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| 型号： | EVAL-AD7910CBZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 6/24页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION FOR AD7910 |
| 标准包装： | 1 |
| ADC 的数量： | 1 |
| 位数： | 10 |
| 采样率（每秒）： | 250k |
| 数据接口： | 串行 |
| 输入范围： | 0 ~ Vdd |
| 在以下条件下的电源（标准）： | 12.5mW @ 250kSPS，5V |
| 工作温度： | -40°C ~ 85°C |
| 已用 IC / 零件： | AD7910 |
| 已供物品： | 板，CD |
| 相关产品： | AD7910ARMZ-ND - IC ADC 10BIT 250KSPS 8MSOP AD7910AKSZ-REEL7-ND - IC ADC 10BIT SRL 250KSPS SC70-6 AD7910AKSZ-500RL7TR-ND - IC ADC 10BIT SRL 250KSPS SC70-6 AD7910AKSZ-REEL-ND - IC ADC 10BIT SRL 250KSPS SC70-6 |
AD7910/AD7920
Rev. C | Page 14 of 24
CONVERTER OPERATION
The AD7910/AD7920 are successive approximation analog-to-
digital converters based around a charge redistribution DAC.
ADC. Figure 14 shows the ADC during its acquisition phase.
When SW2 is closed and SW1 is in Position A, the comparator
is held in a balanced condition, and the sampling capacitor
acquires the signal on VIN.
CHARGE
REDISTRIBUTION
DAC
CONTROL
LOGIC
COMPARATOR
SW2
SAMPLING
CAPACITOR
ACQUISITION
PHASE
SW1
A
B
AGND
VDD/2
VIN
02976-014
Figure 14. ADC Acquisition Phase
When the ADC starts a conversion (see Figure 15), SW2 opens
and SW1 moves to Position B, causing the comparator to become
unbalanced. The control logic and charge redistribution DAC are
used to add and subtract fixed amounts of charge from the
sampling capacitor to bring the comparator back into a balanced
condition. When the comparator is rebalanced, the conversion is
complete. The control logic generates the ADC output code.
Figure 16 shows the ADC transfer function.
CHARGE
REDISTRIBUTION
DAC
CONTROL
LOGIC
COMPARATOR
SW2
SAMPLING
CAPACITOR
CONVERSION
PHASE
SW1
A
B
AGND
VDD/2
VIN
02976-015
Figure 15. ADC Conversion Phase
ADC TRANSFER FUNCTION
The output coding of the AD7910/AD7920 is straight binary.
The designed code transitions occur at the successive integer
LSB values, that is, 1 LSB, 2 LSBs, and so on. The LSB size is
VDD/4096 for the AD7920 and VDD/1024 for the AD7910. The
ideal transfer characteristic for the AD7910/AD7920 is shown
in Figure 16.
000...000
0V
ADC
CODE
ANALOG INPUT
111...111
000...001
000...010
111...110
111...000
011...111
1LSB
+VDD – 1LSB
1LSB = VDD/1024 (AD7910)
1LSB = VDD/4096 (AD7920)
02976-016
Figure 16. Transfer Characteristic
TYPICAL CONNECTION DIAGRAM
Figure 17 shows a typical connection diagram for the AD7910/
AD7920. VREF is taken internally from VDD and, as such, VDD
should be well decoupled. This provides an analog input range of
0 V to VDD. The conversion result is output in a 16-bit word with
four leading zeros followed by the MSB of the 12-bit or 10-bit
result. Two trailing zeros follow the 10-bit result from the
AD7910.
Alternatively, because the supply current required by the
AD7910/AD7920 is so low, a precision reference can be used as
the supply source to the AD7910/AD7920. An REF19x voltage
supply the required voltage to the ADC (see Figure 17). This
configuration is especially useful if the power supply is quite
noisy or if the system supply voltages are at a value other than
5 V or 3 V (for example, 15 V). The REF19x outputs a steady
voltage to the AD7910/AD7920. If the low dropout REF193 is
used, the current it needs to supply to the AD7910/AD7920 is
typically 1.2 mA. When the ADC is converting at a rate of
250 kSPS, the REF193 needs to supply a maximum of 1.4 mA to
the AD7910/AD7920. The load regulation of the REF193 is
typically 10 ppm/mA (REF193, VS = 5 V), which results in an
error of 14 ppm (42 μV) for the 1.4 mA drawn from it. This
corresponds to a 0.057 LSB error for the AD7920 with VDD =
3 V from the REF193 and a 0.014 LSB error for the AD7910.
For applications where power consumption is of concern, the
power-down mode of the ADC and the sleep mode of the
REF19x reference should be used to improve power
performance. See the Modes of Operation section.
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相关代理商/技术参数 |
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| EVAL-AD7912CB | 功能描述:BOARD EVALUATION FOR AD7912 RoHS:否 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7912CBZ | 功能描述:BOARD EVALUATION FOR AD7912 RoHS:是 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7920CB | 制造商:AD 制造商全称:Analog Devices 功能描述:250 kSPS, 10-/12-Bit ADCs in 6-Lead SC70 |
| EVAL-AD7920CBZ | 功能描述:BOARD EVALUATION FOR AD7920 RoHS:是 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7922CB | 制造商:Analog Devices 功能描述:EVALUATION BOARD I.C. - Bulk |
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