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AD7858LAR3 参数 Datasheet PDF下载

AD7858LAR3图片预览
型号: AD7858LAR3
PDF下载: 下载PDF文件 查看货源
内容描述: 3 V至5 V单电源, 200 kSPS的8通道, 12位采样ADC [3 V to 5 V Single Supply, 200 kSPS 8-Channel, 12-Bit Sampling ADC]
分类和应用:
文件页数/大小: 32 页 / 306 K
品牌: ADI [ ADI ]
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AD7858/AD7858L  
DETAILED TIMING SECTION  
Mode 1 (2-Wire 8051 Interface)  
automatically revert back to an input after a time, t14. Note that  
a continuous SCLK shown by the dotted waveform in Figure 35  
can be used provided that the SYNC is low for only 16 clock  
pulses in each of the read and write cycles.  
The read and writing takes place on the DIN line and the con-  
version is initiated by pulsing the CONVST pin (note that in  
every write cycle the 2/3 MODE bit must be set to 1). The  
conversion may be started by setting the CONVST bit in the  
control register to 1 instead of using the CONVST pin.  
In Figure 32 the SYNC line is tied low permanently and this  
results in a different timing arrangement. With SYNC tied low  
permanently the DIN pin will never be three-stated. The 16th  
rising edge of SCLK configures the DIN pin as an input or an  
output as shown in the diagram. Here no more than 16 SCLK  
pulses must occur for each of the read and write operations.  
Below in Figure 31 and in Figure 32 are the timing diagrams for  
Operating Mode 1 in Table X where we are in the 2-wire inter-  
face mode. Here the DIN pin is used for both input and output  
as shown. The SYNC input is level triggered active low and can  
be pulsed (Figure 31) or can be constantly low (Figure 32).  
If reading from and writing to the calibration registers in this  
interface mode, all the selected calibration registers must be  
read from or written to. The read and write operations cannot  
be aborted. When reading from the calibration registers, the  
DIN pin will remain as an output for the full duration of all the  
calibration register read operations. When writing to the calibra-  
tion registers, the DIN pin will remain as an input for the full  
duration of all the calibration register write operations.  
In Figure 31 the part samples the input data on the rising edge  
of SCLK. After the 16th rising edge of SCLK the DIN is con-  
figured as an output. When the SYNC is taken high the DIN is  
three-stated. Taking SYNC low disables the three-state on the  
DIN pin and the first SCLK falling edge clocks out the first data  
bit. Once the 16 clocks have been provided the DIN pin will  
t3 = 0.4tSCLK MIN (NONCONTINUOUS SCLK) ؎0.4tSCLK ns MIN/MAX (CONTINUOUS SCLK),  
t6 = 75/115ns MAX (5V/3V), t7 = 40/60ns MIN (5V/3V), t8 = 20/30ns MIN (5V/3V)  
POLARITY PIN LOGIC HIGH  
SYNC (I/P)  
t11  
t3  
t11  
t3  
1
16  
1
16  
SCLK (I/P)  
t5  
t14  
t7  
t8  
t6  
t12  
t6  
DB15  
DB0  
DB15  
DB0  
DIN (I/O)  
THREE-STATE  
DATA WRITE  
DATA READ  
DIN BECOMES AN INPUT  
DIN BECOMES AN OUTPUT  
Figure 31. Timing Diagram for Read/Write Operation with DIN as an Input/Output  
(i.e., Mode 1)  
t6 = 75/115ns MAX (5V/3V), t7 = 40/60ns MIN (5V/3V), t8 = 20/30ns MIN (5V/3V),  
t13 = 90/130ns MAX (5V/3V), t14 = 50/90ns MIN (5V/3V)  
POLARITY PIN LOGIC HIGH  
1
16  
1
6
16  
SCLK (I/P)  
t14  
t7  
t8  
t6  
t13  
DB0  
t6  
DB0  
DIN (I/O)  
DB15  
DB15  
DATA WRITE  
DATA READ  
DIN BECOMES AN INPUT  
Figure 32. Timing Diagram for Read/Write Operation with DIN as an Input/Output  
and SYNC Input Tied Low (i.e., Interface Mode 1)  
–24–  
REV. B  
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