参数资料
| 型号： | LT1684CN#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 3/16页 |
| 文件大小： | 0K |
| 描述： | IC RING TONE GENERATOR 14-DIP |
| 标准包装： | 25 |
| 功能： | 音频发生器 |
| 电路数： | 1 |
| 工作温度： | 0°C ~ 125°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 14-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 14-PDIP |
| 包装： | 管件 |
11
LT1684
–
+
RF3
RF1
+
–
RF2
VIN
CF2
CF1
VOUT
1684 F4a
Active Filter Tuned Oscillator Block Diagram
The LT1684 can be implemented easily into a telephone
ringer circuit based on the active filter tuned oscillator
topology, eliminating the need for a user-supplied PWM
input signal. The LT1684’s active filter amplifier can be
used as a high-Q bandpass filter element by configuring
it as an active tracking supply bandpass. The LT1684’s
controlled output receiver/buffer is also convenient for
use as the hard limiter. Because the LT1684 receiver/
buffer requires a true differential input for proper opera-
tion, a dual comparator IC such as the LT1017 must be
bootstrapped along with the LT1684 to provide differen-
tial control signals. The LT1017 and LT1684 receiver/
buffer combine to create a high gain hard limiter whose
output is controlled to
±1.25V. The LT1684 active
bandpass filter is then connected as a positive feedback
element with the limiter component, which completes
the active filter tuned oscillator topology.
The active bandpass filter circuit is easily configured using
a basic MFB bandpass configuration, however, the active
tracking supply technique used by the LT1684 requires
“transformation” of this topology. This “transformation”
swaps the amplifier signal polarity, references all signals
to the output, and references all feedback elements to
ground as described previously in the Filter Design and
Component Selection section.
The design equations for the active tracking bandpass
filter are the same as the pretransformation MFB topology,
such that if CF1 = CF2 = C:
RF1 = Q/(ωO C H0)
RF2 = Q/(2Q2 –H0)(ωO C)
RF3 = 2Q/(ωO C)
Example:
Conditions: Output peak voltage = 95V
Ring frequency = 20Hz
Bandpass Q = 9.4
A square wave with peak amplitude A has a fundamental
component with amplitude 4A/
π, where A = 1.25V. There-
fore, the desired filter’s bandpass gain
HO = 95/(4
1.25/
π) ~ 60. Given capacitor values C = 0.22F (a conve-
nient value) and desired filter characteristics of: Q = 9.4,
HO = 60, ωO = 2π(20Hz), then: RF1 = 5.6k, RF2 = 2.7k,
RF3 = 680k. The amplitude, frequency and envelope re-
sponse time of the output signal can be adjusted by simply
changing the values of resistors RF1 to RF3 accordingly.
This produces a high voltage, high quality 20Hz sine wave
at the filter output with a peak amplitude of 95V. Differen-
tial amplitude and frequency characteristics are achieved
by simply changing a few resistor values. The output of the
LT1684 is internally current limited to a minimum of
±100mA peak, allowing this ring tone generation circuit to
be used with loads up to 7 REN with no degradation of the
output waveform.
–
+
RF2
+
–
RF1
VIN
CF2
RF3
CF1
VOUT
1684 F5b
Bandpass MFB Filter
Active Tracking Bandpass MFB Filter
1684 F03
APPLICATIO S I FOR ATIO
WU
UU
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1684CS | 功能描述:IC RING TONE GENERATOR 14-SOIC RoHS:否 类别:集成电路 (IC) >> 接口 - 电信 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 06/Feb/2012 标准包装:750 系列:* |
| LT1684CS#PBF | 功能描述:IC RING TONE GENERATOR 14-SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 电信 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 06/Feb/2012 标准包装:750 系列:* |
| LT1684CS#TR | 功能描述:IC GENERATOR RING TONE 14SOIC RoHS:否 类别:集成电路 (IC) >> 接口 - 电信 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 06/Feb/2012 标准包装:750 系列:* |
| LT1684CS#TRPBF | 功能描述:IC RING TONE GENERATOR 14-SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 电信 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 06/Feb/2012 标准包装:750 系列:* |
| LT1684IN | 功能描述:IC RING TONE GENERATOR 14-DIP RoHS:否 类别:集成电路 (IC) >> 接口 - 电信 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 06/Feb/2012 标准包装:750 系列:* |
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