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參數資料
| 型號： | 73M1903-IM |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 消費家電 |
| 英文描述： | SPECIALTY CONSUMER CIRCUIT, QCC32 |
| 封裝： | QFN-32 |
| 文件頁數： | 36/45頁 |
| 文件大小： | 449K |
| 代理商： | 73M1903-IM |
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73M1903
Modem Analog Front End
DATA SHEET
Page: 41 of 45
2005 TERIDIAN Semiconductor Corporation
Rev 1.4
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
It is also important to note that when Fxtal/Fref is an integer the output of the pre-scaler 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 pre-scaler 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
1903B 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 73M1903 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 pre-scaler, 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.
Ndvsr = Integer [ Fvco/Fref ] = 19
Nrst = 5 – 1 = 4 from Fvco/Fref = 19.2 = 96/5;
Nseq =
÷19, ÷19, ÷19, ÷19, ÷20 => {0,0,0,0,1} =xxx00001 = 01h.
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相關代理商/技術參數 |
參數描述 |
|---|---|
| 73M1903-IM/F | 功能描述:電信線路管理 IC Modem AFE V.22Bis-V.92 RoHS:否 制造商:STMicroelectronics 產品: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 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray |
| 73M1903-IM/F1 | 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產品: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 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray |
| 73M1903-IMR/F | 功能描述:電信線路管理 IC Modem AFE V.22Bis-V.92 RoHS:否 制造商:STMicroelectronics 產品: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 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray |
| 73M1903-IMR/F1 | 功能描述:電信線路管理 IC RoHS:否 制造商:STMicroelectronics 產品: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 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray |
| 73M1903-IVT/F | 功能描述:IC MODEM AFE V.22BIS 20-TSSOP RoHS:是 類別:集成電路 (IC) >> 數據采集 - 模擬前端 (AFE) 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 位數:- 通道數:2 功率（瓦特）:- 電壓 - 電源，模擬:3 V ~ 3.6 V 電壓 - 電源，數字:3 V ~ 3.6 V 封裝/外殼:32-VFQFN 裸露焊盤 供應商設備封裝:32-QFN（5x5） 包裝:帶卷 (TR) |
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