參數(shù)資料
型號(hào)： ICS843020A01
英文描述： FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
中文描述： FEMTOCLOCKS -商標(biāo)680MHZ，晶體至3.3V的差分LVPECL頻率合成器
文件頁(yè)數(shù)： 2/20頁(yè)
文件大?。?/td> 218K
代理商： ICS843020A01
843020AY-01
www.icst.com/products/hiperclocks.html
REV. B APRIL 14, 2005
2
Integrated
Circuit
Systems, Inc.
ICS843020-01
F
EMTO
C
LOCKS
680MH
Z
, C
RYSTAL
-
TO
-
3.3V D
IFFERENTIAL
LVPECL F
REQUENCY
S
YNTHESIZER
NOTE: The functional description that follows describes op-
eration using a 25MHz crystal. Valid PLL loop divider values
for different crystal or input frequencies are defined in the In-
put Frequency Characteristics, Table 5, NOTE 1.
The ICS843020-01 features a fully integrated PLL and there-
fore requires no external components for setting the loop band-
width. 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 560MHz to 680MHz. The output of the M divider is
also applied to the phase detector.
The phase detector and the M divider force the VCO output fre-
quency 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 ICS843020-01 supports either serial or parallel program-
ming modes to program the M feedback divider and N output
divider. The input divider P can only be changed using the P_DIV
pin. It cannot be changed from the default
÷
1 setting using the
serial interface. Figure 1shows 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 transi-
tion 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 serial 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 relation-ship between the VCO frequency, the crystal fre-
quency and the M divider is defined as follows:
fVCO = fxtal x M
The M value and the required values of M0 through M8 are
shown in Table 3B to program the VCO Frequency Function
Table. Valid M values for which the PLL will achieve lock for a
25MHz reference are defined as 23
≤
M
≤
27 (P =
÷
1). The
frequency out is defined as follows:
FOUT = fVCO = fxtal x M
N
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 di-
vider when S_LOAD transitions from LOW-to-HIGH. The M
divide and N output 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 registers T0 and T1 determine the state
of the TEST output as follows:
F
UNCTIONAL
D
ESCRIPTION
T1
T0
TEST Output
0
0
LOW
0
1
S_Data, Shift Register Input
1
0
Output of M divider
1
1
CMOS Fout
F
IGURE
1. P
ARALLEL
& S
ERIAL
L
OAD
O
PERATIONS
*NOTE:
The NULL timing slot must be observed.
Time
S
ERIAL
L
OADING
P
ARALLEL
L
OADING
M, N, P
t
S
t
H
t
S
t
H
t
S
T 1
T0
*
NULL
N1
N0
M8
M7
M6
M5
M4
M3
M2
M1
M0
S_CLOCK
S_DATA
S_LOAD
nP_LOAD
M0:M8, N0:N1, P_DIV
nP_LOAD
P
N x P
相關(guān)PDF資料
PDF描述
ICS843020AY-01 FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843020AY-01LF FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843020AY-01LFT FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843020AY-01T FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843020-01 FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ICS843020AY-01 制造商:ICS 制造商全稱:ICS 功能描述:FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843020AY-01LF 功能描述:IC SYNTHESIZER LVPECL 32-LQFP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:HiPerClockS™, FemtoClock™ 標(biāo)準(zhǔn)包裝:1,000 系列:- 類型:時(shí)鐘/頻率合成器，扇出分配 PLL:- 輸入:- 輸出:- 電路數(shù):- 比率 - 輸入:輸出:- 差分 - 輸入:輸出:- 頻率 - 最大:- 除法器/乘法器:- 電源電壓:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:56-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:56-VFQFP-EP（8x8） 包裝:帶卷 (TR) 其它名稱:844S012AKI-01LFT
ICS843020AY-01LFT 功能描述:IC SYNTHESIZER LVPECL 32-LQFP RoHS:是 類別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 時(shí)鐘發(fā)生器，PLL，頻率合成器 系列:HiPerClockS™, FemtoClock™ 標(biāo)準(zhǔn)包裝:1,000 系列:- 類型:時(shí)鐘/頻率合成器，扇出分配 PLL:- 輸入:- 輸出:- 電路數(shù):- 比率 - 輸入:輸出:- 差分 - 輸入:輸出:- 頻率 - 最大:- 除法器/乘法器:- 電源電壓:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:56-VFQFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:56-VFQFP-EP（8x8） 包裝:帶卷 (TR) 其它名稱:844S012AKI-01LFT
ICS843020AY-01T 制造商:ICS 制造商全稱:ICS 功能描述:FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
ICS843021 制造商:ICS 制造商全稱:ICS 功能描述:FEMTOCLOCKS-TM CRYSTAL-TO- 3.3V LVPECL CLOCK GENERATOR
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