TQ5633 Ver la hoja de datos (PDF) - TriQuint Semiconductor
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TQ5633 Datasheet PDF : 10 Pages
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TQ5631 Product Description
The TQ5633 is a balanced mixer down converter which
integrates the gain step functions required for PCS CDMA
handsets. The device requires minimal components and mates
with the TQ3631 or TQ3632 series of high band LNAs. The
TQ5633 was designed specifically for the needs of systems
using a low IF in the range of 85MHz to 130MHz, as it provides
a very high IP2. Some other outstanding features are 50ohm
matches at the RF input and LO input in both modes.
Simplified theory of operation
The TQ5633 contains a RF amplifier, balanced mixer, LO buffer,
IF amplifier and gain step switches. Figure 1 shows a block
diagram. In the high gain mode, the RF Amp is turned on and
the bypass switch is turned off. RF signal enters pin 1 and is
amplified by 10dB before arriving at the passive balanced mixer.
Total conversion gain is approximately 16dB.
The LO input at pin 8 is amplified by a saturating balanced
driver before being applied to the mixer. By using amplification
the LO drive remains constant over some range of LO input
power and temperature. The LO tuning is internal and centered
around 2070MHz.
The mixer utilizes proprietary techniques for attaining a very
high degree of balance. It converts the PCS band signal down
to approximately 110MHz using a high side LO source. By
utilizing a passive mixer it provides for excellent IP3 response.
The IF signal is taken off of the mixer and applied to an IF
amplifier which provides gain. The source of the IF stage is
brought out to pin 3 so an external tuned circuit can be used to
optimize IP2. The tuned circuit works by providing a high IF
impedance at the source of the output differential pair. High IF
common-mode rejection and balance are achieved by using a
high IF impedance.
The low gain mode differs in that the RF amplifier is turned off
and passive switches route the RF input signal directly to the
mixer. In that case the total conversion gain is approximately
7dB.
TQ5633
Data Sheet
RF
Input
F1
1
2
Vdd
Mixer
3
C3
L2
R4
4
C4
TQ5633
8
C5
7
6
5
C9
Vdd
R3
RFA
C6
R1
C7
LO
Input
C2,
Gain
Select
Vdd
L3
R5 IFA
C8
IF
Output
Figure 1 TQ5633 Simplified Block Diagram and Schematic
Logic truth table and logic control functions
The TQ5633 logic control was designed to mate with the
TQ3631 or TQ3632 PCS Band LNAs. Although the TQ5633
has only one logic control line “C2”, it’s possible to obtain 4
different gain states when used in conjunction with the LNAs.
Moreover, only two logic lines are needed. On the TQ5633 the
“C2” control signal is superimposed on the LO input pin 7. A
simple 2.2k ohm resistor and blocking capacitor serve as the
decoupling network. Table 1 shows the logic control and device
states for a TQ3631-TQ5633 combination.
Control
Lines
System
Mode
LNA State
TQ5633
State
C2 C3
0
0
High Gain
High Gain
High Gain
0
1
High Gain, High Gain, High Gain
Low Linearity Low Linearity
1
0
Mid Gain
High Gain
Low Gain
1
1
Low Gain
Bypass
Low Gain
Logic Table 1
For additional information and latest specifications, see our website: www.triquint.com
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