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參數資料
| 型號： | AD8314ARM-REEL7 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 通信及網絡 |
| 英文描述： | 100 MHz-2500 MHz 45 dB RF Detector/Controller |
| 中文描述： | SPECIALTY TELECOM CIRCUIT, PDSO8 |
| 封裝： | MO-187AA, MSOP-8 |
| 文件頁數： | 9/16頁 |
| 文件大小： | 274K |
| 代理商： | AD8314ARM-REEL7 |
AD8314
–9–
REV. 0
frequencies, due to the declining gain of the amplifier stages and
other effects in the detector cells. For the AD8314, the slope
at low frequencies is nominally 21.3 mV/dB, falling almost linearly
with frequency to about 19.2 mV/dB at 2.5 GHz. These values
are sensibly independent of temperature (see Figure 7) and
almost totally unaffected by the supply voltage from 2.7 V to
5.5 V (Figure 8).
Inverted Output
The second provision is the inclusion of an inverting amplifier
to the output, for use in controller applications. Most power
amplifiers require a gain-control bias that must decrease from a
large positive value toward ground level as the power output is
required to decrease. This control voltage, which appears at the pin
V_DN, is not only of the opposite polarity to V_UP, but also
needs to have an offset added in order to determine its most posi-
tive value when the power level (assumed to be monitored through
a directional coupler at the output of the PA) is minimal.
The starting value of V_DN is nominally 2.25 V, and it falls
on a slope of twice that of V_UP, in other words, –43 mV/dB.
Figure 26 shows how this is achieved: the reference voltage
that determines the maximum output is derived from the on-
chip voltage reference, and is substantially independent of the
supply voltage or temperature. However, the full output cannot
be attained for supply voltages under 3.3 V; Figure 19 shows
this dependency. The relationship between V_UP and V_DN is
shown in Figure 27.
V–I
BAND-GAP
REFERENCE
+2
VSET
FLTR
I–V
1.125V
V
DN
= 2.25V – 2.0
3
V_UP
CURRENTS FROM
DETECTORS
AD8314
V_UP
V_DN
Figure 26. Output Interfaces
INPUT AMPLITUDE – dBV
0
–60
V
2.5
2.0
1.5
1.0
0.5
OUTPUT FOR
PA CONTROL
–50
–40
–30
–20
–10
0
OUTPUT FOR
MEASUREMENT
V_UP
V_DN
Figure 27. Showing V_UP and V_DN Relationship
APPLICATIONS
Basic Connections
Figure 28 shows connections for the basic measurement mode.
A supply voltage of 2.7 V to 5.5 V is required. The supply to
the VPOS pin should be decoupled with a low inductance 0.1
μ
F
surface mount ceramic capacitor. A series resistor of about 10
may be added; this resistor will slightly reduce the supply voltage to
the AD8314 (maximum current into the VPOS pin is approxi-
mately 9 mA when V_DN is delivering 5 mA). Its use should be
avoided in applications where the power supply voltage is very
low (i.e., 2.7 V). A series inductor will provide similar power
supply filtering with minimal drop in supply voltage.
1
2
3
4
ENBL
RFIN
AD8314
8
7
6
5
VSET
FLTR
V DN
VPOS
COMM
V UP
0.1
m
F
OPTIONAL
(SEE TEXT)
OPTIONAL
(SEE TEXT)
V
S
V
DN
V
UP
C
F
V
S
52.3
V
INPUT
Figure 28. Basic Connections for Operation in
Measurement Mode
The ENBL pin is here connected to VPOS. The AD8313 may
be disabled by pulling this pin to ground when the chip current
is reduced to about 20
μ
A from its normal value of 4.5 mA.
The logic threshold is around +V
S
/2 and the enable function
occurs in about 1.5
μ
s. Note, however, further settling time is
generally needed at low input levels.
The AD8314 has an internal input coupling capacitor. This
eliminates the need for external ac-coupling. A broadband input
match is achieved in this example by connecting a 52.3
resis-
tor between RFIN and ground. This resistance combines with
the internal input impedance of approximately 3 k
to give
an overall broadband input resistance of 50
. Several other
coupling methods are possible; these are described in the Input
Coupling section.
The measurement mode is selected by connecting VSET to V_UP,
which establishes a feedback path and sets the logarithmic slope
to its nominal value. The peak voltage range of the measurement
extends from –58 dBV to –13 dBV at 0.9 GHz, and only slightly
less at higher frequencies up to 2.5 GHz. Thus, using the 50
termination, the equivalent power range is –45 dBm to 0 dBm.
At a slope of 21.5 mV/dB, this would amount to an output span
of 967 mV. Figure 29 shows the transfer function for V_UP at a
supply voltage of 3 V, and input frequency of 0.9 GHz.
V_DN, which will generally not be used when the AD8314 is
used in the measurement mode, is essentially an inverted version
of V_UP. The voltage on V_UP and V_DN are related by the
equation.
V
DN
= 2.25 V – 2
V
UP
While V_DN can deliver up to 6 mA, the load resistance on V_UP
should not be lower than 10 k
in order that the full-scale output
of 1 V can be generated with the limited available current of
200
μ
A max. Figure 29 shows the logarithmic conformance
under the same conditions.
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相關代理商/技術參數 |
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| AD8314ARMZ | 功能描述:IC RF DETECTOR/CTRLR 8-MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 檢測器 系列:- 產品變化通告:Product Discontinuation 15/May/2006 標準包裝:3,000 系列:- 頻率:100MHz ~ 2GHz RF 型:手機，GSM，DCS，PCS 輸入范圍:- 精確度:- 電源電壓:2.7 V ~ 5.5 V 電流 - 電源:300µA 包裝:帶卷 (TR) 封裝/外殼:SC-74，SOT-457 其它名稱:NCS5000SNT1GOS |
| AD8314ARMZ | 制造商:Analog Devices 功能描述:Operational Amplifier (Op-Amp) IC |
| AD8314ARMZ-REEL | 功能描述:IC RF DETECTOR\CTRLR 8MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 檢測器 系列:- 產品變化通告:Product Discontinuation 15/May/2006 標準包裝:3,000 系列:- 頻率:100MHz ~ 2GHz RF 型:手機，GSM，DCS，PCS 輸入范圍:- 精確度:- 電源電壓:2.7 V ~ 5.5 V 電流 - 電源:300µA 包裝:帶卷 (TR) 封裝/外殼:SC-74，SOT-457 其它名稱:NCS5000SNT1GOS |
| AD8314ARMZ-REEL7 | 功能描述:IC RF DETECTOR/CTRLR 8-MSOP RoHS:是 類別:RF/IF 和 RFID >> RF 檢測器 系列:- 產品變化通告:Product Discontinuation 15/May/2006 標準包裝:3,000 系列:- 頻率:100MHz ~ 2GHz RF 型:手機，GSM，DCS，PCS 輸入范圍:- 精確度:- 電源電壓:2.7 V ~ 5.5 V 電流 - 電源:300µA 包裝:帶卷 (TR) 封裝/外殼:SC-74，SOT-457 其它名稱:NCS5000SNT1GOS |
| AD8314-EVAL | 制造商:Analog Devices 功能描述:EVAL BD 100 MHZ TO 2.7 GHZ, 45 DB RF DETECTOR/CNTRLR - Bulk |
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