參數(shù)資料
型號(hào)： PCF5078T
廠商： NXP SEMICONDUCTORS
元件分類： 通信及網(wǎng)絡(luò)
英文描述： Power amplifier controller for GSM and PCN systems
中文描述： SPECIALTY TELECOM CIRCUIT, PDSO8
文件頁(yè)數(shù)： 5/20頁(yè)
文件大?。?/td> 90K
代理商： PCF5078T
1999 Apr 12
5
Philips Semiconductors
Product specification
Power amplifier controller for GSM and
PCN systems
PCF5078
After this preset, the control voltage is free to increase
according to the control loop if RF input is present
(see Fig.3).
For higher DAC ramp steps the delay time of opening
switch S3 (and closing switch S4) is reduced. On the
contrary, the delay time between opening switch S2 with
respect to opening switch S3 (and closing switch S4)
remains unchanged.
For a correct start-up it is required that the rising time of the
supply voltage is maximum 20
μ
s.
End of a burst
For a proper down ramp, the final value of the DAC input
voltage should be below the value at the beginning of the
burst and so be able to really shut-off the PA (see Fig.5).
This means the code programmed for the last bit of the
DAC down ramp (CODE
END
) has to be lower than the
initial value of the up ramp (CODE
START
). Moreover, the
last code must be maintained until the supply voltage has
been switched off.
When the voltage on pin VC is detected to be lower than
V
VHOME
a built-in mechanism forces the voltage on pin VC
to V
prebias
by closing switches S1, S2 and S3 and by
opening switches S4 and S5.
For proper operation, the supply voltage should be
switched off at least 15
μ
s later with respect to the end of
the down ramp on pin VDAC.
PA protection against mismatching
A second sensor amplified input is integrated into the
PCF5078 for measuring the reflected wave of the
directional coupler. The signal is added to the measured
RF power signal (see Fig.3). When mismatching at the
output of the PA occurs the power is reduced. A high
Voltage Standing Wave Ratio (VSWR) at the output of the
PA often occurs in systems where the PA is connected to
the antenna via switches with low attenuation instead of
using a duplex filter.
Home position voltage
A forward voltage of an on-chip silicon diode is provided as
the default home position voltage V
home
. This voltage
matches the requirements at the control input of most PAs
and exhibits the same temperature coefficient.
However, if another value is needed for a certain PA the
level can be adjusted by connecting external components
to pin VHOME (see Figs 10 and 11). The home position
voltage can be set between 200 and 1000 mV when using
a capacitor of 50 pF connected between pins VINT
and VC.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PCF5078T/F2 制造商:NXP Semiconductors 功能描述:IC,POWER CONTROL/MANAGEMENT,CMOS,TSSOP,8PIN,PLASTIC
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PCF5079T 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Dual-band power amplifier controller for GSM, PCN and DCS
PCF5081 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:GSM baseband processors for digital mobile cellular radio
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