Tektronix TriMode P7700 Series Use and care manual

xx
P7700 Series
TriMode™ Probes
ZZZ
Technical Reference
*P077112401*
077-1124-01

P7700 Series
TriMode™ Probes
ZZZ
Technical Reference
xx
www.tek.com
077-1124-01

Copyright © Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its subsidiaries
or suppliers, and are protected by national copyright laws and international treaty provisions.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication
supersedes that in all previously published material. Specifications and price change privileges reserved.
TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.
TriMode and TekFlex are trademarks of Tektronix, Inc.
Contacting Tektronix
Tektronix, Inc.
14150 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077
USA
For product information, sales, service, and technical support:
In North America, call 1-800-833-9200.
Worldwide, visit www.tek.com to find contacts in your area.

Warranty
Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one (1)
year from the date of shipment. If any such product proves defective during this warranty period, Tektronix, at its
option, either will repair the defective product without charge for parts and labor, or will provide a replacement
in exchange for the defective product. Parts, modules and replacement products used by Tektronix for warranty
work may be new or reconditioned to like new performance. All replaced parts, modules and products become
the property of Tektronix.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of
the warranty period and make suitable arrangements for the performance of service. Customer shall be responsible
for packaging and shipping the defective product to the service center designated by Tektronix, with shipping
charges prepaid. Tektronix shall pay for the return of the product to Customer if the shipment is to a location within
the country in which the Tektronix service center is located. Customer shall be responsible for paying all shipping
charges, duties, taxes, and any other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage
resulting from attempts by personnel other than Tektronix representatives to install, repair or service the product;
b) to repair damage resulting from improper use or connection to incompatible equipment; c) to repair any damage
or malfunction caused by the use of non-Tektronix supplies; or d) to service a product that has been modified or
integrated with other products when the effect of such modification or integration increases the time or difficulty
of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THE PRODUCT IN LIEU OF ANY
OTHER WARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY
IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
TEKTRONIX' RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE
AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY.
TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL,
OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS
ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
[W2 – 15AUG04]

Table of Contents
Important safety information..................................................................................... iv
General safety summary ..................................................................................... iv
Terms in this manual .......................................................................................... v
Symbols and terms on the product........................................................................... v
Theory of operation ................................................................................................ 1
Introduction..................................................................................................... 1
TriMode operation............................................................................................ 10
Operating voltages............................................................................................ 12
Improving measurement accuracy .......................................................................... 21
Reference........................................................................................................... 31
Single-ended measurements ................................................................................. 31
Differential measurements................................................................................... 32
Specifications ...................................................................................................... 37
Warranted characteristics .................................................................................... 37
Typical characteristics........................................................................................ 40
Host instrument firmware......................................................................................... 47
Index
P7700 Series TriMode Probes Technical Reference i

Table of Contents
List of Figures
Figure 1: P7700 Series TriMode probe components ........................................................... 1
Figure 2: P7700 Series TriMode active probe tips.............................................................. 4
Figure 3: P7700 Series TriMode probe input architecture..................................................... 5
Figure 4: TriMode input structure ............................................................................... 11
Figure 5: P7700 probe tip inputs................................................................................. 12
Figure 6: Operating voltage window (TekFlex solder-in tips)................................................ 13
Figure 7: Dynamic range versus linearity at the probe amplifier step gain settings................ ........ 15
Figure 8: Operating voltage window (P77BRWSR)........................................................... 16
Figure 9: Dynamic range linearity error plot................................................................... 16
Figure 10: Simplified diagram of the P7700 Series probe tip input network ............................... 18
Figure 11: Probe setup screen.................................................................................... 19
Figure 12: Simplified Auto Offset circuitry .................................................................... 20
Figure 13: P77STFLXA solder tip attached with 10 mils (0.250 mm) wires (rise time = 30.5 ps) ...... 23
Figure 14: P77STFLXA solder tip attached with 75 mils (1.90 mm) wires (rise time = 27.9 ps).... .... 23
Figure 15: P77STFLXA solder tip attached with 120 mils (3.05 mm) wires (rise time = 30.1 ps) ...... 24
Figure 16: P77STFLXA solder tip attached with 200 mils (5.08 mm) wires (rise time = 34 ps)......... 24
Figure 17: P77STFLXA solder tip attached with 300 mils (7.62 mm) wires (rise time = 42.8 ps) ...... 25
Figure 18: Simplified diagram of the P7700 Series probe tip input network ............................... 26
Figure 19: Differential input mode signal voltage and offset voltage ....................................... 28
Figure 20: Solder tip measurement configuration.............................................................. 29
Figure 21: Example of LVDS differential signal............................................................... 29
Figure 22: Simplified model of a differential amplifier ....................................................... 33
Figure 23: Typical CMRR........................................................................................ 34
Figure 24: Typical channel isolation ............................................................................ 36
Figure 25: P77STCABL differential impedance............................................................... 43
Figure 26: P77STCABL SE impedance ........................................................................ 43
Figure 27: P77STFLXA differential impedance ........... ................ ................ ................ .... 44
Figure 28: PST77FLXA SE impedance......................................................................... 44
Figure 29: P77BRWSR differential impedance................................................................ 45
Figure 30: Differential mode P77STCABL and P77FLXA equivalent circuit diagram ..... .............. 45
Figure 31: Single-ended P77FLXA equivalent circuit diagram.............................................. 45
Figure 32: P77BRWSR equivalent circuit diagram with 50 mil spacing.................................... 46
Figure 33: P77BRWSR equivalent circuit diagram with 200 mil spacing .................................. 46
ii P7700 Series TriMode Probes Technical Reference

