±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
V BATT
MAX1233
MAX1234
FEEDBACK
AV DD
RESISTORS
SIMPLIFIED DC/DC CONVERTER
DACOUT
R1
i 1
ERROR AMP
R3
DAC
i 3
R2
i 2
V REF
1.25V
CONTROL
V OUT
(LCD BIAS)
MAX1677
Figure 27. LCD Contrast Control Circuit
SPI
CS
SCK
MISO
CS
SCLK
DOUT
MAX1233
MICROWIRE
CS
SCK
MISO
CS
SCLK
DOUT
MAX1233
V DD
MOSI
DIN
MAX1234
MOSI
DIN
MAX1234
BUSY
PENIRQ
KEYIRQ
SS
Figure 28a. SPI Interface
Equation 5 shows that the maximum output voltage occurs
for the minimum DAC voltage, and that the minimum
output voltage occurs for the maximum DAC voltage.
To ensure that the desired output swing is achieved,
choose appropriate values of R1, R2, and R3.
Calculate V OUTMAX using the following equation:
V OUTMAX = V REFMAX + (R1 MAX / R2 MIN )V REFMAX
+ (R1 MAX / R3 MIN ) (V REFMAX - V DACMIN )
[Equation 6]
If V OUTMAX exceeds the maximum ratings of the
LCD/TFT display, the DAC codes that cause the output
voltage to go too high must be avoided.
BUSY
PENIRQ
KEYIRQ
Figure 28b. MICROWIRE Interface
Calculate V OUTMIN using the following equation:
V OUTMIN = V REFMIN + (R1 MIN / R2 MAX )V REFMIN +
(R1 MAX / R3 MIN ) (V REFMIN - V DACMAX )
[Equation 7]
If V OUTMIN is too low for desired operation, avoid the DAC
codes, which cause the output voltage to go too low.
Connection to Standard Interface
SPI and MICROWIRE Interfaces
When using an SPI interface (Figure 28a) or
MICROWIRE (Figure 28b), set the CPOL = CPHA = 0.
At least four 8-bit operations are necessary to read or
write data to/from the MAX1233/MAX1234. DOUT data
transitions on the serial clock ’s falling edge and is
clocked into the μP on the SCLK’s rising edge. The first
______________________________________________________________________________________
41
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相关代理商/技术参数
MAX1234EVKIT 制造商:Maxim Integrated Products 功能描述:+15KV ESD-PROTECTED TOUCH-SCREEN CO - Rail/Tube
MAX1236EUA 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
MAX1236EUA+ 功能描述:模数转换器 - ADC 12-Bit 4Ch 94.4ksps 5.5V 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
MAX1236EUA+T 功能描述:模数转换器 - ADC 12-Bit 4Ch 94.4ksps 5.5V 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
MAX1236EUA-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
MAX1236EVKIT 功能描述:数据转换 IC 开发工具 MAX1236 Eval Kit RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V
MAX1236KEUA 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
MAX1236KEUA+ 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