参数资料
型号: ICS8432DYI-101LFT
元件分类: 时钟及定时
英文描述: 8432 SERIES, PLL BASED CLOCK DRIVER, 2 TRUE OUTPUT(S), 0 INVERTED OUTPUT(S), PQFP32
封装: 7 X 7 MM, 1.40 MM HEIGHT, ROHS COMPLIANT, MS-026, LQFP-32
文件页数: 11/18页
文件大小: 173K
代理商: ICS8432DYI-101LFT
8432DYI-101
www.icst.com/products/hiperclocks.html
REV. A MAY 23, 2005
2
Integrated
Circuit
Systems, Inc.
ICS8432I-101
700MHZ,
DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
rial event occurs. As a result, the M and N bits can be hardwired
to set the M divider and N output divider to a specific default
state that will automatically occur during power-up. The TEST
output is LOW when operating in the parallel input mode. The
relationship between the VCO frequency, the input frequency
and the M divider is defined as follows:
The M value and the required values of M0 through M8 are
shown in Table 3B, Programmable VCO Frequency Function
Table. 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 M divider and N output divider when
S_LOAD transitions from LOW-to-HIGH. The M divide and N out-
put 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 M divider and N output divider 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 reg-
isters T0 and T1 determine the state of the TEST output as follows:
Time
SERIAL LOADING
PARALLEL LOADING
t
S
t
H
t
S
t
H
t
S
M, N
FUNCTIONAL DESCRIPTION
NOTE: The functional description that follows describes op-
eration using a 25MHz clock input. Valid PLL loop divider val-
ues for different input frequencies are defined in the Input Fre-
quency Characteristics, Table 5, NOTE 1.
The ICS8432I-101 features a fully integrated PLL and there-
fore requires no external components for setting the loop band-
width. A differential clock input is used as the input to the
ICS8432-101. This input is fed into the phase detector. A
25MHz clock input provides a 25MHz phase detector refer-
ence frequency. The VCO of the PLL operates over a range
of 250MHz to 700MHz. The output of the M divider is also
applied to the phase detector.
The phase detector and the M divider force the VCO output
frequency to be M times the reference frequency by adjust-
ing 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 ICS8432I-101 support two
input modes to program the PLL M divider and N output divider.
The two input operational modes are parallel and serial.
Figure1
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 M divider and
N output divider. On the LOW-to-HIGH transition of the
nP_LOAD input, the data is latched and the M divider remains
loaded until the next LOW transition on nP_LOAD or until a se-
fVCO = f
IN x M
T1
T0
TEST Output
0
LOW
0
1
S_Data, Shift Register Input
1
0
Output of M divider
1
CMOS Fout
FIGURE 1. PARALLEL & SERIAL LOAD OPERATIONS
*NOTE: The NULL timing slot must be observed.
T1
T0
*NULL N1
N 0
M8
M7
M6
M5
M4
M3
M2
M1
M0
S_CLOCK
S_DATA
S_LOAD
nP_LOAD
M0:M8, N0:N1
nP_LOAD
S_LOAD
fOUT = fVCO = f
IN x M
NN
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相关代理商/技术参数
参数描述
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ICS8432I-101 制造商:ICS 制造商全称:ICS 功能描述:700MHZ, DIFFERENTIAL-TO-3.3V LVPECL FREQUENCY SYNTHESIZER
ICS8432I-51 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
ICS84330 制造商:ICS 制造商全称:ICS 功能描述:700MHZ, LOW JITTER, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS84330-01 制造商:ICS 制造商全称:ICS 功能描述:700MHZ, LOW JITTER, CRYSTAL-TO-3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER