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| 型号： | AD7878LPZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 3/16页 |
| 文件大小： | 0K |
| 描述： | IC ADC 12BIT W/DSP INT 28-PLCC |
| 标准包装： | 1 |
| 位数： | 12 |
| 采样率（每秒）： | 100k |
| 数据接口： | DSP |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 95.5mW |
| 电压电源： | 模拟和数字，双 ± |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-LCC（J 形引线） |
| 供应商设备封装： | 28-PLCC（11.51x11.51） |
| 包装： | 管件 |
| 输入数目和类型： | 1 个单端，双极 |
AD7878
–11–
REV. A
Positive Full-Scale Adjust
Apply a voltage of 2.9978 V (FS/2 – 3/2 LSBs) at V1. Adjust R2
until the ADC output code flickers between 0111 1111 1110
and 0111 1111 1111.
Negative Full-Scale Adjust
Apply a voltage of –2.9993 V (–FS/2 + 1/2 LSB) at Vl and ad-
just R2 until the ADC output code flickers between 1000 0000
0000 and 1000 0000 0001.
Figure 17. AD7878 Full-Scale Adjust Circuit
MICROPROCESSOR INTERFACING
The AD7878 high speed bus timing allows direct interfacing to
DSP processors. Due to the complexity of the AD7878 internal
logic, only synchronous interfacing is allowed. This means that
the ADC clock must be the same as, or a derivative of, the pro-
cessor clock. Suitable processor interfaces are shown in Figures
18 to 21.
AD7878–ADSP-2100/TMS32010/TMS32020
All three interfaces use an external timer for conversion control,
allowing the ADC to sample the analog input asynchronously to
the microprocessor. The AD7878
ALFL output interrupts the
processor when the FIFO preprogrammed word count is
reached. The processor then reads the conversion results from
the AD7878 internal FIFO memory.
Figure 18. AD7878–ADSP-2700 Interface
Figure 19. AD7878–TMS32020 Interface
The interfaces to the ADSP-2100 and the TMS32020 gate the
AD7878
CS and the BUSY to provide a signal which drives the
processor into a wait state if a read/write operation to the ADC
is attempted while the ADC track/hold amplifier is going from
the track to the hold mode. This avoids digital feedthrough to
the analog circuitry. The TMS32020 does not have separate
RD and WR outputs to drive the AD7878 DMWR and
DMRD inputs. These are generated from the processor STRB
and R/
W outputs with the addition of some logic gates.
Figure 20. AD7878–TMS32020 Interface
AD7878–M CC8000
This interface also uses an external timer for conversion control
as described for the previous three interfaces. It is discussed
separately because it needs extra logic due to the nature of its
interrupts. The MC68000 has eight levels of external interrupt.
When interrupting this processor one of these levels (0 to 7)
has to be encoded onto the
IPL2–IPL0 inputs. This is achieved
with a 74148 encoder in Figure 21, (interrupt Level 1 is taken
for example purposes only). The MC68000 places this inter-
rupt level on address bits A3 to A1 at the start of the interrupt
service routine. Additional logic is used to decode this interrupt
level on the address bus and the FC2–FC0 outputs to generate
a
VPA signal for the MC68000. This results in an autovectored
interrupt, the start address for the service routine must be
loaded into the appropriate auto vector location during initial-
ization. For further information on the 68000 interrupts con-
sult the 68000 User’s Manual.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7878LPZ-REEL | 功能描述:IC ADC 12BIT W/DSP 28PLCC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD7878SE | 制造商:AD 制造商全称:Analog Devices 功能描述:LC2MOS Complete 12-Bit 100 kHz Sampling ADC with DSP Interface |
| AD7878SE/883B | 制造商:Rochester Electronics LLC 功能描述:COMPLETE 12-BIT ADC IC - Bulk 制造商:Analog Devices 功能描述:CONVERTER - ADC |
| AD7878SQ | 制造商:Analog Devices 功能描述:ADC SGL SAR 100KSPS 12-BIT PARALLEL 28CDIP - Rail/Tube 制造商:Rochester Electronics LLC 功能描述:COMPLETE 12 BIT ADC IC - Bulk 制造商:Analog Devices 功能描述:IC ADC 12BIT W/DSP INT 28-CDIP 制造商:Analog Devices Inc. 功能描述:Analog to Digital Converters - ADC COMPLETE 12 BIT ADC IC 制造商:Analog Devices 功能描述:CONVERTER - ADC |
| AD7878SQ/883B | 制造商:Analog Devices 功能描述:ADC Single SAR 100ksps 12-bit Parallel 28-Pin CDIP 制造商:Analog Devices 功能描述:ADC SGL SAR 100KSPS 12-BIT PARALLEL 28CDIP - Rail/Tube 制造商:Rochester Electronics LLC 功能描述:COMPLETE 12-BIT ADC IC - Bulk 制造商:Analog Devices Inc. 功能描述:Analog to Digital Converters - ADC COMPLETE 12-BIT ADC IC |
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