Tektronix Trimode TDP7700 Series Use and care manual

TDP7700 Series
TriMode™ Probes
Technical Reference
*P077142700*
077-1427-00

TDP7700 Series
TriMode™ Probes
Technical Reference
www.tek.com
077-1427-00
Revision A

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.

Table of Contents
Important safety information .............................................................................................................. iii
General safety summary ................................................................................................................ iii
Terms in the manual ...................................................................................................................... iv
Terms on the product ..................................................................................................................... iv
Symbols on the product ................................................................................................................. iv
Theory of operation
Introduction .................................................................................................................................... 1
Probe components ..................................................................................................................... 2
Probe tips ................................................................................................................................... 3
Probe input architecture .................................................................................................................. 5
TriMode operation ........................................................................................................................ 10
Operating voltages ........................................................................................................................ 12
Max non-desctruct input voltage ............................................................................................. 12
Input signal dynamic range ..................................................................................................... 13
Offset voltage .......................................................................................................................... 13
Operating voltage window ...................................................................................................... 17
Improving measurement accuracy ................................................................................................ 20
DSP correction filtering ........................................................................................................... 20
Solder-in tip connection wire length ....................................................................................... 21
Using offset voltage to extend TekFlex® solder-in tip input voltage range ............................ 23
Making single ended measurements using the P77BRWSR differential probe tip ................. 25
Temperature compensation ..................................................................................................... 25
Active tip measurement configuration .................................................................................... 25
Skew measurements of differential signals ............................................................................. 26
Reference
Differential measurements ............................................................................................................ 29
Common-mode rejection ratio ................................................................................................. 30
Assessing CMRR error ............................................................................................................ 31
Input impedance effects on CMRR ......................................................................................... 31
Differential-mode rejection ..................................................................................................... 31
Channel isolation ..................................................................................................................... 31
Specifications
TDP7700 Series TriMode Probes Technical Reference i

Impedance graphs ......................................................................................................................... 36
Nominal characteristics ................................................................................................................ 38
Environmental .............................................................................................................................. 38
Performance verification
Test record .................................................................................................................................... 39
Check system noise ...................................................................................................................... 40
Table of Contents
ii TDP7700 Series TriMode Probes Technical Reference

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 rating 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.
Provide proper ventilation. Refer to the installation instructions in the manual for
details on installing the product so it has proper ventilation.
Slots and openings are provided for ventilation and should never be covered or
otherwise obstructed. Do not push objects into any of the openings.
TDP7700 Series TriMode Probes Technical Reference iii

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 specified replacement parts.
Terms in the 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.
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 the marking.
■CAUTION indicates a hazard to property including the product.
Symbols on the product
The following symbols may appear on the product:
Important safety information
iv TDP7700 Series TriMode Probes Technical Reference

Theory of operation
Introduction
The TDP7700 Series TriMode Probes are designed for use with 6 Series MSO
and newer oscilloscopes. Three TDP7700 Series TriMode Probe models are
available with bandwidths from 4 GHz to 8 GHz. 6 Series MSO oscilloscope
models are available at comparable bandwidths. These probe and oscilloscope
models feature the high performance TekVPI intelligent probe interface. Several
TekFlex tip models are available to support different application requirements.
The TDP7700 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 TekFlex connector allows for quickly changing tip accessories with a simple
pinch to open operation. Accessories include small solder-in tips for accessing
high speed signals in tight spaces, a 2.92 mm adapter for connecting to fixtures
and pre installed test points and a high bandwidth adjustable browser for
debugging and non permanent connections.
Figure 1: TDP7700 Series TriMode probe components
TDP7700 Series TriMode Probes Technical Reference 1

