LC7385M View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

View to exact match

LC7385M

DTMF receiver

SANYO -> Panasonic 

LC7385, 7385M

Guard Time Setting

Component values are chosen using the following formula :

tREC=tDP+tGTP

tID=tDA+tGTA

(a) Basic Circuit

tGTP=RC · In [VDD/(VDD–VTST)]

tGTA=RC · In (VDD/VTST)

Guard Time Adjustment

(b) tGTP<tGTRA

tGTP=R1 R2/(R1+R2) · C · In [VDD/(VDD–VTST)]

tGTA=R1 C · In (VDD/VTST)

(c) tGTP>tGTA

tGTP=R1 C · In [VDD/(VDD–VTST)]

tGTA=R1 R2/(R1+R2) · C · In (VDD/VTST)

Differential Input Configuration

Example of component values

C1=C2=0.01µF

R1=R2=R5=100kΩ

R4=60kΩ, R3=37.5kΩ

R3=

R4R5

R4+R5

Voltage gain : AV=

R5

R1

√ Input impedance= 2 R12+

12

2πfC1

No.3003–7/8

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