webinar slides: digital power management and power integrity analysis and testing

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WEBINAR: Digital Power Management, Power Integrity, and Power Rail Sequence Analysis & Testing March 2 nd , 2017 Thank you for joining us. We will begin at 1:00pm EST. NOTE: This presentation includes Q&A. We will be taking questions during the presentation with answers at the end using the questions section of your control panel. March 2, 2017 1

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Page 1: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

WEBINAR: Digital Power Management, Power Integrity, and Power Rail SequenceAnalysis & TestingMarch 2nd, 2017Thank you for joining us. We will begin at 1:00pm EST. NOTE: This presentation includes Q&A. We will be taking questions during the presentation with answers at the end using the questions section of your control panel.

March 2, 2017 1

Page 2: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Teledyne LeCroy Overview

March 2, 2017 2

LeCroy was founded in 1964 by Walter LeCroy Original products were high-speed digitizers

for particle physics research Corporate headquarters is in Chestnut Ridge,

NY Long history of innovation in digital

oscilloscopes First digital storage oscilloscope Highest bandwidth real-time oscilloscope

(100 GHz) LeCroy became the world leader in protocol

analysis with the purchase of CATC and Catalyst Frontline Test Equipment and Quantum

Data were also recently acquired (2016) In 2012, LeCroy was acquired by Teledyne

Technologies and renamed Teledyne LeCroy

Page 3: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

• Product Manager with Teledyne LeCroy for over 15 years

• B.S., Electrical Engineering from Rensselaer Polytechnic Institute

• Awarded three U.S. patents for in the field of simultaneous physical layer and protocol analysis

Ken JohnsonDirector of Marketing, Product ArchitectTeledyne [email protected]

March 2, 2017 3

About the Presenter

Page 4: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Digital Power Management, Power Integrity, and Power Rail SequenceAnalysis & Testing

Test single or multi-phase digital power management ICs (PMICs), voltage regulator modules (VRMs), point-of-load (POLs) switching regulators, low-dropout (LDO) regulators or other DC-DC converter operations under transient load conditions, and test complete embedded systems that contain these devices.

March 2, 2017 4

Page 5: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Agenda

Overview Acquiring DC Voltage/Power Rails Transient Rail Response Analysis

Single Rail Multiple Rails

Multi-phase PMIC DC-DC Converter Current Sharing/Tracking Analysis Voltage/Power Rail Sequence Testing Power Integrity Measurement and Debug Examples Summary Questions

March 2, 2017 5

Page 6: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Overview

March 2, 2017 6

Page 7: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Power Electronics Designs are Used Everywhere…

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Page 8: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

This Webinar’s Focus is on the Following

Digital Power Management The control of various DC-DC converter voltages to

ensure appropriate and prompt delivery of current (power) over one or more DC power/voltage rails to various CPU, memory, or other devices in a motherboard or embedded computing system.

Power Integrity The analysis to determine whether expected voltage

and current requirements are met from regulated DC output to the power consuming device.

Voltage/Power Rail Sequence Testing The control of the ramp times and sequence of the

various DC power/voltage rails in a motherboard or embedded computing system.

March 2, 2017 8

Page 9: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Digital Power Management Overview

An embedded computing system requires one or more different “rails” (e.g., 3.3, 1.8, 1.5, 1.1Vdc) to provide voltage and current to the CPU and other on-board devices.

Bulk power is supplied to an embedded computing system through a high voltage (e.g., 12Vdc) bus/supply.

To provide high efficiency, each DC-DC converter power supply is actually several DC-DC converters in parallel.

In this example, there are four parallel DC-DC converters (called “phases” or “channels”) that each supply 25% of the total output current to the 1.1Vdc rail.

A Power Management IC (PMIC) turns the phases on and off as load power requirements change, and time interleaves the PWM outputs into one output.

The PMIC and CPU are both located on a motherboard of some type. The motherboard may be part of a larger stand-alone embedded system, or it could be used in a server, laptop, tablet, mobile phone, gaming system, consumer device, etc.

