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T73227
27 MHz VCXO Clock Generator IC
October 2002
1.0
* * * * *
Features
3.0
Description
One-chip tunable voltage controlled crystal oscillator (VCXO) allows precise system frequency tuning 3.3V operation 8 pin SOIC and MSOP packages Uses inexpensive 20pF pullable crystals with no external capacitors required. 12mA drive capability at TTL levels
The T73227 is a single-chip, low-jitter Voltage-ControlledCrystal-Oscillator. The device accepts a 27 MHz, 20 pF crystal, 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. This finds use in systems that have frequency matching requirements, such as digital satellite receivers.
2.0
* * *
Applications
Set-top boxes MPEG Video clock source Oscillator replacement
Figure 1: Block Diagram
VDD1 VDD2
VIN
Load Cap Control
X2 27 MHz Pullable Crystal X1 Output Buffer Oscillator CLK
Load Caps
GND1
GND2
This document contains information on a preproduction product. Specifications and information herein are subject to change without notice.
ISO9001
10.29.02
T73227
27 MHz VCXO Clock Generator IC
October 2002
8-pin SOIC/MSOP X1 VDD1 VIN GND2 1 2 3 4 8 7 6 5 X2 GND1 VDD2 CLK
Table 1: Pin Descriptions
PIN TYPE NAME DESCRIPTION
1 2 3 4 5 6 7 8
Xi P I P O P P Xi
X1 VDD1 VIN GND2 CLK VDD2 GND1 X2
Crystal Connection. Connect to a 27 MHz Pullable Crystal Core VDD. Connect to 3.3V Voltage input to VCXO. Zero to 3.3V Signal Controls the Frequency of the VCXO. Connect to Ground. Clock Output Pad Driver VDD . Connect to 3.3V Connect to Ground. Crystal Connection. Connect to a 27 MHz pullable crystal.
Legend: I = Input O = Output P = Power supply connection Xi = Crystal connections.
2
10.29.02
ISO9001
T73227
27 MHz VCXO Clock Generator IC
October 2002
4.0
Functional Block Description
The VCXO provides a tunable, low-jitter frequency reference. Loading capacitance for the crystal is internal to the T73227. No external components (other than the crystal resonator itself) are required for operation of the VCXO. Tuning of the VCXO frequency is accomplished by varying the voltage on Vin (Pin 3). The oscillator operates the crystal resonator in the parallel-resonant mode. Crystal warping, or the "pulling" of the crystal oscillation frequency, is accomplished by altering the effective load capacitance presented to the crystal by the oscillator circuit. The actual amount that changing the load capacitance alters the oscillator frequency will be dependent on the characteristics of the crystal as well as the oscillator circuit itself. Specifically, the motional capacitance of the crystal (usually referred to by crystal manufacturers as C1), the static capacitance of the crystal (C0), and the load capacitance (CL) of the oscillator determine the "warping" or "pulling" capability of the crystal in the oscillator circuit. A simple formula to obtain the warping capability of a crystal oscilT73227 Typical VCXO Deviation vs. Vin lator is:
Deviation From 27 MHz ppm
f ( ppm) =
6 C1 x (C L 2 - C L1)x 10 2 x (C 0 + C L 2 ) x (C 0 + C L1)
150 100 50 0 -50 -100 -150 0.1 0.4 0.7 0.9 1.2 1.5 Vin 1.8 2.0 2.3 2.5 2.7
where CL1 and CL2 are the two extremes of the applied load capacitance. EXAMPLE: A crystal with the following parameters is used. With C1 = 0.025pF, C0 = 6pF, CL1 = 10pF, and CL2 = 20pF, the tuning range is
f =
0.025 x (20 - 10 ) x 10 6 = 300 ppm . 2 x (6 + 20 ) x (6 + 10 )
5.0
Electrical Specifications
Table 2: Absolute Maximum Ratings
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These conditions represent a stress rating only, and functional operation of the device at these or any other conditions above the operational limits noted in this specification is not implied. Exposure to maximum rating conditions for extended conditions may affect device performance, functionality, and reliability.
