Integrated Oscillator Module Designs to Support OEM Custom Requirements
In many instances OEM’s are notified by their long time oscillator supplier that an older generation product family will be placed in an END of LIFE status within 6 to 12 months. Even with sufficient notice OEM’s have a difficult time motivating large oscillator suppliers to develop a custom product for them due to the number of new oscillator projects competing for engineering design time. In the end only the largest revenue potential oscillator projects are staffed in order to maximize return on engineering investment. To add further challenge, most OEM’s do not want to devote their scarce technical resources toward re-designing an older piece of equipment to accommodate a different mechanical package interface. Such a change often involves multiple engineering departments, operations, and potential costly re-qualification efforts with the end user.
Dynamic Engineers is the ideal company to support OEM’s in these situations. The DEI business model utilizes a simplified engineering approach to legacy oscillator design. When an opportunity arises to replace and upgrade legacy oscillator technology, DEI makes every effort to integrate the latest established OCXO or TCXO module into the design. Using this approach simplifies the design effort and ensures that legacy technology is upgraded internally with proven components while offering mechanical package compatibility to the older device.
A brief description of design and performance features is summarized for DEI’s most important integrated module designs.
OCXOCP01-10MHz
The OCXOCP01-10MHz represents a classic example of incorporating the latest OCXO technology inside much larger legacy package dimensions. One of our European customers needed to replace an entire family of legacy OCXO products as their oscillator supplier had issued an end of life notice on the product line. Dynamic Engineers reacted quickly to the requirement by selecting newer technology capable of meeting the overall stability in a 20 x 20 x 10 mm enclosure. The only wrinkle was that our factory produced a 5V supply version while our customer required a 12V version. DEI engineers identified the appropriate high power 5V regulator device to interface with the customer 12V supply. A motherboard was designed to place the smaller OCXO and regulator circuit into the larger 40 x 40 x 56 mm legacy package dimensions. The regulator circuit was strategically placed away from the OCXO module so that its heat dissipation would not affect performance of the OCXO module. The regulator circuit also was low noise and did not degrade phase noise performance required from the original legacy oscillator at 10MHz.
The younger technology by 20 years also delivered a 10X improvement in frequency stability over operating temperature from +/- 50 ppb to +/- 5 ppb typical. And maintaining the same mechanical package interface saved our customer thousands of Euros in engineering changes to the end use product, a GSM cellular base station.
TCXO2515KP-9.6MH
The TCXO2515KP-9.6MHz integrated design platform utilizes a 5x7mm precision VCTCXO module, low noise sine wave buffer circuit, and dual electronic and mechanical frequency adjustment functions. All circuit stages are packaged in a non-standard smd enclosure for compatibility to an older generation design technology.
The prime advantage of supplying the additional mechanical frequency adjustment feature to the device is to allow the customer to make a final frequency adjustment after reflow onto the customer board. Once the frequency adjustment has been made, the overall design is able to achieve better than +/- 250 ppb with respect to nominal frequency over an operating temperature of -40C to 70C.
The low noise sine wave buffer circuit satisfies a unique customer requirement of having the output signal terminated in 300 ohms which is not standard load impedance for TCXO’s.
TCXOT79-20MHz
The TCXOT79-20MHz integrated module design incorporates a 5x7 mm precision TCXO clock module along with a clipped sine to LVCMOS conversion circuit. To satisfy this particular customer requirement all circuit functionality needed to be placed within a rugged 4-pin DIP package with hermetic seal.
Due to special performance requirements, 100% of production units are monitored on an aging system for 14 to 21 days. A twenty year aging projection is calculated based on collected frequency data points.
The predicted twenty year aging shift is added together with frequency shift over temperature, frequency shift with load variation, frequency shift with supply variation, and frequency tolerance at 25C. All shifts must add up to less than +/- 3 PPM to be within compliance. This overall parameter is especially critical to this customer as the TCXO has no frequency adjustment feature.
This customer is very pleased with DEI as very few TCXO companies are willing to confirm long term frequency stability on a power-on active aging system for all production units.
TCXOBEIM-100MHz-B
The TCXOBEIM-100MHz-B integrated design platform offers customers access to a low phase noise 100 MHz VCTCXO device without depending upon the use of higher cost, more unstable 100 MHz crystals. A very low phase noise 50 MHz VCTCXO surface mount 9 mm x 11 mm module is combined with a 2X frequency doubling circuit to derive the 100 MHz output. This approach offers the customer the opportunity to take advantage of the more reliable 50 MHz crystal properties for long term aging, retrace, and frequency jumps.
For any customers requiring TCXO reference clocks greater than 50MHz with very good stability, the TCXOBEIM design technique delivers the best compromise between expected noise and long term stability.