參數(shù)資料
型號(hào)： TSC2003IPWT
廠商： TEXAS INSTRUMENTS INC
元件分類(lèi)： ADC
英文描述： 2-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO16
封裝： PLASTIC, TSSOP-16
文件頁(yè)數(shù)： 4/25頁(yè)
文件大小： 535K
代理商： TSC2003IPWT
TSC2003
12
SBAS162G
www.ti.com
REFERENCE MODE
There is a critical item regarding the reference when making
measurements while the switch drivers are ON. For this
discussion, it is useful to consider the basic operation of the
TSC2003 (see Figure 1). This particular application shows
the device being used to digitize a resistive touch screen. A
measurement of the current Y position of the pointing device
is made by connecting the X+ input to the A/D converter,
turning on the Y+ and Y– drivers, and digitizing the voltage
on X+, as shown in Figure 4. For this measurement, the
resistance in the X+ lead does not affect the conversion; it
does, however, affect the settling time, but the resistance is
usually small enough that this is not a concern. However,
since the resistance between Y+ and Y– is fairly low, the
on-resistance of the Y drivers does make a small difference.
Under the situation outlined so far, it would not be possible
to achieve a 0V input or a full-scale input regardless of where
the pointing device is on the touch screen because some
voltage is lost across the internal switches. In addition, the
internal switch resistance is unlikely to track the resistance of
the touch screen, providing an additional source of error.
This situation is remedied, as shown in Figure 5, by using the
differential mode: the +REF and –REF inputs are connected
directly to Y+ and Y–, respectively. This makes the A/D
converter ratiometric. The result of the conversion is always a
percentage of the external reference, regardless of how it
changes in relation to the on-resistance of the internal switches.
REFERENCE INPUT
The voltage difference between +REF and –REF (see
Figure 2) sets the analog input range. The TSC2003 will
operate with a reference in the range of 2V to +VDD. There are
several critical items concerning the reference input and its
wide-voltage range. As the reference voltage is reduced, the
analog voltage weight of each digital output code is also
reduced. This is often referred to as the LSB (Least Significant
Bit) size, and is equal to the reference voltage divided by 4096
(256 if in 8-bit mode). Any Offset or Gain error inherent in the
A/D converter will appear to increase, in terms of LSB size, as
the reference voltage is reduced. For example, if the offset of
a given converter is 2LSBs with a 2.5V reference, it will
typically be 2.5LSBs with a 2V reference. In each case, the
actual offset of the device is the same, 1.22mV. With a lower
reference voltage, more care must be taken to provide a clean
layout including adequate bypassing, a clean (low-noise, low-
ripple) power supply, a low-noise reference (if an external
reference is used), and a low-noise input signal.
The voltage into the VREF input is not buffered, and directly
drives the Capacitor Digital-to-Analog Converter (CDAC)
portion of the TSC2003. Therefore, the input current is very
low, typically < 6
A.
FIGURE 4. Simplified Diagram of Single-Ended Reference.
FIGURE 5. Simplified Diagram of Differential Reference (Y
Switches Enabled, X+ is Analog Input).
Converter
+IN
+REF
Y+
+V
DD
X+
Y–
GND
–REF
–IN
Converter
+IN
+REF
Y+
+V
DD
V
REF
X+
Y–
GND
–REF
–IN
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TSC2003IR 功能描述:IC TOUCH SCREEN CNTRLLR 16-TSSOP RoHS:否 類(lèi)別:集成電路 (IC) >> 數(shù)據(jù)采集 - 觸摸屏控制器 系列:- 標(biāo)準(zhǔn)包裝:96 系列:- 類(lèi)型:- 觸摸面板接口:- 輸入數(shù)/鍵:- 分辨率（位）:- 評(píng)估套件:* 數(shù)據(jù)接口:- 數(shù)據(jù)速率/采樣率 (SPS，BPS):- 電壓基準(zhǔn):- 電源電壓:- 電流 - 電源:- 工作溫度:- 安裝類(lèi)型:表面貼裝 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:16-TSSOP 包裝:帶卷 (TR)
TSC2003IZQCR 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(lèi)型:Resistive Touch Controllers 輸入類(lèi)型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類(lèi)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
TSC2003-Q1 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:I2C TOUCH SCREEN CONTROLLER
TSC2004 制造商:BB 制造商全稱(chēng):BB 功能描述:1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire TOUCH SCREEN CONTROLLER with I2C⑩ Interface
TSC2004_12 制造商:BB 制造商全稱(chēng):BB 功能描述:1.2V to 3.6V, 12-Bit, Nanopower, 4-Wire
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