MK3722GLF - Integrated Device Technology

DATASHEET

VCXO PLUS AUDIO CLOCK FOR STB MK3722

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 1

MK3722 REV F 122109

Description

The MK3722 is a low cost, low jitter, high performance

VCXO and PLL clock synthesizer designed to replace

expensive discrete VCXOs and multipliers. The patented

on-chip Voltage Controlled Crystal Oscillator accepts a 0 to

3.3 V input voltage to cause the output clocks to vary by

±115 ppm. Using IDT’s analog/digital Phase-Locked Loop

(PLL) techniques, the device uses an inexpensive 27 MHz

pullable crystal input to produce a reference output and a

selectable audio clock.

IDT manufactures the largest variety of VCXO based timing

devices for all applications. Consult IDT to eliminate

VCXOs, crystals, and oscillators from your board.

The frequency of the on-chip VCXO is adjusted by an

external control voltage connected to VIN. Because VIN is

a high impedance input, it can be driven directly from an

PWM RC integrator circuit.

Features

•Packaged in 16-pin TSSOP

•Available in Pb (lead) free package

•Replaces a VCXO and oscillator

•Operating voltage of 3.3V

•Provides output of 27 MHz plus audio clock

•Uses an inexpensive 27 MHz pullable crystal

•On-chip patented VCXO with pull range of 230 ppm

(minimum)

•VCXO tuning voltage of 0 to 3.3 V

•Advanced, low power, sub-micron CMOS process

NOTE: EOL for non-green parts to occur on

5/13/10 per PDN U-09-01

Block Diagram

Voltage

Controlled

Crystal

Oscillator

VIN

27 MHz

Pullable

Crystal

PLL/Clock

Synthesis

Circuitry

ACLK

27MHz

S2:S0

VDD

GND

PDTS

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 2

MK3722 REV F 122109

Pin Assignment

Pin Descriptions

Audio Clock Select Table

VDD

VIN

VDD

27M

GND GND

GND ACLK

PDTS

16 Pin 4.40mm body, 0.65mm pitch TSSOP

S2 S1 S0 ACLK (MHz)

000 8.192

0 0 1 11.2896

0 1 0 12.288

0 1 1 16.9344

1 0 0 18.432

1 0 1 16.384

1 1 0 22.5792

1 1 1 24.576

Number

Name

Type

Pin Description

1 X2 Output Crystal connection. Connect to a 27MHz fundamental mode

pullable crystal.

2 X1 Input Crystal connection. Connect to a 27MHz fundamental mode

pullable crystal.

3 VDD Power Connect to +3.3 V.

4 VDD Power Connect to +3.3 V.

5 VIN Input Voltage input to VCXO. Zero to 3.3V signal which controls the

VCXO frequency.

6 GND Power Connect to ground.

7 GND Power Connect to ground.

8PDTS

Power Power Down Tri-state. This pin powers down entire chip and

tri-states the outputs when low. Internal pull-up.

9 S2 Input Select input S2. Selects ACLK per table above. Internal pull-up.

10 ACLK Output Audio clock output per table above.

11 GND Power Connect to ground.

12 27M Output 27MHz reference clock output.

13 S0 Input Select input S0. Selects ACLK per table above. Internal pull-up.

14 VDD Power Connect to +3.3V.

15 NC -- No connect. Do not connect anything to this pin.

16 S1 Input Select input S1. Selects ACLK per table above. Internal pull-up.

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 3

MK3722 REV F 122109

External Component Selection

The MK3722 requires a minimum number of external

components for proper operation.

Decoupling Capacitors

Decoupling capacitors of 0.01µF should be connected

between VDD and GND on pins 3 and 4, pins 6 and 7, and

pins 11 and 14 as close to the MK3722 as possible. For

optimum device performance, the decoupling capacitors

should be mounted on the component side of the PCB.

Avoid the use of vias in the decoupling circuit.

Series Termination Resistor

When the PCB traces between the clock outputs and the

loads are over 1 inch, series termination should be used. To

series terminate a 50Ω trace (a commonly used trace

impedance) place a 33Ω resistor in series with the clock line,

as close to the clock output pin as possible. The nominal

impedance of the clock output is 20Ω.

Quartz Crystal

The MK3722 VCXO function consists of the external crystal

and the integrated VCXO oscillator circuit. To assure the

best system performance (frequency pull range) and

reliability, a crystal device meeting IDT’ recommended

parameters must be used, and the layout guidelines

discussed in the following section must be followed.

See Application Note MAN05 for a full list of crystal

parameters.

The frequency of oscillation of a quartz crystal is determined

by its “cut” and by the load capacitors connected to it. The

MK3722 incorporates on-chip variable load capacitors that

“pull” (change) the frequency of the crystal. The crystal

specified for use with the MK3722 is designed to have zero

frequency error when the total of on-chip + stray

capacitance is 14pF.

The external crystal must be connected as close to the chip

as possible and should be on the same side of the PCB as

the MK3722. There should be no via’s between the crystal

pins and the X1 and X2 device pins. There should be no

signal traces underneath or close to the crystal.

Crystal Tuning Load Capacitors

The crystal traces should include pads for small fixed

capacitors, one between X1 and ground, and another

between X2 and ground. Stuffing of these capacitors on the

PCB is optional. The need for these capacitors is

determined at system prototype evaluation, and is

influenced by the particular crystal used (manufacture and

frequency) and by PCB layout. The typical required

capacitor value is 1 to 4 pF.

