Oscillators

The E7604 low-power CMOS crystal oscillator circuit from EM Microelectronic is intended to be used with a 32.768kHz tuning fork crystal as a low frequency clock oscillator with no external components required. The IC is also available as the EM1564, which combines the oscillator circuit with a tuning fork crystal in a single, low footprint ceramic package.



This oscillator circuit is suited for precision time references in real-time clocks, timekeeping in network servers and computers, in mobile phones and as an alternative to embedded quartz oscillators. The IC also works for metering electricity, gas and water. The small size and efficiency makes the EM7604 suitable as a general-purpose clock oscillator circuit for digital systems and in portable field communication applications.



The IC is said to use up to 10 times less power than similar circuits from the competition. It can be operated with a supply voltage ranging from 1.2V to 5.5V and power consumption as low as 250nA. The on-chip integrated oscillation capacitor provides desirable stability and tight frequency tolerance at an extended temperature range of up to 125°C.



Pericom Semiconductor announced a set of low voltage 1.2V to 2.5V clock buffers with low skew (70ps), controlled duty cycle and low phase noise integrated oscillator options for networking, storage and telecom infrastructure applications.



The PI6CL1080x, PI6C1080x family of clock buffers operate with supply voltages of 1.2V/1.5V/1.8V/

2.5V, respectively, and accept input voltages up to 3.6V. The PI6C10806, PI6C10808, PI6L1806 and the PICL10808 also have crystal interface options, enabling internal clock generation for frequencies of up to 40MHz without needing an external crystal oscillator. The PI610804/PI6CL10804, PI10806/PI6C10806/PI6CL10806, PI6C10808/PI6CL10808 and PI6C10807/PI6CL1807 provide four, six, eight and 10 outputs, respectively.

The PI6C10804 and PI6CL1804 have a duty cycle shaping option to provide 45 percent/55 percent duty cycle clock outputs when clock input is 40 percent /60 percent and equal to or greater than the supply voltage of the device. This allows cascading of two levels of clock buffers from a crystal oscillator reference while meeting 45 percent/55 percent at reference clock inputs of network physical layer devices that need precise duty cycles. Other devices in the family provide 40 percent/60 percent output clock duty cycle for inputs that are 45 percent/55 percent. Prices range from $0.80 to $1.00 in 5K quantities.



■ Companies Mentioned in

Product Technology Review

• EM Microelectronic

www.emmicroelectronic.com

• Pericom Semiconductor

www.pericom.com

• Vectron International

www.vectron.com

• Raltron

www.raltron.com

• Crystek

www.crystek.com

• Fox Electronics

www.foxonline.com



EM Microelectronic

Product: EM7604 Low Power Crystal Oscillator

Key Highlights:

• Low power consumption: typ. 250nA

• On-chip integrated oscillation capacitor: CL=8pF

• Matched low-cost SMD quartz available from Micro Crystal

• Compatibility with crystals having high series resistance.

• Tight frequency tolerance

• Oscillator stability: 0.2ppm/V



Pericom Semiconductor

Product: PI6CL1080x, PI6C1080x Clock buffers

Key Highlights:

• Operate with supply voltages of 1.2V/1.5V, 1.8V and 2.5V respectively

• Accept input voltages up to 3.6V

• Low skew (70ps)

• Controlled duty cycle

• Low phase noise integrated oscillator options

Vectron International

Vectron’s C4700 double oven crystal oscillator (DOCXO) has a reduced height down to 17.3mm, making it the lowest profile DOCXO on the market according to the company. It is also said to be more stable than a single oven with an available frequency range of 4MHz to 15MHz and temperature stabilities down to 0.2ppb from 0°C to 70°C.



Model: C4700

Type: DOCXO



Dimensions: 50.8mm x 50.8mm x 17.3mm



Frequency: 4MHz to 15MHz

Standard: 5MHz; 10MHz; 15MHz



Jitter: N/A

Stability: 0.4ppb min., +0.4ppb max. (C049)

0.2ppb min., +0.2ppb max. (C029)

Phase Noise: -90dBc/Hz (1Hz at 10MHz)

Duty Cycle: 45% min.; 55% max.

