GEC Plessey Semiconductors NJ8821BA, NJ8821MA Datasheet

THIS DOCUMENT IS FOR MAINTENANCE

PURPOSES ONLY AND IS NOT

RECOMMENDED FOR NEW DESIGNS

NJ8821

NJ8821

FREQUENCY SYNTHESISER (MICROPROCESSOR INTERFACE)

WITH RESETTABLE COUNTERS

Fig.2 Block diagram

PROGRAM

ENABLE (PE)

OSC IN

OSC OUT

D0
D1
D2
D3

F

IN

V

DD

V

SS

LATCH 1 LATCH 2 LATCH 3

‘M’ COUNTER

(10 BITS)

CONTROL LOGIC

LATCH 4 LATCH 5

‘A’ COUNTER

(7 BITS)

FREQUENCY/

PHASE

DETECTOR

V

SS

PDA

PDB

LOCK DETECT (LD)

MODULUS
CONTROL
OUTPUT (MC)

RB CH

15 16 17

f

v

REFERENCE COUNTER

(11BITS)

LATCH 6 LATCH 7 LATCH 8

42

SAMPLE/HOLD

PHASE

DETECTOR

f

r

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

Supply voltage, VDD2V

SS

Input voltage
Open drain output, pin 3
All other pins
Storage temperature

Storage temperature

20·5V to 7V

7V

V

SS

20·3V to VDD10·3V

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

T

he 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

■

Low Power Consumption

■ Microprocessor Compatible

■

High Performance Sample and Hold Phase Detector

■

>10MHz Input Frequency

CH

RB

MC

DS2

DS1

DS0

PE

NC

D3

D2

PDA

PDB

LD

F

IN

V

SS

V

DD

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