参数资料
型号: MAX1245BCAP+
厂商: Maxim Integrated Products
文件页数: 21/21页
文件大小: 0K
描述: IC ADC 12BIT SERIAL 20-SSOP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 66
位数: 12
采样率(每秒): 100k
数据接口: MICROWIRE?,QSPI?,串行,SPI?
转换器数目: 1
功率耗散(最大): 2.4mW
电压电源: 单电源
工作温度: 0°C ~ 70°C
安装类型: 表面贴装
封装/外壳: 20-SSOP(0.209",5.30mm 宽)
供应商设备封装: 20-SSOP
包装: 管件
输入数目和类型: 8 个单端,单极;8 个单端,双极;4 个差分,单极;4 个差分,双极
MAX1245
0.1
F
2.048V
VDD
DGND
AGND
COM
CS
SCLK
DIN
DOUT
SSTRB
SHDN
+2.5V
N.C.
0.01
F
CH7
VREF
C1
0.1
F
0V TO
2.048V
ANALOG
INPUT
OSCILLOSCOPE
CH1
CH2
CH3
CH4
* FULL-SCALE ANALOG INPUT, CONVERSION RESULT = $FFF (HEX)
MAX1245
+2.5V
1.5MHz
OSCILLATOR
SCLK
SSTRB
DOUT*
Figure 5. Quick-Look Circuit
where RIN = 12k, RS = the source impedance of the
input signal, and tACQ is never less than 2.0s. Note
that source impedances below 1k
do not significantly
affect the AC performance of the ADC. Higher source
impedances can be used if an input capacitor is con-
nected to the analog inputs, as shown in Figure 5. Note
that the input capacitor forms an RC filter with the input
source impedance, limiting the ADC’s signal bandwidth.
Input Bandwidth
The ADC’s input tracking circuitry has a 2.25MHz
small-signal bandwidth, so it is possible to digitize
high-speed transient events and measure periodic sig-
nals with bandwidths exceeding the ADC’s sampling
rate by using undersampling techniques. To avoid
high-frequency signals being aliased into the frequency
band of interest, anti-alias filtering is recommended.
Analog Input Protection
Internal protection diodes, which clamp the analog
input to VDD and AGND, allow the channel input pins to
swing from AGND - 0.3V to VDD + 0.3V without dam-
age. However, for accurate conversions near full scale,
the inputs must not exceed VDD by more than 50mV or
be lower than AGND by 50mV.
If the analog input exceeds 50mV beyond the sup-
plies, do not forward bias the protection diodes of
off channels over two milliamperes, as excessive
current will degrade the conversion accuracy of the
on channel.
Quick Look
To quickly evaluate the MAX1245’s analog perfor-
mance, use the circuit of Figure 5. The MAX1245
requires a control byte to be written to DIN before each
conversion. Tying DIN to VDD feeds in control bytes of
$FF (HEX), which trigger single-ended unipolar conver-
sions on CH7 in external clock mode without powering
down between conversions. In external clock mode, the
SSTRB output pulses high for one clock period before
the most significant bit of the 12-bit conversion result is
shifted out of DOUT. Varying the analog input to CH7
alters the sequence of bits from DOUT. A total of 15
clock cycles is required per conversion. All transitions
of the SSTRB and DOUT outputs occur on the falling
edge of SCLK.
How to Start a Conversion
A conversion is started by clocking a control byte into
DIN. With CS low, each rising edge on SCLK clocks a
bit from DIN into the MAX1245’s internal shift register.
After CS falls, the first arriving logic “1” bit defines the
MSB of the control byte. Until this first “start” bit arrives,
any number of logic “0” bits can be clocked into DIN
with no effect. Table 1 shows the control-byte format.
The MAX1245 is compatible with MICROWIRE, SPI, and
QSPI devices. For SPI, select the correct clock polarity
and sampling edge in the SPI control registers: set
CPOL = 0 and CPHA = 0. MICROWIRE, SPI, and QSPI
all transmit a byte and receive a byte at the same time.
Using the
Typical Operating Circuit, the simplest soft-
ware interface requires only three 8-bit transfers to
+2.375V, Low-Power, 8-Channel,
Serial 12-Bit ADC
_______________________________________________________________________________________
9
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MAX1245BCAP+ 功能描述:模数转换器 - ADC 10-Bit 8Ch 100ksps 3.3V 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
MAX1245BCAP+T 功能描述:模数转换器 - ADC 10-Bit 8Ch 100ksps 3.3V 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
MAX1245BCAP-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
MAX1245BCPP 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
MAX1245BCPP+ 功能描述:模数转换器 - ADC 10-Bit 8Ch 100ksps 3.3V 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