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参数资料
| 型号： | AD7859ASZ-REEL |
| 厂商： | Analog Devices Inc |
| 文件页数： | 8/28页 |
| 文件大小： | 0K |
| 描述： | IC ADC 12BIT 8CH LP 44-MQFP T/R |
| 标准包装： | 800 |
| 位数： | 12 |
| 采样率（每秒）： | 200k |
| 数据接口： | 并联 |
| 转换器数目： | 2 |
| 功率耗散（最大）： | 30mW |
| 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： | 44-QFP |
| 供应商设备封装： | 44-MQFP（10x10） |
| 包装： | 带卷 (TR) |
| 输入数目和类型： | 8 个单端，单极；8 个单端，双极；4 个伪差分，单极；4 个伪差分，双极 |
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AD7859/AD7859L
REV. A
–16–
Transfer Functions
For the unipolar range the designed code transitions occur mid-
way between successive integer LSB values (i.e., 1/2 LSB,
3/2 LSBs, 5/2 LSBs . . . FS –3/2 LSBs). The output coding is
straight binary for the unipolar range with 1 LSB = FS/4096 =
3.3 V/4096 = 0.8 mV when VREF = 3.3 V. Figure 12 shows the
unipolar analog input configuration. The ideal input/output
transfer characteristic for the unipolar range is shown in
Figure 14.
1LSB =
FS
4096
OUTPUT
CODE
111...111
111...110
111...101
111...100
000...011
000...010
000...001
000...000
0V 1LSB
+FS –1LSB
VIN = (AIN(+) – AIN(–)), INPUT VOLTAGE
Figure 14. AD7859/AD7859L Unipolar Transfer
Characteristic
Figure 13 shows the AD7859/AD7859L’s
±V
REF/2 bipolar ana-
log input configuration. AIN(+) cannot go below 0 ,V so for
the full bipolar range, AIN(–) should be biased to at least
+VREF/2. Once again the designed code transitions occur mid-
way between successive integer LSB values. The output coding
is 2s complement with 1 LSB = 4096 = 3.3 V/4096 = 0.8 mV.
The ideal input/output transfer characteristic is shown in Fig-
ure 15.
1LSB =
FS
4096
FS = VREFV
OUTPUT
CODE
011...111
011...110
000...001
111...111
000...010
000...001
000...000
+FS –1LSB
VIN = (AIN(+) –AIN(–)), INPUT VOLTAGE
000...000
0V
VREF/2
(VREF/2) +1LSB
(VREF/2) –1LSB
Figure 15. AD7859/AD7859L Bipolar Transfer Characteristic
IC1
+3V TO +5V
10k
10k
10k
V+
V–
10k
50
AD820
AD820-3V
VIN
(–VREF/2 TO +VREF/2)
VREF/2
10F
0.1F
10nF
(NPO)
TO AIN(+) OF
AD7854/AD7854L
Figure 11. Analog Input Buffering
Input Ranges
The analog input range for the AD7859/AD7859L is 0 V to
VREF in both the unipolar and bipolar ranges.
The difference between the unipolar range and the bipolar range
is that in the bipolar range the AIN(–) should be biased up to at
least +VREF/2 and the output coding is 2s complement (See
Table VI and Figures 14 and 15).
Table VI. Analog Input Connections
Analog Input
Input Connections
Connection
Range
AIN(+)
AIN(–)
Diagram
0 V to VREF
1
VIN
AGND
Figure 12
±V
REF/2
2
VIN
VREF/2
Figure 13
NOTES
1Output code format is straight binary.
2Range is
±V
REF/2 biased about VREF/2. Output code format is 2s complement.
Note that the AIN(–) channel on the AD7859/AD7859L can be
biased up above AGND in the unipolar mode, or above VREF/2
in bipolar mode if required. The advantage of biasing the lower
end of the analog input range away from AGND is that the ana-
log input does not have to swing all the way down to AGND.
Thus, in single supply applications the input amplifier does not
have to swing all the way down to AGND. The upper end of the
analog input range is shifted up by the same amount. Care must
be taken so that the bias applied does not shift the upper end of
the analog input above the AVDD supply. In the case where the
reference is the supply, AVDD, the AIN(–) should be tied to
AGND in unipolar mode or to AVDD/2 in bipolar mode.
TRACK AND HOLD
AMPLIFIER
AIN(+)
AIN(–)
DB0
DB15
VIN = 0 TO VREF
AD7859/AD7859L
STRAIGHT
BINARY
FORMAT
Figure 12. 0 to VREF Unipolar Input Configuration
TRACK AND HOLD
AMPLIFIER
AIN(+)
AIN(–)
DB0
DB15
VIN = 0 TO VREF
AD7859/AD7859L
2'S
COMPLEMENT
FORMAT
VREF/2
Figure 13.
±V
REF/2 about VREF/2 Bipolar Input Configuration
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7859BS | 制造商:Analog Devices 功能描述:ADC Single SAR 200ksps 12-bit Parallel 44-Pin MQFP 制造商:Rochester Electronics LLC 功能描述:12-BIT 8 CH.SERIAL 200 KSPS I.C. - Bulk |
| AD7859BSZ | 功能描述:IC ADC 12BIT 8CHAN LP 44-MQFP 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 |
| AD7859L | 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 ADCs |
| AD7859LAS | 制造商:Analog Devices 功能描述:ADC Single SAR 100ksps 12-bit Parallel 44-Pin MQFP 制造商:Rochester Electronics LLC 功能描述:12-BIT 8 CH.PARALLEL 100 KSPS I.C. - Bulk 制造商:Analog Devices 功能描述:IC 12-BIT ADC |
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