Probe components TDP7700 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 TekFlex 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 FlexChannel probe interface. Power,
control signals, and the signal measured by the probe are transferred to and from
the oscilloscope through the FlexChannel interface. The comp box includes a
button to select the TriMode input mode for probe tips that support TriMode
functionality: (For more information see TriMode operation on page 10.)
■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 Setup
configuration menu. The Probe Setup configuration menu is also used to adjust
the probe Differential offset, Common mode offset, A side offset and, B side
offset voltage settings. All other TDP7700 Series probe internal controls, such as
vertical scaling, are handled automatically through communication between the
probe and oscilloscope.
CAUTION. To prevent damage to the probe, use care when handling the probe.
Rough or careless use can damage the probe.
LED indicators. There is a Status indicator LED located on the top plate of the
probe comp box. This LED is normally green, but turns red when any of the
following conditions exist and remains red until the problem condition is cleared:
■Probe power-on self-test failure (clear by disconnecting and reconnecting the
probe)
■Probe over-temperature detected (clear by disconnecting and reconnecting
the probe, allowing time for probe to cool)
■Probe input over-voltage detected (reduce input over-voltage to clear)
■Probe over current detected (adjust Vterm or remove input signal to clear)
If the LED is red, disconnect and reconnect the probe to restart the power-on
diagnostic sequence. If the symptoms continue, connect the probe to another
oscilloscope channel or oscilloscope. If the symptoms remain, return the probe to
Tektronix for repair.
Theory of operation
2 TDP7700 Series TriMode Probes Technical Reference

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.
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 TDP7700 Series probe and a TekFlex 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 TDP7700 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.
Probe tips The probe tips are automatically detected and displayed in the Probe Setup
configuration menu.
Figure 2: TekFlex active probe tips
Theory of operation
TDP7700 Series TriMode Probes Technical Reference 3

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.
Both P77STFLXA Flex circuit based solder tips and P77STFLXB Flex circuit
based DDR memory solder tips are available.
The first time the probe tip is detected, S-parameter data for the probe tip is sent
to the oscilloscope, and probe-tip specific DSP filters are generated. These filters
improve the measurement accuracy of high-frequency measurements.
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 specific
DSP filters are generated.
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.
Theory of operation
4 TDP7700 Series TriMode Probes Technical Reference

P77C292MM adapter. Use the P77C292MM, 2.92 mm adapter to connect a
TDP7700 series probe to a DUT with 50 Ω test point connectors. 2.92 mm
connectors are mechanically compatible with SMA connectors.
Figure 3: P77C292MM adapter
The adapter supports testing of serial standards such as HDMI, MIPI M-PHY,
and DisplayPort; cables and retainer are included.
After connecting the adapter to the flex cable, use the retainer to provide a secure
connection to the flex cable to minimize movement or to attach the adapter to the
hand’s free tripod.
For stacking more than one adapter, use the linkage adapter accessories to secure
the P77C292MM adapters together.
Probe input architecture
Input architecture TDP7700 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 TDP7700 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 TekFlex active probe tip
architecture.
Theory of operation
TDP7700 Series TriMode Probes Technical Reference 5

Figure 4: TDP7700 Series TriMode probe input architecture
The TekFlex 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 Ω also
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 specific probe 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 Ω tip
buffer output impedance and the 50 Ω probe amplifier termination impedance.
Table 1: Probe tip attenuation factors
Attenuation
factor
Rs Rp Dynamic range Offset voltage
range
4x 25 kΩ 25 kΩ 2.5 Vpp ±4.0 V
10x 60 kΩ 15 kΩ 6.0 Vpp ±10.0 V
Theory of operation
6 TDP7700 Series TriMode Probes Technical Reference

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.
TekFlex 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 Ω output 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 TekFlex 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.
The control features of the new TekFlex interface include two analog tip offset
voltage signals and a pair of digital communication signals for accessing the
probe tip S-parameter memory.
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 Ω termination 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 TDP7700 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 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.
Theory of operation
TDP7700 Series TriMode Probes Technical Reference 7

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 TekVPI
interface as a single-ended output.
The ground path for high frequency signal return currents is shown in the probe
architecture figure. (See Figure 4: TDP7700 Series TriMode probe input
architecture on page 6.) 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 TekVPI 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.
Theory of operation
8 TDP7700 Series TriMode Probes Technical Reference

