Micrel, Inc.

SM802108

January 2011

3

M9999-012111-A

Pin Description (Continued)

Pin Number

Pin Name

Pin Type

Pin Level

Pin Function

7, 12, 15, 19

TEST

Factory Test Pins, Do not connect anything to these pins.

8

VDD

PWR

Core Power Supply

9

REF_IN

I, (SE)

LVCMOS

Reference Clock Input

10

XIN

I, (SE)

12pF crystal

Crystal Reference Input, no load caps needed.

See Fig. 5.

11

XOUT

O, (SE)

12pF crystal

Crystal Reference Output, no load caps needed.

See Fig. 5.

13, 14

VSS

PWR

Core Power Supply Ground

18

VDDO1

PWR

Power Supply for Output Bank 1

22

VSSO1

PWR

Power Supply Ground for Output Bank 1

Application Information

Input Reference

When operating with a crystal input reference, do not

apply a switching signal to REF_IN.

Crystal Layout

Keep the layers under the crystal as open as possible.

Do not place switching signals or noisy supplies under

the crystal.

Truth Table

PLL_BYPASS

XTAL_SEL

INPUT

OUTPUT

0

−

−

PLL

1

−

−

XTAL/REF_IN

−

0

REF_IN

−

−

1

XTAL

−