AD7811YN Analog Devices Inc, AD7811YN Datasheet - Page 13

• Manufacturer Part Number: AD7811YN
• Description: IC ADC 10BIT 4-CHAN SRL 16-DIP
• Manufacturer: Analog Devices Inc

Specifications of AD7811YN

• Rohs Status: RoHS non-compliant
• Number Of Bits: 10
• Sampling Rate (per Second): 350k
• Data Interface: DSP, Serial
• Number Of Converters: 1
• Power Dissipation (max): 10.5mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)

For example, if the AD7811 is operated in a continuous sam-
pling mode with a throughput rate of 10 kSPS, PD1 = 1,
PD0 = 0 and using the on chip reference the power consump-
tion is calculated as follows. The power dissipation during nor-
mal operation is 10.5 mW, V
1.5 µs and the conversion time is 2.3 µs, the AD7811 can be
said to dissipate 10.5 mW for 3.8 µs (worst-case) during each
conversion cycle. If the throughput rate is 10 kSPS, the cycle
time is 100 µs and the average power dissipated during each
cycle is (3.8/100) × (10.5 mW) = 400 µW.
Figure 12 shows the Power vs. Throughput Rate for automatic
full power-down.
CONVST
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
0.01
0.1
10
0
1
0
t
0
POWER-UP
1.5 s
17
5
t
35
CONVERT
10
2.3 s
52
15
100 s @ 10kSPS
THROUGHPUT – kSPS
FREQUENCY – kHz
70
DD
20
t
CYCLE
= 3 V. If the power-up time is
87
POWER-DOWN
25
AD7811/12
2048 POINT FFT
SAMPLING 357.142kHz
f
IN
105
= 30.168kHz
30
122
35
140
40
157 174
45
50
QUICK EVALUATION SETUP
The schematic shown in Figure 14 shows a suggested configura-
tion of the AD7812 for a first look evaluation of the part. No
external reference circuit is needed as the V
connected to V
and RFS to enable the serial port. Also by selecting Mode 2
operation (see Operating Modes section) the power performance
of the AD7812 can be evaluated.
The setup uses a full duplex, 16-bit, serial interface protocol,
e.g., SPI. It is possible to use 8-bit transfers by carrying out two
consecutive read/write operations. The MSB of data is trans-
ferred first.
1. When power is first connected to the device it is in a powered
2. The CONVST signal is first pulsed to enable the serial port
3. Next, a 16-bit serial read/write operation is carried out. By
4. It is necessary to wait approximately 1.5 µs before pulsing
5. Approximately 2.3 µs after the falling edge of CONVST, i.e.,
6. By idling the CONVST signal high or low it is possible to
down mode of operation and is consuming only 1 µA. The
AD7812 must first be configured by carrying out a serial
write operation.
(rising and falling edge on RFS and TFS respectively—see
Serial Interface section).
writing 6040 Hex to the AD7812 the part is powered up, set
up to use external reference (i.e., V
V
write operation is invalid.
CONVST again and initiating a conversion. The 1.5 µs is to
allow the AD7812 to power up correctly—see Power-Up
Times section.
after the end of the conversion, a serial read/write can take
place. This time 4040 Hex is written to the AD7812 and the
data read from the part is the result of the conversion. The
output code is in a straight binary format and will be left
justified in the 16-bit serial register (MSB clocked out first).
operate the AD7812 in Mode 1 and Mode 2 respectively.
IN1
SUPPLY
is selected. The data read from the part during this read/
V
0V TO V
DD
INPUT
DD
DD
. The CONVST signal is connected to TFS
10 F
0.1 F
V
V
V
AGND
DGND
V
IN1
IN2
IN7
IN8
V
DD
AD7811/AD7812
AD7812
V
REF
DD
) and the analog input
C
CONVST
REF
REF
DOUT
SCLK
RFS
TFS
DIN
A0
10nF
pin can be