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參數(shù)資料
| 型號： | ADS7843E |
| 元件分類： | 通用總線功能 |
| 英文描述： | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-PDIP -55 to 125 |
| 中文描述： | 觸摸屏控制器 |
| 文件頁數(shù)： | 6/12頁 |
| 文件大小： | 163K |
| 代理商： | ADS7843E |
6
ADS7843
+V
CC
X+
Y+
X–
Y–
GND
IN3
IN4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
DCLK
CS
DIN
BUSY
DOUT
PENIRQ
+V
CC
V
REF
Serial/Conversion Clock
Chip Select
Serial Data In
Converter Status
Serial Data Out
+
1
μ
F
to
10
μ
F
(Optional)
+2.7V to +5V
ADS7843
Auxiliary Inputs
Touch
Screen
0.1
μ
F
Pen Interrupt
100k
(optional)
0.1
μ
F
THEORY OF OPERATION
The ADS7843 is a classic successive approximation register
(SAR) analog-to-digital (A/D) converter. The architecture is
based on capacitive redistribution which inherently includes
a sample/hold function. The converter is fabricated on a
0.6
μ
s CMOS process.
The basic operation of the ADS7843 is shown in Figure 1.
The device requires an external reference and an external
clock. It operates from a single supply of 2.7V to 5.25V. The
external reference can be any voltage between 1V and +V
CC
.
The value of the reference voltage directly sets the input
range of the converter. The average reference input current
depends on the conversion rate of the ADS7843.
The analog input to the converter is provided via a four-
channel multiplexer. A unique configuration of low on-
resistance switches allows an unselected ADC input channel
to provide power and an accompanying pin to provide ground
for an external device. By maintaining a differenital input to
the converter and a differential reference architecture, it is
possible to negate the switch’s on-resistance error (should
this be a source of error for the particular measurement).
ANALOG INPUT
Figure 2 shows a block diagram of the input multiplexer on
the ADS7843, the differential input of the A/D converter, and
the converter’s differential reference. Table I and Table II
show the relationship between the A2, A1, A0, and SER/DFR
control bits and the configuration of the ADS7843. The
control bits are provided serially via the DIN pin—see the
Digital Interface section of this data sheet for more details.
When the converter enters the hold mode, the voltage differ-
ence between the +IN and –IN inputs (see Figure 2) is
captured on the internal capacitor array. The input current on
the analog inputs depends on the conversion rate of the
device. During the sample period, the source must charge the
internal sampling capacitor (typically 25pF). After the ca-
pacitor has been fully charged, there is no further input
current. The rate of charge transfer from the analog source to
the converter is a function of conversion rate.
A2
A1
A0
X+
Y+
IN3
IN4
–IN
(1)
X SWITCHES
Y SWITCHES
+REF
(1)
–REF
(1)
0
1
0
1
0
0
1
1
1
1
0
0
+IN
GND
GND
GND
GND
OFF
ON
OFF
OFF
ON
OFF
OFF
OFF
+V
REF
+V
REF
+V
REF
+V
REF
GND
GND
GND
GND
+IN
+IN
+IN
TABLE I. Input Configuration, Single-Ended Reference Mode (SER/DFR HIGH).
NOTE: (1) Internal node, for clarification only—not directly accessible by the user.
A2
A1
A0
X+
Y+
IN3
IN4
–IN
(1)
X SWITCHES
Y SWITCHES
+REF
(1)
–REF
(1)
0
1
0
1
0
0
1
1
1
1
0
0
+IN
–Y
–X
GND
GND
OFF
ON
OFF
OFF
ON
OFF
OFF
OFF
+Y
+X
–Y
–X
GND
GND
+IN
+IN
+V
REF
+V
REF
+IN
NOTE: (1) Internal node, for clarification only—not directly accessible by the user.
TABLE II. Input Configuration, Differential Reference Mode (SER/DFR LOW).
FIGURE 1. Basic Operation of the ADS7843.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADS7844 | 12-Bit, 8-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER |
| ADS7844E | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-SO -55 to 125 |
| ADS7844EB | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-SO -55 to 125 |
| ADS7844N | 12-Bit, 8-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER |
| ADS7844NB | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-TSSOP -55 to 125 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADS7843E | 制造商:Texas Instruments 功能描述:IC's |
| ADS7843E/2K5 | 功能描述:觸摸屏轉(zhuǎn)換器和控制器 4-wire Touch Screen Controller RoHS:否 制造商:Microchip Technology 類型:Resistive Touch Controllers 輸入類型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類型:4-Wire, 5-Wire, 8-Wire, I2C, SPI 電源電壓:2.5 V to 5.25 V 電源電流:17 mA 工作溫度:- 40 C to + 85 C 封裝 / 箱體:SSOP-20 |
| ADS7843E/2K5G4 | 功能描述:觸摸屏轉(zhuǎn)換器和控制器 4-wire Touch Screen Controller RoHS:否 制造商:Microchip Technology 類型:Resistive Touch Controllers 輸入類型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類型:4-Wire, 5-Wire, 8-Wire, I2C, SPI 電源電壓:2.5 V to 5.25 V 電源電流:17 mA 工作溫度:- 40 C to + 85 C 封裝 / 箱體:SSOP-20 |
| ADS7843EG4 | 功能描述:觸摸屏轉(zhuǎn)換器和控制器 4-wire Touch Screen Controller RoHS:否 制造商:Microchip Technology 類型:Resistive Touch Controllers 輸入類型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類型:4-Wire, 5-Wire, 8-Wire, I2C, SPI 電源電壓:2.5 V to 5.25 V 電源電流:17 mA 工作溫度:- 40 C to + 85 C 封裝 / 箱體:SSOP-20 |
| ADS7843IDBQRQ1 | 功能描述:觸摸屏轉(zhuǎn)換器和控制器 AC 4-wire Touch Screen Cntrlr RoHS:否 制造商:Microchip Technology 類型:Resistive Touch Controllers 輸入類型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類型:4-Wire, 5-Wire, 8-Wire, I2C, SPI 電源電壓:2.5 V to 5.25 V 電源電流:17 mA 工作溫度:- 40 C to + 85 C 封裝 / 箱體:SSOP-20 |
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