6-Channel, Low Noise, Low Power, 24-/16-Bit
∑-Δ ADC with On-Chip In-Amp and Reference
AD7794/AD7795
Industrial process control
Instrumentation
Blood analysis
FEATURES
Up to 23 effective bits
RMS noise: 40 nV @ 4.17 Hz, 85 nV @ 16.7 Hz
Current: 400 μA typical
Smart transmitters
Liquid/gas chromatography
6-digit DVM
Power-down: 1 μA maximum
Low noise, programmable gain, instrumentation amp
Band gap reference with 4 ppm/°C drift typical
Update rate: 4.17 Hz to 470 Hz
Six differential analog inputs
Internal clock oscillator
Simultaneous 50 Hz/60 Hz rejection
Reference detect
Programmable current sources
On-chip bias voltage generator
Burnout currents
Low-side power switch
Power supply: 2.7 V to 5.25 V
Temperature range:
B grade: –40°C to +105°C
C grade: –40°C to +125°C
GENERAL DESCRIPTION
The AD7794/AD7795 are low power, low noise, complete
analog front ends for high precision measurement applications.
They contain a low noise, 24-/16-bit ∑-Δ ADC with six
differential inputs. The on-chip low noise instrumentation
amplifier means that signals of small amplitude can be
interfaced directly to the ADC.
Each device contains a precision, low noise, low drift internal
band gap reference, and can also accept up to two external
differential references. Other on-chip features include
programmable excitation current sources, burnout currents,
and a bias voltage generator that is used to set the common-
mode voltage of a channel to AVDD/2. The low-side power
switch can be used to power down bridge sensors between
conversions, minimizing the system’s power consumption. The
AD7794/AD7795 can operate with either an internal clock or
an external clock. The output data rate from each part can vary
from 4.17 Hz to 470 Hz.
Independent interface power supply
24-lead TSSOP
3-wire serial interface
SPI®, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on SCLK
Both parts operate with a power supply from 2.7 V to 5.25 V.
The B-grade parts (AD7794 and AD7795) are specified for a
temperature range of −40°C to +105°C while the C-grade part
(AD7794) is specified for a temperature range of −40°C to
+125°C. They consume a current of 400 μA typical and are
housed in a 24-lead TSSOP.
APPLICATIONS
Temperature measurement
Pressure measurement
Weigh scales
Strain gage transducers
Gas analysis
FUNCTIONAL BLOCK DIAGRAM
AIN4(+)/REFIN2(+) REFIN1(+) AIN4(–)/REFIN2(–) REFIN1(–)
GND
AV
DD
REFERENCE
DETECT
V
BIAS
BAND GAP
REFERENCE
V
DD
GND
AIN1(+)
AIN1(–)
DOUT/RDY
DIN
SERIAL
INTERFACE
AND
Σ-Δ
ADC
AIN2(+)
BUF
IN-AMP
SCLK
CS
AIN2(–)
LOGIC
CONTROL
AIN3(+)
MUX
AIN3(–)
GND
V
AIN5(+)/IOUT2
AIN5(–)/IOUT1
AIN6(+)/P1
AIN6(–)/P2
TEMP
SENSOR
INTERNAL
CLOCK
DV
DD
AD7794/AD7795
AD7794: 24-BIT ADC
AD7795: 16-BIT ADC
DD
PSW
GND
CLK
Figure 1.
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. 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 use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2004–2007 Analog Devices, Inc. All rights reserved.
5秒后页面跳转
深入解析AD9833：DDS频率合成器的卓越性能与广泛应用
高性能TDA7293音频功率放大器技术特性与应用分析
STM32H743技术深度剖析与应用案例探索
LM321中文资料解析：引脚功能介绍、技术特点、技术特性分析
微信公众号
抖音公众号
浙公网安备 33010502006866号 浙ICP备10014259号-119
营业执照ICP证
数据手册
如果您发现信息不准确，
