lt5546 Linear Technology Corporation, lt5546 Datasheet - Page 11

• Manufacturer Part Number: lt5546
• Description: 40mhz To 500mhz Vga And I/q Demodulator With 17mhz Baseband Bandwidth
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
Evaluation Board
The evaluation circuit schematic is drawn in Figure 6. The
components associated with buffers U2 and U3 are in-
cluded to drive a 50Ω load for evaluation purposes only.
Figure 7. Component Side Silkscreen of Evaluation Board
Figure 9. Bottom Side Silkscreen of Evaluation Board
U
2.4GHz TO 2.5GHz
SYNTHESIZER
SYNTHESIZER
FRONT END
RX INPUT:
MAIN
AUX
RX
U
1ST LO,
2.12GHz
TO 2.22GHz
Figure 11. 2.4GHz to 2.5GHz Receiver Application (RX IF = 280MHz)
IF SAW BP FILTER
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
2ND LO,
560MHz
–10dBm
280MHz
W
3.3pF
3.3pF
15nH
15nH
10pF
39nH
11
10
3
U
2
VGA
1µF
f/2
Q-MIXER
1nF
V
I-MIXER
There is a unity voltage gain relationship for AC signals
between the evaluation board outputs (I and Q) and the
I
when the evaluation board outputs are terminated in 50Ω.
CC
OUT
5, 8
0°
90°
1,4,17
+
1.8V
, I
Figure 8. Component Side Layout of Evaluation Board
LPF
LPF
Figure 10. Bottom Side Layout of Evaluation Board
OUT
CLIPPER
CLIPPER
HARD
LT5546
HARD
–
or Q
16
15
7
6
14
13
12
9
OUT
I-OUTPUTS
IF DET
V
Q-OUTPUTS
CTRL
+
and Q
PROCESSOR
STBY
EN
BASEBAND
OUT
A/D
A/D
D/A
A/D
–
5546 F11
outputs of the LT5546
LT5546
11
5546fa