4 “phase” or “channel”

outputs from one DC-DC converter

1 DC power / voltage rail

March 2, 2017 9

PMIC

The CPU issues serial data commands to the PMIC so as to ensure proper current supply to all devices

Page 10: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Digital Power Management and Power IntegrityHalf-bridge output

The half-bridge output current is commonly called the “inductor current” because it flows through the output inductor (filter). It increases (ramps up)

when PWM signals are “ON” and ramps down when PWM signals are “OFF”

Additional load capacitance will filter this further

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Page 11: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Digital Power Management and Power IntegrityIdeal operation of multiple PMIC phases

Ideally, each PMIC phase under steady-state load condition is balanced Same amplitude (voltage PWM) Phase relationship to other

phases of (1/fs)/N fs is the power semiconductor

device switching frequency N is the number of phases

Example - these are the phase currents under steady-state operating conditions after filtering by the inductor

March 2, 2017 11

Page 12: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Digital Power Management and Power IntegrityNon-ideal operation of multiple phases

If there are amplitude errors between the different phases, output ripple will result

If there are amplitude and phase errors between the different phases, more complicated distortion patterns will be introduced

March 2, 2017 12

Page 13: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

First Polling Question (choose one or more)

What products are you designing and testing? Multi-phase Digital Power Management ICs (PMICs) VRM, POL or LDO regulators Unregulated DC supplies Embedded Systems using one or more of the above None of the above

March 2, 2017 13

Page 14: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails

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Page 15: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails There are three methods (but only one very good method)1. 50Ω Coaxial Cable Terminated at

Oscilloscope Input with DC 1MΩCoupling Reasonable noise performance, but… Requires high offset capability in the

oscilloscope…. or requires use of a DC block (not ideal)

Reflections due to impedance mismatch

Bandwidth limitations2. Conventional 10x Passive Probe

Poor noise performance Bandwidth limitations Maximum gain setting limitations

3. Use of Specialized Active Voltage Rail Probe Ideal solution – lowest noise, highest

bandwidth, lowest circuit loading

March 2, 2017 15

Page 16: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails Using a coaxial cable input terminated in 1 MΩ at the oscilloscope input Requires large native offset capability

in the oscilloscope HDO offset capability is very large

(more than any other oscilloscope) +/-1.6V (1mV to 4.95mV/div) +/-4.0V (5mV to 9.9mV/div) +/-8.0V (10mV to 19.8mV/div) +/-10.0V (20mV to 1V/div)

Or requires a DC block DC blocks don’t pass all AC

frequencies 1 MΩ oscilloscope termination has

limitations Frequency response <1 GHz Reflections due to impedance

mismatch

Signal input via coaxial cable to Teledyne

LeCroy HDO

Same signal as above with 1.8 V offset and gain

of 5 mV/div

March 2, 2017 16

1.8 V

0 V1 V/div

5 mV/div

0 V offset

1.8 V offset

1.8 V

0 V

Page 17: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails What’s wrong with using a conventional 10x passive probe? Passive Probes have 10x attenuation

Therefore, the oscilloscope gain setting is 1/10th that of the desired gain setting

This has the following impacts on the measurement: Increased noise

what is attenuated must be amplified Reduced offset capabilities

Offset capability is determined by underlying oscilloscope gain setting

Higher maximum gain setting i.e., an oscilloscope with a 1 mV/div maximum

gain setting used with a 10x probe will have a 10 mV/div probe+oscilloscope maximum gain setting

Additionally, the Passive Probe also has bandwidth limitations 1 MΩ oscilloscope terminations limit

frequency response to <1 GHz Passive Probe frequency response is typically

~500 MHz (maximum)

March 2, 2017 17

1.8 V

0 V1 V/div

10 mV/div

0 V offset

1.8 V offset

1.8 V

0 V

Signal input via Passive Probe to

Teledyne LeCroy HDO

Same signal as above with 1.8 V offset and gain

of 10 mV/div

Page 18: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails What’s wrong with using a conventional 10x passive probe? (continued)

This is the same example as the previous slide, but with a vertical zoom of Channel 1 Z1 = Zoom(C1)

Gain of vertical zoom is set to be equal to 5 mV/div Creates direct comparison to

previous coaxial cable input example and next (rail probe) example.