Table of Contents
List of Tables
Table 1: Probe tip attenuation factors ............................................................................ 6
Table 2: Rise time and overshoot degradation versus lead length ........................................... 25
Table 3: Single-ended dynamic and offset ranges ............................................................. 31
Table 4: Electrical characteristics................................................................................ 37
Table 5: Environmental characteristics ......................................................................... 39
Table 6: Typical electrical characteristics....................................................................... 40
Table 7: Electromagnetic compatibility (EMC) ..................... .......... ........................ ........ 42
P7700 Series TriMode Probes Technical Reference iii

Important safety information
Important safety information
This manual contains information and warnings that must be followed by the user
for safe operation and to keep the product in a safe condition.
General safety summary
Use the product only as specified. Review the following safety precautions to
avoid injury and prevent damage to this product or any products connected to it.
Carefully read all instructions. Retain these instructions for future reference.
This product is not intended for detection of hazardous voltages.
To avoid fire or personal
injury
Observe all terminal ratings. To avoid fire or shock hazard, observe all ratings
and markings on the product. Consult the product manual for further ratings
information before making connections to the product.
Do not apply a potential to any terminal, including the common terminal, that
exceeds the maximum rating of that terminal.
Do not operate without covers. Do not operate this product with covers or panels
removed, or with the case open. Hazardous voltage exposure is possible.
Avoid exposed circuitry. Do not touch exposed connections and components
when power is present.
Do not operate in wet/damp conditions. Be aware that condensation may occur if
a unit is moved from a cold to a warm environment.
Do not operate in an explosive atmosphere.
Keep product surfaces clean and dry. Remove the input signals before you clean
the product.
Probes and test leads Remove all probes, test leads and accessories that are not in use.
Inspect the probe and accessories. Before each use, inspect probe and accessories
for damage (cuts, tears, or defects in the probe body, accessories, or cable jacket).
Do not use if damaged.
Use only the specified replacement parts.
iv P7700 Series TriMode Probes Technical Reference

Important safety information
Terms in this manual
These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.
Symbols and terms on the product
These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read
the marking.
WARNING indicates an injury hazard not immediately accessible as you
read themarking.
CAUTION indicates a hazard to property including the product.
When this symbol is marked on the product, be sure to consult the manual
to find out the nature of the potential hazards and any actions which have to
be taken to avoid them. (This symbol may also be used to refer the user to
ratings in the manual.)
The following symbol(s) may appear on the product:
P7700 Series TriMode Probes Technical Reference v

Important safety information
vi P7700 Series TriMode Probes Technical Reference

Theory of operation
Introduction
The P7700 Series TriMode Probes are designed for use with MSO/DPO70000C
and newer oscilloscopes. Four P7700 Series TriMode Probe models are available
with bandwidths from 8 GHz to 20 GHz. MSO/DPO70000C oscilloscope models
are available at comparable bandwidths. These probe and oscilloscope models
feature the high performance TekConnect intelligent probe interface. P7700 Series
probes must be operated with an attached P7700 Series probe tip. Several P7700
Series probe tip models are available to support different application requirements.
The P7700 Series probes and probe tips contain device-specific S-parameter data
that, when transferred to the host oscilloscope after the initial connection is made,
create unique system DSP filters. These DSP filters optimize high frequency
performance of the probe and probe tip signal path.
The P7700 Series probes are optimized for high bandwidth; they are not
general-purpose probes. The P7700 Series probe solder tips that can be used
with the probes are miniaturized for electrical characteristics and access to dense
circuitry, and must be handled carefully.
Figure 1: P7700 Series TriMode probe components
P7700 Series TriMode Probes Technical Reference 1

