参数资料
型号: MAX157AEPA+
厂商: Maxim Integrated Products
文件页数: 15/16页
文件大小: 0K
描述: IC ADC 10BIT 108KSPS 2CH 8-DIP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 50
位数: 10
采样率(每秒): 108k
数据接口: MICROWIRE?,QSPI?,串行,SPI?
转换器数目: 1
功率耗散(最大): 727mW
电压电源: 单电源
工作温度: -40°C ~ 85°C
安装类型: 通孔
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-PDIP
包装: 管件
输入数目和类型: 2 个单端,单极
MAX157/MAX159
+2.7V, Low-Power, 2-Channel,
108ksps, Serial 10-Bit ADCs in 8-Pin MAX
8
_______________________________________________________________________________________
The capacitive digital-to-analog converter (DAC)
adjusts during the remainder of the conversion cycle
to restore node ZERO to 0V within the limits of 10-bit
resolution. This action is equivalent to transferring a
16pF [(VIN+) - (VIN-)] charge from CHOLD to the bina-
ry-weighted capacitive DAC, which in turn forms a digi-
tal representation of the analog input signal.
Track/Hold
The ADC’s T/H stage enters its tracking mode on the
falling edge of CS/SHDN. For the MAX157 (single-
ended inputs), IN- is connected to GND and the con-
verter samples the positive (“+”) input. For the MAX159
(pseudo-differential inputs), IN- connects to the nega-
tive input (“-”), and the difference of [(VIN+) - (VIN-)] is
sampled. At the end of the conversion, the positive
input connects back to IN+ and CHOLD charges to the
input signal.
The time required for the T/H stage to acquire an input
signal is a function of how fast 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. The acquisition time,
tACQ, is the maximum time the device takes to acquire
the signal, and is also the minimum time required for
the signal to be acquired. Calculate this with the follow-
ing equation:
tACQ = 7(RS + RIN)CIN
where RS is the source impedance of the input signal,
RIN (9k) is the input resistance, and CIN (16pF) is the
input capacitance of the ADC. Source impedances
below 4k
have no significant impact on the AC perfor-
mance of the MAX157/MAX159.
Higher source impedances can be used if a 0.01F
capacitor is connected to the individual analog inputs.
Together with the input impedance, this capacitor forms
an RC filter, limiting the ADC’s signal bandwidth.
Input Bandwidth
The MAX157/MAX159 T/H stage offers both a 2.25MHz
small-signal and a 1MHz full-power bandwidth, which
makes it possible to use the parts for digitizing high-
speed transients and measuring periodic signals with
bandwidths exceeding the ADC’s sampling rate by
using undersampling techniques. To avoid high-fre-
quency signals being aliased into the frequency band
of interest, anti-alias filtering is recommended. Most
aliasing problems can be fixed easily with an external
resistor and a capacitor. However, if DC precision is
required, it is usually best to choose a continuous
or switched-capacitor filter, such as the MAX7410/
MAX7414 (Figure 4). Their Butterworth characteristic
generally provides the best compromise (with regard to
rolloff and attenuation) in filter configurations, is easy to
design, and provides a maximally flat passband re-
sponse.
Analog Input Protection
Internal protection diodes, which clamp the analog
input to VDD and GND, allow each input channel to
swing within GND - 300mV to VDD + 300mV without
damage. However, for accurate conversions both
inputs must not exceed VDD + 50mV or be less than
GND - 50mV.
If an off-channel analog input voltage exceeds the
supplies, limit the input current to 4mA.
MAX157
MAX159
10+2 BIT
SAR
ADC
SCLK
IN
OUT
ANALOG
INPUT
MUX
(2 CHANNEL)
CH0
(CH+)
CH1
(CH-)
REF
( ) ARE FOR MAX159
T/H
CONTROL
LOGIC
SCLK
CS/SHDN
INTERNAL
CLOCK
OUTPUT
REGISTER
DOUT
Figure 2. MAX157/MAX159 Simplified Functional Diagram
CH0
(CH+)
CH1
(CH-)
GND
CSWITCH
TRACK
T/H
RIN
9k
HOLD
CAPACITIVE DAC
CONTROL
LOGIC
REF
ZERO
TO SAR
( ) ARE FOR MAX159
COMPARATOR
+
CHOLD
16pF
SINGLE-ENDED MODE: CHO, CH1 = IN+; GND = IN-
DIFFERENTIAL MODE: CH+ = IN+; CH- = IN-
INPUT
MUX
Figure 3. Analog Input Channel Structure
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相关代理商/技术参数
参数描述
MAX157AEPA+ 功能描述:模数转换器 - ADC 10-Bit 2Ch 108ksps 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
MAX157AEUA 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
MAX157AEUA+ 功能描述:模数转换器 - ADC 10-Bit 2Ch 108ksps 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
MAX157AEUA+T 功能描述:模数转换器 - ADC 10-Bit 2Ch 108ksps 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
MAX157AEUA-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