参数资料
型号: MAX1444EHJ+
厂商: Maxim Integrated Products
文件页数: 4/20页
文件大小: 0K
描述: IC ADC 10BIT 40MSPS 32-TQFP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 360
位数: 10
采样率(每秒): 40M
数据接口: 并联
转换器数目: 1
电压电源: 单电源
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 32-TQFP
供应商设备封装: 32-TQFP(5x5)
包装: 托盘
输入数目和类型: 2 个单端,双极;1 个差分,双极
产品目录页面: 1397 (CN2011-ZH PDF)
MAX1444
10-Bit, 40Msps, 3.0V, Low-Power
ADC with Internal Reference
12
______________________________________________________________________________________
The MAX1444 provides three modes of reference oper-
ation:
Internal reference mode
Buffered external reference mode
Unbuffered external reference mode
In internal reference mode, the internal reference out-
put (REFOUT) can be connected to the REFIN pin
through a resistor (e.g., 10k
Ω) or resistor-divider if an
application requires a reduced full-scale range. For sta-
bility purposes, it is recommended to bypass REFIN
with a >10nF capacitor to GND.
In buffered external reference mode, the reference vol-
tage levels can be adjusted externally by applying a
stable and accurate voltage at REFIN. In this mode,
REFOUT may be left open or connected to REFIN
through a >10k
Ω resistor.
In unbuffered external reference mode, REFIN is con-
nected to GND, thereby deactivating the on-chip
buffers of REFP, COM, and REFN. With their buffers
shut down, these pins become high impedance inputs
and can be driven by external reference sources.
Clock Input (CLK)
The MAX1444 CLK input accepts CMOS-compatible
clock signals. Since the interstage conversion of the
device depends on the repeatability of the rising and
falling edges of the external clock, use a clock with low
jitter and fast rise and fall times (<2ns). In particular,
sampling occurs on the falling edge of the clock signal,
mandating this edge to provide lowest possible jitter.
Any significant aperture jitter would limit the SNR per-
formance of the ADC as follows:
SNR = 20log (1 / 2
πfINtAJ)
where fIN represents the analog input frequency, and
tAJ is the time of the aperture jitter.
Clock jitter is especially critical for undersampling
applications. The clock input should always be consid-
ered as an analog input and routed away from any ana-
log input or other digital signal lines.
The MAX1444 clock input operates with a voltage
threshold set to VDD/2. Clock inputs with a duty cycle
other than 50% must meet the specifications for high
and low periods as stated in the
Electrical Character-
istics. See Figures 3a, 3b, 4a, and 4b for the relation-
ship between spurious-free dynamic range (SFDR),
signal-to-noise ratio (SNR), total harmonic distortion
(THD), or signal-to-noise plus distortion (SINAD) versus
clock duty cycle.
Output Enable (
OE), Power Down (PD),
and Output Data (D0–D9)
All data outputs, D0 (LSB) through D9 (MSB), are
TTL/CMOS-logic compatible. There is a 5.5 clock-cycle
latency between any particular sample and its valid
output data. The output coding is straight offset binary
(Table 1). With
OE and PD (power down) high, the digi-
tal output enters a high-impedance state. If
OE is held
low with PD high, the outputs are latched at the last
value prior to the power down.
The capacitive load on the digital outputs D0–D9
should be kept as low as possible (<15pF) to avoid
large digital currents that could feed back into the ana-
log portion of the MAX1444, thus degrading its dynam-
ic performance. The use of buffers on the ADC’s digital
outputs can further isolate the digital outputs from
heavy capacitive loads.
Figure 5 displays the timing relationship between out-
put enable and data output valid as well as power-
down/wake-up and data output valid.
Table 1. MAX1444 Output Code for Differential Inputs
DIFFERENTIAL INPUT VOLTAGE*
DIFFERENTIAL INPUT
STRAIGHT OFFSET BINARY
VREF
× 511/512
+Full Scale -1LSB
11 1111 1111
VREF
× 510/512
+Full Scale -2LSB
11 1111 1110
VREF
× 1/512
+1LSB
10 0000 0001
0
Bipolar Zero
10 0000 0000
- VREF
× 1/512
-1LSB
01 1111 1111
- VREF
× 511/512
Negative Full Scale + 1LSB
00 0000 0001
- VREF
× 512/512
Negative Full Scale
00 0000 0000
*
VREF = VREFP - VREFN
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相关代理商/技术参数
参数描述
MAX1444EHJ/V+ 功能描述:模数转换器 - ADC ANALOG TO DIGITAL CONVERTER 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
MAX1444EHJ/V+T 功能描述:模数转换器 - ADC 10-Bit 40Msps 3.0V Low-Power ADC with Internal Reference 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
MAX1444EHJ+ 功能描述:模数转换器 - ADC 10-Bit 40Msps 3V High Speed 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
MAX1444EHJ+T 功能描述:模数转换器 - ADC 10-Bit 40Msps 3V High Speed 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
MAX1444EHJ-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