参数资料
| 型号： | ISL267450AIUZ |
| 厂商： | Intersil |
| 文件页数： | 5/18页 |
| 文件大小： | 0K |
| 描述： | IC INTERFACE |
| 标准包装： | 980 |
| 系列： | * |
ISL267440, ISL267450A
13
FN7708.2
June 28, 2012
Converter Operation
The ISL267440 and ISL267450A are designed to minimize
power consumption by only powering up the SAR comparator
during conversion time. When the converter is in track mode (its
sample capacitors are tracking the input signal) the SAR
comparator is powered down. The state of the converter is
dictated by the logic state of CS. When CS is high, the SAR
comparator is powered down while the sampling capacitor array
is tracking the input. When CS transitions low, the capacitor array
immediately captures the analog signal that is being tracked.
After CS is taken low, the SCLK pin is toggled 16 times. For the
first 3 clocks, the comparator is powered up and auto-zeroed,
then the SAR decision process is begun. This process uses 12
SCLK cycles for the 12-bit ISL267450A. Each SAR decision is
presented to the SDATA output on the next clock cycle after the
SAR decision is performed. The SAR process (12 bits) is
completed on SCLK cycle 15. At this point in time, the SAR
comparator is powered down and the capacitor array is placed
back into Track mode. The last SAR comparator decision is
output from SDATA on the 16th SCLK cycle. When the last data
bit is output from SDATA, the output switches to a logic 0 until CS
is taken high, at which time, the SDATA output enters a High-Z
state.
12, and 10-bit converters respectively.
Power-On Reset
When power is first applied, the ISL267440/ISL267450A
performs a power-on reset that requires approximately 2.5ms to
execute. After this is complete, a single dummy conversion must
be executed (by taking CS low) in order to initialize the switched
capacitor track and hold. The dummy conversion cycle will take
1s with an 18MHz SCLK. Once the dummy cycle is complete,
the ADC mode will be determined by the state of CS. Regular
conversions can be started immediately after this dummy cycle
is completed and time has been allowed for proper acquisition.
Acquisition Time
To achieve the maximum sample rate (1MSps) in the
ISL267450A device, the maximum acquisition time is 200ns. For
slower conversion rates, or for conversions performed using a
slower SCLK value than 18MHz, the minimum acquisition time is
200ns. This same minimum applies to the ISL267440. This
minimum acquisition time also applies to all the devices if short
cycling is utilized.
Short Cycling
In cases where a lower resolution conversion is acceptable, CS
can be pulled high before all SCLK falling edges have elapsed.
This is referred to as short cycling, and it can be used to further
optimize power dissipation. In this mode, a lower resolution
result will be output, but the ADC will enter static mode sooner
and exhibit a lower average power consumption than if the
complete conversion cycle were carried out. The minimum
acquisition time (tACQ) requirement of 200ns must be met for
the next conversion to be valid.
FIGURE 27. PRECISION VOLTAGE REFERENCE FOR +5V SUPPLY
1
2
3
4
8
7
6
5
DNC
VIN
COMP
GND
DNC
VOUT
TRIM
0.1F
VDD
0.1F
2.5V
VREF
0.1F
BULK
+
5V
ISL21090
ISL267440
ISL267450A
FIGURE 28. VOLTAGE REFERENCE FOR +2.7V TO +3.6V, OR FOR +5V SUPPLY
VDD
0.1F
VREF
0.1F
BULK
+
+2.7V TO +3.6V
ISL21010
GND
VIN
VOUT
1
2
3
0.1F
1.25, 2.048 OR 2.5V
OR +5V
ISL267440
ISL267450A
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL267450AIUZ-T | 功能描述:模数转换器 - ADC 12 BIT 1MSPS SAR ADC 8LD 3 X 3 PROPRIETRY RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| ISL267450AIUZ-T7A | 功能描述:模数转换器 - ADC 12 BIT 1MSPS SAR ADC 8LD RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| ISL267450IBZ | 制造商:Intersil Corporation 功能描述:12 BIT 1MSPS SAR ADC, 8 LD SOIC - Rail/Tube 制造商:Intersil Corporation 功能描述:IC ADC 12BIT SPI/SRL 1MSPS 8SOIC 制造商:Intersil 功能描述:12 Bit 1MSPS SAR ADC , 8 LD SOIC |
| ISL267450IBZ-T | 制造商:Intersil Corporation 功能描述:12 BIT 1MSPS SAR ADC, 8 LD SOIC, T&R - Tape and Reel 制造商:Intersil Corporation 功能描述:IC ADC 12BIT SPI/SRL 1MSPS 8SOIC 制造商:Intersil 功能描述:12 Bit 1MSPS SAR ADC , 8 LD SOIC, T&R |
| ISL267450IBZ-T7A | 制造商:Intersil Corporation 功能描述:12 BIT 1MSPS SAR ADC, 8 LD SOIC, 250PC REEL - Tape and Reel 制造商:Intersil Corporation 功能描述:IC ADC 12BIT SPI/SRL 1M 8-SOIC 制造商:INTERSIL 功能描述:ISL267450 Series 2.7 - 5.25 V 12 Bit 1 MSPS Single Channel ADC - SOIC-8 制造商:Intersil 功能描述:12 Bit 1MSPS SAR ADC , 8 LD SOIC, 250pc R |
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