Scoping the challenge of mobile.
Low power, high bandwidth and low pin count are all essential for mobile device interfaces, which makes standards issued by MIPI, the international organisation that develops interface specifications for mobile and mobile-influenced industries, challenging for test engineers.
Tektronix has announced the first physical layer transmitter characterisation and debug solution for the recently-approved MIPI M-PHYv3.1 specification. The new solution includes support for MIPI MPHY High Speed Gears 1, 2 and 3, PWM Mode (G0-G7) and SYS Mode, and offers the industry's lowest noise solution for MIPI M-PHY measurements when used with Tektronix MSO/DPO 70000DX oscilloscopes and P7600 series probes.
The new MIPI M-PHY serial interface presents some significant challenges for oscilloscope measurements and probing, including minimising common mode loading on the device under test (DUT) and signal fidelity requirements such as wide bandwidth, low noise, and high sensitivity.
"We're seeing a growing emphasis on performance in mobile device design, meaning that more and more designs are incorporating MIPI MPHY Gear 3 to operate at the highest data rate possible under the MIPI M-PHY specifications," said Brian Reich, general manager, Performance Oscilloscopes, Tektronix. "This in turn has introduced new signal acquisition challenges due to the combination of low amplitude signals and high speeds. Tektronix probing solutions are significantly ahead of the industry and fully meet MIPI M-PHY v3.1 requirements."
Testing MIPI M-PHY transmitters running in highspeed mode requires a scope and probe system with rise time three times faster than the signal rise time, sensitivity of 200mVFS, minimal added noise (<1 or 2mVrms), and high return loss as specified in the MIPI M-PHY standard.
Looking forward, MIPI Alliance is developing the next generation M-PHY HS Gear 4 that will increase data rates. This will introduce the need for new measurement methodologies and equalisation techniques. Characterisation of the bit error ratio (BER) of devices requires a breakdown of the impact of both jitter and noise. At the receiver side, the eye will be completely closed due to attenuation of the signal and equalisation will be needed.