AD7608 Analog Devices, AD7608 Datasheet - Page 22

• Manufacturer Part Number: AD7608
• Description: 8-Channel DAS with 18-Bit, Bipolar, Simultaneous Sampling ADC
• Manufacturer: Analog Devices

Specifications of AD7608

• Resolution (bits): 18bit
• # Chan: 8
• Sample Rate: 200kSPS
• Interface: Par,Ser,SPI
• Analog Input Type: Diff-Bip
• Ain Range: Bip 10V,Bip 5.0V
• Adc Architecture: SAR
• Pkg Type: QFP

AD7608
TYPICAL CONNECTION DIAGRAM
Figure 40 shows the typical connection diagram for the AD7608.
There are four AVCC supply pins on the part, and each of the
four pins should be decoupled using a 100 nF capacitor at each
supply pin and a 10 µF capacitor at the supply source. The AD7608
can operate with the internal reference or an externally applied
reference. In this configuration, the AD7608 is configured to
operate with the internal reference. When using a single AD7608
device on the board, the REFIN/REFOUT pin should be
decoupled with a 10 µF capacitor. Refer to the Internal/External
Reference section when using an application with multiple
AD7608 devices. The REFCAPA and REFCAPB pins are
shorted together and decoupled with a 10 µF ceramic
capacitor.
The V
cessor. The V
output logic signals. For layout, decoupling, and grounding
hints, see the Layout Guidelines section.
After supplies have been applied to the AD7608, apply a RESET
signal to the device to ensure it is configured for the correct
mode of operation.
POWER-DOWN MODES
There are two power-down modes available on the AD7608:
standby mode and shutdown mode. The
whether the AD7608 is in normal mode or in one of the two
power-down modes.
DRIVE
supply is connected to the same supply as the pro-
DRIVE
voltage controls the voltage value of the
EIGHT ANALOG
INPUTS V1 TO V8
1
2
DECOUPLING SHOWN ON THE AV
DECOUPLING CAPACITOR CAN BE SHARED BETWEEN AV
DECOUPLING SHOWN ON THE REGCAP PIN APPLIES TO EACH REGCAP PIN (PIN 36, PIN 39).
10µF
+
STBY
10µF
E E
A A
pin controls
REFIN/REFOUT
REFCAPA
REFCAPB
REFGND
V1
V1GND
V2
V2GND
V3
V3GND
V4
V4GND
V5
V5GND
V6
V6GND
V7
V7GND
V8
V8GND
+
Figure 40. Typical Connection Diagram
CC
PIN APPLIES TO EACH AV
1µF
Rev. A | Page 22 of 32
AD7608
REGCAP
AGND
100nF
ANALOG SUPPLY
2
VOLTAGE 5V
AV
The power-down mode is selected through the state of the
RANGE pin when the
configurations required to choose the desired power-down
mode. When the AD7608 is placed in standby mode, the
current consumption is 8 mA maximum and power-up time
is approximately 100 µs because the capacitor on the REFCAPA
and REFCAPB pins must charge up. In standby mode, the
on-chip reference and regulators remain powered up, and the
amplifiers and ADC core are powered down.
When the AD7608 is placed in shutdown mode, the current
consumption is 11 µA maximum and power-up time is approx-
imately 13 ms (external reference mode). In shutdown mode,
all circuitry is powered down. When the AD7608 is powered
up from shutdown mode, a RESET signal must be applied to
the AD7608 after the required power-up time has elapsed.
Table 7. Power-Down Mode Selection
Power-Down Mode
Standby
Shutdown
PAR/SER SEL
DB0 TO DB15
CONVST A, B
CC
REF SELECT
CC
PIN 37 AND PIN 38.
CC
RANGE
RESET
V
BUSY
PIN (PIN 1, PIN 37, PIN 38, PIN 48).
1
STBY
OS 2
OS 1
OS 0
DRIVE
RD
CS
DIGITAL SUPPLY
VOLTAGE +2.3V TO +5V
100nF
INTERFACE
PARALLEL
OVERSAMPLING
V
STBY
A A
DRIVE
V
DRIVE
E E
A A
pin is low. Table 7 shows the
S TBY
A A
0
0
E E
Data Sheet
RANGE
1
0