AD7685BRMZ Analog Devices Inc, AD7685BRMZ Datasheet - Page 23
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AD7685BRMZ
Manufacturer Part Number
AD7685BRMZ
Description
IC ADC 16BIT PSEUDO-DIFF 10-MSOP
Manufacturer
Analog Devices Inc
Series
PulSAR®r
Datasheet
1.AD7685BCPZRL7.pdf
(28 pages)
Specifications of AD7685BRMZ
Data Interface
DSP, MICROWIRE™, QSPI™, Serial, SPI™
Design Resources
Parametric Measurement Unit and Supporting Components for PAD Appls Using AD5522 and AD7685 (CN0104) Integrated Device Power Supply for PAD with Output Voltage Range 0 V to 25 V (CN0130)
Number Of Bits
16
Sampling Rate (per Second)
250k
Number Of Converters
1
Power Dissipation (max)
15mW
Voltage Supply Source
Single Supply
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
10-TFSOP (0.118", 3.00mm Width)
Resolution (bits)
16bit
Sampling Rate
250kSPS
Input Channel Type
Pseudo Differential
Supply Voltage Range - Analog
2.3V To 5.5V
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
EVAL-AD7685CBZ - BOARD EVAL FOR AD7685
Lead Free Status / RoHS Status
Lead free / RoHS Compliant, Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD7685BRMZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD7685BRMZ-REEL
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD7685BRMZ-RL7
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Company:
Part Number:
AD7685BRMZRL7
Manufacturer:
MOLEX
Quantity:
2 000
CHAIN MODE WITH BUSY INDICATOR
This mode can also be used to daisy chain multiple AD7685s on
a 3-wire serial interface while providing a BUSY indicator. This
feature is useful for reducing component count and wiring
connections, for example, in isolated multiconverter applications or
for systems with a limited interfacing capacity. Data readback is
analogous to clocking a shift register.
A connection diagram example using three AD7685s is shown
in Figure 44, and the corresponding timing is given in Figure 45.
When SDI and CNV are low, SDO is driven low. With SCK
high, a rising edge on CNV initiates a conversion, selects the
chain mode, and enables the BUSY indicator feature. In this
mode, CNV is held high during the conversion phase and the
subsequent data readback. When all ADCs in the chain have
completed their conversions, the nearend ADC (ADC C in
ACQUISITION
SDO
SDO
CNV = SDI
t
HSCKCNV
A
B
SCK
= SDI
= SDI
SDO
A
B
C
C
SDI
CONVERSION
t
t
DSDOSDI
t
SSCKCNV
t
AD7685
CONV
DSDOSDI
t
EN
CNV
SCK
A
SDO
t
t
t
SSDISCK
HSDO
DSDO
1
D
D
D
C
A
B
2
15 D
15 D
15 D
Figure 45. Chain Mode with BUSY Indicator Serial Interface Timing
Figure 44. Chain Mode with BUSY Indicator Connection Diagram
C
3
A
B
14 D
14 D
14 D
t
SDI
SCKH
C
A
B
4
t
HSDISCK
13
13
13
AD7685
CNV
SCK
B
15
t
SCK
Rev. B | Page 23 of 28
D
D
D
SDO
16
C
B
A
1
1
1
t
SCKL
D
D
D
17
C
A
B
0
0 D
0
D
ACQUISITION
18
B
A
15 D
15 D
t
CYC
Figure 44) SDO is driven high. This transition on SDO can be
used as a BUSY indicator to trigger the data readback controlled
by the digital host. The AD7685 then enters the acquisition
phase and powers down. The data bits stored in the internal
shift register are then clocked out, MSB first, by subsequent
SCK falling edges. For each ADC, SDI feeds the input of the
internal shift register and is clocked by the SCK falling edge.
Each ADC in the chain outputs its data MSB first, and 16 × N + 1
clocks are required to readback the N ADCs. Although the
rising edge can be used to capture the data, a digital host also
using the SCK falling edge allows a faster reading rate and,
consequently, more AD7685s in the chain, provided the digital
host has an acceptable hold time. For instance, with a 5 ns
digital host setup time and 3 V interface, up to eight AD7685s
running at a conversion rate of 220 kSPS can be daisy-chained
to a single 3-wire port.
19
B
SDI
A
t
14
14
ACQ
AD7685
CNV
SCK
31
C
D
D
32
B
A
SDO
1
1
D
D
33
B
A
0 D
0
34
A
15
D
35
A
14
CLK
CONVERT
DATA IN
IRQ
DIGITAL HOST
47
t
DSDOSDI
D
48
t
A
DSDOSDI
t
1
DSDOSDI
D
49
A
0
AD7685