AD7734 Datasheet, PDF (1/32 Pages) Analog Devices – 4-Channel, +-10 V Input Range, High Throughput, 24-Bit sigma ADC

4-Channel, ±10 V Input Range, High
Throughput, 24-Bit ∑-∆ ADC
AD7734
FEATURES
High resolution ADC
24 bits no missing codes
±0.0025% nonlinearity
Optimized for fast channel switching
18-bit p-p resolution (21 bits effective) at 500 Hz
16-bit p-p resolution (19 bits effective) at 2 kHz
14-bit p-p resolution (18 bits effective) at 15 kHz
On-chip per channel system calibration
4 single-ended analog inputs
Input ranges +5 V, ±5 V, +10 V, ±10 V
Overvoltage tolerant
Up to ±16.5 V not affecting adjacent channel
Up to ±50 V absolute maximum
3-wire serial interface
SPI™, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on logic inputs
Single-supply operation
5 V analog supply
3 V or 5 V digital supply
Package: 28-lead TSSOP
APPLICATIONS
PLCs/DCS
Multiplexing applications
Process control
Industrial instrumentation
GENERAL DESCRIPTION
The AD7734 is a high precision, high throughput analog front
end. True 16-bit p-p resolution is achievable with a total
conversion time of 500 µs (2 kHz channel switching), making it
ideally suitable for high resolution multiplexing applications.
The part can be configured via a simple digital interface, which
allows users to balance the noise performance against data
throughput up to a 15.4 kHz.
The analog front end features four single-ended input channels
with unipolar or true bipolar input ranges to ±10 V while
operating from a single +5 V analog supply. The part has an
overrange and underrange detection capability and accepts an
analog input overvoltage to ±16.5 V without degrading the
performance of the adjacent channels.
FUNCTIONAL BLOCK DIAGRAM
REFIN(–) REFIN(+)
AIN0
REFERENCE
DETECT
AIN1
AIN2
MUX
BUFFER
24-BIT
Σ−∆ ADC
AIN3
BIASHI
BIASLO
AD7734
CALIBRATION
CIRCUITRY
SERIAL
INTERFACE
SCLK
DOUT
DIN
CS
P0
SYNC/P1
I/O PORT
CLOCK
GENERATOR
CONTROL
LOGIC
RDY
RESET
AGND AV_DD MCLKOUT MCLKIN DGND DV_DD
Figure 1.
The differential reference input features “No-Reference” detect
capability. The ADC also supports per channel system
calibration options. The digital serial interface can be
configured for 3-wire operation and is compatible with
microcontrollers and digital signal processors. All interface
inputs are Schmitt triggered.
The part is specified for operation over the extended industrial
temperature range of –40°C to +105°C.
Other parts in the AD7734 family are the AD7732 and
the AD7738.
The AD7732 is similar to AD7734, but its analog front end
features two fully differential input channels.
The AD7738 analog front end is configurable for four fully
differential or eight single-ended input channels, features
0.625 V to 2.5 V bipolar/unipolar input ranges, and accepts a
common-mode input voltage from 200 mV to AVDD–300 mV.
The AD7738 multiplexer output is pinned out externally,
allowing the user to implement programmable gain or signal
conditioning before being applied to the ADC.
Rev. 0
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