AD7466/AD7467/AD7468

Rev. C | Page 20 of 28

POWER CONSUMPTION

The AD7466/AD7467/AD7468 automatically enter power-

down mode at the end of each conversion or if CS is brought

high before the conversion is finished.

When the AD7466/AD7467/AD7468 are in power-down mode,

all the analog circuitry is powered down and the current con-

sumption is typically 8 nA.

To achieve the lowest power dissipation, there are some

considerations the user should keep in mind.

The conversion time is determined by the serial clock

frequency; the faster the SCLK frequency, the shorter the

conversion time. This implies that as the frequency increases,

the part dissipates power for a shorter period of time when the

conversion is taking place, and it remains in power-down mode

for a longer percentage of the cycle time or throughput rate.

Figure 26 shows two AD7466s running with two different

SCLK frequencies, SCLK A and SCLK B, with SCLK A having

the higher SCLK frequency. For the same throughput rate, the

AD7466 using SCLK A has a shorter conversion time than the

AD7466 using SCLK B, and it remains in power-down mode

longer. The current consumption in power-down mode is very

low; thus, the average power consumption is greatly reduced.

This reduced power consumption can be seen in Figure 25,

which shows the supply current vs. SCLK frequency for various

supply voltages at a throughput rate of 100 kSPS. For a fixed

throughput rate, the supply current (average current) drops as

the SCLK frequency increases because the part is in power-

down mode most of the time. It can also be seen that, for a

lower supply voltage, the supply current drops accordingly.

390

360

330

300

270

240

210

180

150

120

90

60

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

SCLK FREQUENCY (MHz)

TEMP = 25

°C

Figure 25. Supply Current vs. SCLK Frequency

for a Fixed Throughput Rate and Different Supply Voltages

SCLK B

SCLK A

116

116

CONVERSION TIME A

CONVERSION TIME B

1/THROUGHPUT

CS

Figure 26. Conversion Time Comparison for Different SCLK Frequencies and a Fixed Throughput Rate

POWER DOWN TIME B

1/THROUGHPUT B

1/THROUGHPUT A

POWER DOWN TIME A

CONVERSION TIME A

CONVERSION TIME B

CS A

SCLK

CS B

116

Figure 27. Conversion Time vs. Power-Down Time for a Fixed SCLK Frequency and Different Throughput Rates