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參數(shù)資料
| 型號(hào)： | THAT2181A |
| 廠商： | Electronic Theatre Controls, Inc. |
| 英文描述： | Trimmable IC Voltage Controlled Amplifiers |
| 中文描述： | 微調(diào)IC電壓控制放大器 |
| 文件頁數(shù)： | 5/10頁 |
| 文件大?。?/td> | 252K |
| 代理商： | THAT2181A |
ship is temperature dependent. Therefore, the gain of
any log-antilog VCA depends on its temperature.
Figure 8 shows the effect of temperature on the nega-
tive control port. (The positive control port behaves in the
same manner.) Note that the gain at Ec = 0 V is 0 dB, re-
gardless of temperature. Changing temperature changes
the
scale factor
of the gain by 0.33%/ C, which pivots the
curve about the 0 dB point.
Mathematically, the 2181's gain characteristic is
Gain
E
E
0.0033 T)
(0.0061)(1
C
C
,
Eq. 1
where
(25 C) and the actual temperature, and Gain is the
gain in decibels. At room temperature, this reduces to
T is the difference between room temperature
Gain
E
E
0.0061
C
C
,
Eq. 2
If only the positive control port is used, this becomes
Gain
E
0.0061
C
,
Eq. 3
If only the negative control port is used, this becomes
Gain
E
0.0061
C
,
Eq. 4
DC Bias Currents
The 2181 current consumption is determined by the
resistor between pin 5 (V-) and the negative supply voltage
(V
EE
). Typically, with 15V supplies, the resistor is 5.1 k ,
which provides approximately 2.4 mA. This current is
split into two paths: 570
A is used for biasing the IC,
and the remainder becomes Icell as shown in Figure 5.
Icell is further split in two parts: about 20
core transistors (Q1 through Q4), the rest is available for
input and output signal current.
A biases the
Trimming
The 2181-Series VCAs are intended to be adjusted for
minimum distortion by applying a small variable offset
voltage to pin 4, the SYM pin. Note that there is a 25
sistor internal to the 2181 between pin 4 and pin 2. As
shown in Figure 2, Page 3, the usual method of applying
this offset is to use the internal 25
re-
resistor along with a
larger value resistor to form a voltage divider connected
to the wiper of a trim pot across the supply rails.
This trim should be adjusted for minimum harmonic
distortion. This is usually done by applying a mid-
dle-level, middle-frequency signal (e.g. 1 kHz at 1 V) to
the audio input, setting the VCA to 0 dB gain, and adjust-
ing the SYM trim while observing THD at the output. In
the 2181, this adjustment coincides closely with the set-
ting
which
produces
feedthrough, though the two settings are not always iden-
tical.
minimum
control-voltage
DC Feedthrough
Normally, a small dc error term flows in pin 8 (the
output). When the gain is changed, the dc term changes.
This control-voltage feedthrough is more pronounced
with gain; the –A version of the part produces the least
feedthrough, the –C version the most. See Figure 9 for
typical curves for dc offset vs. gain
THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA
Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com
600030
Rev 01
Page 5
Figure 10. 1 kHz THD+Noise Vs. Input Level, 0 dB Gain
Figure 11. 1 kHz THD+Noise Vs. Input Level, +15 dB
Gain
Figure 9. Representative DC Offset Vs. Gain
Figure 12. 1 kHz THD+Noise Vs. Input Level, -15 dB
Gain
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| THAT2181B | Trimmable IC Voltage Controlled Amplifiers |
| THAT2181C | Trimmable IC Voltage Controlled Amplifiers |
| THAT300 | Low-Noise Matched Transistor Array ICs |
| THAT300P | Low-Noise Matched Transistor Array ICs |
| THAT300S | Low-Noise Matched Transistor Array ICs |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| THAT2181AL08-U | 制造商:THAT CORPORATION 功能描述:AMP VOLT CONTROLLED TRIMMABLE 2181 制造商:THAT CORPORATION 功能描述:AMP, VOLT CONTROLLED, TRIMMABLE, 2181 制造商:THAT CORPORATION 功能描述:IC, AMPLIFIER, VOLT CONTROLLED, TRIMMABLE, SIP-8; IC Function:Voltage Controlled Amplifier; Supply Voltage Min:4V; Supply Voltage Max:18V; Operating Temperature Min:0C; Operating Temperature Max:70C; Digital IC Case Style:SIP ;RoHS Compliant: Yes |
| THAT2181B | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Trimmable IC Voltage Controlled Amplifiers |
| THAT2181BL08-U | 制造商:THAT CORPORATION 功能描述:AMP VOLT CONTROLLED TRIMMABLE 2181 制造商:THAT CORPORATION 功能描述:IC, AMP, VOLTAGE CONTROLLED; IC Function:Voltage Controlled Amplifier; Brief Features:Current In & Current Out Device, Dual Gain Control Ports, Low Distortion; Supply Voltage Min:4V; Supply Voltage Max:18V; Digital IC Case Style:SIP ;RoHS Compliant: Yes |
| THAT2181C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Trimmable IC Voltage Controlled Amplifiers |
| THAT2181CL08-U | 制造商:THAT CORPORATION 功能描述:AMP VOLT CONTROLLED TRIMMABLE 2181 制造商:THAT CORPORATION 功能描述:AMP, VOLT CONTROLLED, TRIMMABLE, 2181 制造商:THAT CORPORATION 功能描述:AMP, VOLT CONTROLLED, TRIMMABLE, 2181; IC Function:Voltage Controlled Amplifier; Brief Features:Exponential Gain Control, Wide Gain Range; Supply Voltage Min:-18V; Supply Voltage Max:18V; Operating Temperature Min:0C; Operating ;RoHS Compliant: Yes |
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