March 2, 2017 18

1.8 V

0 V1 V/div

5 mV/div

0 V offset

1.8 V offset

1.8 V

0 V

Signal input via Passive Probe to

Teledyne LeCroy HDO

Same signal as above with 1.8 V offset and vertically

zoomed to 5 mV/div

Page 19: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage Rails Using a specialized Rail Probe Provides four important capabilities for rail

voltage acquisitions: 50 kΩ Input Impedance

Very low circuit loading on the DC rail 1.2x Attenuation

Keeps scope+probe noise very low ~165 μVrms at 1 GHz and 1 mV/div

(HDO) +/-30V Offset built-in

Center a DC signal and use a high-sensitivity gain setting (e.g., 1-20 mV/div)

4 GHz of bandwidth +/-800 mV dynamic/differential range

Offset must be applied or a >800mV signal will not appear on the oscilloscope grid

Can also be re-purposed for full dynamic range voltage/power rail acquisitions Use an SMA to BNC adapter and attach

directly to BNC input with 1 MΩ coupling

March 2, 2017 19

1.8 V

0 V200 mV/div

5 mV/div

0 V offset

1.8 V offset

1.8 V

0 V

Signal input via RP4030 Active Voltage Rail Probe to Teledyne

LeCroy HDO

Same signal as above with 1.8 V offset and gain

of 5 mV/div

Page 20: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Acquiring DC Power/Voltage RailsComparison summary from previous four slides

March 2, 2017 20

Coaxial Cable Input Terminated at 1 MΩ

February 1, 2017 20

5 mV/div 1.8 V offset

1.8 V

0 V

5 mV/div 1.8 V offset

1.8 V

0 V

Passive Probe

5 mV/div 1.8 V offset

1.8 V

0 V

Active Voltage Rail Probe

Best Solution

Page 21: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

RP4030 Active Voltage/Power Rail ProbeA wide variety of tips and leads for DUT connection are supplied

ProBus-compatible amplifier MCX PCB Mounts (4 GHz)

(good for larger circuit boards – attach and leave in place for quick and easy connection to cable)

MCX Solder-in Lead (4 GHz)(can be soldered-in and left in circuit)

SMA to MCX short cable

March 2, 2017 21

MCX to U.FL Lead (3 GHz)(attaches to compact U.FL PCB

Mounts).

MCX to SMA Adapter

U.FL PCB Mounts(compact size for dense, mobile or

handheld systems)

Page 22: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

RP4030 Equivalent Circuit DiagramThe RP4030 probe is shaded in gray, and the cable and oscilloscope are not shaded

March 2, 2017 22

High Bandwidth SMA Connector

MCX Termination Provides Flexibility for DUT Connection

High DC Input Impedance (Low DUT Loading) with Low

High Frequency Input Impedance

High precision, high dynamic range offset DAC

(16-bit, 30V)

Auto Zero of Probe Can be Done While Connected to DUT

Page 23: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

RP4030 U.FL Solution for Compact PCBs

Hirose U.FL ultra-miniature PCB mounts can be designed in to make probing easy 3mm x 3mm Functionally equivalent to IPX

and UMCC connectors 3 GHz Low cost

March 2, 2017 23

Removal is simple with a widely available special-purpose extraction tool

Page 24: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

RP4030 Solder-in Lead

Solder-in Lead Provides Optimum Performance 4 GHz Reasonable cost

Multiple Leads Can be Soldered-in and Left in Place

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Page 25: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

RP4030 Optional Browser

SMA to SMA Cable

(for connecting to the RP4030 ProBus

compatible amplifier)

SMA to BNC Adapter

(for connecting directly to a scope BNC input if used as

a PP066 Transmission Line Probe)

Browser Tip with 0Ω Resistor

(for low attenuation, good noise performance)

450Ω and 950ΩResistors

(for use as 10x or 20x PP066 equivalent)

March 2, 2017 25

Page 26: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Other Teledyne LeCroy Voltage and Current ProbesThat are commonly used in Digital Power Management and Power Integrity Testing

