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參數(shù)資料
| 型號(hào)： | U2740B |
| 英文描述： | UHF AM/FM Transmitter |
| 中文描述： | 超高頻調(diào)幅/調(diào)頻發(fā)射機(jī) |
| 文件頁(yè)數(shù)： | 3/10頁(yè) |
| 文件大小： | 264K |
| 代理商： | U2740B |
U2740B
Preliminary Information
TELEFUNKEN Semiconductors
Rev. A3, 24-Feb-97
3 (10)
Circuit Description
The transmitter PLL U2740B contains the complete RF
part for a radio control system. The IC consists of a VCO,
a complete PLL circuit, a crystal oscillator, a power
amplifier and a power-up module. An integrated switch
can be used to change the load capacitance of the crystal.
VCO
The VCO is a voltage-controlled current source. The
frequency is determined by the external LC-tank. The
frequency is changed via a Varicap diode.
PLL
The complete PLL consists of a prescaler, a digital
phase/frequency detector (PFD) with charge-pump
output. The output frequency is locked to 128 times the
frequency of the XTO. The PFD, however, operates at a
frequency four times lower than that of the XTO. A lock-
detect output indicates that the PLL is locked.
Crystal Oscillator (XTO)
It is a single-pin crystal oscillator, operating at the series
resonant frequency of the crystal. Depending on the type
of crystal used, this oscillator takes 3 to 20 ms until
settling after setting CS to V
S
. The integrated switch can
be used to change the load capacitance. Thus, the output
frequency is FSK modulated.
Power Amplifier (PA)
As figure 4 shows, the differential PA switches its output
current between the two power output pins (ANT1,
ANT2). The output current is seven times the current
flowing into the AM_in Pin. The achievable output power
is about 1.5 mW.
Power-up
When CS = 0 V, the circuit is in standby mode with a
power–down supply current of type. IS,off = 0.1
μ
A. With
CS = V
S
, the circuit is in power-up mode.
PAGND
VS
ANT1
ANT2
AM_in
4.6 k
0.7 V
Iout = 3.5 mA
0.5 mA
VCO
Q1
Q2
1
7
0.7 V
Figure 4. Power output stage of U2740B
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| U2740B-BFP | 制造商:TEMIC 制造商全稱:TEMIC Semiconductors 功能描述:UHF AM/FM Transmitter |
| U2741A | 制造商:AGILENT TECHNOLOGIES, INC. 功能描述:USM MODULAR DIGITAL MULTIMETER, 5 1/2 DIGIT 制造商:Agilent Technologies 功能描述:U2741A 5 1/2 Digit Benchtop DMM 制造商:Agilent Technologies 功能描述:MULTIMETER, DIGITAL, BENCH, 5-1/2 DIGIT; DMM Type:Bench; Voltage Measuring Range DC:100mV to 300V; Voltage Measuring Range AC:100mV to 250V; Current Measuring Range DC:10mA to 2A; Current Measuring Range AC:10mA to 2A ;RoHS Compliant: NA |
| U2741AOPT900+PLG | 制造商:Agilent Technologies 功能描述:U2741A Multimeter, USB module |
| U2741B | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:UHF ASK/FSK TRANSMITTER |
| U2741B_05 | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:UHF ASK/FSK TRANSMITTER |
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