Vaishali VT73227 Technical data

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VT73227

(Voltage-Controlled Crystal Oscillator)

27 MHz 3.3V

Applications

•= Set-top boxes

•= Telecom switching

General Description

The Vaishali VT73227 is a single-chip, low-jitter Voltage-Controlled-Crystal-Oscillator. The device accepts
a 27 MHz, 20 pF (pull range of 200 ppm) crystal input, and produces a low jitter output at the same
frequency. A 0 to 3.0V control signal is used to fine tune the output clock frequency in the ±100ppm range.

Features

•= 3.3V operating voltage

•= Uses inexpensive pullable crystal

•= 12mA drive capability at TTL levels

•= Oscillator replacement

•= MPEG Video clock source

•= On-chip oscillator with 200 ppm pull

range (±100 ppm)

•= 8 pin SOIC package

VCXO

Figure 1. Functional Block Diagram

27 MHz
Pullable
Crystal

VIN

X2

X1

Load Cap Control

Load
Caps

VDD1

Oscillator

GND1

VDD2

GND2

Output

Buffer

LK1

2001-04-02 Page 1 MDST-0006-03

Vaishali Semiconductor  1300 White Oaks Road, Ste. 200  Campbell  CA 95008  Ph. 408.377.6060  Fax [phone]

VT73227

Figure 2. Pin Configuration

VT73227

X1 X2

1

8

VDD1

GND2

2

3

4

7

GND1

6

VDD2 VIN

5

CLK

8 pin (150 mil) SOIC

Table 1. Pin Description

Name Pin # Type Description

X1 1 Xi Crystal connection. Connect to a 27 MHz pullable crystal

VDD1 2 P Core VDD. Connect to 3.3V

VIN 3 I Voltage input to VCXO. Zero to 3.3V signal controls the frequency of the VCXO.

GND2 4 P Connect to ground.

CLK 5 O Clock output

VDD2 6 P Pad driver V

GND1 7 P Connect to ground.

. Connect to 3.3V

DD

X2 8 Xi Crystal connection. Connect to a 27 MHz pullable crystal.

Legend: I = Input
O = Output

P = Power supply connection

Xi = Crystal connections.

Table 2. Absolute Maximum Ratings

Parameter Conditions Min Typ Max Units

Supply voltage, VDD Referenced to GND 7 V

Inputs and Clock Outputs Referenced to GND -0.5 VDD+0.5 V

Soldering Temperature Max of 10 seconds 260 °C

Storage temperature -65 150 °C

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These
ratings are stress specifications only and correct functional operation of the device at these or any other conditions
above those listed in the operational sections of the specifications is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect product reliability.

Table 3. Operating Conditions

Parameter Conditions Min Typ Max Units

Operating Voltage, VDD 3.15 3.3 3.45 V

Input High Voltage, VIH, X1 pin only 2.5 V

Input Low Voltage, VIL, X1 pin only 0.4 V

Operating Temperature 0 70 °C

Input crystal accuracy ±30 ppm

VCXO control voltage, VIN 0 3.3 V

2001-04-02 Page 2 MDST-0006-03

Vaishali Semiconductor  1300 White Oaks Road, Ste. 200  Campbell  CA 95008  Ph. 408.377.6060  Fax [phone]