5991-2848EN How to Test a MIPI M-PHY High-speed Receiver - Challenges and Keysight Solutions

Text preview for : 5991-2848EN How to Test a MIPI M-PHY High-speed Receiver - Challenges and Keysight Solutions - Appli part of

| Home

How to Test a MIPI M-PHY
High-Speed Receiver
Challenges and Agilent Solutions

Application Note

50
C
C
TT
TT

M- loop
RX back
M- Err
TX Ctr
Table of contents
1. Introduction ......................................................................................................................................................................................... 3
1.1. The MIPI alliance ................................................................................................................................................................................ 3
2. The M-PHY interface .......................................................................................................................................................................... 5
2.1 Data rates and tolerances ................................................................................................................................................................. 6
2.2. M-PHY RX state machine .................................................................................................................................................................. 7
2.3. M-PHY jitter specification for high-speed RXs .............................................................................................................................. 8
2.4. Specification of receiver eye opening and accumulated differential receiver input voltage ................................................ 9
3. Setup and calibration procedure for TX test .................................................................................................................................. 10
3.1 MIPI M-PHY RX test .......................................................................................................................................................................... 10
3.2 Set up used for HS_RX test and calibration of the high-speed stress signal ....................................................................... 11
3.3. Verifying the test setup ................................................................................................................................................................... 11
3.4. The Jitter cocktail for HS_RX tolerancing ................................................................................................................................... 12
3.5. Realization of the RX-test stress signal with Agilent J-BERT N4903B .................................................................................. 13
3.6. Excursion: PWM mode .................................................................................................................................................................... 17
4. The RX Test ....................................................................................................................................................................................... 19
4.1. DUT-RX clocking ............................................................................................................................................................................... 19
4.2. RX test modes ................................................................................................................................................................................... 19
4.3. Verifying BER <10-10 ............................................................................................................................................................................ 21
4.4. The Agilent N5990A-165 automation software for calibration and test ................................................................................ 22
5. Summary: Testing MIPI M-PHY RXs with Agilent test solution .............................................................................................. 22
6. Appendix ............................................................................................................................................................................................ 23
6.1 Test equipment ................................................................................................................................................................................. 23
6.2. Specifications for RX-stress signal ............................................................................................................................................... 24
6.3. References ......................................................................................................................................................................................... 25
6.4. Glossary .............................................................................................................................................................................................. 26

2
Word of caution Introduction
At the time of issue of this 1.1. The MIPI alliance
document MIPI M-Phy rev. 3 was
released, while the work on M-Phy The rapid spread of cell-phones from simple voice-capable devices to smartphones
rev. 4 got underway. Addressing or even tablet PCs with the constant addition of capabilities and features came along
Gear 3 data rates with rev. 3 with a proliferation of interfaces between ASICs and "sensors" or "terminal devices"
generated new requirements and such as microphones, cameras, loudspeakers, displays, and peripheral electrical
has resulted in new specifications devices as depicted in Figure 1, which made ASIC development and system integra-
and device capabilities. Addressing tion an increasingly difficult task.
Gear 4 with rev.4 will probably
result in new requirements as well, The MIPI organization was founded in 2003 (MIPI at that time stood for Mobile
which are not reflected throughout Industry Processor Interface) in order to structure the intestines of "mobile devices
this paper. ranging from smartphones, wireless-enabled tablets and netbooks" and to "benefit
the entire mobile industry by establishing standards for hardware and software inter-
Conformance test suite (CTS) rev faces in these devices" enabling reuse and compatibility in mobile devices making
1.0 was released only covering rev. "system integration less burdensome than in the past." "The distinctive requirements
1 and 2 of the M-PHY specification. of mobile terminals drive the development of MIPI Specifications."
Changes and additions are to be
expected.

The reader is therefore advised,
Technology challenges in mobile
Too many interfaces, all different
before following all statements and
procedures of this application note, Videophone Main display
camera
to check the current version of the
specification / the CTS for possible
Storage
changes versus the versions system Caller ID
display
mentioned above. Megapixel
camera

Multi-band cellular
About this document transceiver
Loudspeaker
Auxillary connectivity
This application selectively
describes critical parts of the MIPI Background
microphone
M-Phy-specification and related
receiver (RX) tests. It is not a Primary
microphone Earpiece
so-called Method of Implementa- Power speaker
management
tion (MOI) and therefore does not Analog Digital functions
completely cover all aspects of
the specification and the related
Figure 1. Smartphone with a variety of interfaces to sensors, terminal and electrical peripheral devices.
testing. It describes the main
properties of the M-Phy interface,
especially the definition of the jitter
stress signal, its calibration, and
aspects of High Speed Receiver
(HS_RX) testing.

1. Citations taken from MIPI website: http://mipi.org/

3
This application note will focus on
those interfaces that transport digital
data with an aggregate BW in the multi
Gb/s range, either per lane or on mul-
IEEE 1149.7*
tiple lanes. In contrast to other digital Debug and trace connector(s)
or SD card with NIDnt connector
standards, such as USB or PCIe, which LLI/M-PCIe USB 2.0/3.0 network connector

are monolithic, i.e. contain both protocol WLAN, WiGig,
UniPort/SSIC*
DSI Display(s)

GBT/SP
as well as phy-layers, most of the WirelessHD, etc.

PTI
high-speed MIPI standards are not, i.e.
Bluetooth, GPS
different protocols reside on the same FM-radio, NFC CSI Camera(s)
common phy-layer (see Figure 3).
Application
Speaker(s) processor
(Host)
WIP* UFS* Mass storage

SLIMbus
Audio codec
LLI/M-PCIe
WIP*
UniPort/SSIC*
LLI/M-PCIe
Microphone(s) UniPort/SSIC*
Companion
or bridge chip

Power amp ETPS Modem
Power

SPMI
management

eTrak
Switch D-PHY or M-PHY