RF137 查看數據表（PDF） - Conexant Systems
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RF137 Datasheet PDF : 15 Pages
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RF137
Ceramic
Filter
Transceiver
IF1IN+
IF1IN-
Rx
Sx
GSEL1
RES1
RES2
BPC
LO1IN+
LO1IN-
÷2
÷4
90˚
RXMXO
+
RX LO2
SX LO2 ÷2
÷4
VHF
Synthesizer
UHF
Synthesizer
Tx
TXRFIN+
TXRFIN-
TLCPO
TX LO2
÷2
÷4
÷1
÷2
CHP
PFD
÷1
÷2
GSEL2
IF2IN+
IF2IN-
Rx
Sx
Bias
3-Wire
Control
Tx
IF2O+
IF2O-
VCPO
FREF
RXENA
TXENA
SXENA
LD
CLK
DATA
LE
UCPO
TXI+
TXI-
90˚
TXQ+
TXQ-
C018
Figure 2. RF137 Block Diagram
Technical Description
The RF137 Transceiver consists of three main sections:
• Receive (Rx) section
• Transmit (Tx) section
• Synthesizer (Sx) section
The Rx, Tx, and Sx sections can be powered up or down
independently by setting RXENA, TXENA, and SXENA high or
low.
The signal pin assignments and functional pin descriptions are
found in Table 1. Table 2 provides the absolute maximum
ratings of the RF137. The general electrical characteristics are
provided in Table 3.
Receive Section. The receive section consists of the following
functional blocks:
• A first IF amplifier (selectable gain step of 24 dB).
• An image reject mixer that downconverts from a first IF to a
second IF.
• A buffer amplifier that precedes a second IF ceramic filter.
• A second IF amplifier (selectable gain step of 12 dB) with
differential outputs.
The first IF amplifier is a Programmable Gain Amplifier (PGA)
with selectable gains of +18 or –6 dB. The amplifier gain is
controlled by a three-wire bus. The first IF amplifier is at a high
gain state when bit S7 = 1 (Rx Gain Sel1) and CO = 1 or at a
low gain state when bit S7 = 0 (Rx Gain Sel1) and CO = 1.
The image reject mixer relaxes the first IF filtering requirements
at the image frequency of the second mixer. Image rejection is
achieved for a high side/low side injection when bit S9 is set to
the appropriate logic level and CO = 1. Table 4 defines the
three-wire bus control and output states.
2
October 11, 2000
Conexant - Proprietary
Data Subject to Change
100777C
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