______________________________________________________________________________________________________________________________________________

DSC2020

Page 2

MK-Q-B-P-D-12042603-02

DSC2020

0

Low-Jitter Configurable LVPECL Oscillator

Pin Description

Pin No.

Pin Name

Pin Type

Description

1

Enable

I

Enables outputs when high and disables when low

2

NC

NA

Leave unconnected or grounded

3

NC

NA

Leave unconnected or grounded

4

GND

Power

Ground

5

FS0

I

Least significant bit for frequency selection

6

FS1

I

Most significant bit for frequency selection

7

NC

NA

Leave unconnected or grounded

8

Output+

O

Positive LVPECL Output

9

Output-

O

Negative LVPECL Output

10

NC

NA

Leave unconnected or grounded

11

NC

NA

Leave unconnected or grounded

12

VDD2

Power

Power Supply

13

VDD

Power

Power Supply

14

NC

NA

Leave unconnected or grounded

Operational Description

The DSC2020 is a LVPECL oscillator consisting

of a MEMS resonator and a support PLL IC.

The LVPECL output is generated through

independent 8-bit programmable dividers from

the output of the internal PLL.

The actual frequency output by the DSC2020

is controlled by an internal pre-programmed

memory (OTP).

This memory stores all

coefficients required by the PLL for up to four

different frequencies. Two control pins (FS0 –

FS1) select the output frequency.

Discera

supports customer defined versions of the

DSC2020.

Standard frequency options are

described in the following sections.

When Enable (pin 1) is floated or connected to

VDD, the DSC2020 is in operational mode.

Driving Enable to ground will tri-state output

driver (hi-impedance mode).

Output Clock Frequencies

Table 1 lists the standard frequency configurations and the associated ordering information to be

used in conjunction with the ordering code. Customer defined combinations are available.

Table 1. Pre-programmed pin-selectable output frequency combinations

Ordering

Info

Freq

(MHz)

Freq Select Bits [FS1, FS0] – Default is [11]

00

01

10

11

B0001

125

212.5

106.25

156.25

B000X

Contact factory for additional configurations.

Frequency select bit are weakly tied high so if left unconnected the default setting will be [11] and

the device will output the associated frequency highlighted in Bold.