CXA3355ERVQFN SONY [Sony Corporation], CXA3355ERVQFN Datasheet - Page 20

• Manufacturer Part Number: CXA3355ERVQFN
• Description: GPS Down Converter IC
• Manufacturer: SONY [Sony Corporation]

2. Using an External Filter
When using the CXA3355ER in 4fo mode with the initial settings (see page 17) which do not require serial
data setting, input and output are performed via the test circuit located between the internal IF filter and the IF
AMP2 in the following stage, so an external filter is necessary.
The external filter uses Pins 36 to 39. Differential I/O is performed with Pin 38 (TESTOUTP) and Pin 39
(TESTOUTN) as the internal IF filter output pins and Pin 36 (TESTINP) and Pin 37 (TESTINN) as the input
pins to IF AMP2. Also, the impedance is 200
Note that the bias voltage is determined inside the IC, so Pins 36 and 37 should not be connected directly with
Pins 38 and 39. When not using an external filter, eliminate the DC components using an approximately 10nF
capacitor.
The overall external filter block and the external filter configuration are shown below.
Pin 38
Pin 39
C1
C2, C3
C4
C5, C6
C7
C8, C9, C12, C13
C10, C11
C1
Chip C
Pin 36: TESTINP
Pin 37: TESTINN
Pin 38: TESTOUTP
Pin 39: TESTOUTN
C2
C3
L1
L2
CXA3355ER
C4
1500
[pF]
300
240
130
680
91
91
Secondary LPF
C6
L3
C5
L4
LPF
C7
L1, L2
L3, L4
L5, L6
Chip L
C8
C9
C10
C11
External Filter Configuration
Overall External Filter Block
Secondary HPF
[µH]
L5, L6
(2 series)
2.2
3.9
4.7
C12
C13
HPF
Zout
200
(differential) for both input and output.
– 20 –
Pin 37
Pin 36
39
External filter I/O circuit
External filter
38
–10
–20
–30
–40
–50
–60
–70
10
0
0
37
1
(Example of representative characteristics)
Internal filter
Internal filter + External filter
2
36
CXA3355ER IF Filter Response
IF AMP2
Detuning frequency [MHz]
3
Zin
Normalized at 4MHz
200
4
5
To the comparator
6
7
CXA3355ER
8
9
10