Differential Amplifiers (DA1855A) and Probes (AP033) with 10x Gain Ideal for shunt/series resistor

measurements Up to 100 dB CMRR

High Sensitivity Current Probes 50 or 100 MHz

Low-cost 1 GHz Active FET Probe Great for general probing or

power sequence testing

March 2, 2017 26

Page 27: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

10x Gain Differential Voltage Probe for Series/Shunt ResistorTop is a conventional diff probe, bottom is a CMRR optimized probe amplifier with 10x gain

March 2, 2017 27

Page 28: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Second Polling Question (choose one or more)

What types of probes do you use today to probe DC power/voltage rails? Coaxial cables (50Ω input coupled to oscilloscope) Coaxial cables (1MΩ input coupled to oscilloscope) Conventional 10x passive probes Conventional single-ended active voltage probes Active voltage rail probe (power rail probe)

March 2, 2017 28

Page 29: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Transient Rail Response AnalysisOf a single voltage/power rail

March 2, 2017 29

Page 30: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Typical Digital Power Management and Power Integrity TestsFor One PMIC (One DC Voltage/Power Rail) PMIC Transient DC Rail Response

Addition or release (subtraction) of load Dynamic test Long capture time is very useful Correlate activity to other signals

Serial data commands Clocks / Strobes Enable lines

Measure DC Rail and Ensure that Tolerances are Met Mean voltage value Ripple Ringing Peak+ and Peak- Settling Time Droop

DC Rail

March 2, 2017 30

Page 31: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Example of Commonly Measured Voltage/Power Rail Parameters

March 2, 2017 31

7 mV/div993 mV offset

DroopRipple

(Periodic and Random Disturbances)

Settling

RippleCurrent

Transient

Peak -

Recovery Time

Page 32: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response TestingAcquiring and Viewing the Transient Response of a Single DC Rail

Load increased from ~0 to 20A

DC Rail voltage transient response is monitored

7 mV/div gain setting with 1Vdc offset

March 2, 2017 32

20A

No-load (near 0A)

Mean DC = 999.67mVMean DC = 1003mV

Load current

1.0V multi-phase railAcquired using the

RP4030 Active Voltage Rail Probe

Acquired using the CP030A High-sensitivity

Current Probe

Page 33: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dQuantifying the Transient Response of a Single DC Rail with Measurement Parameters Measurement

Parameters with Gates can be used to measure VdcRAIL before and after load. 999.67 mV before 1003.00 mV after

Zooms and measurement parameters can be used to understand high-frequency behaviors Z1 = VMIN at step

(967.70 mV) Z5 = VMAX before

step (1012.21 mV) Z7 = VMAX after step

(1016.38 mV) Measure Parameter can

be used to measure step load change 20.436 A

March 2, 2017 33

DC Rail Current

DC Rail Voltage

Mean DC = 999.67mVMean DC = 1003mV

12-bit Resolution

Page 34: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dPer-cycle Waveforms and Numerics to understand rail behaviors (DIG-PWR-MGMT option)

March 2, 2017 34

Load current

Mean Value Numerics Table of 1V Rail

Acquired Waveforms

Per-cycle Calculated WaveformsThese waveforms have one calculated

value for one per-cycle calculation period.

1.0V multi-phase rail

Page 35: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Transient Rail Response AnalysisOf multiple voltage/power rails

March 2, 2017 35

Page 36: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dMultiple PMICs and Multiple DC Rails

Same Tests as Single Rail Case Objective is to Understand

Impacts of Load Changes on All Rails at One Time

Clocks / StrobesEnablesSerial Data, etc.

