U4285BM

TELEFUNKEN Semiconductors

Rev. A3, 14-May-97

1 (10)

AM / FM - PLL

Description

The U4285BM is an integrated circuit in BICMOS

technology for frequency synthesizers. It performs all the

functions of a PLL radio tuning system and is controlled

synthesizer applications in radio receivers, as well as

RDS ( Radio Data System ) applications.

Features

D Reference oscillator up to 15 MHz

D Two programmable 16 bit dividers

adjustable from 2 to 65535

D Fine tuning steps:

AM

y 1 kHz

FM

y 2 kHz

D 4 programmable switching outputs

(open drain up to 15 V)

D Few external component required due to

integrated loop-push-pull stage for AM/FM

D High signal/ noise ratio

Ordering Information

Extended Type Number

Package

Remarks

U4285BM-AFS

SSO20 plastic

U4285BM-AFSG3

SSO20 plastic

Taping according to IEC-286-3

Block Diagram

R-divider

N-divider

interface

Oscillator

Phase

Current

sources

Switching outputs

AM/FM

18

19

2

3

4

9

11

OSCOUT

OSCIN

SCL

AS

FMOSC

AMOSC

SDA

56

78

10

1

20

SWO1

SWO4

SWO2 SWO3

14

15

16

17

12

13

PDAM

PDAMO

VA

C

PDFMO

PDFM

GND2

GND1

DD

V

95 10120

switch

detector

Figure 1.