PARAMETER Supply Voltage (VSS = ground) Input Voltage, dc Output Voltage, dc Input Clamp Current, dc (VI < 0 or VI > VDD) Output Clamp Current, dc (VI < 0 or VI > VDD) Storage Temperature Range (non-condensing) Ambient Temperature Range, Under Bias Junction Temperature Lead Temperature (soldering, 10s) Input Static Discharge Voltage Protection
SYMBOL VDD VI VO IIK IOK TS TA TJ
MIN. VSS-0.5 VSS-0.5 VSS-0.5 -25 -50 -65 -55
MAX. 5 VDD+0.5 VDD+0.5 25 50 150 125 125 260 2
UNITS V V V mA mA C C C C KV
3
10.29.02
ISO9001
T73227
27 MHz VCXO Clock Generator IC
October 2002
Table 3: Operating Conditions
PARAMETER Core Supply Voltage (VDD) VCXO Control Voltage, VIN Ambient Operating Temperature Range Crystal Resonator Frequency Crystal Load Capacitance SYMBOL VDD VIN TA fXTAL CL(xtal) Fundamental Mode AT cut CONDITIONS/DESCRIPTION MIN. 3.15 0 0 20 27 20 TYP. 3.3 MAX. 3.45 VDD 70 30 UNITS V V C MHz pF
Table 4: DC Electrical Specifications
Unless otherwise stated, VDD = 3.15V to 3.45V , no load on any output, and ambient temperature range TA = 0C to 70C.
PARAMETER Overall Supply Current, Dynamic, with no load Output High Voltage Output Low Voltage
SYMBOL
CONDITIONS/DESCRIPTION
MIN.
TYP.
MAX.
UNITS
IDD VOH VOL
fXTAL = 27MHz IOH = -12mA IOL = 12mA 2.4
25 0.4
mA V V
Voltage Controlled Crystal Oscillator - VDD=3.3V Crystal Loading Capacitance Crystal Gamma VCXO Tuning Range VCXO Tuning Characteristic Crystal ESR CL(xtal) CO/C1
fXTAL = 27MHz; CL(xtal) = 20pF; gamma = 240
As seen by a crystal connected to XIN and XOUT (@ VXTUNE = 1.65V)
20 240 250 75 50
pF
ppm ppm/V
Note: positive F for positive V
Table 5: AC Timing Specifications
Unless otherwise stated, VDD = 3.15V to 3.45V, no load on any output, and ambient temperature range TA = 0C to 70C. Parameters denoted with an asterisk ( * ) represent nominal characterization data and are not production tested to any specific limits.
PARAMETER Clock Output (CLK) Duty Cycle * Jitter, Period (peak-peak) * Rise Time * Fall Time *
SYMBOL
CONDITIONS/DESCRIPTION
MIN.
TYP.
MAX.
UNITS
Ratio of high pulse width (as measured from rising edge to next falling edge at VDD/2) to one clock period tj(P) tr tf From rising edge to next rising edge at VDD/2, CL = 10pF Measured 0.8V to 2.0V, CL = 10pF Measured 2.0V to 0.8V; CL = 10pF
40
60 150 1.5 1.5
% ps ns ns
4
10.29.02
ISO9001
T73227
27 MHz VCXO Clock Generator IC
October 2002
Phase Noise vs. Frequency Offset
- 50
Phase Noise, dBc/Hz
- 70
- 90
- 110
- 130
- 150
100
1K
10K
100K
1M
Frequency Offset from 27MHz
6.0
Ordering Information
PACKAGE TYPE 8-pin SOIC 8-pin SOIC 8-pin MSOP 8-pin MSOP DIE SHIPPING CONFIGURATION Tubes Tape and Reel Tubes Tape and Reel Waffle-Pack
ORDERING PART NUMBER T73227-S08 T73227-S08-TNR T73227-M08 T73227-M08-TNR T73227-DIE
TLSI reserves the right to make changes to its products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. TLSI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TLSI's standard warranty. Testing and other quality control techniques are utilized to the extent TLSI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. Customers are responsible for their applications using TLSI devices. Information furnished by TLSI is believed to be accurate and reliable. However, no responsibility is assumed by TLSI for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of TLSI. TLSI and Silicon Driven are trademarks of TLSI, Inc. All other trademarks are the property of their respective owners.
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743 * (631) 755-7005 * Fax 631-755-7626 * www.tlsi.com 5
10.29.02
ISO9001

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