DC Rail 1

DC Rail 2

DC Rail 3

DC Rail 4

+

March 2, 2017 36

Page 37: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dAcquiring and Viewing the Transient Response of a Load Release on Multiple Rails

Monitored input signals included Simple DC Rails

700mV 900mV 1.2V 1.5V

Multi-phase DC Rail (1.0V)

12V supply Rail Load Current

(20A to 0A) PWM Clock

March 2, 2017 37

PWM Clock Frequency

900mV rail

700mV rail

1.5V rail

1.2V rail

1.0V multi-phase rail

12V input supply

Load current

Page 38: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dDigital Power Management (DIG-PWR-MGMT) Software Provides More Information

March 2, 2017 38

PWM Clock Frequency(used to determine period over which calculations can be made)

900mV rail

700mV rail

1.5V rail

1.2V rail

1.0V multi-phase rail

12V input supply

Load current

Mean Value Numerics Table

Acquired Waveforms

Calculated Waveforms

Q-Scape Tabbed Display

Mean DC rail values calculated once per PWM clock cycle and plotted over time, time-correlated to original acquisitions.

Mean DC values of 1.0V rail more clearly shows settling time and rail droop.

Load release on 12V supply can be clearly observed as an 80mV voltage increase with an improved voltage tolerance (sdev).

Page 39: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dZoom+Gate provides capability to understand details of system response

March 2, 2017 39

PWM Clock Frequency(used to determine period over which calculations can be made)

Load current

Mean Value Numerics Table

50x Zooms of Acquired Waveforms

50x Zooms of Calc’dWaveforms

These alternating color-coded highlights indicate the identified periods we are making the per-cycle calculations during.

These waveforms have one calculated value for one per-cycle calculation period.

Page 40: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Multi-phase PMIC DC-DC Converter Current Sharing/Tracking Analysis

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Page 41: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

PMIC Transient Rail Response Testing, cont’dFor Multiple Phases in One PMIC

PMIC Load/Current Sharing/Tracking Measure voltage/current on each

individual phase output Difficult to do – PMIC normally does not

make output accessible for measuring current

Phase 1

Phase 4

Phase 3

Phase 2

March 2, 2017 41

Page 42: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Combined Research Project (Oracle + Teledyne LeCroy) “A Generic Test Tool for Power

Distribution Networks” Dr. Istvan Novak

Senior Principal Engineer, Oracle Peter Pupalaikis

VP Technology Development, Teledyne LeCroy

Presented February 2, 2017 at DesignCon 2017 in Santa Clara, California (USA)

http://cdn.teledynelecroy.com/files/whitepapers/designcon-2017-a-generic-test-tool-for-power.pdf

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Page 43: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Transient source

3 x AP033 differential

probes

DUT

Lab Setup

HDO81088ch, 12 bit, 1 GHz oscilloscope

March 2, 2017 43

Page 44: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

DUT: 3-phase non-isolated buck converter

Device Under Test (DUT) Setup

March 2, 2017 44

Page 45: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Potential variables: DC load current DC input voltage DC output voltage Temperature AC excitation current

Impedance magnitude [Ohm]

Output Impedance vs. DC Load Current (Light Load)

March 2, 2017 45

Page 46: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Output voltage transient

Current-sense voltage Sum of inductor

currents

Three inductor currents

Transient Current Step

March 2, 2017 46

Page 47: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Current Sharing vs. Frequency

March 2, 2017 47

Page 48: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Voltage/Power Rail Sequence Testing

March 2, 2017 48

Page 49: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

What is Sequence Testing? For the computing system to

“boot-up” correctly, the DC rails must turn ON in a specific order with specific “wait times” between each turn ON.

For example, First 3.3Vdc goes high Then, 200-500ms later, 1.8Vdc

goes high Then 200-500ms later, 1.5Vdc

goes high Lastly, 500ms-800ms later,

1.1Vdc goes high

March 2, 2017 49

Page 50: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

What are Sequencing Tests? Acquire as many DC rail signals as

possible More is better – great 8ch application

Acquire other signals, e.g.: Clocks PMIC enable Strobes Serial data command signals to PMIC

Measure timing between signals Usually with cursors Serial TDME options could be useful to

some customers Long capture times with high SR are

common 250 Mpts of memory is very useful Capture a lot of time at high sample

rate in many different start-up scenarios, and zoom for details

The image above is a start-up sequencing requirement (timing details are omitted) for a TI embedded ARM microprocessor (http://www.ti.com.cn/product/cn/AM3358-EP/datasheet/6_ZHCSE24A

