DATA SHEET

IDT5V7855-DPK REVISION A MARCH 11, 2010

1

©2010 Integrated Device Technology, Inc.

EEPROM Programmable PLL Die for

LVCMOS Crystal Oscillator

IDT5V7855

General Description

The IDT5V7855 is a programmable PLL-based clock generator used

for crystal oscillator modules. The device incorporates an on-chip

crystal oscillator with a programmable capacitor tuning array to

support direct connection with fundamental-mode crystals between

16MHz – 50MHz. The capacitor tuning array offers a total of 9 bits of

resolution and provides a step of 0.01pF.

The device incorporates on-chip non-volatile EEPROM cells which

can store all the device settings and maintain them even when there

is no power. The serial programming interface is implemented with

dual-use pins for the clock and data. The CONT input can be

programmed as either a power down input or an output enable input.

Crystal oscillator modules using this device can be stocked as blank

parts and custom frequencies programmed in package at the last

stage before shipping. This enables fast-turn manufacture of custom

and standard crystal oscillators without the need for expensive

dedicated crystals.

The IDT PLL uses a patent-pending fractional multiplier technique to

provide ultra-high resolution multiplication and division from input to

output with low jitter. In addition, prescaler and post-

divider circuits are included to enhance the granularity of clock

scaling. The PLL may also be bypassed in order to operate the

device as a non-PLL fundamental-mode crystal oscillator for

applications that do not require frequency multiplication. The device

is fabricated using advance technology and can support both 2.5V

and 3.3V operation. The device is small enough to fit into

small-footprint crystal oscillators. This is the industry’s smallest

programmable die and can support crystal oscillator packages as

small as 20mm x 16mm.

Features

1MHz – 50MHz in non-PLL mode

– 19-bit high-resolution fractional programmable multiplier

– 3-bit prescaler

– 7-bit output divider

– 9-bit crystal oscillator tuning capacitor array

– Selectable function power down or OE control pin

– HBM: 2000V

– MM: 200V

Tuning

Cap

9-bit

19-bit

7-bit

OUT

CONT

xd

xg

3-bit

Fractional

Multiplier

Output

Divider

Pre-Scaler

VCO

PFD

OSC

EEPROM

Pullup

x2

÷2

0

1

Functional Block Diagram

CONT

xg

xd

OUT

2

3

4

5

7

6

8

IDT5V7855

0.75mm x 0.75mm Die

Pad Assignment