ADL5513 CLPF VOUT filtering

Hi all,

Our customer start to optimize and evaluate the ADL5513 .

In the datasheet, connecting a ground-referenced capacitor (CFLT) to the CLPF pin recommended.

About design for the CLPF pin and VOUT pin filter @ ADL5513,
1.Is the RC filter connecting to CLPF pin available ?
If available, which is Recommended, RC paralel or RC series ?
Is there recommended (limmited) value range of R,C ?

2.RC filter connecting to VOUT pin ,
Recommended (limmited) value range R,C ?
Note is following only?
"The ADL5513 output can drive over 1 nF of capacitance.
When driving such high output capacitive loads, it is required to capacitively load the CLPF pin.
The capacitance on the CLPF pin should be at least 1/50th that of the capacitance on the VOUT pin."

Best regards,

sss

Parents
  • Hello sss,

    1. When CLPF pin opens or no external capacitor connecting to its, the Vout output has about 10MHz video bandwidth. The CLPF pin’s capacitor is depending on your input signal. If you connect a capacitor from this CLPF pin to ground, you will reduce the Vout output video bandwidth and improve the output ripples (feedthrough from the input signal, if any). Figure 27 shows the lowpass filtering capacitor connection, CFLT and the formula on page 14 for calculating the capacitor value.
    2. If you must add a capacitor from the Vout pin to ground, this capacitor will further improve the ripples that feedthrough from input signal. This capacitor (at Vout pin) must be 1/50 greater than the capacitor at CLP pin.

    Hope these can help.

    John_C

Reply
  • Hello sss,

    1. When CLPF pin opens or no external capacitor connecting to its, the Vout output has about 10MHz video bandwidth. The CLPF pin’s capacitor is depending on your input signal. If you connect a capacitor from this CLPF pin to ground, you will reduce the Vout output video bandwidth and improve the output ripples (feedthrough from the input signal, if any). Figure 27 shows the lowpass filtering capacitor connection, CFLT and the formula on page 14 for calculating the capacitor value.
    2. If you must add a capacitor from the Vout pin to ground, this capacitor will further improve the ripples that feedthrough from input signal. This capacitor (at Vout pin) must be 1/50 greater than the capacitor at CLP pin.

    Hope these can help.

    John_C

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