AD7472 Analog Devices, AD7472 Datasheet - Page 14

• Manufacturer Part Number: AD7472
• Description: 12-Bit, 2.7 V to 5.25 V, 1.5 MSPS Low Power ADC
• Manufacturer: Analog Devices

Specifications of AD7472

• Resolution (bits): 12bit
• # Chan: 1
• Sample Rate: 1.5MSPS
• Interface: Par
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref)
• Adc Architecture: SAR
• Pkg Type: SOIC,SOP

AD7470/AD7472
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 typically 2 mA, and the quiescent current is
typically 650 µA. The conversion time of 531.66 ns contributes
2.658 mW to the overall power dissipation in the following way:
The contribution to the total power dissipated by the remaining
1.468 µs of the cycle is 2.38 mW.
Thus the power dissipated during each cycle is
CONVST
(1.468 µs/2 µs) × (5 × 650 µA) = 2.38 mW
BUSY
(531.66 ns/2 µs) × (5 × 2 mA) = 2.658 mW
Figure 14. Mode 1 Power Dissipation
2.658 mW + 2.38 mW = 5.038 mW
t
531.66ns
CONVERT
2 s
t
QUIESCENT
1.468 s
–14–
TPC 1 sand TPC 2 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
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 typically 2 mA, while the sleep current is 1 µA
max. The power dissipated during this power-down is negli-
gible, and is thus not worth considering in the total power fig-
ure. During the wake-up phase, the AD7472 will draw 650 µA
typically. Overall power dissipated is
(
531 66
CONVST
BUSY
.
ns
/
2
Figure 15. Mode 2 Power Dissipation
µ
s
)
t
WAKEUP
×
1 s
(
5
×
2
mA
t
531.66ns
CONVERT
)
+
(
2 s
1
µ
s
/
2
µ
s
)
×
t
(
QUIESCENT
5
1.468 s
×
650
µ
A
)
=
4 283
REV. B
.
mW