参数资料
型号: MAX1138EEE
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: ADC
英文描述: 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial 10-Bit ADCs
中文描述: 12-CH 10-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO16
封装: 0.150 INCH, 0.025 INCH PITCH, MO-137-AB, QSOP-16
文件页数: 10/22页
文件大小: 471K
代理商: MAX1138EEE
M
signal. At the end of the acquisition interval, the T/H
switches move to the hold position retaining the charge
on C
T/H
as a stable sample of the input signal.
During the conversion interval, the switched capacitive
DAC adjusts to restore the comparator input voltage to
0V within the limits of 10-bit resolution. This action
requires 10 conversion clock cycles and is equivalent
to transferring a charge of 11pF
(V
IN+
- V
IN-
) from
C
T/H
to the binary weighted capacitive DAC, forming a
digital representation of the analog input signal.
Sufficiently low source impedance is required to ensure
an accurate sample. A source impedance of up to 1.5k
does not significantly degrade sampling accuracy. To
minimize sampling errors with higher source impedances,
connect a 100pF capacitor from the analog input to GND.
This input capacitor forms an RC filter with the source
impedance limiting the analog-input bandwidth. For larg-
er source impedances, use a buffer amplifier to maintain
analog-input signal integrity and bandwidth.
When operating in internal clock mode, the T/H circuitry
enters its tracking mode on the eighth rising clock edge
of the address byte (see the
Slave Address
section). The
T/H circuitry enters hold mode on the falling clock edge of
the acknowledge bit of the address byte (the ninth clock
pulse). A conversion, or series of conversions, are then
internally clocked and the MAX1136
MAX1139 holds
SCL low. With external clock mode, the T/H circuitry
enters track mode after a valid address on the rising
edge of the clock during the read (R/W = 1) bit. Hold
mode is then entered on the rising edge of the second
clock pulse during the shifting out of the first byte of the
result. The conversion is performed during the next 10
clock cycles.
The time required for the T/H circuitry to acquire an
input signal is a function of the input sample capaci-
tance. If the analog-input source impedance is high,
the acquisition time constant lengthens and more time
must be allowed between conversions. The acquisition
time (t
ACQ
) is the minimum time needed for the signal
to be acquired. It is calculated by:
t
ACQ
9
(R
SOURCE
+ R
IN
)
C
IN
where R
SOURCE
is the analog-input source impedance,
R
IN
= 2.5k
, and C
IN
= 22pF. t
ACQ
is 1.5/f
SCL
for internal
clock mode and t
ACQ
= 2/f
SCL
for external clock mode.
Analog Input Bandwidth
The MAX1136
MAX1139 feature input-tracking circuitry
with a 5MHz small-signal bandwidth. The 5MHz input
bandwidth makes it possible to digitize high-speed
transient events and measure periodic signals with
bandwidths exceeding the ADC
s sampling rate by
using under sampling techniques. To avoid high-fre-
quency signals being aliased into the frequency band
of interest, anti-alias filtering is recommended.
Analog Input Range and Protection
Internal protection diodes clamp the analog input to
V
DD
and GND. These diodes allow the analog inputs to
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial 10-Bit ADCs
10
______________________________________________________________________________________
T
T
H
C
T/H
C
T/H
T
TRACK
H
AIN0
AIN1
AIN2
AIN3/REF
GND
ANALOG INPUT MUX
CAPACITIVE
DAC
REF
CAPACITIVE
DAC
REF
MAX1136
MAX1137
H
HOLD
TRACK
HOLD
V
DD
/2
Figure 4. Equivalent Input Circuit
相关PDF资料
PDF描述
MAX1139EEE Low-Voltage Adjustable Precision Shunt Regulator 3-SOT-89 -40 to 85
MAX1136EUA 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial 10-Bit ADCs
MAX1137EUA 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial 10-Bit ADCs
MAX1150AIZS Circular Connector; No. of Contacts:13; Series:MS27473; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:10; Circular Contact Gender:Pin; Circular Shell Style:Straight Plug; Insert Arrangement:10-35 RoHS Compliant: No
MAX1150 Low-Voltage Adjustable Precision Shunt Regulator 3-SOT-23 0 to 70
相关代理商/技术参数
参数描述
MAX1138EEE+ 功能描述:模数转换器 - ADC 10-Bit 12Ch 94.4ksps 5.5V 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
MAX1138EEE+T 功能描述:模数转换器 - ADC 10-Bit 12Ch 94.4ksps 5.5V 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
MAX1138EEE-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
MAX1138KEEE 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
MAX1138KEEE+ 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