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参数资料
| 型号： | MAX187BEWE |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | ADC |
| 英文描述： | +5V, Low-Power, 12-Bit Serial ADCs |
| 中文描述： | 1-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO16 |
| 封装： | 0.300 INCH, SOP-16 |
| 文件页数： | 10/20页 |
| 文件大小： | 177K |
| 代理商： | MAX187BEWE |
M
+5V, Low-Power, 12-Bit S erial ADCs
10
______________________________________________________________________________________
COMPLETE CONVERSION SEQUENCE
t
WAKE
POWERED UP
POWERED DOWN
POWERED UP
CONVERSION 0
CONVERSION 1
DOUT
CS
SHDN
Input Bandwidth
The ADCs’ input tracking circuitry has a 4.5MHz small-
signal bandwidth, and an 8V/μs slew rate. It is possible
to digitize high-speed transient events and measure
periodic signals with bandwidths exceeding the ADC's
sampling rate by using undersampling techniques. To
avoid aliasing of unwanted high-frequency signals into
the frequency band of interest, an anti-alias filter is rec-
ommended. See the MAX274/MAX275 continuous-time
filters data sheet.
Input Protection
Internal protection diodes that clamp the analog input
allow the input to swing from GND - 0.3V to V
+ 0.3V
without damage. However, for accurate conversions
near full scale, the input must not exceed V
DD
by more
than 50mV, or be lower than GND by 50mV.
If the analog input exceeds the supplies by more than
50mV beyond the supplies, limit the input current to
2mA, since larger currents degrade conversion
accuracy.
Driving the Analog Input
The input lines to AIN and GND should be kept as short
as possible to minimize noise pickup. Shield longer
leads. Also see the Input Protection section.
Because the MAX187/MAX189 incorporate a T/H, the
drive requirements of the op amp driving AIN are less
stringent than those for a successive-approximation
ADC without a T/H. The typical input capacitance is
16pF. The amplifier bandwidth should be sufficient to
handle the frequency of the input signal. The MAX400
and OP07 work well at lower frequencies. For higher-
frequency operation, the MAX427 and OP27 are practi-
cal choices. The allowed input frequency range is limit-
ed by the 75ksps sample rate of the MAX187/MAX189.
Therefore, the maximum sinusoidal input frequency
allowed is 37.5kHz. Higher-frequency signals cause
aliasing problems unless undersampling techniques
are used.
Referenc e
The MAX187 can be used with an internal or external ref-
erence, while the MAX189 requires an external reference.
Internal Reference
The MAX187 has an on-chip reference with a buffered
temperature-compensated bandgap diode, laser-
trimmed to +4.096V ±0.5%. Its output is connected to
REF and also drives the internal DAC. The output can
be used as a reference voltage source for other com-
ponents and can source up to 0.6mA. Decouple REF
with a 4.7μF capacitor. The internal reference is
enabled by pulling the
SHDN
pin high. Letting
SHDN
float disables the internal reference, which allows the
use of an external reference, as described in the
External Reference section.
External Reference
The MAX189 operates with an external reference at the
REF pin. To use the MAX187 with an external reference,
disable the internal reference by letting
SHDN
float. Stay
within the voltage range +2.5V to V
DD
to achieve speci-
fied accuracy. The minimum input impedance is 12k
for DC currents. During conversion, the external refer-
ence must be able to deliver up to 350μA DC load cur-
rent and have an output impedance of 10
or less. The
recommended minimum value for the bypass capacitor
is 0.1μF. If the reference has higher output impedance
or is noisy, bypass it close to the REF pin with a 4.7μF
capacitor.
Figure 5. MAX187/MAX189 Shutdown Sequence
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相关代理商/技术参数 |
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| MAX187BEWE+ | 功能描述:模数转换器 - ADC 12-Bit 75ksps 5.25V Precision ADC 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 |
| MAX187BEWE+T | 功能描述:模数转换器 - ADC 12-Bit 75ksps 5.25V Precision ADC 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 |
| MAX187BEWE-T | 功能描述:模数转换器 - ADC 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 |
| MAX187BMJA | 功能描述:模数转换器 - ADC 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 |
| MAX187CCPA | 功能描述:模数转换器 - ADC Integrated Circuits (ICs) 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 |
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