Note the many different rail voltages (5 different) and multiple 1.8Vdc rails – this is very common Important reason why 8ch is very, very useful

March 2, 2017 50

Page 51: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Voltage/Power Rail Sequence Testing on Power Down50 Mpt capture at 250 MS/s (200 ms) – using timing parameters to measure delta times

March 2, 2017 51

900mV rail

700mV rail

1.5V rail

1.2V rail

1.0V multi-phase rail

Unregulated 1.0V rail

Load current

Measurements of Delay Time from Ch3 Going Low to Other

Rails Going Low

Scope trigger set to first rail known to go low.

1.0V multi-phase rail

Unregulated 900mV rail

Page 52: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Voltage/Power Rail Sequence Testing – Using Serial Data Toolsets Trigger on a Serial Data Message, Decode It, and Make Automated Timing Measurements

March 2, 2017 52

900mV rail700mV rail1.5V rail1.2V rail

Unregulated 1.0V rail

Load current

Serial Data message initiates power-up

1.0V multi-phase rail

Unregulated 900mV rail

Time from serial data message to power up calculated using automated parameter and decoded serial data.

Decoded serial data message that initiated sequencing activities

Page 53: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Serial Data Toolsets – Measurements and Graphing Timing Measurements

Message to Analog Analog to Message Message to Message

Message to Value “Serial DAC”

Automatic Run corner cases,

gather statistics Display histograms Correlate cause-effect

timing relationships to other events

March 2, 2017 53

Page 54: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Message to Value parameter

View serial data change over time

Examples PMbus voltage I2C or SPI

temperature CAN steering

wheel angle CAN wheel

speed (ABS) I2S audio

“Serial Data DAC” Graphing of Digitally Decoded Data

March 2, 2017 54

Serial Data messages (100s or 1000s)

Track of Message to Value parameter

Message to Value parameter

Page 55: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

SPMI (System Power Management Interface) Decoder

SPMI MIPI standard

More than 20+ other complete solutions I2C (PMbus) UART-RS232 SPI USB2 HSIC etc.

March 2, 2017 55

Page 56: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Power Integrity Measurement and Debug Examples

March 2, 2017 56

Page 57: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Power Integrity Measurement and Debug Example 1

Jitter on a 10 MHz clock circuit is traced back to a 2.9 MHz Point-of-load (POL) DC-DC converter

March 2, 2017 57

Page 58: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Overview of DUTPower Delivery System for a Wireless Router

Switched-mode AC-DC power

supply

Point-of-Load (POL) DC-DC

converter

Power delivery network

March 2, 2017 58

Page 59: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

2.9 MHz POL DC-DC Converter Spectral MeasurementsThe oscilloscope Spectrum Analyzer capability is used to frequency peaks of the POL

March 2, 2017 59

Short Acquisition @ 20 GS/s

Long Acquisition 250 MS/s

Spectrum Analyzer

Table

Peak Markers Correspond to Table

Page 60: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

POL Ripple Contributes to Clock Jitter JitterKit can be used to quantify jitter on 10 MHz clock and trace it back to the POL

March 2, 2017 60

10 MHz clock acquisition (500 μs long)

TIE Jitter vs. time for the 10 MHz clock

TIE Jitter Overlay of 10 MHz clock

acquisition

TIE Jitter Spectrum of 10 MHz Clock

Histogram of TIE measurements

Spectrum Analysis Table from 2.9 MHz POL

Page 61: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Power IntegrityMeasurement and Debug Example 2

Understanding the impact of the power delivery network (PDN) impedance on clock jitter coupling

March 2, 2017 61

Page 62: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Background - The Importance of Impedance

+-

+ + + ++

LoadVRM

Bulk Caps Decoupling Caps

Capacitance of Planes Package

Package Lead Inductance

Control Loop Inductance

+

-LoadVCC

Impedance of PDN

VChip

ZPDN

IMax

Vcc ≠ VChip

March 2, 2017 62

Page 63: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

An LDO DC-DC Converter Supplies Power to 10 and 125 MHz Clocks

March 2, 2017 63

Page 64: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Impedance – Measurement Example