Supply Voltage: 12V typ.

Output Logic/Signal: HCMOS

Other Specs: Temperature stabilities down to 0.2ppb from 0°C to 70°C



Operating Temp. Range: 0°C to 70°C



Applications: CDMA2000 and UMTS base stations; test and measurement equipment



Price: From $150 to $200 (1 k-pieces)



Raltron

Raltron has introduced a family of high-frequency clock oscillators -- CS9 (3.3V, LVPECL), CLD (3.3V, LCDS), CSP (2.5V, LVPECL) and CLP (2.5V, LVDS). Frequencies are 106.250 and 425 MHz for Fibre Channel; 125.000 and 312.500MHz for Gigabit Ethernet; 156.250, 250.000 and 644.5312MHz for 10 Gigabit Ethernet; and 155.520, 311.040 and 622.080MHz for SONET. Low Jitter is <1 ps rms.



Model: CS9L

Type: High-frequency clock oscillator



Dimensions: 7mm x 5mm



Frequency: 150MHz to 700MHz

Jitter: 0.3ps rms typ.

Stability: ±20ppm, ±25ppm, ±50ppm

±100ppm (max.)

Phase Noise: -65dBc/Hz at 212.5MHz,

Df =10Hz

Duty Cycle: 40/60% to 60/40% or 45/55% to 55/45%

Supply Voltage: 3.3V DC or 2.5V DC ±5%

PECL

• Rise/fall times: 0.7ns typ.;

Output Logic/Signal: 1.0ns max.

Other Specs: • 80mA max. supply current

• Analog multiplication

• Output can be tri-stated



Operating Temp. Range: -40°C to +85°C



Applications: Infiniband, Fiber Channel, SATA, 10GbE, network processors, SOHO routing, switches



Price: $8 each (10,000-piece lots)



Crystek

Model CVS575 -- a 622.08MHz voltage controlled SAW oscillator (VCSO) designed for high-performance PLLs -- is suitable for telecommunications applications with low jitter generation requirements. Phase noise is -130dBc/Hz at 10kHz offset, which translates to 150fs rms max. jitter for SONET OC-192 (50kHz to 80MHz). The CVS575 is offered in a 5mm x 7.5mm x 2.5mm SMD package.



Model: CVS575

Type: VCSO



Dimensions: 5mm x 7.5mm x 2.5mm



Frequency: 315MHz to 1GHz



Jitter: <0.2ps rms (50kHz to 80MHz)

Stability: ±150ppm

Phase Noise: -130dBc/Hz at 10kHz offset

Duty Cycle: 50% typ.

Supply Voltage: 3.3V

Output Logic/Signal: LVPECL

Other Specs: • Rise/fall times: 100ps min.; 240ps max.

• 82mA supply current

• CMOS logic enable/disable



Operating Temp. Range: -20°C to 70°C



Applications: Frequency translation, clock smoothing (de-jittering), SONET/ SDH/ATM networks, OC-192, PLLs, test and measurement



Price:Approx. $45 each in small volumes



Fox Electronics

The FHS501AH HCMOS half-size, eight-pin DIP OCXO (oven controlled crystal oscillator) uses a smaller crystal, which allows many other individual components in the OCXO to also be decreased. Its small form factor is said to offer the same high frequency stability as a full-size OCXO package, at ±4.6ppm. It features a frequency range of 10MHz to 80MHz and supply voltage of 5V ±5 percent.



Model: FHS501AH

Type: OCXO



Dimensions: 13.2mm x 13.2mm



Frequency: 5MHz to 80MHz



Jitter: Period: approx. 2.2ps rms typ.

Stability: ±4.6ppm

Phase Noise: -115dBc, -140dBc/Hz at 100Hz, 10kHz

Duty Cycle: N/A

Supply Voltage: 5V ±5%

Output Logic/Signal: HCMOS



Operating Temp. Range: 0°C to 70°C



Applications: GPS and time code instruments, base stations, test equipment, synthesizers and digital switching equipment



Price: $52.25 each (1,000-piece lots)