DataSheet.es    


PDF AD7795 Data sheet ( Hoja de datos )

Número de pieza AD7795
Descripción 24-/16-Bit ADC
Fabricantes Analog Devices 
Logotipo Analog Devices Logotipo



Hay una vista previa y un enlace de descarga de AD7795 (archivo pdf) en la parte inferior de esta página.


Total 30 Páginas

No Preview Available ! AD7795 Hoja de datos, Descripción, Manual

6-Channel, Low Noise, Low Powerw,w2w.4Da-ta/S1he6e-t4BU.citom
-Δ ADC with On-Chip In-Amp and Reference
AD7794/AD7795
FEATURES
Up to 23 effective bits
RMS noise: 40 nV @ 4.17 Hz
85 nV @ 16.7 Hz
Current: 400 μA typ
Power-down: 1 μA max
Low noise, programmable gain, instrumentation amp
Band gap reference with 4 ppm/°C drift typ
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
–40°C to +105°C temperature range
Independent interface power supply
24-lead TSSOP
3-wire serial interface
SPI®, QSPI™, MICROWIRE™, and DSP compatible
Schmitt trigger on SCLK
APPLICATIONS
Temperature measurement
Pressure measurement
Weigh scales
Strain gauge transducers
Gas analysis
Industrial process control
Instrumentation
Blood analysis
Smart transmitters
Liquid/gas chromatography
6-digit DVM
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, which 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.
Both parts operate with a power supply from 2.7 V to 5.25 V.
Each consumes a current of 400 μA typical and is housed in a
24-lead TSSOP.
FUNCTIONAL BLOCK DIAGRAM
GND AVDD
AIN4(+)/REFIN2(+) REFIN1(+) AIN4(–)/REFIN2(–) REFIN1(–)
VBIAS
AIN1(+)
AIN1(–)
AIN2(+)
AIN2(–)
AIN3(+)
AIN3(–)
AIN5(+)/IOUT2
AIN5(–)/IOUT1
AIN6(+)/P1
AIN6(+)/P2
PSW
GND
BAND GAP
REFERENCE
VDD
BUF
MUX
GND
IN-AMP
GND
Σ-Δ
ADC
REFERENCE
DETECT
SERIAL
INTERFACE
AND
LOGIC
CONTROL
DOUT/RDY
DIN
SCLK
CS
TEMP
SENSOR
VDD
INTERNAL
CLOCK
AD7794/AD7795
AD7794: 24-BIT ADC
AD7795: 16-BIT ADC
DVDD
Figure 1.
CLK
Rev. B
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.Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
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
©2006 Analog Devices, Inc. All rights reserved.

1 page




AD7795 pdf
ADw7w7w9.D4at/aAShDe7et74U9.c5om
Parameter1
AD7794/AD7795 CHOP ENABLED or
DISABLED REFERENCE INPUT
Internal Reference
Internal Reference Initial Accuracy
Internal Reference Drift2
Power Supply Rejection
External Reference
External REFIN Voltage
Reference Voltage Range2
AD7794B/AD7795B
1.17 ± 0.01%
4
15
85
2.5
0.1
AVDD
Absolute REFIN Voltage Limits2
Average Reference Input Current
Average Reference Input Current
Drift
Normal Mode Rejection2
Common-Mode Rejection
Reference Detect Levels
EXCITATION CURRENT SOURCES
(IEXC1 and IEXC2)
Output Current
Initial Tolerance at 25°C
Drift
Current Matching
Drift Matching
Line Regulation (AVDD)
Load Regulation
Output Compliance
BIAS VOLTAGE GENERATOR
VBIAS
VBIAS Generator Start-Up Time
GND − 30 mV
AVDD + 30 mV
400
±0.03
100
0.3
0.65
10/210/1000
±5
200
±0.5
50
2
0.2
AVDD − 0.65
AVDD − 1.1
GND − 30 mV
AVDD/2
Unit
V min/max
ppm/°C typ
ppm/°C max
dB typ
V nom
V min
V max
V min
V max
nA/V typ
nA/V/°C typ
dB typ
V min
V max
μA nom
% typ
ppm/°C typ
% typ
ppm/°C typ
%/V typ
%/V typ
V max
V max
V min
V nom
ms/nF typ
TEMPERATURE SENSOR
Accuracy
Sensitivity
LOW-SIDE POWER SWITCH
RON
Allowable Current2
DIGITAL OUTPUTS (P1 and P2)
VOH, Output High Voltage2
VOL, Output Low Voltage2
VOH, Output High Voltage2
VOL, Output Low Voltage2
INTERNAL/EXTERNAL CLOCK
Internal Clock
Frequency2
Duty Cycle
±2
0.81
7
9
30
AVDD − 0.6
0.4
4
0.4
64 ± 3%
50:50
°C typ
mV/°C typ
Ω max
Ω max
mA max
V min
V max
V min
V max
kHz min/max
% typ
Rev. B | Page 5 of 36
Test Conditions/Comments
AVDD = 4 V, TA = 25°C
REFIN = REFIN(+) − REFIN(−)
When VREF = AVDD, the differential input must be
limited to 0.9 × VREF/gain if the in-amp is active
Same as for analog inputs
NOXREF bit active if VREF < 0.3 V
Matching between IEXC1 and IEXC2, VOUT = 0 V
AVDD = 5 V ± 5%
Current sources programmed to 10 μA or 210 μA
Current sources programmed to 1 mA
Dependent on the capacitance connected to AIN;
See Figure 11
Applies if user calibrates the temperature sensor
AVDD = 5 V
AVDD = 3 V
Continuous current
AVDD = 3 V, ISOURCE = 100 μA
AVDD = 3 V, ISINK = 100 μA
AVDD = 5 V, ISOURCE = 200 μA
AVDD = 5 V, ISINK = 800 μA