Theory of operation
Probe components P7700 Series probes are comprised of a probe compensation box (comp box),
a TekFlex connector for attaching probe tips, and an interconnect cable that
transfers measured signals, power, and control signals between the probe comp
box and the TekFlex connector probe head. A P7700 Series probe tip must be
inserted into the TekFlex connector probe head to make the final connection to
the DUT (device under test).
Probe compensation box. The probe compensation box assembly mates to the
host instrument through an intelligent TekConnect probe interface. Power,
control signals, and the signal measured by the probe are transferred to and from
the oscilloscope through the TekConnect interface. The comp box includes a
membrane toggle switch to select the TriMode input mode for probe tips that
support TriMode functionality:
Differential (A–B)
A input (single-ended to ground)
B input (single-ended to ground)
Common-mode ((A+B)/2 to ground)
The probe input mode can also be selected using the oscilloscope probe controls or
Probe Setup menu. The Probe Setup menu is also used to adjust the probe Offset A
and Offset B voltage settings and to initiate a DC Probe Compensation operation.
All other P7700 Series probe internal controls are handled automatically through
communication between the probe and oscilloscope.
An LED on the top panel of the comp box indicates the selected input mode.
Another LED indicates when a warning condition exists. Warnings are caused
when parameters such as input voltages exceed the safe limits of the probe.
A mechanical latch and optional retention thumbscrew hold the probe securely to
the instrument during use. The thumbscrew is only intended to be finger-tightened,
and is machined to prevent tools from being used to over-torque it. To remove
the probe, loosen the thumbscrew counterclockwise, depress the latch button to
release the probe, and then pull out the probe.
CAUTION. To prevent damage to the probe, use care when handling the probe.
Rough or careless use can damage the probe.
Main interconnect cable. This cable assembly consists of a pair of matched,
low-loss coaxial signal cables that carry the acquired signal from the probe head to
the probe comp box. The cable assembly includes an 8-conductor bundle of wires
that supply probe tip head power and control signals from the probe comp box
through the TekFlex connector interface. Some of the wires carry bidirectional
data, such as queries and responses about the type of probe tip attached to the
TekFlex connector, and other probe tip-specific information.
2 P7700 Series TriMode Probes Technical Reference

Theory of operation
TekFlex™ connector. The new TekFlex connector technology combines a high
speed signal path with low speed control signaling in a single, easy to connect
accessory connector. The TekFlex connector has a pinch-to-open design that
when open requires minimal force to attach an accessory tip. When the TekFlex
connector is closed, it provides a secure connection to the accessory to avoid
accidental disconnections.
The connector provides a light-weight electrical and mechanical interface
between a P7700 Series probe and a P7700 Series active probe tip. It contains
a spring-loaded set of electrical contacts that connect between the main cable
wiring and contact patterns on the attached probe tip. There is a differential,
high-frequency contact pattern on the top of the probe tip that connects the probe
tip dual signal inputs and grounds to the probe main cable coaxial pair. There is
also an eight-finger contact pattern on the bottom of the probe tip that connects
the probe tip power and control signals to a ribbon wire in the main cable. The
TekFlex connector provides mechanical alignment between a keyed hole pattern
on the probe tip and a pair of pins inside the spring loaded connector housing.
With the TekFlex connector, the P7700 series probes offer a set of active probe
tips with the probe's buffer amplifier only millimeters from the input connections.
The short signal path enabled with the active tips provides high fidelity and a high
impedance input. It minimizes signal loss, capacitance, and additive noise.
P7700 Series TriMode Probes Technical Reference 3

Theory of operation
Probe tips. The probe tips are automatically detected and displayed in the Probe
Setup screen.
Figure 2: P7700 Series TriMode active probe tips
1. TekFlex solder-in tips. These tips use flex circuit material and provide
soldered, multi-point connections. They support full TriMode measurement
capabilities and full probe bandwidth. If care is taken during the soldering
process, these probe tips can be reused through multiple soldering operations.
The small size and low cost design are good for high interconnect density
measurements.
The first time the probe tip is detected, S-parameter data for the probe tip is
sent to the oscilloscope, and probe-tip specificDSPfilters are generated. These
filters improve the measurement accuracy of high-frequency measurements.
2. P77STCABL. This optional tip provides a soldered, multi-point connection
that supports full TriMode measurement capabilities at full probe bandwidth.
If care is taken during the soldering process, this probe tip can be reused
through multiple soldering operations. In some applications the robust
mechanical design of the tip and flexible cable construction provides better
usability, compared to the lower cost flex circuit tips. The first time the probe
tip is detected, S-parameter data for the probe tip is sent to the oscilloscope,
and probe-tip specificDSPfilters are generated.
3. P77BRWSR. The optional browser connects to the circuit using two input
contacts with very fine point tips. These tips have built-in compliance 0.02 in
(0.5 mm) and adjustable spacing 0.008 in to 0.210 in (0.2 mm – 5.3 mm).
The input contacts include an embedded damping resistor for optimum
measurement performance.
The browser tip can be held in place or can be used to make hands-free
connections to the DUT when using the Browser Tri-Pod accessory, or a probe
positioner, such as the Tektronix PPM203B. The browser includes multiple
sets of S-parameters based on the spacing of the tips. The spacing is monitored
and the correct set of S-parameters are automatically used.
4 P7700 Series TriMode Probes Technical Reference

