EM92547DP Ver la hoja de datos (PDF) - ELAN Microelectronics

Número de pieza

componentes Descripción

Fabricante

EM92547DP

CALLER ID FSK DECODER

ELAN Microelectronics 

Application Note

1. Input capacitor and input resistor

EM92547A/B/D

CALLER ID FSK DECODER

C1

R1

TIP

C2 R2

RING

Differential Input

OP Amp

A

500k

500k

B

Input voltage of OP Amp are "A" and "B" which are equal to 500k/(Z1+500k) and 500k/(Z2+500k),

where Z1=Zc1+R1, Z2=Zc2+R2. There is no difference in the input sensitivity when the external

resistors R1 and R2 is more less than 500k ohms. Although R1 and R2 will not critically effect input

sensitivity, we suggest the value of R1 and R2 are 30k to 50k to reduce the ring current into "A" and

"B" for stable operation.

Input coupling capacitors C1 and C2 will slightly effect the input sensitivity. The value of C1 and

C2 could not choose too large to avoid ring voltage discharge time debiasing OP Amp. We suggest

that the value C1 and C2 are less than 0.01uF.

2. VDD pin and VSS pin

To reduce noise effects, connect a ceramic capacitor of about 0.1uF set as close as possible to the

pin to the VSS pin.

3. OSCIN pin, OSCOUT pin

For proper oscillator working, the feedback resistor 1MΩ should be shunt with the 3.58MHz crystal

and 20pF capacitors connected from these two pins to the ground.

________________________________________________________________________________________________________________________________________________________

* This specification are subject to be changed without notice.

1998

~ 12 ~

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