5 Page





AD7795 arduino
ADw7w7w9.D4at/aAShDe7et74U9.c5om
Pin No.
17
18
19
20
21
22
23
24
Mnemonic
AIN4(+)/REFIN2(+)
AIN4()/REFIN2()
PSW
GND
AVDD
DVDD
DOUT/RDY
DIN
Description
Analog Input/Positive Reference Input.
AIN4(+) is the positive terminal of the differential analog input pair AIN4(+)/AIN4(−).
This pin also functions as a reference input. REFIN2(+) can lie anywhere between AVDD and GND + 0.1 V.
The nominal reference voltage (REFIN2(+) − REFIN2(−)) is 2.5 V, but the part functions with a reference from
0.1 V to AVDD.
Analog Input/Negative Reference Input.
AIN4(−) is the negative terminal of the differential analog input pair AIN4(+)/AIN4(−).
This pin also functions as the negative reference input for REFIN2. This reference input can lie anywhere
between GND and AVDD − 0.1 V.
Low-Side Power Switch to GND.
Ground Reference Point.
Supply Voltage, 2.7 V to 5.25 V.
Serial Interface Supply Voltage, 2.7 V to 5.25 V. DVDD is independent of AVDD. Therefore, the serial interface
operates at 3 V with AVDD at 5 V or vice versa.
Serial Data Output/Data Ready Output. DOUT/RDY serves a dual purpose.
It functions as a serial data output pin to access the output shift register of the ADC. The output shift register
can contain data from any of the on-chip data or control registers. In addition, DOUT/RDY operates as a data
ready pin, going low to indicate the completion of a conversion. If the data is not read after the conversion,
the pin goes high before the next update occurs.
The DOUT/RDY falling edge can also be used as an interrupt to a processor, indicating that valid data is
available. With an external serial clock, the data can be read using the DOUT/RDY pin. With CS low, the
data/control word information is placed on the DOUT/RDY pin on the SCLK falling edge and is valid on the
SCLK rising edge.
Serial Data Input to the Input Shift Register on the ADC. Data in this shift register is transferred to the control
registers within the ADC with the register selection bits of the communications register identifying the
appropriate register.
Rev. B | Page 11 of 36

11 Page







PáginasTotal 30 Páginas
PDF Descargar[ Datasheet AD7795.PDF ]




Hoja de datos destacado

Número de piezaDescripciónFabricantes
AD77914-Bit 128 kSPS Complete Sampling ADCAnalog Devices
Analog Devices
AD779016-Bit Buffered Sigma-Delta ADCAnalog Devices
Analog Devices
AD7791Buffered 24-Bit Sigma-Delta ADCAnalog Devices
Analog Devices
AD7792(AD7792 / AD7793) 16/24-Bit Sigma-Delta ADCAnalog Devices
Analog Devices

Número de piezaDescripciónFabricantes
SLA6805M

High Voltage 3 phase Motor Driver IC.

Sanken
Sanken
SDC1742

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices


DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.


DataSheet.es    |   2020   |  Privacy Policy  |  Contacto  |  Buscar