TQ5631 데이터 시트보기 (PDF) - TriQuint Semiconductor
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TQ5631 Datasheet PDF : 14 Pages
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TQ5631 Product Description
Simplified theory of operation
TQ5631
Data Sheet
Logic truth table and logic control functions
TABLE 1
TRUTH TABLE
The TQ5631 contains an RF amp, mixer, IF amp, and RF
switches. Pin count is reduced by doubling the function of
several pins, where dc control bias and RF signal are present at
the same time. (Figure 1)
In the low gain modes, the RF amp is disabled and the the input
signal is routed directly to the mixer. In the high gain modes, a
cascode amp is switched in before the mixer. Control for this
function is made via a dc signal on the RF input pin 8. A
number of switches are used internally to eliminate any parasitic
signal paths.
The IF amp gain can be stepped as well via a control line at pin
5. The general IF amp gain and current draw can be set using
external components at the GIC pin 4.
The TQ5631 uses an off chip inductor with a bypass capacitor at
pin 6 for tuning the LO buffer. Although the device can be
connected directly to 50Ω at the RF input, a better match is
obtained by using a small series inductor and shunt capacitor at
the RF input .
RFA GAIN SELECT, C2
CONTROL LINES
Receiver
Mode
RFA Gain
Select
C2
IFA Gain
Select
C3
LNA
State
Mixer State
RFA
IFA
CDMA HG
CDMA HGLL
CDMA MG
CDMA LG
0
0 HG CDMA Idd
HG
LG
0
1 HG Low Idd
HG
HG
1
0 HG CDMA Idd
Bypassed
LG
1
1 Bypassed
Bypassed
HG
HG=High Gain; HGLL=High Gain Low Linearity; MG=Mid Gain; LG=Low Gain
TABLE 1
When used in conjunction with the TQ3631, the TQ5631 down
convert mixer can be set to a variety of different gain states.
This allows the receiver (LNA + downconvert mixer) to operate
with a wide dynamic range, while optimizing current draw and
overall receiver performance.
Two external control lines set the LNA + downconverter into any
one of the four states, described below.
a) CDMA Low Gain Mode: This mode is selected in very high
signal environment. The current draw in this case is 16mA
for the receive chain.
b) CDMA High Gain Mode: This mode is selected in very
weak signal environment. The receiver is in it’s maximum
sensitivity.
c) CDMA High Gain Low Linearity Mode: This mode is
selected when the phone is in standby mode. The phone
RF IN
power amplifier will be off in this state, removing the
possibility of self jamming.
1 GND
RF
IN
8
VDD
d) CDMA Mid Gain Mode. This mode is selected in a medium
signal strength environment.
GND
2
VDD
7
IF OUT
VDD
IF
3
GIC
4
LO TUNE
6
LO/C3
5
VDD
IF GAIN
SELECT, C3
DOWNCONVERTER APPLICATION HINTS:
Printed Circuit Board Layout guidelines for
GIC ADJUST
LO IN
FIGURE 3
TQ5631 SIMPLIFIED CIRCUIT
stability
With good layout practices the circuit will be stable. However,
poor layout may lead to oscillation problems. Good grounding is
especially important for the TQ5631 since it uses an off-chip LO
For additional information and latest specifications, see our website: www.triquint.com
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