参数资料
型号: AD7856KRZ
厂商: Analog Devices Inc
文件页数: 6/32页
文件大小: 0K
描述: IC ADC 14BIT 8CHAN 5V 24SOIC
标准包装: 31
位数: 14
采样率(每秒): 285k
数据接口: 8051,QSPI?,串行,SPI? µP
转换器数目: 2
功率耗散(最大): 89.25mW
电压电源: 模拟和数字
工作温度: 0°C ~ 105°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: 管件
输入数目和类型: 8 个单端,单极;4 个伪差分,单极
AD7856
–14–
REV. A
START
WRITE TO CONTROL REGISTER SETTING STCAL = 0, RDSLT1 = 1,
RDSLT0 = 0, AND CALSLT1, CALSLT0 = 00, 01, 10, 11
CAL REGISTER POINTER IS
AUTOMATICALLY RESET
READ CAL REGISTER
CAL REGISTER POINTER IS
AUTOMATICALLY INCREMENTED
LAST
REGISTER
READ
OPERATION
OR
ABORT
?
FINISHED
YES
NO
Figure 9. Flowchart for Reading from the Calibration
Registers
Adjusting the Offset Calibration Register
The offset calibration register contains 16 bits, two leading zeros
and 14 data bits. By changing the contents of the offset register
different amounts of offset on the analog input signal can be
compensated for. Increasing the number in the offset calibration
register compensates for negative offset on the analog input
signal, and decreasing the number in the offset calibration regis-
ter compensates for positive offset on the analog input signal.
The default value of the offset calibration register is approxi-
mately 0010 0000 0000 0000. This is not an exact value, but
the value in the offset register should be close to this value. Each
of the 14 data bits in the offset register is binary weighted: the
MSB has a weighting of 5% of the reference voltage, the MSB-1
has a weighting of 2.5%, the MSB-2 has a weighting of 1.25%,
and so on down to the LSB, which has a weighting of 0.0006%.
This gives a resolution of approximately
±0.0006% of V
REF.
More accurately the resolution is
±(0.05 × V
REF )/2
13 volts =
±0.015 mV, with a 2.5 V reference. The maximum specified
offset that can be compensated for is
±3.75% of the reference
voltage but is typically
±5%, which equates to ±125 mV with a
2.5 V reference and
±250 mV with a 5 V reference.
Q. If a +20 mV offset is present in the analog input signal and the
reference voltage is 2.5 V, what code needs to be written to the
offset register to compensate for the offset?
A. 2.5 V reference implies that the resolution in the offset regis-
ter is 5%
× 2.5 V/213 = 0.015 mV. +20 mV/0.015 mV =
1310.72; rounding to the nearest number gives 1311. In
binary terms this is 0101 0001 1111. Therefore, decrease the
offset register by 0101 0001 1111.
This method of compensating for offset in the analog input
signal allows for fine tuning the offset compensation. If the
offset on the analog input signal is known, there will be no need
to apply the offset voltage to the analog input pins and do a
system calibration. The offset compensation can take place in
software.
Adjusting the Gain Calibration Register
The gain calibration register contains 16 bits, two leading 0s
and 14 data bits. The data bits are binary weighted as in the
offset calibration register. The gain register value is effectively
multiplied by the analog input to scale the conversion result
over the full range. Increasing the gain register compensates for
a smaller analog input range and decreasing the gain register
compensates for a larger input range. The maximum analog
input range for which the gain register can compensate is
1.01875 times the reference voltage; the minimum input range
is 0.98125 times the reference voltage.
相关PDF资料
PDF描述
LTC2392CLX-16#PBF IC ADC 16BIT SER/PAR 500K 48LQFP
ADM3078EYRZ-REEL7 TXRX 3V 15KV 500KBPS ESD 8-SOIC
AD7572AJRZ10 IC ADC 12BIT HS LC2MOS 24SOIC
ADM211EARU-REEL IC TXRX RS-232 5V 0.1UF 28TSSOP
ADM207EARU-REEL IC TXRX RS232 5DVR/3REC 24TSSOP
相关代理商/技术参数
参数描述
AD7858 制造商:AD 制造商全称:Analog Devices 功能描述:3 V to 5 V Single Supply, 200 kSPS 8-Channel, 12-Bit Sampling ADC
AD7858AN 功能描述:IC ADC 12BIT 8CH SRL 24-DIP RoHS:否 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
AD7858ANZ 功能描述:IC ADC 12BIT 8CHAN SRL 24-DIP 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:12 采样率(每秒):300k 数据接口:并联 转换器数目:1 功率耗散(最大):75mW 电压电源:单电源 工作温度:0°C ~ 70°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 包装:带卷 (TR) 输入数目和类型:1 个单端,单极;1 个单端,双极
AD7858AR 功能描述:IC ADC 12BIT 8CH SRL 24-SOIC RoHS:否 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:12 采样率(每秒):300k 数据接口:并联 转换器数目:1 功率耗散(最大):75mW 电压电源:单电源 工作温度:0°C ~ 70°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 包装:带卷 (TR) 输入数目和类型:1 个单端,单极;1 个单端,双极
AD7858AR-REEL 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 12-bit Serial 24-Pin SOIC W T/R 制造商:Analog Devices 功能描述:ADC SGL SAR 200KSPS 12-BIT SERL 24SOIC W - Tape and Reel 制造商:Rochester Electronics LLC 功能描述:SELF CAL.SERIAL 8CH. 12-BIT ADC I.C. - Tape and Reel