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参数资料
| 型号： | MAX1237MEUA |
| 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, 12-Bit ADCs |
| 中文描述： | 4-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO8 |
| 封装： | MICRO MAX PACKAGE-8 |
| 文件页数： | 18/22页 |
| 文件大小： | 407K |
| 代理商： | MAX1237MEUA |
M
Automatic shutdown results in dramatic power savings,
particularly at slow conversion rates and with internal
clock. For example, at a conversion rate of 10ksps, the
average supply current for the MAX1237 is 60μA (typ) and
drops to 6μA (typ) at 1ksps. At 0.1ksps the average sup-
ply current is just 1μA, or a minuscule 3μW of power con-
sumption, see Average Supply Current vs. Conversion
Rate in the
Typical Operating Characteristics
section).
Reference Voltage
SEL[2:0] of the setup byte (Table 1) control the reference
and the AIN_/REF configuration (Table 6). When
AIN_/REF is configured to be a reference input or refer-
ence output (SEL1 = 1), differential conversions on
AIN_/REF appear as if AIN_/REF is connected to GND
(see Note 2 and Table 4). Single-ended conversion in
scan mode AIN_/REF is ignored by the internal limiter,
which sets the highest available channel at AIN2 or
AIN10.
Internal Reference
The internal reference is 4.096V for the MAX1236/
MAX1238 and 2.048V for the MAX1237/MAX1239. SEL1 of
the setup byte controls whether AIN_/REF is used for an
analog input or a reference (Table 6). When AIN_/REF is
configured to be an internal reference output (SEL[2:1] =
11), decouple AIN_/REF to GND with a 0.1μF capacitor.
Once powered up, the reference always remains on until
reconfigured. The reference should not be used to supply
current for external circuitry.
External Reference
The external reference can range from 1V to V
DD
. For
maximum conversion accuracy, the reference must be
able to deliver up to 40μA and have an output imped-
ance of 500k
or less. If the reference has a higher out-
put impedance or is noisy, bypass it to GND as close to
AIN_/REF as possible with a 0.1μF capacitor.
Transfer Functions
Output data coding for the MAX1236
–
MAX1239 is bina-
ry in unipolar mode and two
’
s complement in bipolar
mode with 1 LSB = (V
REF
/ 2N) where
“
N
”
is the number
18
______________________________________________________________________________________
of bits (12). Code transitions occur halfway between
successive-integer LSB values. Figures 12 and 13
show the input/output (I/O) transfer functions for unipo-
lar and bipolar operations, respectively.
Layout, Grounding, and Bypassing
Only use PC boards. Wire-wrap configurations are not
recommended since the layout should ensure proper
separation of analog and digital traces. Do not run ana-
log and digital lines parallel to each other, and do not
layout digital signal paths underneath the ADC pack-
age. Use separate analog and digital PC board ground
sections with only one star point (Figure 14) connecting
the two ground systems (analog and digital). For lowest
noise operation, ensure the ground return to the star
ground
’
s power supply is low impedance and as short
as possible. Route digital signals far away from sensi-
tive analog and reference inputs.
2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial, 12-Bit ADCs
SEL2
SEL1
SEL0
REFERENCE VOLTAGE
AIN_/REF
INTERNAL REFERENCE
STATE
Always Off
Always Off
Always Off
Always On
Always Off
Always On
0
0
1
1
1
1
0
1
0
0
1
1
X
X
0
1
0
1
V
DD
Analog Input
Reference Input
Analog Input
Analog Input
Reference Output
Reference Output
External Reference
Internal Reference
Internal Reference
Internal Reference
Internal Reference
Table 6. Reference Voltage and AIN_/REF Format
111...111
111...110
OUTPUT CODE
FS = REF + GND
ZS = GND
FULL-SCALE
TRANSITION
100...010
100...001
100...000
011...111
011...110
011...101
000...001
000...000
0
1
2048
INPUT VOLTAGE (LSB)
GND
FS 2
REF
1 LSB = V
Figure 12. Unipolar Transfer Function
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1236MEUA | 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs |
| MAX1236LEUA | 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs |
| MAX1238EEE | CAP .0012UF 100V PPS FILM ECH-S |
| MAX1239EEE | 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs |
| MAX1237LEUA | 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1237MEUA+ | 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 |
| MAX1237MEUA+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 |
| MAX1237MEUA-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 |
| MAX1238EEE | 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 |
| MAX1238EEE/V+ | 功能描述:模数转换器 - ADC 12-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 |
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