- 您現在的位置：買賣IC網 > PDF目錄374675 > SA571DR2 (ON SEMICONDUCTOR) Compandor PDF資料下載
參數資料
| 型號： | SA571DR2 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 運動控制電子 |
| 英文描述： | Compandor |
| 中文描述： | DUAL COMPANDER, 0.02 MHz BAND WIDTH, PDSO16 |
| 封裝： | PLASTIC, SOIC-16 |
| 文件頁數： | 4/11頁 |
| 文件大?。?/td> | 111K |
| 代理商： | SA571DR2 |
SA571
http://onsemi.com
4
Circuit Description
The SA571 compandor building blocks, as shown in the
block diagram, are a fullwave rectifier, a variable gain cell,
an operational amplifier and a bias system. The arrangement
of these blocks in the IC result in a circuit which can perform
well with few external components, yet can be adapted to
many diverse applications.
The fullwave rectifier rectifies the input current which
flows from the rectifier input, to an internal summing node
which is biased at V
REF
. The rectified current is averaged on
an external filter capacitor tied to the C
RECT
terminal, and
the average value of the input current controls the gain of the
variable gain cell. The gain will thus be proportional to the
average value of the input signal for capacitivelycoupled
voltage inputs as shown in the following equation. Note that
for capacitivelycoupled inputs there is no offset voltage
capable of producing a gain error. The only error will come
from the bias current of the rectifier (supplied internally)
which is less than 0.1 A.
G
|V
IN
V
REF
| avg
R
1
or
G
| V
IN
| avg
R
1
The speed with which gain changes to follow changes in
input signal levels is determined by the rectifier filter
capacitor. A small capacitor will yield rapid response but
will not fully filter low frequency signals. Any ripple on the
gain control signal will modulate the signal passing through
the variable gain cell. In an expander or compressor
application, this would lead to third harmonic distortion, so
there is a tradeoff to be made between fast attack and decay
times and distortion. For step changes in amplitude, the
change in gain with time is shown by this equation.
10k
C
RECT
G(t)
(G
initial
G
final
) e
t
G
final
The variable gain cell is a currentin, currentout device
with the ratio I
OUT
/I
IN
controlled by the rectifier. I
IN
is the
current which flows from the
summing node biased at V
REF
. The following equation
applies for capacitivelycoupled inputs. The output current,
I
OUT
, is fed to the summing node of the op amp.
V
IN
R
2
A compensation scheme built into the
compensates for temperature and cancels out odd harmonic
distortion. The only distortion which remains is even
harmonics, and they exist only because of internal offset
voltages. The THD trim terminal provides a means for
nulling the internal offsets for low distortion operation.
The operational amplifier (which is internally
compensated) has the noninverting input tied to V
REF
, and
the inverting input connected to the G cell output as well
G input to an internal
I
IN
V
REF
V
IN
R
2
G cell
as brought out externally. A resistor, R
3
, is brought out from
the summing node and allows compressor or expander gain
to be determined only by internal components.
The output stage is capable of
±
20 mA output current.
This allows a +13 dBm (3.5 V
RMS
) output into a 300 load
which, with a series resistor and proper transformer, can
result in +13 dBm with a 600 output impedance.
A bandgap reference provides the reference voltage for all
summing nodes, a regulated supply voltage for the rectifier
and G cell, and a bias current for the G cell. The low
tempco of this type of reference provides very stable biasing
over a wide temperature range.
The typical performance characteristics illustration
shows the basic inputoutput transfer curve for basic
compressor or expander circuits.
+20
+10
0
10
20
30
40
50
60
70
80
40
30 20 10
0
+10
COMPRESSOR OUTPUT LEVEL
OR
EXPANDOR INPUT LEVEL (dBm)
C
Figure 2. Basic InputOutput Transfer Curve
O
13
3, 14
2, 15
4
1, 16
200pF
Figure 3. Typical Test Circuit
V
1
V
2
V
O
V
CC
= 15V
0.1 F
V
REF
G
10 F
2.2 F
2.2 F
20k
10k
2.2 F
5, 12
8.2k
8, 9
30k
20k
6, 11
7, 10
+
相關PDF資料 |
PDF描述 |
|---|---|
| SA571DR2G | Compandor |
| SA571NG | Compandor |
| SA572DG | Programmable Analog Compandor |
| SA572DR2 | Programmable Analog Compandor |
| SA572DR2G | Programmable Analog Compandor |
相關代理商/技術參數 |
參數描述 |
|---|---|
| SA571DR2G | 功能描述:音頻放大器 Dual Gain Compandor Industrial Temp RoHS:否 制造商:STMicroelectronics 產品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| SA571E-2200 | 制造商:Elan 功能描述:TOUCH PAD |
| SA571FB | 制造商:SIGNET 功能描述: |
| SA571N | 功能描述:音頻放大器 Dual Gain Compandor RoHS:否 制造商:STMicroelectronics 產品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| SA571N,602 | 制造商:NXP Semiconductors 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復。