVST falling edge jitter

10

ps

tw3

Pulse duration, BUSY signal low

Min(tACQ)

µs

tw4

Pulse duration, BUSY signal high

1.4

µs

th1

Hold time, first data bus transition (CS low for read cycle, or RD or BYTE or BUS 18/16

input changes) after CONVST low

40

600

ns

td1

Delay time, CS low to RD low

0

ns

tsu2

Setup time, RD high to CS high

0

ns

tw5

Pulse duration, RD low

50

ns

ten

Enable time, RD low (or CS low for read cycle) to data valid

30

ns

td2

Delay time, data hold from RD high

10

ns

td3

10

30

ns

tw6

Pulse duration, RD high time

20

ns

tw7

Pulse duration, CS high time

20

ns

th2

Hold time, last CS rising edge or changes of RD, BYTE, or BUS18/16 to CONVST

falling edge

125

ns

tpd4

Propagation delay time, BUSY falling edge to next RD (or CS for read cycle) falling

edge

Max(td5)

ns

td4

Delay time, BYTE edge to BUS18/16 edge skew

0

ns

tsu3

Setup time, BYTE or BUS18/16 transition to RD falling edge

10

ns

th3

Hold time, BYTE or BUS18/16 transition to RD falling edge

10

ns

tdis

Disable time, RD High (CS high for read cycle) to 3-stated data bus

30

ns

td5

Delay time, BUSY low to MSB data valid delay time

40

ns

tsu5

Setup time, BYTE transition to next BYTE transition, or BUS18/16 transition to next

BUS18/16 transition

50

ns

tsu(AB)

Setup time, from the falling edge of CONVST (used to start the valid conversion) to the

next falling edge of CONVST (when CS = 0 and CONVST used to abort) or to the next

falling edge of CS (when CS is used to abort).

70

1000

ns

tf(CONVST) Falling time, (CONVST falling edge)

10

30

ns

tsu6

Setup time, CS falling edge to CONVST falling edge when RD = 0

125

ns

(1) All input signals are specified with tr = tf = 5 ns (10% to 90% of +VBD) and timed from a voltage level of (VIL + VIH)/2 except for CONVST.

(2) See timing diagrams.

(3) All timing are measured with 10 pF equivalent loads on all data bits and BUSY pins.