NJ8821

NJ8821

FREQUENCY SYNTHESISER (MICROPROCESSOR INTERFACE)

WITH RESETTABLE COUNTERS

Fig.2 Block diagram

PROGRAM

ENABLE (PE)

OSC IN

OSC OUT

D0

D1

D2

D3

LATCH 1

LATCH 2

LATCH 3

‘M’ COUNTER

(10 BITS)

CONTROL LOGIC

LATCH 4

LATCH 5

‘A’ COUNTER

(7 BITS)

FREQUENCY/

PHASE

DETECTOR

PDA

PDB

LOCK DETECT (LD)

MODULUS

CONTROL

OUTPUT (MC)

RB

CH

15

16

17

REFERENCE COUNTER

(11BITS)

LATCH 6

LATCH 7

LATCH 8

42

SAMPLE/HOLD

PHASE

DETECTOR

LATCH SELECT

LOGIC

DS0 DS1 DS2

14

7

8

9

10

11

12

4

6

5

TO

INTERNAL

LATCHES

DATA SELECT INPUTS

19

20

1

2

3

18







DATA

INPUTS

ABSOLUTE MAXIMUM RATINGS

Input voltage

Open drain output, pin 3

All other pins

Storage temperature

Storage temperature

20·5V to 7V

7V

265

°C to 1150°C

(DG package, NJ8821MA)

255

°C to 1125°C

(DP and MP packages, NJ8821)

ORDERING INFORMATION

NJ8821 BA DP Plastic DIL Package

NJ8821 BA MP Miniature Plastic DIL Package

NJ8821 MA DG Ceramic DIL Package

The NJ8821 is a synthesiser circuit fabricated on the GPS

CMOS process and is capable of achieving high sideband

attenuation and low noise performance. It contains a reference

oscillator, 11-bit programmable reference divider, digital and

sample-and-hold comparators, 10-bit programmable ‘M’ counter,

7-bit programmable ‘A’ counter and the necessary control and

latch circuitry for accepting and latching the input data.

Data is presented as eight 4-bit words under external control

from a suitable microprocessor..

It is intended to be used in conjunction with a two-modulus

prescaler such as the SP8710 series to produce a universal

binary coded synthesiser.

The NJ8821 is available in Plastic DIL (DP) and Miniature

Plastic DIL (MP) packages, both with operating temperature

range of 230

°C to 170°C. The NJ8821MA is available only in

Ceramic DIL package with operating temperature range of

240

°C to 185°C.

FEATURES

CH

RB

MC

DS2

DS1

DS0

PE

NC

D3

D2

PDA

PDB

LD

OSC IN

OSC OUT

D0

D1

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

NJ8821

DS3278-1.3

Fig.1 Pin connections - top view

DP20, MP20

DG20