Theory of operation
Probe input architecture P7700 Series probes feature a new probe architecture that addresses the need
for high frequency response with decreased probe loading for high-speed, low
power applications such as MIPI® and LPDDR. High performance probes with
multi-GHz bandwidth have evolved in recent years, starting from traditional
designs with metal pin tips attached to a probe head amplifier located at the end of
a coaxial cable. As the probe bandwidth extended to 10 GHz and above, probe
designs migrated to connectorized amplifier input structures that supported a
variety of high frequency passive probe tips, including solderable tip designs.
These probe tips typically provide a passive input attenuator network at the
probe tip followed by a long cable attached to the probe amplifier connection
socket. Although these passive tip, probe designs enable good, high frequency
performance, they show higher probe loading in the frequency band below 1 GHz
than earlier traditional designs with an amplifier closer to the probe tip. A probe
with this higher loading characteristic below 1 GHz has problems when taking
measurements of signals such as MIPI that can be switched to an unterminated,
high impedance mode for low power operation. The P7700 Series probe solves
this loading problem by introducing an active probe tip design with a tiny
buffer amplifier located near the tip inputs. By locating an amplifier with a high
impedance attenuator network at the probe tip inputs, the probe tip parasitic
capacitance can be kept much lower than passive cable tip designs, thus reducing
probe loading in the low power signaling frequency band used by serial data
standards such as MIPI.
The following figure shows a simplified diagram of the P7700 Series active
probe tip architecture.
Figure 3: P7700 Series TriMode probe input architecture
P7700 Series TriMode Probes Technical Reference 5

Theory of operation
The P7700 Series active probe tip has two inputs, A_IN and B_IN, which can,
depending on the tip design, support TriMode measurements. With a TriMode tip,
such as a TekFlex solder-in tip, it is possible to make differential, single-ended
A, single-ended B, and common-mode measurements, all from a single soldered
differential signal connection to a DUT. The soldered wire connections between
the two probe tip input signal vias and DUT differential signal nodes should be
kept as short as possible (as should the ground via connections if single-ended
measurements will be made). The A and B input signals on the probe tip pass to a
matched pair of damping resistors, Rd, that isolate the probe connection to the
DUT. The damping resistor value of approximately 100 Ωalso serves to tune the
probe tip high frequency response. Following each input damping resistor is a pair
of attenuation resistors, Rs and Rp. The attenuation resistor values depend on the
specificp
robe tip attenuation factor design. There are currently two attenuation
factors available as shown in the following table with approximate attenuation
resistor values. The probe tip attenuation factor in the table includes an additional
2X factor due to attenuation from the 50 Ωtip buffer output impedance and the
50 Ωprobe amplifier termination impedance.
Table 1: Probe tip attenuation factors
Attenuation
factor Rs Rp
Dynamic
range
Offset voltage
range
4x 25 kΩ25 kΩ2.5 Vpp ±4.0 V
10x 60 kΩ15 kΩ6.0 Vpp ±10.0 V
The input attenuation resistors serve three major functions for the dual input
tip buffer:
The high resistance of the attenuation resistors provides very light loading
on the probe input signals.
The probe tip attenuation factor expands the linear dynamic range of the
probe tip inputs.
The probe tip attenuation network provides a resistive summing junction for
injecting an offset voltage signal to extend the probe tip operating voltage
window.
The P7700 Series active tips contain a pair of unity gain amplifiers that buffer the
DUT differential input signal. These buffer amplifiers provide an impedance
conversion for the input signals from the high impedance input attenuator at the
tip input to the 50 Ωoutput drive at the tip output. The buffer amplifier 50 Ω
output impedance is needed to drive the probe TekFlex connector and meter-long
main cable transmission lines with good high frequency fidelity. The new TekFlex
interface to which the P7700 Series probe tips are attached includes both a dual
high frequency connection for the probe tip signals as well as a low frequency
connection for eight messenger wires that provide power and control for the
active probe tips.
6 P7700 Series TriMode Probes Technical Reference

