AD7467 Analog Devices, AD7467 Datasheet - Page 20

• Manufacturer Part Number: AD7467
• Description: 1.6 V Micro-Power 10-Bit ADC
• Manufacturer: Analog Devices

Specifications of AD7467

• Resolution (bits): 10bit
• # Chan: 1
• Sample Rate: 200kSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Uni
• Ain Range: Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SOP,SOT

AD7466/AD7467/AD7468
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.
SCLK A
SCLK B
SCLK
CS A
CS B
CS
1
1
1
CONVERSION TIME A
CONVERSION TIME B
CONVERSION TIME A
Figure 27. Conversion Time vs. Power-Down Time for a Fixed SCLK Frequency and Different Throughput Rates
Figure 26. Conversion Time Comparison for Different SCLK Frequencies and a Fixed Throughput Rate
1/THROUGHPUT A
CONVERSION TIME B
16
16
1/THROUGHPUT B
POWER DOWN TIME A
POWER DOWN TIME B
1/THROUGHPUT
Rev. C | Page 20 of 28
16
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
for a Fixed Throughput Rate and Different Supply Voltages
2.2
V
V
V
DD
DD
DD
Figure 25. Supply Current vs. SCLK Frequency
= 2.7V
= 1.8V
= 1.6V
2.4
2.6
SCLK FREQUENCY (MHz)
2.8
3.0
f
TEMP = 25°C
SAMPLE
3.2
V
V
V
DD
DD
DD
= 100kSPS
3.4
= 3.6V
= 3.0V
= 2.2V
3.6