The procedure for determining the value of these capacitors

can be found in application note MAN05.

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 4

MK3722 REV F 122109

Absolute Maximum Ratings

Stresses above the ratings listed below can cause permanent damage to the MK3722. These ratings, which are

standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the device at these

or any other conditions above those indicated in the operational sections of the specifications is not implied.

Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical

parameters are guaranteed only over the recommended operating temperature range.

Recommended Operation Conditions

DC Electrical Characteristics

VDD=3.3 V ±5% , Ambient temperature 0 to +70°C, unless stated otherwise

Item Rating

Supply Voltage, VDD 7 V

All Inputs and Outputs -0.5 V to VDD+0.5 V

Ambient Operating Temperature 0 to +70°C

Storage Temperature -65 to +150°C

Soldering Temperature 260°C

Parameter Min. Typ. Max. Units

Ambient Operating Temperature 0 +70 °C

Power Supply Voltage (measured in respect to GND) +3.15 +3.45 V

Reference crystal parameters Refer to page 3

Parameter Symbol Conditions Min. Typ. Max. Units

Operating Voltage VDD 3.15 3.45 V

Output High Voltage VOH IOH = -12 mA 2.4 V

Output Low Voltage VOL IOL = 12 mA 0.4 V

Output High Voltage (CMOS Level) VOH IOH = -4 mA VDD-0.4 V

Input High Voltage (S1:S0) VIH 2.0 V

Input High Voltage (S2) VIH 2.5 V

Input Low Voltage (S1:S0) VIL 0.8 V

Input Low Voltage (S2) VIL 0.5 V

Operating Supply Current IDD No load, 2

outputs

11 mA

Short Circuit Current IOS ±50 mA

VIN, VCXO Control Voltage VIA 03.3V

On Chip Pull-up Resistor, inputs RPU S0, S1, S2 150 kΩ

Input Capacitance CIN S0, S1, S2 5 pF

Nominal Output Impedance ZOUT 20 Ω

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 5

MK3722 REV F 122109

AC Electrical Characteristics

VDD = 3.3 V ±5%, Ambient Temperature 0 to +70° C, unless stated otherwise

Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3.

Thermal Characteristics

Parameter Symbol Conditions Min. Typ. Max. Units

Crystal Pullability fP0V< VIN < 3.3 V, Note 1 + 100 ppm

VCXO Gain VIN = VDD/2 + 1 V, Note 1 80 ppm/V

Output Rise Time tOR 0.8 to 2.0 V, CL=15 pF 0.75 1.5 ns

Output Fall Time tOF 2.0 to 0.8 V, CL=15 pF 0.75 1.5 ns

Output Clock Duty Cycle tDMeasured at 1.65 V, CL=15 pF 40 50 60 %

Maximum Output Jitter,

short term

tJCL=15 pF +150 ps

Parameter Symbol Conditions Min. Typ. Max. Units

Thermal Resistance Junction to

Ambient

θJA Still air 78 °C/W

θJA 1 m/s air flow 70 °C/W

θJA 3 m/s air flow 68 °C/W

Thermal Resistance Junction to Case θJC 37 °C/W

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER

IDT™

VCXO PLUS AUDIO CLOCK FOR STB 6

MK3722 REV F 122109

Package Outline and Package Dimensions (16-pin TSSOP, 4.40 mm Body, 0.65 mm Pitch)

Package dimensions are kept current with JEDEC Publication No. 95

Ordering Information

*NOTE: EOL for non-green parts to occur on 5/13/10 per PDN U-09-01

Parts that are ordered with a "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.

While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes

no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No

other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications

such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not

recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT

does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.

Part / Order Number Marking Shipping Packaging Package Temperature

MK3722G* MK3722G Tubes 16-pin TSSOP 0 to +70° C

MK3722GTR* MK3722G Tape and Reel 16-pin TSSOP 0 to +70° C

MK3722GLF MK3722GL Tubes 16-pin TSSOP 0 to +70° C

MK3722GLFTR MK3722GL Tape and Reel 16-pin TSSOP 0 to +70° C

INDEX

AREA

1 2

E1 E

SEATING

PLANE

- C -

.10 (.004) C

Millimeters Inches

Symbol Min Max Min Max

A--1.20--0.047

A1 0.05 0.15 0.002 0.006

A2 0.80 1.05 0.032 0.041

b 0.19 0.30 0.007 0.012

C 0.09 0.20 0.0035 0.008

D 4.90 5.1 0.193 0.201

E 6.40 BASIC 0.252 BASIC

E1 4.30 4.50 0.169 0.177

e 0.65 Basic 0.0256 Basic

L 0.45 0.75 0.018 0.030

α0°8°0°8°

Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered

trademarks used to identify products or services of their respective owners.

Printed in USA

Corporate Headquarters

Integrated Device Technology, Inc.

www.idt.com

For Sales

800-345-7015

408-284-8200

Fax: 408-284-2775

For Tech Support

www.idt.com/go/clockhelp

Innovate with IDT and accelerate your future networks. Contact:

www.IDT.com

MK3722

VCXO PLUS AUDIO CLOCK FOR STB VCXO AND SYNTHESIZER