4-Channel, ± ±1 ꢀ ꢁnꢂpu ꢃanꢄe, ꢅHꢄh
Thropꢄhꢂpu, 24-BHu ∑-∆ ADC
AD7734
FEATURES
FUNCTIONAL BLOCK DIAGRAM
REFIN(–) REFIN(+)
High resolution ADC
24 bits no missing codes
±±0±±25% nonlinearity
AIN0
AIN1
AIN2
AIN3
REFERENCE
DETECT
Optimized for fast channel switching
18-bit p-p resolution (21 bits effective) at 5±± 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, +1± V, ±1± V
Overvoltage tolerant
BUFFER
MUX
24-BIT
Σ−∆ ADC
AD7734
BIASHI
BIASLO
SCLK
DOUT
Up to ±1605 V not affecting adꢀacent channel
Up to ±5± V absolute maximum
3-wire serial interface
CALIBRATION
CIRCUITRY
SERIAL
INTERFACE
CS
SPI™, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on logic inputs
Single-supply operation
P0
RDY
CLOCK
CONTROL
LOGIC
I/O PORT
GENERATOR
RESET
SYNC/P1
5 V analog supply
3 V or 5 V digital supply
Package: 28-lead TSSOP
AGND AV
MCLKOUT MCLKIN DGND DV
DD
DD
Figure 1.
APPLICATIONS
PLCs/DCS
Multiplexing applications
Process control
Industrial instrumentation
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.
GENERAL DESCRIPTION
The part is specified for operation over the extended industrial
temperature range of –40°C to +105°C.
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.
Other parts in the AD7734 family are the AD7732 and
the AD7738.
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 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.
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.
Rev0 ±
Information furnished by Analog Devices is believed to be accurate and reliable0
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use0
Specifications subꢀect to change without notice0 No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices0 Trademarks and
registered trademarks are the property of their respective companies0
One Technology Way, P0O0 Box 91±6, Norwood, MA ±2±62-91±6, U0S0A0
Tel: 7810329047±±
Fax: 7810326087±3
www0analog0com
© 2±±3 Analog Devices, Inc0 All rights reserved0