参数资料
| 型号： | AD7294BCPZRL |
| 厂商： | Analog Devices Inc |
| 文件页数： | 19/49页 |
| 文件大小： | 0K |
| 描述： | IC ADC 12BIT I2C/SRL 1M 56LFCSP |
| 标准包装： | 2,500 |
| 类型： | ADC，DAC |
| 分辨率（位）： | 12 b |
| 采样率（每秒）： | 22.22k |
| 数据接口： | I²C，串行 |
| 电压电源： | 模拟和数字 |
| 电源电压： | 4.4 V ~ 5.5 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 56-VFQFN 裸露焊盘，CSP |
| 供应商设备封装： | 56-LFCSP-VQ（8x8） |
| 包装： | 带卷 (TR) |
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页当前第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页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页
Data Sheet
AD7294
Rev. H | Page 25 of 48
Series Resistance Cancellation
The AD7294 has been designed to automatically cancel out the
effect of parasitic, base, and collector resistance on the tempera-
ture reading. This gives a more accurate result, without the need
for any user characterization of the parasitic resistance. The
AD7294 can compensate for up to 100 Ω in a process that is
transparent to the user.
DAC OPERATION
The AD7294 contains four 12-bit DACs that provide digital
control with 12 bits of resolution with a 2.5 V internal reference.
The DAC core is a thin film 12-bit string DAC with a 5 V output
span and an output buffer that can drive the high voltage output
stage. The DAC has a span of 0 V to 5 V with a 2.5 V reference
input. The output range of the DAC, which is controlled by the
offset input, can be positioned from 0 V to 15 V.
Resistor String
The resistor string structure is shown in Figure 48. It consists of
a string of 2n resistors, each of Value R. The code loaded to the
DAC register determines at which node on the string the voltage
is tapped off to be fed into the output amplifier. The voltage is
tapped off by closing one of the switches connecting the string
to the amplifier. This architecture is inherently monotonic,
voltage out, and low glitch. It is also linear because all of the
resistors are of equal value.
R
TO OUTPUT
AMPLIFIER
05747-
028
Figure 48. Resistor String Structure
Output Amplifier
Referring to Figure 48, the purpose of A1 is to buffer the DAC
output range from 0 V to VREF. The second amplifier, A2, is
configured such that when an offset is applied to OFFSET IN x,
its output voltage is three times the offset voltage minus twice
the DAC voltage.
VOUT = 3VOFFSET 2VDAC
The DAC word is digitally inverted on-chip such that
VOUT = 3VOFFSET + 2(VDAC VREF)
and VDAC =
×
n
REF
D
V
2
where:
VDAC is the output of the DAC before digital inversion.
D is the decimal equivalent of the binary code that is loaded to the
DAC register.
n is the bit resolution of the DAC.
An example of the offset function is given in Table 8.
Table 8. Offset Voltage Function Example
Offset
Voltage
VOUT with 0x000
V
OUT with 0xFFF
1.67 V
0 V
5 V 1 LSB
3.33 V
5 V
10 V 1 LSB
5.00 V
10 V
15 V 1 LSB
The user has the option of leaving the offset pin open, in which
case the voltage on the noninverting input of Op Amp A2 is set
by the resistor divider, giving
VOUT = 2VDAC
This generates the 5 V output span from a 2.5 V reference.
Digitally inverting the DAC allows the circuit to operate as a
generic DAC when no offset is applied. If the offset pin is not
being driven, it is best practice to place a 100 nF capacitor
between the pin and ground to improve both the settling time
and the noise performance of the DAC.
Note that a significant amount of power can be dissipated in the
DAC outputs. A thermal shutdown circuit sets the DAC outputs
to high impedance if a die temperature of >150°C is measured
by the internal temperature sensor. This also sets the overtem-
perature alert bit in Alert Register C, see the Alerts and Limits
Theory section. Note that this feature is disabled when the
temperature sensor powers down.
ADC AND DAC REFERENCE
The AD7294 has two independent internal high performance
2.5 V references, one for the ADCs and the other for the four
on-chip DACs. If the application requires an external reference,
it can be applied to the REFOUT/REFIN DAC pin and/or to the
REFOUT/REFIN ADC pin. The internal reference should be buffered
before being used by external circuitry. Decouple both the REFOUT/
REFIN DAC pin and the REFOUT/REFIN ADC pin to AGND using a
220 nF capacitor. On power-up, the AD7294 is configured for
use with an external reference. To enable the internal references,
write a zero to both the D4 and D5 bits in the power-down
register (see the Register Setting section for more details). Both
the ADC and DAC references require a minimum of 60 μs to
power up and settle to a 12-bit performance when a 220 nF
decoupling capacitor is used.
相关PDF资料 |
PDF描述 |
|---|---|
| AD7306AN | IC TXRX RS-232 RS-422 24-DIP |
| AD7339BSZ-REEL | IC ADC/QUAD DAC 5V W/REF 52-MQFP |
| AD7376ARUZ100 | IC POT DIGITAL 128POS 14-TSSOP |
| AD7391SRZ | IC DAC 10BIT SERIAL 3V 8SOIC |
| AD7392AR | IC DAC 12BIT PARALLEL 3V 20-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7294BSUZ | 功能描述:模数转换器 - ADC 12B Monitor & Cntrl System w/ Temp Sensr RoHS:否 制造商:Analog Devices 通道数量: 结构: 转换速率: 分辨率: 输入类型: 信噪比: 接口类型: 工作电源电压: 最大工作温度: 安装风格: 封装 / 箱体: |
| AD7294BSUZRL | 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (2-Wire, I2C) 64-Pin TQFP 制造商:Analog Devices 功能描述:TEMP SENSOR DGTL SERL (2-WIRE, I2C) 64TQFP - Tape and Reel 制造商:Analog Devices 功能描述:IC ADC 12BIT W/DAC/TEMP 64TQFP 制造商:Analog Devices Inc. 功能描述:Analog to Digital Converters - ADC 12-Bit Multi-Channel ADC DAC wt Temp IC 制造商:Analog Devices 功能描述:CONVERTER - ADC |
| AD7298 | 制造商:AD 制造商全称:Analog Devices 功能描述:8-Channel, 1MSPS, 12-Bit SAR ADC with Temperature Sensor |
| AD7298-1BCPZ | 功能描述:IC ADC 10BIT SPI/SRL 8CH 20LFCSP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 其它有关文件:TSA1204 View All Specifications 标准包装:1 系列:- 位数:12 采样率（每秒）:20M 数据接口:并联 转换器数目:2 功率耗散（最大）:155mW 电压电源:模拟和数字 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-TQFP 供应商设备封装:48-TQFP（7x7） 包装:Digi-Reel® 输入数目和类型:4 个单端，单极；2 个差分，单极 产品目录页面:1156 (CN2011-ZH PDF) 其它名称:497-5435-6 |
| AD7298-1BCPZ-RL | 功能描述:IC ADC 10BIT SPI/SRL 8CH 20LFCSP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:2,500 系列:- 位数:16 采样率（每秒）:15 数据接口:MICROWIRE?，串行，SPI? 转换器数目:1 功率耗散（最大）:480µW 电压电源:单电源 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:38-WFQFN 裸露焊盘 供应商设备封装:38-QFN（5x7） 包装:带卷 (TR) 输入数目和类型:16 个单端，双极；8 个差分，双极 配用:DC1011A-C-ND - BOARD DELTA SIGMA ADC LTC2494 |
发布紧急采购，3分钟左右您将得到回复。