AD7492 Analog Devices, AD7492 Datasheet - Page 17

• Manufacturer Part Number: AD7492
• Description: 1MSPS, 4mW Internal Ref & Clk, 12-Bit Parallel ADC
• Manufacturer: Analog Devices

Specifications of AD7492

• Resolution (bits): 12bit
• # Chan: 1
• Sample Rate: 1MSPS
• Interface: Par
• Analog Input Type: SE-Uni
• Ain Range: Uni 2.5V
• Adc Architecture: SAR
• Pkg Type: SOIC,SOP

Mode 2 (Full Sleep Mode)
Figure 23 shows the AD7492 conversion sequence in Mode 2,
full sleep mode, using a throughput rate of approximately
100 kSPS. At 5 V supply the current consumption for the part
when converting is 3 mA, while the full sleep current is 1 μA
maximum. The power dissipated during this power-down is
negligible and thus not worth considering in the total power
figure. During the wake-up phase, the AD7492 draws typically
1.8 mA. Overall power dissipated is
CONVST
Mode 2 (Partial Sleep Mode)
Figure 24 shows the AD7492 conversion sequence in Mode 2,
partial sleep mode, using a throughput rate of 1 kSPS. At 5 V
supply, the current consumption for the part when converting is
3 mA, while the partial sleep current is 250 μA maximum.
During the wake-up phase, the AD7492 typically draws 1.8 mA.
Power dissipated during wake-up and conversion is
Power dissipated during power-down is
Overall power dissipated is
CONVST
BUSY
BUSY
(880 ns/10 ms) × (5 × 3 mA) + (500 μs/10 ms) × (5 × 1.8 mA)
= 451.32 μW
(880 ns/1 ms) × (5 × 3 mA) + (20 μs/1 ms) × (5 × 1.8 mA) =
193.2 mW
(979 μs/1 ms) × (5 × 250 μA) = 1.22 mW
193.2 μW + 1.22 mW = 1.41 mW
t
t
WAKEUP
WAKEUP
500µs
Figure 24. Partial Sleep Power Dissipation
20µs
Figure 23. Full Sleep Power Dissipation
t
t
CONVERT
CONVERT
880ns
880ns
1ms
10ms
t
t
QUIESCENT
QUIESCENT
9.5ms
979µs
Rev. A | Page 17 of 24
Figure 25, Figure 26, and Figure 27 show a typical graphical
representation of power vs. throughput for the AD7492 when in
Mode 1 @ 5 V and 3 V, Mode 2 in full sleep mode @ 5 V and 3
V, and Mode 2 in partial sleep mode @ 5 V and 3 V.
12
10
3.5
3.0
2.5
2.0
1.5
1.0
0.5
2.5
2.0
1.5
1.0
0.5
8
6
4
2
0
0
0
0
0
0
100
10
10
(Mode 2 in Partial Sleep Mode @ 5 V and 3 V)
(Mode 2 in Full Sleep Mode @ 5 V and 3 V)
200
20
20
Figure 25. Power vs. Throughput
Figure 26. Power vs. Throughput
Figure 27. Power vs. Throughput
300
30
(Mode 1 @ 5 V and 3 V)
30
THROUGHPUT (kHz)
5V
THROUGHPUT (kHz)
THROUGHPUT (kHz)
3V
400
40
40
3V
5V
5V
500
50
50
600
60
60
3V
700
70
70
800
80
80
900
90
90
AD7492
1000
100
100