GS9015BCPJ Просмотр технического описания (PDF) - Gennum -> Semtech

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производитель

GS9015BCPJ

Serial Digital Reclocker

Gennum -> Semtech 

0.1µ

-5V

4 3 2 1 28 27 26

390

390

-5V

25

100

DATA

ECL

DATA

5

DDI

6

SDO

24

SDO

100

DATA

0.1µ

D -5V

INPUTS

DDI

7 VCC1

8 VEE1

9 VEE1

10 ƒ/2

11 VEE3

GS9015B

23

SCO

22

SCO

SS1 21

20

SS0

19

CD

12 13 14 15 16 17 18

DE 5.6p

910

10n

0.1µ

-5V

100

100

390

390

10k

CLOCK

CLOCK

CARRIER

DETECT

OUTPUT

EN NS ÷2

M IG ÷1

M S -5V

STAR

ROUTED

-5V

See Figure 15

LOOP

VOLTAGE

-5V

CO DE All resistors in ohms, all capacitors in microfarads unless otherwise stated.

EFig. 13 GS9015B Typical Test Circuit Using -5V Supply

R EW VCO Frequency Setting Resistors

T There are two modes of VCO operation available in the

N GS9015B depending on the state of the ÷2 block. The

O ÷2 block is enabled according to : ÷2 ENABLE = ƒ/2 • SS1.

N R When the ƒ/2 ENABLE (pin 10) is LOW, any of the four VCO

frequency setting resistors, RVCO0 through RVCO3, (pins

13, 14, 15 and 17) may be used for any data r a t e f r o m 100

O Mb/s t o 4 0 0 M b / s . F o r e x a m p l e , f o r 143 Mb/s data

F rate, the value of the total RVCO resistance is approximately

When ƒ/2 (Pin 10) is HIGH, two of the RVCO pins are assigned

to data rates below 200 Mb/s and two are assigned to data

rates over 200 Mb/s. The selection is dependent upon the

level of STANDARD SELECT BIT, SS1 (pin 21). When SS1

is LOW, RVCO0 and RVCO1 (pins 13 and 14) are used for

the higher data rates. When SS1 is HIGH, the VCO frequency

is now twice the bit rate and its frequency is set by RVCO2 and

RVCO3 (pins 15 and 17).

6k8 and for 270 Mb/s operation, the value is

approximately 3k5. The 5k potentiometers will then tune

the desired data rate near their mid-points.

For 143 Mb/s and 270 Mb/s operation, (the VCO is at

286 MHz and 270 MHz respectively) the total resistance

required is approximately the same for both data rates. This

Jitter performance at the lower data rates (143, 177 Mb/s) is also applies for 177 Mb/s and 360 Mb/s operation (the VCO

improved by operating the VCO at twice the normal frequency. is tuned to 354 MHz and 360 MHz respectively). This means

This is accomplished by enabling the divide by two block in that one potentiometer may be used for each frequency pair

the PLL section of the GS9015B.

with only a small variation of the fixed resistor value. This

halves the number of adjustments required.

10 of 13

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