参数资料
型号: PIC18F8628T-I/PT
厂商: Microchip Technology
文件页数: 30/60页
文件大小: 0K
描述: IC PIC MCU FLASH 48KX16 80TQFP
产品培训模块: Asynchronous Stimulus
标准包装: 1,200
系列: PIC® 18F
核心处理器: PIC
芯体尺寸: 8-位
速度: 40MHz
连通性: EBI/EMI,I²C,SPI,UART/USART
外围设备: 欠压检测/复位,HLVD,POR,PWM,WDT
输入/输出数: 70
程序存储器容量: 96KB(48K x 16)
程序存储器类型: 闪存
EEPROM 大小: 1K x 8
RAM 容量: 3.8K x 8
电压 - 电源 (Vcc/Vdd): 4.2 V ~ 5.5 V
数据转换器: A/D 16x12b
振荡器型: 内部
工作温度: -40°C ~ 85°C
封装/外壳: 80-TQFP
包装: 带卷 (TR)
配用: XLT80PT3-ND - SOCKET TRAN ICE 80MQFP/TQFP
其它名称: PIC18F8628T-I/PTTR
PIC18F8723 FAMILY
DS39894B-page 36
2009 Microchip Technology Inc.
2.1
A/D Acquisition Requirements
For the A/D Converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 2-3. The source
impedance (RS) and the internal sampling switch (RSS)
impedance directly affect the time required to charge
the capacitor, CHOLD. The sampling switch (RSS)
impedance varies over the device voltage (VDD). The
source impedance affects the offset voltage at the ana-
log input (due to pin leakage current). The maximum
recommended impedance for analog sources is
2.5 k
Ω. After the analog input channel is selected
(changed), the channel must be sampled for at least
the minimum acquisition time before starting a
conversion.
To calculate the minimum acquisition time, Equation 2-1
may be used. This equation assumes that 1/2 LSb error
is used (4096 steps for the 12-bit A/D). The 1/2 LSb error
is the maximum error allowed for the A/D to meet its
specified resolution.
Example 2-3 shows the calculation of the minimum
required acquisition time, TACQ. This calculation is
based
on
the
following
application
system
assumptions:
CHOLD
=
25 pF
Rs
=
2.5 k
Ω
Conversion Error
1/2 LSb
VDD
=3V
→ Rss = 4 kΩ
Temperature
=
85
°C (system max.)
EQUATION 2-1:
ACQUISITION TIME
EQUATION 2-2:
A/D MINIMUM CHARGING TIME
EQUATION 2-3:
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
Note:
When the conversion is started, the
holding capacitor is disconnected from the
input pin.
TACQ
=
Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
=TAMP + TC + TCOFF
VHOLD
=
(VREF – (VREF/4096)) (1 – e(-TC/CHOLD(RIC + RSS + RS)))
or
TC
=
– (CHOLD)(RIC + RSS + RS) ln(1/4096)
TACQ
=TAMP + TC + TCOFF
TAMP
=0.2 s
TCOFF
=
(Temp – 25
°C)(0.02 s/°C)
(85
°C – 25°C)(0.02 s/°C)
1.2 s
Temperature coefficient is only required for temperatures > 25
°C. Below 25°C, TCOFF = 0 s.
TC
=
-(CHOLD)(RIC + RSS + RS) ln(1/4096) s
-(25 pF) (1 k
Ω + 4 kΩ + 2.5 kΩ) ln(0.0002441) s
1.56 s
TACQ
=
0.2 s + 1.56
μs + 1.2 s
2.96 s
相关PDF资料
PDF描述
DG202BDQ-E3 IC SWITCH QUAD CMOS 16TSSOP
PIC17C43-33/PQ IC MCU OTP 4KX16 PWM 44-MQFP
DG9408DN-T1-E4 IC MUX ANA DUAL 8/4CH 16QFN
PIC17C43-25/PQ IC MCU OTP 4KX16 PWM 44-MQFP
PIC18F4685-E/ML IC PIC MCU FLASH 48KX16 44QFN
相关代理商/技术参数
参数描述
PIC18F8680-E/PT 功能描述:8位微控制器 -MCU 64KB 3328 RAM 68I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F8680-I/PT 功能描述:8位微控制器 -MCU 64KB 3328 RAM 68I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
PIC18F8680-I/PT 制造商:Microchip Technology Inc 功能描述:IC 8BIT FLASH MCU 18F8680 TQFP80
PIC18F8680-I/PTG 制造商:Microchip Technology 功能描述:MCU 8-bit PIC18 PIC RISC 64KB Flash 5V 80-Pin TQFP Tray
PIC18F8680T-I/PT 功能描述:8位微控制器 -MCU 64KB 3328 RAM 68I/O RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT