参数资料
型号: MAX1293ACEG
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: ADC
英文描述: 250ksps, +3V, 8-/4-Channel, 12-Bit ADCs with +2.5V Reference and Parallel Interface
中文描述: 4-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDSO24
封装: 0.150 INCH, QSOP-24
文件页数: 16/20页
文件大小: 224K
代理商: MAX1293ACEG
M
When applying an external reference to REF, disable
the internal reference buffer by connecting REFADJ to
V
DD
. The DC input resistance at REF is 25k
.
Therefore, an external reference at REF must deliver up
to 200μA DC load current during a conversion and
have an output impedance less than 10
. If the refer-
ence has higher output impedance or is noisy, bypass
it close to the REF pin with a 4.7μF capacitor.
Power-Down Modes
Save power by placing the converter in a low-current
shutdown state between conversions. Select standby
mode or shutdown mode via bits D6 and D7 of the con-
trol byte (Tables 1 and 2). In both software power-down
modes, the parallel interface remains active, but the
ADC does not convert.
Standby Mode
While in standby mode, the supply current is 850μA
(typ). The part will power up on the next rising edge on
WR
and is ready to perform conversions. This quick
turn-on time allows the user to realize significantly
reduced power consumption for conversion rates
below 250ksps.
Shutdown Mode
Shutdown mode turns off all chip functions that draw qui-
escent current, reducing the typical supply current to
2μA immediately after the current conversion is complet-
ed. A rising edge on
WR
causes the MAX1291/MAX1293
to exit shutdown mode and return to normal operation.
To achieve full 12-bit accuracy with a 4.7μF reference
bypass capacitor, 500μs is required after power-up.
Waiting this 500μs in standby mode instead of in full-
power mode can reduce power consumption by a factor
of 3 or more. When using an external reference, only
50μs is required after power-up. Enter standby mode by
performing a dummy conversion with the control byte
specifying standby mode.
Note:
Bypassing capacitors larger than 4.7μF between
REF and GND will result in longer power-up delays.
Transfer Function
Table 6 shows the full-scale voltage ranges for unipolar
and bipolar modes.
Figure 8 depicts the nominal, unipolar input/output (I/O)
transfer function and Figure 9 shows the bipolar I/O
transfer function. Code transitions occur halfway
between successive-integer LSB values. Output coding
is binary, with 1LSB = (V
REF
/4096).
Maximum Sampling Rate/
Achieving 300ksps
When running at the maximum clock frequency of
4.8MHz, the specified throughput of 250ksps is
achieved by completing a conversion every 19 clock
cycles: 1 write cycle, 3 acquisition cycles, 13 conver-
250ksps, +3V, 8-/4-Channel, 12-Bit ADCs
with +2.5V Reference and Parallel Interface
16
______________________________________________________________________________________
111
. . .
111
111
. . .
110
100
. . .
010
100
. . .
001
100
. . .
000
011
. . .
111
011
. . .
110
011
. . .
101
000
. . .
001
000
. . .
000
1
0
2
INPUT VOLTAGE (LSB)
OUTPUT CODE
ZS = COM
FS = REF + COM
FS
2048
(COM)
1LSB = 4096
FS -
3
/
2
LBS
FULL-SCALE
TRANSITION
Figure 8. Unipolar Transfer Function
011
. . .
111
011
. . .
110
000
. . .
010
000
. . .
001
000
. . .
000
111
. . .
111
111
. . .
110
111
. . .
101
100
. . .
001
100
. . .
000
- FS
COM*
INPUT VOLTAGE (LSB)
OUTPUT CODE
ZS = COM
+FS - 1LSB
*COM
V
REF
/2
+ COM
FS
= REF
2
-FS =
+ COM
-REF
2
1LSB = 4096
Figure 9. Bipolar Transfer Function
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相关代理商/技术参数
参数描述
MAX1293ACEG+ 功能描述:模数转换器 - ADC 12-Bit 4Ch 250ksps 3.6V 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
MAX1293ACEG+T 功能描述:模数转换器 - ADC 12-Bit 4Ch 250ksps 3.6V 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
MAX1293ACEG-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
MAX1293AEEG 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
MAX1293AEEG+ 功能描述:模数转换器 - ADC 12-Bit 4Ch 250ksps 3.6V 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