參數(shù)資料
型號： LTC1068CG-200
廠商： LINEAR TECHNOLOGY CORP
元件分類： 運(yùn)動控制電子
英文描述： Clock-Tunable, Quad Second Order, Filter Building Blocks
中文描述： QUAD SWITCHED CAPACITOR FILTER, RESISTOR PROGRAMMABLE, UNIVERSAL, PDSO28
封裝： 0.209 INCH, PLASTIC, SSOP-28
文件頁數(shù)： 11/28頁
文件大小： 535K
代理商： LTC1068CG-200
11
LTC1068 Series
ODES OF OPERATIO
W
Linear Technology’s universal switched-capacitor filters
are designed for a fixed internal, nominal f
CLK
/f
O
ratio. The
f
CLK
/f
O
ratio is 100 for the LTC1068, 200 for the LTC1068-
200, 50 for the LTC1068-50 and 25 for the LTC1068-25.
Filter designs often require the f
CLK
/f
O
ratio of each section
to be different from the nominal ratio and in most cases
different from each other. Ratios other than the nominal
value are possible with external resistors. Operating modes
use external resistors, connected in different arrange-
ments to realize different f
CLK
/f
O
ratios. By choosing the
proper mode, the f
CLK
/f
O
ratio can be increased or de-
creased from the part’s nominal ratio.
The choice of operating mode also effects the transfer
function at the HP/N pins. The LP and BP pins always give
the lowpass and bandpass transfer functions respectively,
regardless of the mode utilized. The HP/N pins have a
different transfer function depending on the mode used.
Mode 1 yields a notch transfer function. Mode 3 yields a
highpass transfer function. Mode 2 yields a highpass
notch transfer function (i.e., a highpass with a stopband
notch). More complex transfer functions, such as lowpass
notch, allpass or complex zeros, are achieved by summing
two or more of the LP, BP or HP/N outputs. This is
illustrated in sections Mode 2n and Mode 3a.
Choosing the proper mode(s) for a particular application
is not trivial and involves much more than just adjusting
the f
CLK
/f
O
ratio. Listed here are four of the nearly twenty
modes available. To make the design process simpler and
quicker, Linear Technology has developed the FilterCAD
for Widows design software. FilterCAD is an easy-to-use,
powerful and interactive filter design program. The de-
signer can enter a few filter specifications and the program
produces a full schematic. FilterCAD allows the designer to
concentrate on the filter’s transfer function and not get
bogged down in the details of the design. Alternatively,
those who have experience with the Linear Technology
family of parts can control all of the details themselves. For
a complete listing of all the operating modes, consult the
appendices of the FilterCAD manual or the Help files in
FilterCAD. FilterCAD can be obtained free of charge on the
Linear Technology web site (www.linear-tech.com) or you
can order the FilterCAD CD-ROM by contacting Linear
Technology Marketing.
U
Mode 1
In Mode 1, the ratio of the external clock frequency to the
center frequency of each 2nd order section is internally
fixed at the part’s nominal ratio. Figure 4 illustrates Mode
1 providing 2nd order notch, lowpass and bandpass
outputs. Mode 1 can be used to make high order Butter-
worth lowpass filters; it can also be used to make low Q
notches and for cascading 2nd order bandpass functions
tuned at the same center frequency. Mode 1 is faster than
Mode 3.
Please refer to the Operating Limits paragraph under Appli-
cations Information for a guide to the use of capacitor C
C
.
Mode 1b
Mode 1b is derived from Mode 1. In Mode 1b (Figure 5)
two additional resistors R5 and R6 are added to lower the
amount of voltage fed back from the lowpass output into
the input of the SA (or SB) switched-capacitor summer.
This allows the filter’s clock-to-center frequency ratio to
be adjusted beyond the part’s nominal ratio. Mode 1b
maintains the speed advantages of Mode 1 and should be
considered an optimum mode for high Q designs with f
CLK
to f
CUTOFF
(or f
CENTER
) ratios greater than the part’s
nominal ratio.
The parallel combination of R5 and R6 should be kept
below 5k.
Please refer to the Operating Limits paragraph under Appli-
cations Information for a guide to the use of capacitor C
C
.
Figure 4. Mode 1, 2nd Order Filter Providing Notch,
Bandpass and Lowpass Outputs
–
+
Σ
∫
∫
AGND
R1
N
BP
LP
V
IN
1068 F04
+
–
S
R2
R3
C
C
f
O
= f
n
= f
O
Q = R3
ON
= – R1
OBP
= –
H
OLP
= H
ON
R3
R1
CLK
DEVICE
LTC1068
LTC1068-200
LTC1068-50
LTC1068-25
RATIO
100
200
50
25
相關(guān)PDF資料
PDF描述
LTC1068IG Clock-Tunable, Quad Second Order, Filter Building Blocks
LTC1068IG-200 CONNECTOR ACCESSORY
LTC1068IG-25 Metal Connector Backshell; Connector Shell Size:15; For Use With:MIL-C-3899 Series III and IV Connectors; Leaded Process Compatible:No; Peak Reflow Compatible (260 C):No; Contact Plating:Cadmium Over Nickel RoHS Compliant: NA
LTC1068IG-50 STR RELIEF SZ 17 BLK ANDZ RoHS Compliant: No
LTC1068IN CONNECTOR ACCESSORY
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC1068CG-25 制造商:LINER 制造商全稱:Linear Technology 功能描述:Clock-Tunable, Quad Second Order, Filter Building Blocks
LTC1068CG-50 制造商:LINER 制造商全稱:Linear Technology 功能描述:Clock-Tunable, Quad Second Order, Filter Building Blocks
LTC1068CG-PBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Clock-Tunable, Quad Second Order, Filter Building Blocks
LTC1068CN 功能描述:IC FILTR BUILDNG BLK QUAD 24-DIP RoHS:否 類別:集成電路 (IC) >> 接口 - 濾波器 - 有源 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1,000 系列:- 濾波器類型:連續(xù)時間，帶通低通 頻率 - 截止或中心:150kHz 濾波器數(shù):4 濾波器階數(shù):8th 電源電壓:4.74 V ~ 11 V，±2.37 V ~ 5.5 V 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:28-SOIC W 包裝:帶卷 (TR)
LTC1068CN#PBF 功能描述:IC FILTR BUILDNG BLK QUAD 24-DIP RoHS:是 類別:集成電路 (IC) >> 接口 - 濾波器 - 有源 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1,000 系列:- 濾波器類型:連續(xù)時間，帶通低通 頻率 - 截止或中心:150kHz 濾波器數(shù):4 濾波器階數(shù):8th 電源電壓:4.74 V ~ 11 V，±2.37 V ~ 5.5 V 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:28-SOIC W 包裝:帶卷 (TR)
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