+

-LoadVCC

Impedance of PDN

VChip

ZPDN

IMax

March 2, 2017 64

Power Rail Voltage Measured at VCC

Power Rail Voltage Measured at VCHIP

Page 65: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

10 MHz Clock Causing Ripple on Input Voltage Rail (VCC)

March 2, 2017 65

Long acquisition of VCC

Spectrum Analysis of VCC

Spectrum Analysis Table of VCC

Page 66: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

10 MHz Clock Induced Ripple on VCC Impacts 125 MHz ClockRipple adds 1ps of jitter on the output of the125 MHz clock

March 2, 2017 66

TIE Jitter Spectrum of 125 MHz Clock

Histogram of TIE measurements

This is a TIE jitter analysis of the 125 MHz clock (the original acquisition is not shown)

Page 67: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Measuring Impedance of the PDNThe plot indicates the impact of the ESR and ESL on the circuit

Omicron Bode 100 40 MHz Network

Analyzer

March 2, 2017 67

Image source http://www.powerelectronictips.com/ceramic-or-electrolytic-output-capacitors-in-dcdc-converters-why-not-both/

Power/Voltage Rail behaviors during load changes correlate to PDN impedance Equivalent series resistance (ESR) and

inductance (ESL) for half-bridge output capacitor (COut)

Voltage transients at load changes are primarily caused by ESL or impedance of the output cap at very high frequencies.

Slew rates impacted by the reactive power of the capacitor (QC)

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A Decoupling Capacitor Can Be Used to Lower ImpedanceTIE jitter is reduced by more than 1psrms in this example

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S301-2 ON w/o decoupling C

S301-2 ON w/ decoupling C

Page 69: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Power IntegrityMeasurement and Debug Example 3

High clock jitter and malfunction can be seen to be caused by POL DC-DC converter voltage droop.

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Page 70: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

POL DC-DC Converter Transient Load ResponseThis provides information about the impedance of the PDN

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Load Current (acquired with a differential voltage probe

and not rescaled to amps)

POL Output Voltage

dI/dt Calculated Waveform

single-phase operation single-phasemulti-phase operation

Page 71: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Transient Load Response Jitter AnalysisThe POL output voltage droop to the clock causes large clock jitter

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TIE Jitter Overlay of 10 MHz clock acquisitionThis persistence overlay of the clock cycles shows very little

jitter with a small number of clock edges having significant jitter

TIE Jitter vs. time for the 10 MHz clockJitter can be seen to vary significantly during voltage droop

200ps TIE Jitter per vertical

division

POL Output Voltage to 10 MHz clock vs. time100mV droop occurs during step load

Jitter is quantified with Time Interval Error measurement. Peak to peak jitter is 1ns which is 1/8 of a period

Page 72: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Transient Load Response – Power Switched on to a Second ClockLoad of second clock causes POL voltage droop and impacts 10 MHz clock functioning

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POL Output Voltage to 10 MHz clock vs. time

Zoom of above trace

10 MHz Clock Voltage vs. time

Zoom of above trace

Page 73: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Third Polling Question (choose one or more)

What types of testing do you do? Analysis of a single or multiple voltage/power rail(s) Multi-phase current tracking/sharing Power rail sequence testing and timing Embedded system debug for some/all of the above None of the above

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Page 74: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Summary

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Page 75: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Teledyne LeCroy Equipment for Digital Power Management, Power Integrity, and Power Sequencing Test and Analysis

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4 or 8 channel, 12 bit, 1 GHz Oscilloscopes

Comprehensive Probe Offering

DIG-PWR-MGMT Digital Power Management Analysis Software Option

Serial Trigger, Decode, Measure/Graph and Eye Diagram

(TDME) Options

4 channel, 10 bit, 4 GHz Oscilloscopes

JITKITJitter Kit Toolbox Analysis

Software Option

SPECTRUMSpectrum Analyzer software

(standard on most HDOs)

Page 76: Webinar Slides: Digital Power Management and Power Integrity Analysis and Testing

Questions?

You can also reach the presenter at [email protected]

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