Fremont, Calif.Slated primarily for designers of RF systems, fabless semiconductor supplier Optichron, Inc. is starting to sample low-distortion 100-Msample/s hybrid 16-bit A/D (analog-to-digital) converter modules. The company claims these hybrids can reduce non-linear distortion by more than 90% in pipelined data converters.
When they roll out in quantity later this year, they should be just the ticket for high-IF (intermediate frequency) radio strips, where they offer an enhanced ENOB (effective number of bits), bestowing higher data rates. These modules will also enhance your ability to include more channels in a system, and lower overall system cost.
In application, the 3.3-V CMOS-compatible multi-device modules require power-supply voltages of 5-V (for their analog circuit elements), 3.3-V (for digital and analog elements), and 1.8-V (for I/O).
On your board, one of these FR4-housed modules would occupy a compact 1.7 x 0.78-in. small-form-factor footprint. They use 130-pin BGA (ball-grid array) interconnects. That footprint is one-half the size of Optichron's previous modules. The modules include larger components such as input balun transformers.
Operationally, these modules can accept inputs from baseband to 250-MHz. Using Optichron's proprietary Turbolinear technology, the OM1600M-100 A/D modules exhibit SFDR (spurious-free dynamic range) specs of up to 95-dB. They also maintain a SNR (signal-to-noise ratio) of 78-dB.
In this set of example curves, the blue line represents corrected SFDR performance; the black line is uncorrected.
As such, they should fill the bill for circuits in multi-channel and multi-mode RF receivers, base stations, and SDRs (software-defined radios). Moreover, they should help designers of medical imaging equipment, industrial signal-processing, and even ATE (automatic test equipment).
Using a hard-wired so-called linearizer engine (a dedicated IC), coupled with the company's Turbolinear approach, both main module components are linearized (a Maxim Integrated Products MAX19588 A/D chip, and low-noise push-pull differential buffer amplifiers; the buffers provide gain and isolation, as well as source impedance matching). The company contends its approach provides an unparalleled improvement in SFDRup to 25-dB over conventional data converters.
Differential signals are also applied to the input of these A/Ds. Applying differential inputs provides common-mode rejection of stray signals such as LO (local oscillator) feed-through, as well as rejection of ground and power supply noise.
The differential inputs also help enhance AC performance at high sample rates, and enable a very high usable input bandwidth. That's important in under-sampling applications.
Lowering distortion can also boost a radio's IP3 (third-order intercept point) characteristics, and lower THD (total harmonic distortion). Significantly, the company's linearization process doesn't affect the Max19588's output signal-to-noise ratio.
Scalable And Adaptive
Turbolinear signal processing, Optichron's proprietary approach to correcting distortion in communications channels and mixed-signal environments, is also scalable, letting you enable or disable filter blocks to meet your design needs.
Turbolinear signal processing is also adaptive. It optimizes filter parameters to track changes in the properties of a transmission medium. The technology can be applied to all types of non-linear distortion (static, dynamic, continuous, discontinuous, distortion with memory effects) that degrade the performance of data conversion and communications architectures.
In use, the module supports sample rates that range from 60-Msamples/s to 100-Msamples/s. Input sensitivity is rated at -14-dBm. The module dissipates 3.125-W (at 100-Msample/s speeds).
Features include a single-ended 50-ohm analog input buffer, selectable 2s-complement or binary outputs, and an output clock for data output latching.
Price And Availability
Optichron says its OM1600M-100 is available now in sample quantities, and with evaluation boards. Production volume is expected by the third quarter. Pricing is about $80 per module at 10,000 unit quantities.
These modules are also available in different versions depending on the desired Nyquist zone of operation and desired sampling frequency. The device's linearizer is programmed to cancel non-linear distortion in the desired combination of Nyquist zone and sampling frequency.
When ordering, you specify the center frequency and bandwidth in which your input signal will fall in order to establish a desired sampling frequency.
For more details contact Optichron, Inc., 4221 Technology Dr., Fremont, Calif. 94538. Phone: 510-249-5230. E-mail: email@example.com
Optichron, 510-249-5230, www.optichron.com