參數(shù)資料
型號(hào): ADC128S022CIMT
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: ADC
英文描述: 8-Channel, 50 kSPS to 200 kSPS, 12-Bit A/D Converter
中文描述: 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO16
封裝: TSSOP-16
文件頁數(shù): 14/18頁
文件大小: 848K
代理商: ADC128S022CIMT
1.0 Functional Description
The ADC128S022 is a successive-approximation analog-to-
digital converter designed around a charge-redistribution
digital-to-analog converter.
1.1 ADC128S022 OPERATION
Simplified schematics of the ADC128S022 in both track and
hold operation are shown in
Figure 4
and
Figure 5
respec-
tively. In
Figure 4
, the ADC128S022 is in track mode: switch
SW1 connects the sampling capacitor to one of eight analog
input channels through the multiplexer, and SW2 balances
the comparator inputs. The ADC128S022 is in this state for
the first three SCLK cycles after CS is brought low.
Figure 5
shows the ADC128S022 in hold mode: switch SW1
connects the sampling capacitor to ground, maintaining the
sampled voltage, and switch SW2 unbalances the compara-
tor. The control logic then instructs the charge-redistribution
DAC to add or subtract fixed amounts of charge to or from
the sampling capacitor until the comparator is balanced.
When the comparator is balanced, the digital word supplied
to the DAC is the digital representation of the analog input
voltage. The ADC128S022 is in this state for the last thirteen
SCLK cycles after CS is brought low.
1.2 SERIAL INTERFACE
An operational timing diagram and a serial interface timing
diagram for the ADC128S022 are shown in The Timing
Diagrams section. CS, chip select, initiates conversions and
frames the serial data transfers. SCLK (serial clock) controls
both the conversion process and the timing of serial data.
DOUT is the serial data output pin, where a conversion result
is sent as a serial data stream, MSB first. Data to be written
to the ADC128S022’s Control Register is placed on DIN, the
serial data input pin. New data is written to DIN with each
conversion.
A serial frame is initiated on the falling edge of CS and ends
on the rising edge of CS. Each frame must contain an integer
multiple of 16 rising SCLK edges. The ADC’s DOUT pin is in
a high impedance state when CS is high and is active when
CS is low. Thus, CS acts as an output enable. Similarly,
SCLK is internally gated off when CS is brought high.
During the first 3 cycles of SCLK, the ADC is in the track
mode, acquiring the input voltage. For the next 13 SCLK
cycles the conversion is accomplished and the data is
clocked out. SCLK falling edges 1 through 4 clock out lead-
ing zeros while falling edges 5 through 16 clock out the
conversion result, MSB first. If there is more than one con-
version in a frame (continuous conversion mode), the ADC
will re-enter the track mode on the falling edge of SCLK after
the N*16th rising edge of SCLK and re-enter the hold/
convert mode on the N*16+4th falling edge of SCLK. "N" is
an integer value.
The ADC128S022 enters track mode under three different
conditions. In
Figure 1
, CS goes low with SCLK high and the
ADC enters track mode on the first falling edge of SCLK. In
the second condition, CS goes low with SCLK low. Under
this condition, the ADC automatically enters track mode and
the falling edge of CS is seen as the first falling edge of
SCLK. In the third condition, CS and SCLK go low simulta-
20162709
FIGURE 4. ADC128S022 in Track Mode
20162710
FIGURE 5. ADC128S022 in Hold Mode
A
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ADC128S022CIMT-NOPB 制造商:TI 制造商全稱:Texas Instruments 功能描述:8-Channel, 50 kSPS to 200 kSPS, 12-Bit A/D Converter
ADC128S022CIMTX 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
ADC128S022CIMTX/NOPB 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
ADC128S022EVAL 制造商:NSC 制造商全稱:National Semiconductor 功能描述:8-Channel, 50 kSPS to 200 kSPS, 12-Bit A/D Converter