参数资料
型号: DS1086LU-B66+
厂商: Maxim Integrated Products
文件页数: 4/17页
文件大小: 0K
描述: IC ECONOSILL 3.3V SS 8-USOP
其它有关文件: Automotive Product Guide
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 50
系列: EconOscillator™
类型: 扩展频谱时钟发生器
PLL:
输入: 时钟
输出: 时钟
电路数: 1
比率 - 输入:输出: 2:1
差分 - 输入:输出: 无/无
除法器/乘法器: 是/无
电源电压: 2.7 V ~ 3.6 V
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 8-TSSOP,8-MSOP(0.118",3.00mm 宽)
供应商设备封装: 8-uMAX
包装: 管件
3.3V Spread-Spectrum EconOscillator
12
Maxim Integrated
DS1086L
Example Frequency Calculations
Example #1:
Calculate the register values needed to
generate a desired output frequency of 11.0592MHz.
Since the desired frequency is not within the valid mas-
ter oscillator range of 33.3MHz to 66.6MHz, the
prescaler must be used. Valid prescaler values are 2x
where x equals 0 to 8 (and x is the value that is pro-
grammed into the P3 to P0 bits of the PRESCALER reg-
ister). Equation 1 shows the relationship between the
desired frequency, the master oscillator frequency, and
the prescaler.
By trial and error, x is incremented from 0 to 8 in
Equation 2, finding values of x that yield master oscillator
frequencies within the range of 33.3MHz to 66.6MHz.
Equation 2 shows that a prescaler of 4 (x = 2) and a
master oscillator frequency of 44.2368MHz generates
our desired frequency. Writing 0080h to the
PRESCALER register sets the PRESCALER to 4. Be
aware that other settings also reside in the PRESCALER
register.
fMASTER OSCILLATOR = fDESIRED x prescaler = fDESIRED x 2X
fMASTER OSCILLATOR = 11.0592MHz x 22 = 44.2368MHz
Once the target master oscillator frequency has been
calculated, the value of offset can be determined.
Using Table 2, 44.2368MHz falls within both OS - 1 and
OS - 2. However, choosing OS - 1 would be a poor
choice since 44.2368MHz is so close to OS - 1’s mini-
mum frequency. On the other hand, OS - 2 is ideal
since 44.2368MHz is close to the center of
OS - 2’s frequency span. Before the OFFSET register
can be programmed, the default value of offset (OS)
must be read from the RANGE register (last five bits). In
this example, 12h (18 decimal) was read from the
RANGE register. OS - 2 for this case is 10h (16 deci-
mal). This is the value that is written to the OFFSET reg-
ister.
Finally, the two-byte DAC value needs to be deter-
mined. Since OS - 2 only sets the range of frequencies,
the DAC selects one frequency within that range as
shown in Equation 3.
fMASTER OSCILLATOR = (MIN FREQUENCY OF SELECTED OFFSET
RANGE) + (DAC value x 5kHz)
Valid values of DAC are 0 to 1023 (decimal) and 5kHz
is the step size. Equation 4 is derived from rearranging
Equation 3 and solving for the DAC value.
Since the two-byte DAC register is left justified, 647 is
converted to hex (0287h) and bit-wise shifted left six
places. The value to be programmed into the DAC reg-
ister is A1C0h.
In summary, the DS1086L is programmed as follows:
PRESCALER = 0080h
OFFSET = OS - 2 or 10h (if range was read as 12h)
DAC = A1C0h
Notice that the DAC value was rounded. Unfortunately,
this means that some error is introduced. To calculate
how much error, a combination of Equation 1 and
Equation 3 is used to calculate the expected output fre-
quency. See Equation 5.
f
MIN FREQUENCY OF SELECTED OFFSET
OUTPUT
(
=
)(
)
RANGE
DAC VALUE x kHz STEP SIZE
pres
+
5
c
caler
f
MHz
x kHz
OUTPUT
(.
)
(
)
=
+
41 0
647
5
4
==
=
.
44 235
4
11 05875
MHz
DAC VALUE
f
MIN FREQU
MASTER OSCILLATOR
(
=
E
ENCY OF SELECTED
OFFSET RANGE
kHz STEP SI
)
5
Z
ZE
DAC VALUE
MHz
kHz S
(.
.
)
=
44 2368
41 0
5
T
TEP SIZE
decimal
.(
)
=≈
647 36
647
f
prescaler
f
DESIRED
MASTER OSCILLATOR
M
=
A
ASTER OSCILLATOR
X
2
(1)
(4)
(2)
(3)
(5)
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DS1086LU-B66+T 功能描述:可编程振荡器 3.3V Spread-Spectrum EconOscillator RoHS:否 制造商:IDT 封装 / 箱体:5 mm x 7 mm x 1.5 mm 频率:15.476 MHz to 866.67, 975 MHz to 1300 MHz 频率稳定性:+/- 50 PPM 电源电压:3.63 V 负载电容:10 pF 端接类型:SMD/SMT 输出格式:LVPECL 最小工作温度:- 40 C 最大工作温度:+ 85 C 尺寸:7 mm W x 5 mm L x 1.5 mm H 封装:
DS1086LU-C01+ 功能描述:可编程振荡器 3.3V Spread-Spectrum EconOscillator RoHS:否 制造商:IDT 封装 / 箱体:5 mm x 7 mm x 1.5 mm 频率:15.476 MHz to 866.67, 975 MHz to 1300 MHz 频率稳定性:+/- 50 PPM 电源电压:3.63 V 负载电容:10 pF 端接类型:SMD/SMT 输出格式:LVPECL 最小工作温度:- 40 C 最大工作温度:+ 85 C 尺寸:7 mm W x 5 mm L x 1.5 mm H 封装:
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DS1086LU-C02+ 功能描述:可编程振荡器 3.3V Spread-Spectrum EconOscillator RoHS:否 制造商:IDT 封装 / 箱体:5 mm x 7 mm x 1.5 mm 频率:15.476 MHz to 866.67, 975 MHz to 1300 MHz 频率稳定性:+/- 50 PPM 电源电压:3.63 V 负载电容:10 pF 端接类型:SMD/SMT 输出格式:LVPECL 最小工作温度:- 40 C 最大工作温度:+ 85 C 尺寸:7 mm W x 5 mm L x 1.5 mm H 封装: