ADF4113BRU(Rev0) 查看數據表（PDF） - Analog Devices
零件编号
产品描述 (功能)
生产厂家
ADF4113BRU Datasheet PDF : 24 Pages
| |||
ADF4110/ADF4111/ADF4112/ADF4113
DIRECT CONVERSION MODULATOR
In some applications a direct conversion architecture can be used
in base station transmitters. Figure 33 shows the combination
available from ADI to implement this solution.
The circuit diagram shows the AD9761 being used with the
AD8346. The use of dual integrated DACs such as the AD9761
with specified ± 0.02 dB and ± 0.004 dB gain and offset match-
ing characteristics ensures minimum error contribution (over
temperature) from this portion of the signal chain.
The Local Oscillator (LO) is implemented using the ADF4113.
In this case, the OSC 3B1-13M0 provides the stable 13 MHz
reference frequency. The system is designed for a 200 kHz
channel spacing and an output center frequency of 1960 MHz.
The target application is a WCDMA base station transmitter.
Typical phase noise performance from this LO is –85 dBc/Hz at
a 1 kHz offset.
The LO port of the AD8346 is driven in single-ended fashion.
LOIN is ac-coupled to ground with the 100 pF capacitor and
LOIP is driven through the ac coupling capacitor from a 50 Ω
source. An LO drive level of between –6 dBm and –12 dBm is
required. The circuit of Figure 33 gives a typical level of –8 dBm.
The RF output is designed to drive a 50 Ω load but must be
ac-coupled as shown in Figure 33. If the I and Q inputs are
driven in quadrature by 2 V p-p signals, the resulting output
power will be around –10 dBm.
REFIO
IOUTA
MODULATED
DIGITAL
DATA
IOUTB
AD9761
TxDAC
QOUTA
FS ADJ QOUTB
2k⍀
4.7k⍀
OSC 3B1-13M0
TCXO
RSET
REFIN
CP
SERIAL
DIGITAL
NTERFACE
ADF4113 910pF
RFINB RFINA
LOW-PASS
FILTER
LOW-PASS
FILTER
IBBP
IBBN
QBBP
QBBN
AD8346
100pF
VOUT
LOIN LOIP
100pF
100pF
RFOUT
3.3k⍀
3.9k⍀
620pF
9.1nF
100pF 18⍀
18⍀
VCO190-1960T
18⍀
100pF
100pF
51⍀
POWER SUPPLY CONNECTIONS AND DECOUPLING
CAPACITORS ARE OMITTED FROM DIAGRAM FOR CLARITY.
Figure 33. Direct Conversion Transmitter Solution
–22–
REV. 0
Share Link: 