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| 型号： | MAX1249ACEE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 23/24页 |
| 文件大小： | 0K |
| 描述： | IC ADC 10BIT SERIAL 16-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 100 |
| 位数： | 10 |
| 采样率（每秒）： | 133k |
| 数据接口： | MICROWIRE?，QSPI?，串行，SPI? |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 667mW |
| 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： | 16-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 16-QSOP |
| 包装： | 管件 |
| 输入数目和类型： | 4 个单端，单极；4 个单端，双极；2 个差分，单极；2 个差分，双极 |
MAX1248/MAX1249
+2.7V to +5.25V, Low-Power, 4-Channel,
Serial 10-Bit ADCs in QSOP-16
8
_______________________________________________________________________________________
_______________Detailed Description
The MAX1248/MAX1249 analog-to-digital converters
(ADCs) use a successive-approximation conversion
technique and input track/hold (T/H) circuitry to convert
an analog signal to a 10-bit digital output. A flexible
serial interface provides easy interface to microproces-
sors (Ps). Figure 3 is a block diagram of the
MAX1248/MAX1249.
Pseudo-Differential Input
The sampling architecture of the ADC’s analog com-
parator is illustrated in the equivalent input circuit
(Figure 4). In single-ended mode, IN+ is internally
switched to CH0–CH3, and IN- is switched to COM. In
differential mode, IN+ and IN- are selected from two
pairs: CH0/CH1 and CH2/CH3. Configure the channels
with Tables 2 and 3. Please note that the codes for
CH0–CH3 in the MAX1248/MAX1249 correspond to
the codes for CH2–CH5 in the eight-channel
(MAX148/MAX149) versions.
In differential mode, IN- and IN+ are internally switched
to either of the analog inputs. This configuration is
pseudo-differential to the effect that only the signal at
IN+ is sampled. The return side (IN-) must remain sta-
ble within ±0.5LSB (±0.1LSB for best results) with
respect to AGND during a conversion. To accomplish
this, connect a 0.1F capacitor from IN- (the selected
analog input) to AGND.
During the acquisition interval, the channel selected as
the positive input (IN+) charges capacitor CHOLD. The
acquisition interval spans three SCLK cycles and ends
on the falling SCLK edge after the last bit of the input
control word has been entered. At the end of the acqui-
sition interval, the T/H switch opens, retaining charge
on CHOLD as a sample of the signal at IN+.
The conversion interval begins with the input multiplex-
er switching CHOLD from the positive input (IN+) to the
negative input (IN-). In single-ended mode, IN- is sim-
ply COM. This unbalances node ZERO at the compara-
tor’s input. The capacitive DAC adjusts during the
remainder of the conversion cycle to restore node
ZERO to 0V within the limits of 10-bit resolution. This
action is equivalent to transferring a charge of 16pF x
[(VIN+) - (VIN-)] from CHOLD to the binary-weighted
capacitive DAC, which in turn forms a digital represen-
tation of the analog input signal.
Track/Hold
The T/H enters its tracking mode on the falling clock
edge after the fifth bit of the 8-bit control word has been
shifted in. It enters its hold mode on the falling clock
edge after the eighth bit of the control word has been
shifted in. If the converter is set up for single-ended
inputs, IN- is connected to COM, and the converter
samples the “+” input. If the converter is set up for dif-
ferential inputs, IN- connects to the “-” input, and the
difference of
|IN+ - IN-| is sampled. At the end of the
conversion, the positive input connects back to IN+,
and CHOLD charges to the input signal.
The time required for the T/H to acquire an input signal
is a function of how quickly its input capacitance is
charged. If the input signal’s source impedance is high,
INPUT
SHIFT
REGISTER
CONTROL
LOGIC
INT
CLOCK
OUTPUT
SHIFT
REGISTER
+1.21V
REFERENCE
(MAX1248)
T/H
ANALOG
INPUT
MUX
SAR
ADC
IN
DOUT
SSTRB
VDD
DGND
AGND
SCLK
DIN
COM
REFADJ
VREF
OUT
REF
CLOCK
+2.500V
20k
A
≈ 2.06*
*A
≈ 2.00 (MAX1249)
7
8
9
6
12
13
14
15
16
CH3
5
CH2
4
CH1
3
CH0
2
MAX1248
MAX1249
CS
SHDN
1
11
10
Figure 3. Block Diagram
CH0
CH1
CH2
CH3
COM
CSWITCH
TRACK
T/H
SWITCH
RIN
9k
CHOLD
HOLD
CAPACITIVE DAC
VREF
ZERO
COMPARATOR
–
+
16pF
SINGLE-ENDED MODE: IN+ = CHO–CH3, IN- = COM.
DIFFERENTIAL MODE: IN+ AND IN- SELECTED FROM PAIRS OF
CH0/CH1 AND CH2/CH3.
AT THE SAMPLING INSTANT,
THE MUX INPUT SWITCHES
FROM THE SELECTED IN+
CHANNEL TO THE SELECTED
IN- CHANNEL.
INPUT
MUX
Figure 4. Equivalent Input Circuit
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1249ACEE+ | 功能描述:模数转换器 - ADC 10-Bit 4Ch 133ksps 5.25V 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 |
| MAX1249ACEE+T | 功能描述:模数转换器 - ADC 10-Bit 4Ch 133ksps 5.25V 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 |
| MAX1249ACEE-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 |
| MAX1249ACPE | 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 |
| MAX1249ACPE+ | 功能描述:模数转换器 - ADC 10-Bit 4Ch 133ksps 5.25V 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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