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参数资料
| 型号： | ICS8432AY-51LFT |
| 元件分类： | 时钟产生/分配 |
| 英文描述： | 700 MHz, OTHER CLOCK GENERATOR, PQFP32 |
| 封装： | 7 X 7 MM, 1.40 MM HEIGHT, MS-026, LQFP-32 |
| 文件页数： | 9/16页 |
| 文件大小： | 166K |
| 代理商： | ICS8432AY-51LFT |
8432AY-51
www.icst.com/products/hiperclocks.html
REV. A AUGUST 20, 2001
2
PRELIMINARY
Integrated
Circuit
Systems, Inc.
ICS8432-51
700MHZ, CYRSTAL-TO-3.3V DIFFERENTIAL
LVPECL FREQUENCY SYNTHESIZER
FUNCTIONAL DESCRIPTION
NOTE: The functional description that follows describes operation using a 25MHz crystal. Valid PLL loop divider values for
different crystal or input frequencies are defined in the Input Frequency Characteristics, Table 6, NOTE 1.
The ICS8432-51 features a fully integrated PLL and therefore requires no external components for setting the loop bandwidth.
A fundamental crystal is used as the input to the on-chip oscillator. The output of the oscillator is fed into the phase detector.
A 25MHz crystal provides a 25MHz phase detector reference frequency. The VCO of the PLL operates over a range of
200MHz to 700MHz. The output of the loop divider is also applied to the phase detector.
The phase detector and the loop filter divider force the VCO output frequency to be M times the reference frequency by
adjusting the VCO control voltage. Note that for some values of M (either too high or too low) the PLL will not achieve lock. The
output of the VCO is scaled by a divider prior to being sent to each of the LVPECL output buffers. The divider provides a 50%
output duty cycle.
The programmable features of the ICS8432-51 support two input modes and programmable PLL loop divider and output
divider. The two input operational modes are parallel and serial.
Figure 1 shows the timing diagram for each mode. In parallel
mode the nP_LOAD input is initially LOW. The data on inputs M0 through M8 and N0 and N1 is passed directly to the ripple
counter. On the LOW-to-HIGH transition of the nP_LOAD input the data is latched and the ripple counter remains loaded until
the next LOW transition on nP_LOAD or until a serial event occurs. As a result the M and N bits can be hardwired to set the
ripple counter to a specific default state that will automatically occur during power-up. The TEST output is LOW when operat-
ing in the parallel input mode. The relationship between the VCO frequency, the crystal frequency and the loop divider is
defined as follows:
The M count and the required values of M0 through M8 are shown in Table 4B, Programmable VCO Frequency Function.
Valid M values for which the PLL will achieve lock for a 25MHz reference are defined as 8
≤ M ≤ 28. The frequency out is
defined as follows:
Serial operation occurs when nP_LOAD is HIGH and S_LOAD is LOW. The shift register is loaded by sampling the
S_DATA bits with the rising edge of S_CLOCK. The contents of the shift register are loaded into the ripple counter when
S_LOAD transitions from LOW-to-HIGH. The ripple counter divide values are latched on the HIGH-to-LOW transition of
S_LOAD. If S_LOAD is held HIGH data at the S_DATA input is passed directly to the ripple counter on each rising edge of
S_CLOCK. The serial mode can be used to program the M and N bits and test bits T1 and T0. The internal registers T0 and T1
determine the state of the TEST output as follows:
fVCO = fxtal x M
T1
T0
TEST Output
0
LOW
0
1
S_Data
1
0
Output of M divider
1
CMOS Fout
FIGURE 1. PARALLEL & SERIAL LOAD OPERATIONS
FOUT = fVCO = fxtal x M
N
Time
T1
T0
*NULL
N 1
N 0
M8
M7
M6
M5
M4
M3
M2
M1
M0
S_DATA
S_CLOCK
S_LOAD
M0:M8, N0:N1
nP_LOAD
*NOTE: The NULL timing slot must be observed.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ICS8432BI51 | 制造商:IDT 制造商全称:Integrated Device Technology 功能描述:700MHZ, CYRSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER |
| ICS8432BI-51L | 制造商:IDT 制造商全称:Integrated Device Technology 功能描述:700MHZ, CYRSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER |
| ICS8432BK-51 | 制造商:ICS 制造商全称:ICS 功能描述:700MHZ, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER |
| ICS8432BK-51LF | 功能描述:IC SYNTHESIZER LVPECL 32-VFQFPN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:HiPerClockS™ 标准包装:1,000 系列:- 类型:时钟/频率合成器，扇出分配 PLL:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 除法器/乘法器:- 电源电压:- 工作温度:- 安装类型:表面贴装 封装/外壳:56-VFQFN 裸露焊盘 供应商设备封装:56-VFQFP-EP（8x8） 包装:带卷 (TR) 其它名称:844S012AKI-01LFT |
| ICS8432BK-51LFT | 功能描述:IC SYNTHESIZER LVPECL 32-VFQFPN RoHS:是 类别:集成电路 (IC) >> 时钟/计时 - 时钟发生器，PLL，频率合成器 系列:HiPerClockS™ 标准包装:1,000 系列:- 类型:时钟/频率合成器，扇出分配 PLL:- 输入:- 输出:- 电路数:- 比率 - 输入:输出:- 差分 - 输入:输出:- 频率 - 最大:- 除法器/乘法器:- 电源电压:- 工作温度:- 安装类型:表面贴装 封装/外壳:56-VFQFN 裸露焊盘 供应商设备封装:56-VFQFP-EP（8x8） 包装:带卷 (TR) 其它名称:844S012AKI-01LFT |
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