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APPLICATION INFORMATIONS

1. The LA7129S requires only one

external inductor for input matching.

If the device/phone manufacturers

implement very good power supply

filtering on their boards, the bypass

capacitor mentioned in this applica-

tion circuit may be optional. With

the capacitor we can get better

performance like a little higher gain

etc. The value is optimized for the

best gain, noise figure, return loss

performance. Typical value of in-

ductor is 9.1nH. For schematics see

2. The output of LA7129Sis internally

matched to 50 ohm and a DC

blocking capacitor is integrated

on-chip, thus no external compo-

nent is required at the output.

3. The LA7129S should be placed

close to the GPS antenna with the

input-matching inductor. Use 50-

ohm microstrip lines to connect RF

INPUT and RF OUTPUT. Bypass

capacitor should be located close to

the device. For long Vcc lines, it

may be necessary to add more

decoupling

capacitors.

Proper

grounding of the GND pins is very

important.

Table 4 lists the recommended inductor types and values;

Table 4: list of inductor

Part Number

Inductance Q(min)

Q Test

Frequency

Supplier

Size

Units

nH

MHz

LQW15A

9.1

25

250

Murata

0402

SDWL1005C

9.1

24

250

Sunlord

0402

HQ1005C

9.1

22

250

Sunlord

0402

LQP03TG47N

7.5

11

250

Murata

0603

LESHAN RADIO COMPANY, LTD.