AD7606BSTZ-6RL Analog Devices Inc, AD7606BSTZ-6RL Datasheet - Page 24

• Manufacturer Part Number: AD7606BSTZ-6RL
• Description: Simulat Sampliing Bipolar 16 Bit I.C.
• Manufacturer: Analog Devices Inc
• Type: Data Acquisition System (DAS), ADCr

Specifications of AD7606BSTZ-6RL

• Design Resources: Layout Considerations for an Expandable Multichannel Simultaneous Sampling Data Acquisition System Based on AD7606 (CN0148)
• Resolution (bits): 16 b
• Sampling Rate (per Second): 200k
• Data Interface: DSP, MICROWIRE™, Parallel, QSPI™, Serial, SPI™
• Voltage Supply Source: Single Supply
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AD7606BSTZ-6RL

AD7606/AD7606-6/AD7606-4
INTERNAL/EXTERNAL REFERENCE
The AD7606/AD7606-6/AD7606-4 contain an on-chip 2.5 V
bandgap reference. The REFIN/REFOUT pin allows access to
the 2.5 V reference that generates the on-chip 4.5 V reference
internally, or it allows an external reference of 2.5 V to be applied
to the AD7606/AD7606-6/AD7606-4. An externally applied
reference of 2.5 V is also gained up to 4.5 V, using the internal
buffer. This 4.5 V buffered reference is the reference used by the
SAR ADC.
The REF SELECT pin is a logic input pin that allows the user to
select between the internal reference or an external reference.
If this pin is set to logic high, the internal reference is selected
and enabled. If this pin is set to logic low, the internal reference
is disabled and an external reference voltage must be applied
to the REFIN/REFOUT pin. The internal reference buffer is
always enabled. After a reset, the AD7606/AD7606-6/AD7606-4
operate in the reference mode selected by the REF SELECT pin.
Decoupling is required on the REFIN/REFOUT pin for both
the internal and external reference options. A 10 μF ceramic
capacitor is required on the REFIN/REFOUT pin.
The AD7606/AD7606-6/AD7606-4 contain a reference buffer
configured to gain the REF voltage up to ~4.5 V, as shown in
Figure 40. The REFCAPA and REFCAPB pins must be shorted
together externally, and a ceramic capacitor of 10 μF applied to
REFGND, to ensure that the reference buffer is in closed-loop
operation. The reference voltage available at the REFIN/REFOUT
pin is 2.5 V.
When the AD7606/AD7606-6/AD7606-4 are configured in
external reference mode, the REFIN/REFOUT pin is a high
input impedance pin. For applications using multiple AD7606
devices, the following configurations are recommended,
depending on the application requirements.
External Reference Mode
One ADR421 external reference can be used to drive the
REFIN/REFOUT pins of all AD7606 devices (see Figure 41).
In this configuration, each REFIN/REFOUT pin of the
AD7606/AD7606-6/AD7606-4 should be decoupled with at
least a 100 nF decoupling capacitor.
Rev. A | Page 24 of 36
Internal Reference Mode
One AD7606/AD7606-6/AD7606-4 device, configured to operate
in the internal reference mode, can be used to drive the remaining
AD7606/AD7606-6/AD7606-4 devices, which are configured to
operate in external reference mode (see Figure 42). The REFIN/
REFOUT pin of the AD7606/AD7606-6/AD7606-4, configured
in internal reference mode, should be decoupled using a 10 μF
ceramic decoupling capacitor. The other AD7606/AD7606-6/
AD7606-4 devices, configured in external reference mode,
should use at least a 100 nF decoupling capacitor on their
REFIN/REFOUT pins.
Figure 42. Internal Reference Driving Multiple AD7606/AD7606-6/AD7606-4
ADR421
Figure 41. Single External Reference Driving Multiple AD7606/AD7606-6/
REFIN/REFOUT
AD7606
REF SELECT
REFIN/REFOUT
AD7606
REF SELECT
REFIN/REFOUT
0.1µF
+
10µF
2.5V
REF
V
DRIVE
100nF
Figure 40. Reference Circuitry
BUF
AD7606-4 REFIN Pins
REFIN/REFOUT
AD7606
REF SELECT
REFIN Pins
REFIN/REFOUT
SAR
AD7606
REF SELECT
100nF
REFCAPA
REFCAPB
100nF
REFIN/REFOUT
10µF
AD7606
REFIN/REFOUT
REF SELECT
AD7606
REF SELECT
100nF
100nF