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DSC2140 DSC2240

Page 2

MK-Q-B-P-D-12050110

DSC2140

DSC2240

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

DSC2140: Leave unconnected or grounded

SCLK

I

DSC2240: Serial clock from master

4

GND

Power

Ground

5

SDA

I

MOSI

DSC2240: SPI Serial Data from Master to Slave

6

SCL

I

MISO

O

DSC2240: SPI Serial Data from Slave to Master

7

CS_bar

I

SS

I

DSC2240: SPI Slave Select (Active Low)

8

Output1+

O

Positive HCSL Output

9

Output1-

O

Negative HCSL 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

FS

I

Default output clock frequency bit

Operational Description

The DSC2140/2240 is a HCSL oscillator

consisting of a MEMS resonator and a support

PLL IC.

The HCSL output is generated

through

independent

8-bit

programmable

dividers from the output of the internal PLL.

DSC2140/2240 allows for easy programming

interface. Upon power-up, the initial output

frequency is controlled by an internal pre-

programmed memory (OTP).

This memory

stores all coefficients required by the PLL for

two different default frequencies. The control

pin (FS) selects the initial frequency.

Once

the device is powered up, a new output

frequency can be programmed. Programming

details are provided in the Programming

Guide. Standard default frequencies are

described in the following sections.

Discera

supports customer defined versions of the

DSC2140/2240.

When Enable (pin 1) is floated or connected to

VDD, the DSC2140/2240 is in operational

mode. Driving Enable to ground will disable

both output drivers (hi-impedance mode).

Output Clock Frequencies

Table 2 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 2. Pre-programmed pin-selectable output frequency combinations

Ordering

Info

Freq

(MHz)

Select Bit [FS] – Default is [1]

0

1

D0001

125

156.25

DXXXX

Contact factory for additional configurations.

Frequency select bit are weakly tied high so if left unconnected the default setting will be [1] and

the device will output the associated frequency highlighted in Bold.