Theory of operation
The control features of the new TekFlex interface include two analog tip offset
voltage signals, a pair of digital communication signals for accessing the probe tip
S-parameter memory, and a probe tip temperature monitor signal.
The probe tip S-parameter memory contains characterization data for use with
DSP correction filters that are unique to the probe tip. The S-parameter memory
includes a unique data header used in automatically identifying the probe tip
type and serial number. The A and B signal outputs from the probe tip are
connected by high frequency spring contacts in the TekFlex connector to a pair of
delay-matched coaxial cables that carry the input signals through the main cable
and into the comp box. These signals terminate to a pair of 50 Ωtermination
resistors at the probe amplifier in the comp box. The termination resistors have
an adjustable termination voltage connection for optimal loading of the probe
tip output signals. The TekFlex interface messenger wires are routed as a small
gauge ribbon cable, along with the delay-matched coaxial cables, inside a shielded
main cable assembly.
The P7700 Series probe amplifier has several cascaded amplifier stages that
condition the probe tip differential signal for precision measurement fidelity. The
complex input stage of the probe amplifier selects the desired TriMode input mode.
This input stage of the probe amplifier includes connections for injecting a pair
of adjustable probe offset voltages for precision control of the probe output zero
voltage, which is a measure of the output signal with zero volts at both probe
tip inputs.
The next stage in the probe amplifier is the step gain stage. The step gain stage
provides several switchable, coarse gain steps, that extend the sensitivity range of
the probe measurement down to the millivolt level with good noise performance.
The step gain stage is automatically switched to its optimum setting by the
oscilloscope as the oscilloscope vertical channel sensitivity is adjusted by the user.
The final stage of the probe amplifier is the variable gain stage. The variable
gain stage is used for fine tune adjustment of the gain of the probe and probe tip
to its calibrated value. The calibrated gain setting is determined from calibration
constants characterized during manufacturing testing of the probe and probe
tip and includes compensation for probe temperature variation. Although the
signal that passes through the probe amplifier is processed as a differential signal
through the internal amplifier stages, it is routed to the oscilloscope’s TekConnect
interface as a single-ended output.
P7700 Series TriMode Probes Technical Reference 7

Theory of operation
The ground path for high frequency signal return currents is shown in the probe
architecture figure. (See Figure 3 on page 5.) The probe ground path is continuous
and along the following path:
Extends from the DUT ground vias connections at the probe tip input
Through the probe tip ground path
Through the TekFlex connector ground spring contacts
Along the main cable coaxial shields into the probe comp box
Through the probe amplifier circuit board ground plane inside the probe comp
box, and
Through the TekConnect interface to the host oscilloscope ground
A TriMode tip requires a short DUT ground reference for making low noise
single-ended probe measurements.
Although two ground via connections are available on the probe tip input, a
single ground via wire connection is usually adequate for making single-ended
measurements of both the A and B input signals or a common-mode measurement,
all of which are ground referenced.
If only one single ended signal will be connected to the probe, the user has the
choice of connecting the A input to the signal and the B input to ground, or
connecting the A input to the signal and the ground input of the probe to the
ground input of the DUT. In this situation, Tektronix recommends using A-B
mode with the B input connected to ground. Reasons for this recommendation
include that with the B input left disconnected, there is a possibility of an
interfering signal coupling into the input of the probe and distorting the measured
signal acquired on the A side.
A second reason for using A-B vs. A-ground is that it is often more convenient to
connect the differential inputs of the probe to a device and keep the wire lengths
short. The ground connections of the probe are set back from the tip and may not
be as convenient to connect to a DUT with tightly spaced test points.
The optional accessory P77BRWSR is a variable-spacing probe tip which operates
in Differential Input mode only. The P77BRWSR Browser probe tip does not have
a physical ground connection at the probe tip; but the differential measurement
process itself provides a high frequency virtual ground connection between the
A and B signal input pins. A low frequency ground connection is optionally
available at a square-pin socket on the browser probe tip housing.
The comp box receives power and control signals from the oscilloscope through
the TekConnect interface. The TekConnect interface is an intelligent probe
connection that includes many automated and manual control features. For
example, there is a probe S-parameter memory in the comp box that stores high
frequency characterization data for the probe signal path.
8 P7700 Series TriMode Probes Technical Reference