- 您现在的位置：买卖IC网 > PDF目录10149 > AD7712ARZ-REEL (Analog Devices Inc)IC ADC 24BIT SGNL CONDTNR 24SOIC PDF资料下载
参数资料
| 型号： | AD7712ARZ-REEL |
| 厂商： | Analog Devices Inc |
| 文件页数： | 8/28页 |
| 文件大小： | 0K |
| 描述： | IC ADC 24BIT SGNL CONDTNR 24SOIC |
| 标准包装： | 1,000 |
| 位数： | 24 |
| 采样率（每秒）： | 1.03k |
| 数据接口： | 串行 |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 45mW |
| 电压电源： | 模拟和数字，双 ± |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 24-SOIC W |
| 包装： | 带卷 (TR) |
| 输入数目和类型： | 1 个单端，单极；1 个差分，单极；1 个差分，双极 |
第1页第2页第3页第4页第5页第6页第7页当前第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页
REV. F
–16–
AD7712
ANALOG INPUT FUNCTIONS
Analog Input Ranges
The analog inputs on the AD7712 provide the user with consid-
erable flexibility in terms of analog input voltage ranges. One of
the inputs is a differential, programmable gain, input channel
that can handle either unipolar or bipolar input signals. The
common-mode range of this input is from VSS to AVDD provided
that the absolute value of the analog input voltage lies between
VSS – 30 mV and AVDD + 30 mV. The second analog input is a
single-ended, programmable gain, high level input that accepts
analog input ranges of 0 to +4
VREF/GAIN or
±4 V
REF/GAIN.
The dc input leakage current on the AIN1 input is 10 pA maxi-
mum at 25
°C (±1 nA over temperature). This results in a dc
offset voltage developed across the source impedance. However,
this dc offset effect can be compensated for by a combination of
the differential input capability of the part and its system cali-
bration mode. The dc input current on the AIN2 input depends
on the input voltage. For the nominal input voltage range of
±10 V, the input current is ±225 A typ.
Burnout Current
The AIN1(+) input of the AD7712 contains a 4.5
A current
source that can be turned on/off via the control register. This
current source can be used in checking that a transducer has not
burned out or gone open circuit before attempting to take mea-
surements on that channel. If the current is turned on and is
allowed to flow into the transducer and a measurement of the
input voltage on the AIN1 input is taken, it can indicate that the
transducer is not functioning correctly. For normal operation,
this burnout current is turned off by writing a 0 to the BO bit in
the control register.
Bipolar/Unipolar Inputs
The two analog inputs on the AD7712 can accept either unipo-
lar or bipolar input voltage ranges. Bipolar or unipolar options
are chosen by programming the B/U bit of the control register.
This programs both channels for either unipolar or bipolar
operation. Programming the part for either unipolar or bipolar
operation does not change any of the input signal conditioning;
it simply changes the data output coding. The data coding is
binary for unipolar inputs and offset binary for bipolar inputs.
The AIN1 input channel is differential and, as a result, the
voltage to which the unipolar and bipolar signals are referenced
is the voltage on the AIN1(–) input. For example, if AIN1(–) is
1.25 V and the AD7712 is configured for unipolar operation
with a gain of 1 and a VREF of 2.5 V, the input voltage range on
the AIN1(+) input is 1.25 V to 3.75 V. If AIN1(–) is 1.25 V and
the AD7712 is configured for bipolar mode with a gain of 1 and
a VREF of 2.5 V, the analog input range on the AIN1(+) input is
–1.25 V to +3.75 V. For the AIN2 input, the input signals are
referenced to AGND.
REFERENCE INPUT/OUTPUT
The AD7712 contains a temperature compensated 2.5 V refer-
ence, which has an initial tolerance of
±1%. This reference
voltage is provided at the REF OUT, pin and can be used as the
reference voltage for the part by connecting the REF OUT pin
to the REF IN(+) pin. This REF OUT pin is a single-ended
output, referenced to AGND, which is capable of providing up
to 1 mA to an external load. In applications where REF OUT
is connected directly to REF IN(+), REF IN(–) should be tied
to AGND to provide the nominal 2.5 V reference for the
AD7712.
The reference inputs of the AD7712, REF IN(+) and
REF IN(–), provide a differential reference input capability.
The common-mode range for these differential inputs is from
VSS to AVDD. The nominal differential voltage, VREF (REF
IN(+) – REF IN(–)), is 2.5 V for specified operation, but the
reference voltage can go to 5 V with no degradation in perfor-
mance provided that the absolute value of REF IN(+) and REF
IN(–) does not exceed its AVDD and VSS limits and the VBIAS
input voltage range limits are obeyed. The part is also functional
with VREF voltages down to 1 V but with degraded performance
as the output noise will, in terms of LSB size, be larger. REF
IN(+) must always be greater than REF IN(–) for correct opera-
tion of the AD7712.
Both reference inputs provide a high impedance, dynamic load
similar to the AIN1 analog inputs. The maximum dc input
leakage current is 10 pA (
±1 nA over temperature), and source
resistance may result in gain errors on the part. The reference
inputs look like the AIN1 analog input (see Figure 7). In this
case, RINT is 5 k
typ and C
INT varies with gain. The input
sample rate is fCLK IN/256 and does not vary with gain. For gains
of 1 to 8, CINT is 20 pF; for a gain of 16, it is 10 pF; for a gain
of 32, it is 5 pF; for a gain of 64, it is 2.5 pF; and for a gain of
128, it is 1.25 pF.
The digital filter of the AD7712 removes noise from the refer-
ence input just as it does with the analog input, and the same
limitations apply regarding lack of noise rejection at integer
multiples of the sampling frequency. The output noise perfor-
mance outlined in Tables I and II assumes a clean reference. If
the reference noise in the bandwidth of interest is excessive, it
can degrade the performance of the AD7712. Using the on-chip
reference as the reference source for the part (i.e., connecting
REF OUT to REF IN) results in somewhat degraded output
noise performance from the AD7712 for portions of the noise
table that are dominated by the device noise. The on-chip refer-
ence noise effect is eliminated in ratiometric applications where
the reference is used to provide its excitation voltage for the analog
front end. The connection scheme shown in Figure 9 between
the REF OUT and REF IN pins of the AD7712 is recommended
when using the on-chip reference. Recommended reference
voltage sources for the AD7712 include the AD780 and AD680
2.5 V references.
REF OUT
REF IN(+)
AD7712
REF IN(–)
Figure 9. REF OUT/REF IN Connection
相关PDF资料 |
PDF描述 |
|---|---|
| VE-2NN-MX-F4 | CONVERTER MOD DC/DC 18.5V 75W |
| D38999/20WB98SA | CONN RCPT 6POS WALL MNT W/SCKT |
| PXA911/04/P | CONN PLUG 4POS W/PINS LG CABLE |
| VE-2NN-MX-F3 | CONVERTER MOD DC/DC 18.5V 75W |
| VE-B30-IV-F2 | CONVERTER MOD DC/DC 5V 150W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7712ARZ-REEL7 | 功能描述:IC ADC 24BIT SGNL CONDTNR 24SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD7712EB | 制造商:AD 制造商全称:Analog Devices 功能描述:LC 2 MOS Signal Conditioning ADC(229.08 k) |
| AD7712SQ | 制造商:Analog Devices 功能描述: 制造商:Rochester Electronics LLC 功能描述:24 BIT SIGMA DELTA ADC IC - Bulk |
| AD7713 | 制造商:AD 制造商全称:Analog Devices 功能描述:LC2MOS Loop-Powered Signal Conditioning ADC |
发布紧急采购，3分钟左右您将得到回复。