AD7911ARMZ Analog Devices Inc, AD7911ARMZ Datasheet - Page 20

• Manufacturer Part Number: AD7911ARMZ
• Description: IC ADC 10BIT DUAL 2CH 8-MSOP
• Manufacturer: Analog Devices Inc

Specifications of AD7911ARMZ

• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Operating Temperature: -40°C ~ 85°C
• Number Of Bits: 10
• Sampling Rate (per Second): 250k
• Number Of Converters: 1
• Power Dissipation (max): 20mW
• Voltage Supply Source: Single Supply
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Resolution (bits): 10bit
• Input Channel Type: Single Ended
• Supply Voltage Range - Analogue: 2.35V To 5.25V
• Supply Current: 4mA
• No. Of Pins: 8
• Sampling Rate: 250kSPS
• Rohs Compliant: Yes
• Number Of Elements: 1
• Resolution: 10Bit
• Architecture: SAR
• Sample Rate: 250KSPS
• Input Polarity: Unipolar
• Input Type: Voltage
• Rated Input Volt: 5.25V
• Differential Input: No
• Power Supply Requirement: Single
• Single Supply Voltage (typ): 3/5V
• Single Supply Voltage (min): 2.35V
• Single Supply Voltage (max): 5.25V
• Dual Supply Voltage (typ): Not RequiredV
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Power Dissipation: 20mW
• Differential Linearity Error: ±0.5LSB
• Integral Nonlinearity Error: ±0.5LSB
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: MSOP
• Input Signal Type: Single-Ended
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7911/AD7921
POWER VS. THROUGHPUT RATE
By using the power-down mode on the AD7911/AD7921 when
not converting, the average power consumption of the ADC
decreases at lower throughput rates. Figure 29 shows how, as the
throughput rate is reduced, the device remains in its power-
down state longer and the average power consumption over
time drops accordingly.
For example, if the AD7911/AD7921 are operating in a
continuous sampling mode with a throughput rate of 50 kSPS
and a SCLK of 5 MHz (V
power-down mode between conversions, then the power
consumption is calculated as follows. The power dissipation
during normal operation is 20 mW (V
cycle powers up the part between conversions (3.2 µs), and the
remaining conversion time is another cycle (3.2 µs), then the
AD7911/AD7921 dissipate 20 mW for 6.4 µs during each
conversion cycle. If the throughput rate is 50 kSPS and the cycle
time is 20 µs, then the average power dissipated during each
cycle is
If V
down mode between conversions, then the power dissipation
during normal operation is 6 mW. The AD7911/AD7921 now
dissipate 6 mW for 6.4 µs during each conversion cycle. With a
throughput rate of 50 kSPS, the average power dissipated during
each cycle is
DD
(6.4/20) × (20 mW) = 6.4 mW
(6.4/20) × (6 mW) = 1.92 mW
= 3 V, SCLK= 5 MHz, and the device is again in power-
DD
= 5 V) and the devices are placed in
DD
= 5 V). If one dummy
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In the previous examples, the power dissipation when the part is
in power-down mode has not been taken into account, because
the shutdown current is so low that it does not have any effect
on the overall power dissipation value. Figure 29 shows the
power consumption versus throughput rate when using the
power-down mode between conversions with both 5 V and 3 V
supplies.
Power-down mode is intended for use with throughput rates of
approximately 120 kSPS and under, because higher sampling
rates do not have a power saving in power-down mode.
0.01
100
0.1
10
1
0
Figure 29. Power Consumption vs. Throughput Rate
15
30
V
DD
= 5V, SCLK = 5MHz
45
THROUGHPUT (kSPS)
V
DD
60
= 3V, SCLK = 5MHz
75
90
105
120
135