参数资料
型号: MAX187AMJA
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: ADC
英文描述: Fixed-Point Digital Signal Processor 288-BGA MICROSTAR
中文描述: 1-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, CDIP8
封装: 0.300 INCH, CERDIP-8
文件页数: 9/20页
文件大小: 177K
代理商: MAX187AMJA
Track/Hold
In track mode, the analog signal is acquired and stored
in the internal hold capacitor. In hold mode, the T/H
switch opens and maintains a constant input to the
ADC’s SAR section.
During acquisition, the analog input AIN charges
capacitor C
HOLD
. Bringing
CS
low ends the acquisition
interval. At this instant, the T/H switches the input side
of C
to GND. The retained charge on C
rep-
resents a sample of the input, unbalancing the node
ZERO at the comparator’s input.
In hold mode, the capacitive DAC adjusts during the
remainder of the conversion cycle to restore node
ZERO to 0V within the limits of a 12-bit resolution. This
action is equivalent to transferring a charge from
C
to the binary-weighted capacitive DAC, which in
turn forms a digital representation of the analog input
signal. At the conversion’s end, the input side of C
switches back to AIN, and C
HOLD
charges to the input
signal again.
The time required for the T/H to acquire an input signal
is a function of how quickly its input capacitance is
charged. If the input signal’s source impedance is
high, the acquisition time lengthens and more time
must be allowed between conversions. Acquisition time
is calculated by:
t
ACQ
= 9 (R
S
+ R
IN
) 16pF,
where R
= 5k
, R
S
= the source impedance of the
input signal, and t
is never less than 1.5μs. Source
impedances below 5k
do not significantly affect the
AC performance of the ADC.
M
+5V, Low-Power, 12-Bit S erial ADCs
_______________________________________________________________________________________
9
AIN
TRACKINPUT
HOLD
CPACKAGE
GND
TRACK
HOLD
5k
R
IN
CHOLD
16pF
-
+
CSWITCH
COMPARATOR
ZERO
REF
12-BIT CAPACITIVE DAC
AT THE SAMPLING INSTANT,
THE INPUT SWITCHES FROM
AIN TOGND.
ON
OFF
REFERENCE
INPUT
SHUTDOWN
INPUT
ANALOG INPUT
0V TO+5V
+5V
1
2
3
4
VDD
AIN
SHDN
REF
8
7
6
5
SCLK
CS
DOUT
GND
SERIAL
INTERFACE
0.1
μ
F
4.7
μ
F
0.1
μ
F
MAX189
ON
OFF
SHUTDOWN
INPUT
ANALOG INPUT
0V TO+5V
+5V
1
2
3
4
VDD
AIN
SHDN
REF
8
7
6
5
SCLK
CS
DOUT
GND
SERIAL
INTERFACE
4.7
μ
F
4.7
μ
F
0.1
μ
F
MAX187
Figure 3a. MAX187 Operational Diagram
Figure 3b. MAX189 Operational Diagram
Figure 4. Equivalent Input Circuit
相关PDF资料
PDF描述
MAX187CEPA +5V, Low-Power, 12-Bit Serial ADCs
MAX189CEPA 031-0560-161
MAX189BEWE CANMS3121E16-26SF0
MAX189BMJA +5V, Low-Power, 12-Bit Serial ADCs
MAX1904 500kHz Multi-Output, Low-Noise Power-Supply Controllers for Notebook Computers
相关代理商/技术参数
参数描述
MAX187BC/D 功能描述:模数转换器 - ADC +5V Low-Power 12-Bit Serial ADCs 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
MAX187BCPA 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
MAX187BCPA+ 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
MAX187BCWE 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
MAX187BCWE+ 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