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| 型号： | DS1090U-8+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/8页 |
| 文件大小： | 0K |
| 描述： | IC ECONOSCILLATOR 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： | 3,000 |
| 系列： | EconOscillator™ |
| 类型： | 时钟发生器 |
| PLL： | 无 |
| 输入： | 时钟 |
| 输出： | CMOS，TTL |
| 电路数： | 1 |
| 比率 - 输入:输出： | 1:1 |
| 差分 - 输入:输出： | 无/无 |
| 频率 - 最大： | 8MHz |
| 除法器/乘法器： | 是/无 |
| 电源电压： | 3 V ~ 5.5 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： | 带卷 (TR) |
DS1090
Low-Frequency, Spread-Spectrum
EconOscillator
_____________________________________________________________________
7
Detailed Description
The DS1090 is a center-dithered, spread-spectrum sili-
con oscillator for use as an external clock in reduced-
EMI applications. With a combination of factory-
programmed prescalers and a user-selected external
resistor, output frequencies from 125kHz to 8MHz can
be achieved. The output center frequency can be
dithered by selecting the desired dither rate and ampli-
tude with discrete inputs J0, J1, JC0, and JC1.
The DS1090 contains four basic circuit blocks: master
oscillator, factory-programmed prescaler, dither gener-
ator, and the voltage-bias circuit that provides the feed-
back path to the master oscillator for frequency control
and dithering functions.
Master Oscillator
The master oscillator is programmable in the applica-
tion by the use of an external resistor (RSET) tied to
ground (GND). Resistor values of 45k
Ω to 91kΩ vary
the square-wave output frequency of the voltage-con-
trolled master oscillator (fMOSC) from 8MHz down to
4MHz (see Figure 1).
The master oscillator (Hz) frequency can be stated as
Factory-Programmed Prescaler
The prescaler divides the frequency of the master oscil-
lator by 1, 2, 4, 8, 16, or 32 to generate the square-
wave output clock (fOSC). This divisor is factory-set and
is an ordering option.
Dither Generator
Spread-spectrum functionality is achieved by a user-
configurable divider (determines dither rate), a triangle
generator, and a user-configurable dither amplitude cir-
cuit (see
Block Diagram).
The input to the triangle-wave generator is derived from
the internal master oscillator and is fed through a user-
configurable divider. The settings of control pins JC0
and JC1 determine this dither rate divisor setting (see
Table 1), dividing the master clock by 4, 8, 16, or 32.
The clock signal is further divided by 128 in the
triangle-wave generator, which results in a triangle-
wave signal of either 1/512th, 1/1024th, 1/2048th, or
1/4096th of the master oscillator (fMOD), depending
upon the user’s divisor setting.
The dithering frequency can be also expressed as the
result of
where Divisor is 4, 8, 16, or 32.
f
Divisor
MOD
MOSC
=
×128
f
E
sistor
MOSC
+
3 6461
11
.
Re
MASTER OSCILLATOR FREQUENCY vs.
EXTERNAL RESISTOR SELECTION
DS1090
fig01
RSET RESISTANCE (k
Ω)
f MOSC
(MHz)
90
80
70
60
50
4
5
6
7
8
9
3
40
Figure 1. Master Oscillator Frequency
f MOSC
TIME
DITHER
AMOUNT
(2, 4, OR 8%)
IF DITHER AMOUNT = 0%
(- 1, 2, or 4% of fMOSC)
fMOD
1
(+ 1, 2, or 4% of fMOSC)
Programmed fMOSC
Figure 2. Center Frequency Dither Diagram
JC1
JC0
DITHERING PERCENTAGE
(fMOSC/n)
DIVISOR
SETTING
00
FMOSC / 512
4
01
FMOSC / 1024
8
10
fMOSC / 2048
16
11
fMOSC / 4096
32
Table 1. Dither Rate Divisor Settings
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| DS1091LN-66+ | 功能描述:时钟发生器及支持产品 Spread-Spectrum EconOscillator Auto RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| DS1091LU-66+ | 功能描述:时钟发生器及支持产品 Spread-Spectrum EconOscillator Auto RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| DS1091LUA-027+ | 功能描述:时钟发生器及支持产品 Spread-Spectrum EconOscillator Auto RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| DS1091LUA-027+T | 功能描述:时钟发生器及支持产品 Spread-Spectrum EconOscillator Auto RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
| DS1091LUA-030/V+ | 功能描述:时钟发生器及支持产品 Spread-Spectrum EconOscillator RoHS:否 制造商:Silicon Labs 类型:Clock Generators 最大输入频率:14.318 MHz 最大输出频率:166 MHz 输出端数量:16 占空比 - 最大:55 % 工作电源电压:3.3 V 工作电源电流:1 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-56 |
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