- 您现在的位置：买卖IC网 > PDF目录10676 > AD7795BRUZ (Analog Devices Inc)IC ADC 16BIT 6CH LOW-PWR 24TSSOP PDF资料下载
参数资料
| 型号： | AD7795BRUZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 28/37页 |
| 文件大小： | 0K |
| 描述： | IC ADC 16BIT 6CH LOW-PWR 24TSSOP |
| 标准包装： | 62 |
| 位数： | 16 |
| 采样率（每秒）： | 470 |
| 数据接口： | DSP，MICROWIRE?，QSPI?，串行，SPI? |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 2.5mW |
| 电压电源： | 模拟和数字 |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 24-TSSOP |
| 包装： | 管件 |
| 输入数目和类型： | 6 个差分，单极；6 个差分，双极 |
| 产品目录页面： | 779 (CN2011-ZH PDF) |
第1页第2页第3页第4页第5页第6页第7页第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页当前第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页
AD7794/AD7795
Rev. D | Page 33 of 36
input also drives the reference voltage for the parts, the effect of
the low frequency noise in the excitation source is removed,
because the application is ratiometric. If the AD7794/AD7795
are used in nonratiometric applications, a low noise reference
should be used.
Recommended 2.5 V reference voltage sources for the
low noise, low power references. Also, note that the reference
inputs provide a high impedance, dynamic load. Because the
input impedance of each reference input is dynamic, resis-
tor/capacitor combinations on these inputs can cause dc gain
errors, depending on the output impedance of the source
driving the reference inputs.
Reference voltage sources (for example, the ADR391) typically
have low output impedances and are, therefore, tolerant to
having decoupling capacitors on REFIN(+) without introducing
gain errors in the system. Deriving the reference input voltage
across an external resistor means that the reference input sees a
significant external source impedance. External decoupling on
the REFIN pins is not recommended in this type of circuit
configuration.
REFERENCE DETECT
The AD7794/AD7795 include on-chip circuitry to detect if they
have a valid reference for conversions or calibrations when the
user selects an external reference as the reference source. This
feature is enabled when the REF_DET bit in the configuration
register is set to 1. If the voltage between the selected REFIN(+)
and REFIN(–) pins goes below 0.3 V, or either the REFIN(+) or
REFIN(–) inputs are open circuit, the AD7794/AD7795 detect
that they no longer have valid references. In this case, the
NOXREF bit of the status register is set to 1. If the AD7794/
AD7795 are performing normal conversions and the NOXREF
bit becomes active, the conversion results revert to all 1s.
Therefore, it is not necessary to continuously monitor the status
of the NOXREF bit when performing conversions. It is only
necessary to verify its status if the conversion result read from
the ADC data register is all 1s. If the AD7794/AD7795 are
performing either offset or full-scale calibrations and the
NOXREF bit becomes active, the updating of the respective
calibration registers is inhibited to avoid loading incorrect
coefficients to these registers, and the ERR bit in the status
register is set. If the user is concerned about verifying that a
valid reference is in place every time a calibration is performed,
the status of the ERR bit should be checked at the end of the
calibration cycle.
RESET
The circuitry and serial interface of the AD7794/AD7795 can
be reset by writing 32 consecutive 1s to the device. This resets
the logic, the digital filter, and the analog modulator, and all on-
chip registers are reset to their default values. A reset is
automatically performed on power-up. When a reset is initiated,
the user must allow a period of 500 μs before accessing any of
the on-chip registers. A reset is useful if the serial interface
becomes asynchronous due to noise on the SCLK line.
AVDD MONITOR
Along with converting external voltages, the ADC can be
used to monitor the voltage on the AVDD pin. When Bit CH2
to Bit CH0 equals 1, the voltage on the AVDD pin is internally
attenuated by 6, and the resulting voltage is applied to the
∑-Δ modulator using an internal 1.17 V reference for analog-
to-digital conversion. This is useful because variations in the
power supply voltage can be monitored.
CALIBRATION
The AD7794/AD7795 provide four calibration modes that can
be programmed via the mode bits in the mode register. These
are internal zero-scale calibration, internal full-scale calibration,
system zero-scale calibration, and system full-scale calibration,
which effectively reduce the offset error and full-scale error to
the order of the noise. After each conversion, the ADC
conversion result is scaled using the ADC calibration registers
before being written to the data register. The offset calibration
coefficient is subtracted from the result prior to multiplication
by the full-scale coefficient.
To start a calibration, write the relevant value to the MD2 to
MD0 bits in the mode register. After the calibration is
completed, the contents of the corresponding calibration
registers are updated, the RDY bit in the status register is set,
the DOUT/RDY pin goes low (if CS is low), and the
AD7794/AD7795 revert to idle mode.
During an internal zero-scale or full-scale calibration, the
respective zero input and full-scale input are automatically
connected internally to the ADC input pins. A system calibration,
however, expects the system zero-scale and system full-scale
voltages to be applied to the ADC pins before initiating the
calibration mode. In this way, external ADC errors are removed.
From an operational point of view, a calibration should be
treated like another ADC conversion. A zero-scale calibration,
if required, should always be performed before a full-scale
calibration. System software should monitor the RDY bit in the
status register or the DOUT/RDY pin to determine the end of
calibration via a polling sequence or an interrupt-driven routine.
With chop enabled, both an internal offset calibration and
a system offset calibration take two conversion cycles. With
chop enabled, an internal offset calibration is not needed
because the ADC itself removes the offset continuously. With
chop disabled, an internal offset calibration or system offset
calibration takes one conversion cycle to complete. Internal
offset calibrations are required with chop disabled and should
occur before the full-scale calibration.
To perform an internal full-scale calibration, a full-scale input
voltage is automatically connected to the selected analog input
for this calibration. When the gain equals 1, a calibration takes
two conversion cycles to complete when chop is enabled and
相关PDF资料 |
PDF描述 |
|---|---|
| VI-271-IX-B1 | CONVERTER MOD DC/DC 12V 75W |
| VI-B7V-MY-B1 | CONVERTER MOD DC/DC 5.8V 50W |
| VI-JWF-MY-F1 | CONVERTER MOD DC/DC 72V 50W |
| VI-20K-IX-B1 | CONVERTER MOD DC/DC 40V 75W |
| CS5526-BSZ | IC ADC 20BIT W/4BIT LATCH 20SSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7795BRUZ1 | 制造商:AD 制造商全称:Analog Devices 功能描述:6-Channel, Low Noise, Low Power, 24-/16-Bit ?￡-?? ADC with On-Chip In-Amp and Reference |
| AD7795BRUZ-REEL | 功能描述:IC ADC 16BIT 6CH LOW-PWR 24TSSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1,000 系列:- 位数:16 采样率（每秒）:45k 数据接口:串行 转换器数目:2 功率耗散（最大）:315mW 电压电源:模拟和数字 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC W 包装:带卷 (TR) 输入数目和类型:2 个单端，单极 |
| AD7795BRUZ-REEL1 | 制造商:AD 制造商全称:Analog Devices 功能描述:6-Channel, Low Noise, Low Power, 24-/16-Bit ?￡-?? ADC with On-Chip In-Amp and Reference |
| AD7796 | 制造商:AD 制造商全称:Analog Devices 功能描述:Low Power, 16-/24-Bit Sigma-Delta ADC for Bridge Sensors |
| AD7796BRUZ | 功能描述:IC ADC 16BIT SIG-DEL 1CH 16TSSOP 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:microPOWER™ 位数:8 采样率（每秒）:1M 数据接口:串行，SPI? 转换器数目:1 功率耗散（最大）:- 电压电源:模拟和数字 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:24-VFQFN 裸露焊盘 供应商设备封装:24-VQFN 裸露焊盘（4x4） 包装:Digi-Reel® 输入数目和类型:8 个单端，单极 产品目录页面:892 (CN2011-ZH PDF) 其它名称:296-25851-6 |
发布紧急采购，3分钟左右您将得到回复。