参数资料
型号: MCR705JP7CDWE
厂商: Freescale Semiconductor
文件页数: 146/164页
文件大小: 0K
描述: MCU 8BIT 224B RAM 28-SOIC
标准包装: 26
系列: HC05
核心处理器: HC05
芯体尺寸: 8-位
速度: 2.1MHz
连通性: SIO
外围设备: POR,温度传感器,WDT
输入/输出数: 22
程序存储器容量: 6KB(6K x 8)
程序存储器类型: OTP
RAM 容量: 224 x 8
电压 - 电源 (Vcc/Vdd): 2.7 V ~ 5.5 V
数据转换器: A/D 4x12b
振荡器型: 内部
工作温度: -40°C ~ 85°C
封装/外壳: 28-SOIC(0.295",7.50mm 宽)
包装: 管件
Analog Subsystem
MC68HC705JJ7 MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
82
Freescale Semiconductor
these bits and the ISEN bit are cleared when the device is reset, the MC68HC705JJ7/MC68HC705JP7
starts with the charge and discharge function disabled.
The length of time required to reach the maximum voltage to be measured and the speed of the time
counting mechanism will determine the resolution of the reading. The time to ramp the external capacitor
voltage to match the maximum voltage is dependent on:
Charging current to external capacitor
Value of the external capacitor
Clock rate for timing function
Any prescaling of the clock to the timing function
Desired resolution
The charging behavior is described by the general equation:
tCHG = CEXT x VX / ICHG
Where:
tCHG= Charge time (seconds)
CEXT= Capacitance (F)
VX= Unknown voltage (volts)
ICHG= Charge current (A)
Since the MCU can measure time in a variety of ways, the resolution of the conversion will depend on the
length of the time keeping function and its prescaling to the oscillator frequency (fOSC). Therefore, the
charge time also equals:
tCHG = P x N / fOSC
Where:
P= Prescaler value (
÷ 2, ÷ 4, ÷ 8, etc.)
N= Number of counts during charge time
fOSC= Oscillator clock frequency (Hz)
NOTE
Noise on the system ground or the external ramping capacitor can cause
the comparator to trip prematurely. Therefore, in any given application it is
best to use the fastest possible ramp rate (shortest charge time).
The previous two equations for the charge time, tCHG, can be combined to form the following expression
for the full scale count (NFS) of the measured time versus the full scale unknown voltage (VFS):
NFS = CEXT x VFS x fOSC / (P x ICHG)
Since a given timing method has a fixed charge current and prescaler, then the variation in the resultant
count for a given unknown voltage is mainly dependent on the operating frequency and the capacitance
value used. The desired external capacitance for a given voltage range, fOSC, conversion method, and
resolution is defined as:
CEXT = NFS x P x ICHG / (VFS x fOSC)
NOTE
The value of any capacitor connected directly to the PB0/AN0 pin should be
limited to less than 2 microfarads. Larger capacitances will create high
discharge currents which may damage the device or create signal noise.
相关PDF资料
PDF描述
MCHC705JP7CDWE IC MCU 8BIT 224 BYTES RAM 28SOIC
LF13WBJ-20P CONN JACK WATERPROOF 20POS MALE
MK20DX128VMP5 IC ARM CORTEX MCU 128KB 64BGA
MC908AP8ACBE IC MCU 8K FLASH 8MHZ 42-SDIP
VE-2N2-IY-F2 CONVERTER MOD DC/DC 15V 50W
相关代理商/技术参数
参数描述
MCR706A 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:Silicon Controlled Rectifiers
MCR706AT4 功能描述:SCR 400V 4A RoHS:否 制造商:STMicroelectronics 最大转折电流 IBO:480 A 额定重复关闭状态电压 VDRM:600 V 关闭状态漏泄电流(在 VDRM IDRM 下):5 uA 开启状态 RMS 电流 (It RMS): 正向电压下降:1.6 V 栅触发电压 (Vgt):1.3 V 最大栅极峰值反向电压:5 V 栅触发电流 (Igt):35 mA 保持电流(Ih 最大值):75 mA 安装风格:Through Hole 封装 / 箱体:TO-220 封装:Tube
MCR706AT4G 功能描述:SCR THY 4A 400V SCR RoHS:否 制造商:STMicroelectronics 最大转折电流 IBO:480 A 额定重复关闭状态电压 VDRM:600 V 关闭状态漏泄电流(在 VDRM IDRM 下):5 uA 开启状态 RMS 电流 (It RMS): 正向电压下降:1.6 V 栅触发电压 (Vgt):1.3 V 最大栅极峰值反向电压:5 V 栅触发电流 (Igt):35 mA 保持电流(Ih 最大值):75 mA 安装风格:Through Hole 封装 / 箱体:TO-220 封装:Tube
MCR707A 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:Silicon Controlled Rectifiers
MCR708A 功能描述:SCR 600V 4A RoHS:否 制造商:STMicroelectronics 最大转折电流 IBO:480 A 额定重复关闭状态电压 VDRM:600 V 关闭状态漏泄电流(在 VDRM IDRM 下):5 uA 开启状态 RMS 电流 (It RMS): 正向电压下降:1.6 V 栅触发电压 (Vgt):1.3 V 最大栅极峰值反向电压:5 V 栅触发电流 (Igt):35 mA 保持电流(Ih 最大值):75 mA 安装风格:Through Hole 封装 / 箱体:TO-220 封装:Tube