Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

LM1971M Scheda tecnica(PDF) 7 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor. Click here to check the latest version.
Il numero della parte LM1971M
Spiegazioni elettronici  LM1971 Overture??Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator with/Mute
Download  11 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  NSC [National Semiconductor (TI)]
Homepage  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM1971M Scheda tecnica(HTML) 7 Page - National Semiconductor (TI)

Back Button LM1971M Datasheet HTML 3Page - National Semiconductor (TI) LM1971M Datasheet HTML 4Page - National Semiconductor (TI) LM1971M Datasheet HTML 5Page - National Semiconductor (TI) LM1971M Datasheet HTML 6Page - National Semiconductor (TI) LM1971M Datasheet HTML 7Page - National Semiconductor (TI) LM1971M Datasheet HTML 8Page - National Semiconductor (TI) LM1971M Datasheet HTML 9Page - National Semiconductor (TI) LM1971M Datasheet HTML 10Page - National Semiconductor (TI) LM1971M Datasheet HTML 11Page - National Semiconductor (TI)  
Zoom Inzoom in Zoom Outzoom out
 7 / 11 page
background image
Application Information (Continued)
µPOT LADDER ARCHITECTURE
The µPot contains a chain of R1/R2 resistor dividers in a lad-
der form, as shown in
Figure 4. Each R1 is actually a series
of 8 resistors, with a CMOS switch that taps into the resistor
chain according to the attenuation level chosen. For any
given attenuation setting, there is only one CMOS switch
closed (no paralleling of ladders). The input impedance
therefore remains constant, while the output impedance
changes as the attenuation level changes. It is important to
note that the architecture is a series of resistor dividers, and
not a straight, tapped resistor, so the µPot is not a variable
resistor; it is a variable voltage divider.
ATTENUATION STEP SCHEME
The fundamental attenuation step scheme for the LM1971 is
shown in
Figure 5. It is also possible to obtain any integer
value attenuation step through programming, in addition to
the 2 dB and 4 dB steps shown in
Figure 5. All higher attenu-
ation step schemes can have clickless and popless perfor-
mance. Although it is possible to “skip” attenuation points by
not sending all of the data, clickless and popless perfor-
mance will suffer. It is highly recommended that all of the
data points should be sent for each attenuation level. This
ensures flawless operation and performance when making
steps larger than 1 dB.
INPUT IMPEDANCE
The input impedance of a µPot is constant at a nominal
40 k
Ω. Since the LM1971 is a single-supply operating de-
vice, it is necessary to have both input and output coupling
caps as shown in
Figure 1. To ensure full low-frequency re-
sponse,a1µF coupling cap should be used.
OUTPUT IMPEDANCE
The output impedance of a µPot varies typically between
25 k
Ω and 35 kΩ and changes nonlinearly with step
changes. Since a µPot is made up of a resistor ladder net-
work with logarithmic attenuation, the output impedance is
nonlinear. Due to this configuration, a µPot cannot be con-
sidered as a linear potentiometer; it is a logarithmic attenua-
tor.
The linearity of a µPot cannot be measured directly without a
buffer because the input impedance of most measurement
systems is not high enough to provide the required accuracy.
The lower impedance of the measurement system would
load down the output and an incorrect reading would result.
To prevent loading, a JFET input op amp should be used as
the buffer/amplifier.
OUTPUT BUFFERING
There are two performance issues to be aware of that are re-
lated to a µPot’s output stage. The first concern is to prevent
audible clicks with attenuation changes, while the second is
to prevent loading and subsequent linearity errors. The out-
put stage of a µPot needs to be buffered with a low input bias
DS012353-4
FIGURE 3. Serial Data Format Transfer Process
DS012353-5
FIGURE 4. Resistor Ladder Architecture
LM 1971 Channel Attenuation
vs Digital Step Value
(1 dB, 2 dB, and 4 dB Steps)
DS012353-6
FIGURE 5. LM1971 Attenuation Step Scheme
www.national.com
7


Codice articolo simile - LM1971M

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Texas Instruments
LM1971M TI-LM1971M Datasheet
939Kb / 19P
[Old version datasheet]   LM1971 Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
LM1971M TI1-LM1971M Datasheet
965Kb / 20P
[Old version datasheet]   Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
LM1971M/NOPB TI1-LM1971M/NOPB Datasheet
965Kb / 20P
[Old version datasheet]   Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
LM1971MX TI-LM1971MX Datasheet
939Kb / 19P
[Old version datasheet]   LM1971 Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
LM1971MX TI1-LM1971MX Datasheet
965Kb / 20P
[Old version datasheet]   Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
More results

Descrizione simile - LM1971M

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Texas Instruments
LM1971MX TI-LM1971MX Datasheet
939Kb / 19P
[Old version datasheet]   LM1971 Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
LM1971 TI1-LM1971_14 Datasheet
965Kb / 20P
[Old version datasheet]   Overture Audio Attenuator Series Digitally Controlled 62 dB Audio Attenuator
logo
National Semiconductor ...
LM1972 NSC-LM1972 Datasheet
301Kb / 11P
   Pot 2-Channel 78dB Audio Attenuator with Mute
LM1973 NSC-LM1973 Datasheet
305Kb / 11P
   關Pot??-Channel 76dB Audio Attenuator with Mute
logo
Texas Instruments
LM4766 TI-LM4766_15 Datasheet
955Kb / 23P
[Old version datasheet]    Overture Audio Power Amplifier Series Dual 40W Audio Power Amplifier with Mute
logo
National Semiconductor ...
LM4781 NSC-LM4781 Datasheet
1Mb / 25P
   Overture??Audio Power Amplifier Series 3 Channel 35W Audio Power Amplifier with Mute
LM4701 NSC-LM4701 Datasheet
541Kb / 15P
   LM4701 Overture??Audio Power Amplifier Series 30W Audio Power Amplifier with Mute and Standby Modes
logo
Texas Instruments
LM1972 TI1-LM1972_14 Datasheet
1,016Kb / 21P
[Old version datasheet]   LM1972 關Pot 2-Channel 78dB Audio Attenuator with Mute
LM1973 TI1-LM1973_14 Datasheet
1,010Kb / 20P
[Old version datasheet]   LM1973 關Pot 3-Channel 76dB Audio Attenuator with Mute
logo
National Semiconductor ...
LM4700 NSC-LM4700 Datasheet
529Kb / 15P
   Overture??Audio Power Amplifier Series 30W Audio Power Amplifier with Mute and Standby Modes
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11


Scheda tecnica Scarica

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEETIT.COM
Lei ha avuto il aiuto da alldatasheet?  [ DONATE ] 

Di alldatasheet   |   Richest di pubblicita   |   contatti   |   Privacy Policy   |   scambio Link   |   Ricerca produttore
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com