参数资料
型号: AD654JNZ/+
厂商: Analog Devices Inc
文件页数: 9/12页
文件大小: 354K
描述: IC CONV VOLT-FREQ 500KHZ 8DIP
标准包装: 50
类型: 电压至频率
频率 - 最大: 500kHz
全量程: ±50ppm/°C
线性: ±0.2%
安装类型: 通孔
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-PDIP
包装: 管件
AD654
REV.
9
8
7
6
5
1
2
3
4
AD654
1k
V
IN
(0V TO 1V)
1000pF
5V
10k
825
1%
500
A
D
+

6MHz
20pF
20pF
1F
XTAL1
XTAL2
RESET
EA
SS
INT
T0
T1
P10
P17
P20
P27
DB0
DB7
PORT 1
PORT 2
BUS
PORT
V
CC
V
DD
V
SS
5V
GND
ALE PSEN PROG WR RD
8048
NC
NC   NC
NC = NO CONNECT
Figure 11. AD654 VFC as an ADC
FREQUENCY DOUBLING
Since the AD654s output is a square-wave rather than a pulse
train, information about the input signal is carried on both
halves of the output waveform. The circuit in Figure 12 converts
the output into a pulse train, effectively doubling the output
frequency, while preserving the better low frequency linearity of
the AD654. This circuit also accommodates an input voltage
that is greater than the AD654 supply voltage.
Resistors R1R3 are used to scale the 0 V to +10 V input voltage
down to 0 V to +1 V as seen at Pin 4 of the AD654. Recall that
V
IN
 must be less than V
SUPPLY
 4 V, or in this case less than 1 V.
The timing resistor and capacitor are selected such that this 0 V
to +1 V signal seen at Pin 4 results in a 0 kHz to 200 kHz output
frequency.
The use of R4, C1 and the XOR gate doubles this 200 kHz
output frequency to 400 kHz. The AD654 output transistor is
basically used as a switch, switching capacitor C1 between a
charging mode and a discharging mode of operation. The voltages
seen at the input of the 74LS86 are shown in the waveform dia-
gram. Due to the difference in the charge and discharge time
constants, the output pulse widths of the 74LS86 are not equal.
The output pulse is wider when the capacitor is charging due to
its longer rise time than fall time. The pulses should therefore be
counted on their rising, rather than falling, edges.
AD654
R
T
1k
C
T
500pF
R
PU
2.87k
R3
1k
R2
2k
R1
8.06k
C1
1000pF
R4
1k
5V
A
B
C
74LS86
V
IN
(0V TO 10V)
V/F OUTPUT
FS = 400MHz
OFF
ON
V
0
V
0
5
0
TRANSISTOR
A
B
C
WAVEFORM DIAGRAM
OSC/
DRIVER
Figure 12. Frequency Doubler
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AD654JNZ/+ 功能描述:IC CONV VOLT-FREQ 500KHZ 8DIP RoHS:是 类别:集成电路 (IC) >> PMIC - V/F 和 F/V 转换器 系列:- 标准包装:1 系列:- 类型:频率至电压 频率 - 最大:10kHz 全量程:- 线性:±0.3% 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:Digi-Reel® 其它名称:LM2917MX-8/NOPBDKR
AD654JR 功能描述:IC V-F CONVERTER MONO 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - V/F 和 F/V 转换器 系列:- 标准包装:1 系列:- 类型:频率至电压 频率 - 最大:10kHz 全量程:- 线性:±0.3% 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:Digi-Reel® 其它名称:LM2917MX-8/NOPBDKR
AD654JR-REEL 功能描述:IC V-F CONV MONO 500KHZ 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - V/F 和 F/V 转换器 系列:- 标准包装:1 系列:- 类型:频率至电压 频率 - 最大:10kHz 全量程:- 线性:±0.3% 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:Digi-Reel® 其它名称:LM2917MX-8/NOPBDKR
AD654JR-REEL7 功能描述:IC V-F CONVERTER MONO 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - V/F 和 F/V 转换器 系列:- 标准包装:1 系列:- 类型:频率至电压 频率 - 最大:10kHz 全量程:- 线性:±0.3% 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:Digi-Reel® 其它名称:LM2917MX-8/NOPBDKR
AD654JRZ 功能描述:IC V-F CONVERTER MONO 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - V/F 和 F/V 转换器 系列:- 标准包装:1 系列:- 类型:频率至电压 频率 - 最大:10kHz 全量程:- 线性:±0.3% 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:Digi-Reel® 其它名称:LM2917MX-8/NOPBDKR