Document Number: 002-08298 Rev. *A

Page 8 of 27

MB88155

6. Block Diagram

CKOUT

REFOUT

= 1 MΩ

XOUT

XIN

ENS/XPD

SEL

1

−

M

1

−

N

1

−

L

IDAC

ICO

Modulation rate

setting

Reference

clock

PLL block

Clock output

Phase

compare

V/I

conversion

Loop filter

Reference

clock

Modulation logic

Modulation

clock

output

Modulation rate

setting/

Modulation

enable setting

Modulation enable/

power down setting

MB88155 PLL block

A glitchless IDAC (current output D/A converter) provides precise modulation, thereby dramatically reducing

EMI.

Reference clock output

Power down signal

Charge

pump