REV. A

AD7470/AD7472

–12–

Mode 1

Figure 14 shows the AD7472 conversion sequence in Mode 1

using a throughput rate of 500 kSPS and a clock frequency of

26 MHz. At 5 V supply the current consumption for the part

when converting is 2 mA and the quiescent current is 650

µA.

The conversion time of 531.66 ns contributes 2.658 mW to the

overall power dissipation in the following way:

(531.66 ns/2

µs) × (5 × 2 mA) = 2.658 mW

The contribution to the total power dissipated by the remaining

1.468

µs of the cycle is 2.38 mW.

(1.468

µs/2 µs) × (5 × 650 µA) = 2.38 mW

Thus the power dissipated during each cycle is:

2.658 mW + 2.38 mW = 5.038 mW

CONVST

BUSY

531.66ns

1.468 s

2 s

Figure 14. Mode 1 Power Dissipation

Mode 2

Figure 15 shows the AD7472 conversion sequence in Mode 2

using a throughput rate of 500 kSPS and a clock frequency of

26 MHz. At 5 V supply the current consumption for the part

when converting is 2 mA, while the sleep current is 1

µA max.

The power dissipated during this power-down is negligible and

is thus not worth considering in the total power figure. During

the wake-up phase, the AD7472 will draw 650

µA. Overall

power dissipated is:

531 66

2

5

2

1

2

5

650

4 283

./

/

.

ns

s

mA

s

s

A

mW

µµ

µ

µ

CONVST

BUSY

531.66ns

1.468 s

2 s

1 s

Figure 15. Mode 2 Power Dissipation

Figure 16 and Figure 17 show a typical graphical representation

of Power vs. Throughput for the AD7472 when in (a) Mode 1

@ 5 V and 3 V and Mode 2 @ 5 V and 3 V.

THROUGHPUT – kHz

8

4

0

50

300

1500

1300

1100

1000

800

600

7

3

6

2

5

1

+5V

+3V

Figure 16. Power vs. Throughput (Mode 1 @ 5 V and 3 V)

THROUGHPUT – kHz

4

0

50 100

750

700

650

600

300

200

7

3

6

2

5

1

150

350

250

400 450 500 550

+5V

+3V

Figure 17. Power vs. Throughput (Mode 2 @ 5 V and 3 V)

CODE

1

0

–1

0

4096

–0.8

3584

3072

2560

2048

1536

1024

512

–0.6

–0.4

–0.2

0.2

0.4

0.6

0.8

Figure 18. Typical INL for 2.75 V @ +25

°C