AD7898 datasheet(3/16 Pages) AD

3 / 16 page

–3–

REV. 0

AD7898

Parameter

Limit at TMIN, TMAX

Unit

Description

Mode 0 Operation

ns min

CONVST Pulsewidth

ns min

SCLK High Pulsewidth, VDRIVE = 5 V

± 5%

ns min

SCLK Low Pulsewidth, VDRIVE = 5 V

± 5%

302

ns min

SCLK High Pulsewidth VDRIVE = 2.7 V to 3.6 V

ns min

SCLK Low Pulsewidth VDRIVE = 2.7 V to 3.6 V

ns max

Data Access Time after Falling Edge of SCLK, VDRIVE = 5 V

± 5%

703

ns max

Data Access Time after Falling Edge of SCLK, VDRIVE = 2.7 V to 3.6 V

ns min

Data Hold Time after Falling Edge of SCLK

ns max

Bus Relinquish Time after Falling Edge of SCLK

tCONVERT

3.3

µs

Mode 1 Operation

fSCLK

kHz min

3.7

MHz max

tCONVERT

× t

SCLK

tSCLK = 1/fSCLK

4.33

µs max

fSCLK = 3.7 MHz

tQUIET

100

ns min

Minimum Quiet Time Required between Conversions

ns min

CS to SCLK Setup Time

ns max

Delay from

CS Until SDATA Three-State Disabled

ns max

Data Access Time after SCLK Falling Edge

108

ns min

SCLK High Pulsewidth

108

ns min

SCLK Low Pulsewidth

ns min

SCLK to Data Valid Hold Time

ns min

SCLK Falling Edge to SDATA High Impedance

ns max

SCLK Falling Edge to SDATA High Impedance

tPOWER-UP

4.33

µs max

Power-Up Time from Power-Down Mode

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.

2The SCLK maximum frequency is 15 MHz for Mode 0 operation for 220 kSPS throughput with V

DRIVE = 5 V

± 5%, SCLK = 13 MHz with V

DRIVE = 2.7 V to 3.6 V.

The mark/space ratio for SCLK is specified for at least 40% high time (with corresponding 60% low time) or 40% low time (with corresponding 60% high time). As

the SCLK frequency is reduced, the mark/space ratio may vary, provided limits are not exceeded. Care must be taken when interfacing to account for the data access

time, t4, and the set-up time required for the users processor. These two times will determine the maximum SCLK frequency that the user’s system can operate with.

See Serial Interface section.

3Measured with the load circuit of Figure 1 and defined as the time required for the output to cross 0.8 V or 2.0 V.

6 and t8 are derived from 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 extrapo-

lated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the time, t 6 and t8, quoted in the timing characteristics is the true bus

relinquish time of the part and is independent of the bus loading.

5Mark/Space ratio for the SCLK input is 40/60 to 60/40.

Specifications subject to change without notice.

TIMING SPECIFICATIONS1

(VDD = 4.75 V to 5.25 V; VDRIVE = 2.7 V to 5.25 V; REF IN = 2.5 V; TA = TMIN to TMAX, unless otherwise

noted.)

AD7898 Datasheet(PDF) 3 Page - Analog Devices

AD7898 Datasheet(HTML) 3 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Datasheet Download

Link URL