參數(shù)資料
型號: MAX149BCAP
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: ADC
英文描述: +2.7V to +5.25V, Low-Power, 8-Channel, Serial 10-Bit ADCs
中文描述: 8-CH 10-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDIP20
封裝: PLASTIC, DIP-20
文件頁數(shù): 11/24頁
文件大小: 221K
代理商: MAX149BCAP
M
+2.7V to +5.25V, Low-Power, 8-Channel,
S erial 10-Bit ADCs
______________________________________________________________________________________
11
Simple Software Interface
Make sure the CPU’s serial interface runs in master
mode so the CPU generates the serial clock. Choose a
clock frequency from 100kHz to 2MHz.
1) Set up the control byte for external clock mode and
call it TB1. TB1 should be of the format: 1XXXXX11
binary, where the Xs denote the particular channel
and conversion mode selected.
2) Use a general-purpose I/O line on the CPU to pull
CS
low.
3) Transmit TB1 and, simultaneously, receive a byte
and call it RB1. Ignore RB1.
4) Transmit a byte of all zeros ($00 hex) and, simulta-
neously, receive byte RB2.
5) Transmit a byte of all zeros ($00 hex) and, simulta-
neously, receive byte RB3.
6) Pull
CS
high.
Figure 6 shows the timing for this sequence. Bytes RB2
and RB3 contain the result of the conversion, padded
with one leading zero, two sub-LSB bits, and three trail-
ing zeros. The total conversion time is a function of the
serial-clock frequency and the amount of idle time
between 8-bit transfers. To avoid excessive T/H droop,
make sure the total conversion time does not exceed
120μs.
Digital Output
In unipolar input mode, the output is straight binary
(Figure 17). For bipolar input mode, the output is twos
complement (Figure 18). Data is clocked out at the
falling edge of SCLK in MSB-first format.
Cloc k Modes
The MAX148/MAX149 may use either an external
serial clock or the internal clock to perform the succes-
sive-approximation conversion. In both clock modes,
the external clock shifts data in and out of the
SSTRB
CS
SCLK
DIN
DOUT
1
4
8
12
16
20
24
START
SEL2 SEL1 SEL0
UNI/
BIP
DIF
PD1
PD0
B9
B8
B7
B6
B5
B4
B3
B2
B1
S0
S1
B0
ACQUISITION
1.5
μ
s
(f
SCLK
= 2MHz)
IDLE
FILLED WITH
ZEROS
IDLE
CONVERSION
t
ACQ
A/D STATE
RB1
RB2
RB3
Figure 6. 24-Clock External Clock Mode Conversion Timing (MICROWIRE and SPI-Compatible, QSPI-Compatible with f
SCLK
2MHz)
SEL2
SEL1
SEL0
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
0
0
0
+
0
0
1
+
0
1
0
+
0
1
1
+
1
0
0
+
1
0
1
+
1
1
0
+
1
1
1
+
Table 3. Channel Selection in Differential Mode (SGL/
DIF
= 0)
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
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MAX149BCAP+T 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 10-Bit 8Ch 133ksps 5.25V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
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