The comp box receives power and control signals from the oscilloscope through
the TekVPI interface. The TekVPI 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.
The downloaded S-parameter data for a probe and attached probe tip is used by
the oscilloscope to generate a DSP correction filter for optimum measurement
fidelity. Because this S-parameter data is unique and serialized for each probe
and probe tip, it only needs to be downloaded once to an oscilloscope.
Automatic probe tip type identification is another example of the intelligent
operation of the TDP7700 Series probes. When no probe tip is attached to the
TekFlex connector of a TDP7700 Series probe, the TekFlex probe tip interface
power is disabled. When a probe tip is attached to the TekFlex connector, the
attachment is detected by the probe and the probe queries the probe tip memory
to check for a valid identification header. If a valid probe tip type is verified by
this TekFlex data interface query, the probe tip power is enabled until the probe
tip detachment is detected.
When probe tip power is enabled, an LED is activated on the probe tip, indicating
that the TekFlex interface and attached probe tip appear to be operating properly.
If the probe tip type attached to the TekFlex connector is a browser probe tip, the
probe tip automatically detects the current tip spacing and communicates that
information to the oscilloscope.
There are several calibrated tip spacing regions defined for the browser tip, which
affect the frequency response of the browser tip signal. Wider tip spacing tends to
degrade the browser tip frequency response. The oscilloscope uses the current tip
spacing region information to select the optimum DSP correction filter for use
with the browser tip measurements.
Input architecture with the
P77C292MM SMA adapter
The P77C292MM adapter is a passive probe adapter; there are no active
components within the adapter. It is intended to connect the TDP7700 series
probes to 50 Ω RF test points.
The following figure shows the simplified diagram of the TDP7700 Series
TriMode probe input architecture with the P77C292MM SMA adapter. Because
there are no active components within the adapter the A and B inputs are passed
through directly to the probe amplifier.
Theory of operation
TDP7700 Series TriMode Probes Technical Reference 9

Figure 5: TDP7700 Series TriMode probe input architecture with the P77C292MM SMA adapter
TriMode operation
The TriMode feature of the TDP7700 Series probes is designed for improved
convenience and enhanced capability in measuring differential signal quality.
Because a differential signal is composed of two complementary single-ended
signals, full characterization of a differential signal requires more than a simple
differential measurement.
A TriMode probe features four input modes that allow a differential signal to be
fully characterized with four measurements:
■Differential
■Positive polarity, single-ended
■Negative polarity, single-ended
■Common mode
A TriMode probe provides improved efficiency and convenience by enabling full
differential signal characterization from a single soldered connection.
TekFlex active probe solder tips support the TriMode functionality of a TDP7700
Series probe by buffering a matched pair of input signals from a DUT differential
signal connection. These active solder tips support the transmission of high-
frequency return currents through a probe tip ground path referenced to the DUT
ground connection.
Theory of operation
10 TDP7700 Series TriMode Probes Technical Reference

Using any of the TekFlex solder-in tips, probe connections are made to the two
complementary signals (the A signal and the B signal) and a ground reference.
From this single DUT connection, the internal electronic switching control of the
TriMode probe allows any one of the four probe input modes to be selected at a
time. The TriMode probe inputs are routed to an ASIC (application-specific
integrated circuit) inside the probe to a set of four independent input amplifiers
that perform the following signal calculations:
■A – B (for differential signal measurement)
■A – GND (for A input single-ended measurement)
■B – GND (for B input single-ended measurement)
■[A+B]/2 - GND (for common mode measurement)
NOTE. In the B – GND Mode, the negative polarity B input is not inverted.
The four input amplifiers are multiplexed together and only the selected input
mode function is sent to the connected oscilloscope. The following figure shows
a conceptual view of the TriMode probe input structure, where the C input
provides the probe ground reference and is connected to the probe tip ground
interconnect using the probe’s cable coaxial shields.
Figure 6: TriMode input structure
Theory of operation
TDP7700 Series TriMode Probes Technical Reference 11

Operating voltages
The TDP7700 Series probes are designed to probe high-frequency, low-voltage
circuits. Before probing a circuit, take into account the limits for the operating
voltages discussed in this section.
■Max non-destruct input voltage
■Input signal dynamic range
■Offset voltage
■Operating voltage window
Figure 7: TekFlex probe tip inputs
Max non-desctruct input
voltage
The maximum input voltage is the maximum voltage to ground that the inputs
can withstand without damaging the probe input circuitry. The TekFlex active
probe tips include some over-voltage protection circuitry at the probe tip signal
inputs. (See Figure 7: TekFlex probe tip inputs on page 12.) Transient voltage
suppression diodes, Da and Db, provide bidirectional voltage clamping of signals
applied to the probe tip inputs. These TVS diodes limit potential ESD damage as
well as signal over-voltage damage to the active tip buffer amplifier device.
CAUTION. To avoid damaging the inputs of the probe, do not apply more than
±15 V (DC + peak AC) between either probe input and ground.
Theory of operation
12 TDP7700 Series TriMode Probes Technical Reference