參數(shù)資料
型號： 73M1903C-IM
廠商： MAXIM INTEGRATED PRODUCTS INC
元件分類： 消費(fèi)家電
英文描述： SPECIALTY CONSUMER CIRCUIT, QCC32
封裝： LEAD FREE, QFN-32
文件頁數(shù)： 35/45頁
文件大小： 459K
代理商： 73M1903C-IM
73M1903C
Modem Analog Front End
DATA SHEET
Page: 40 of 45
2005 TERIDIAN Semiconductor Corporation
Rev 3.4
Example 2: Fxtal = 18.432MHz, Fref = 2.304 MHz.
Pdvsr = Integer [Fxtal/Fref] = 8 = 8h;
Prst[2:0] = 1- 1 = 0 from Fref/Fxtal = 18.432/2.304 = 8/1;
Pseq = {x,x,x,x,x,x,x,x} = xxh
Example 3: Fxtal = 24.576MHz, Fref = 2.4576MHz.
Pdvsr = Integer [ Fxtal/Fref] = 10 = Ah;
Prst[2:0] = 1- 1 = 0 from Fref/Fxtal = 24.576/2.4576 = 10/1;
Pseq = {x,x,x,x,x,x,x,x} = xxh
Example 4: Fxtal = 24.576MHz, Fref = 3.072MHz.
Pdvsr = Integer [ Fxtal/Fref] = 8 = 8h;
Prst[2:0] = 1- 1 = 0 from Fref/Fxtal = 24.576/3.072 = 8/1;
Pseq = {x,x,x,x,x,x,x,x} = xxh
It is also important to note that when Fxtal/Fref is an integer the output of the prescaler is a straight
frequency divider (example 2). As such there will be no jitter generated at Fref. However if Fxtal/Fref is
a fractional number, Fref, at the output of the prescaler NCO would be exact only in an average sense
(example 1) and there will be a certain amount of fixed pattern (repeating) jitter associated with Fref which
can be filtered out by the PLL that follows by appropriately programming the PLL. It is important to note,
however, that the fixed pattern jitter does not degrade the performance of the sigma delta modulators so
long as its frequency is >> 4kHz.
PLL
VCO
Kvco
NCO
Prescaler
PFD
Charge
Pump
NCO
Kd
Up
Dn
R1
C1
C2
Divide
by 2/1
Ichp Control
3
Fref
Kvco Control
Figure B-2 PLL Block Diagram
73M1903C has a built in PLL circuit to allow an operation over wide range of Fs. It is of a conventional
design with the exception of an NCO based feedback divider. (See Figure B-2: PLL Block Diagram).
The architecture of the 73M1903C dictates that the PLL output frequency, Fvco, be related to the
sampling rate, Fs, by Fvco = 2 x 2304 x Fs. The NCO must function as a divider whose divide ratio
equals Fref/Fvco.
Just as in the NCO prescaler, a set of three numbers– Ndvsr ( 7 bits ), Nrst ( 3 bits ) and Nseq ( 8 bits )
must be entered thru a serial port to effect this divide:
Ndvsr = Integer [Fref/Fxtal] ;
Nrst = Denominator of the ratio (Fvco/Fref), Dnco1, minus 1, when it is expressed as a ratio of two
smallest integers = Nnco1/Dnco1;
Nseq = Divide Sequence
Example 1: Fs = 7.2kHz or Fvco = 2 x 2304 x 7.2kHz =33.1776MHz, Fref = 1.728MHz.
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73M1903C-IM/F 功能描述:電信線路管理 IC Modem Analog Front End RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IM/F1 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IMR/F 功能描述:電信線路管理 IC Modem Analog Front End RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903C-IMR/F1 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
73M1903-EVM-600 功能描述:網(wǎng)絡(luò)開發(fā)工具 73M1903 w/Ppu & 600 Ohm Term-Usa & Japan RoHS:否 制造商:Rabbit Semiconductor 產(chǎn)品:Development Kits 類型:Ethernet to Wi-Fi Bridges 工具用于評估:RCM6600W 數(shù)據(jù)速率:20 Mbps, 40 Mbps 接口類型:802.11 b/g, Ethernet 工作電源電壓:3.3 V
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