Keysight N2894A User manual

N2870A-Series and
N2894A Passive Probes
User’s
Guide

2
Notices
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- 2014, 2016, 2018
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Manual Part Number
N2876-97002
Edition
October 2018
Printed in Germany
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Safety Notices
CAUTION
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formed or adhered to, could
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notice until the indicated condi-
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Keysight N2870A-Series and N2894A Passive Probes User’s Guide

Keysight N2870A-Series and N2894A Passive Probes User’s Guide 3
Contents
Introduction 4
Safety Information 7
Low-Frequency Compensation 9
Accessories 10
Replacing Rigid, Solid Probe Tip, and Spring-Loaded Probe Tips 11
Short Ground Blade and Ground Spring 12
Sprung Hooks 13
15 cm Ground Lead 13
BNC Adapter 13
Copper Pads 14
Insulator Cap 14
Channel Identification Rings 14
IC Caps 15
PCB Adapter Kit 16
Available Accessories 17
Accessories in Kits 17
Other Individually Orderable Accessories 21
Characteristics and Specifications 24
Performance Verification Procedures 29
Performance Verification Test Record 32
IEC Measurement Category Definitions 33
IEC Pollution Degrees Definitions 34

Introduction
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
4
Introduction
When used with a Keysight oscilloscope, the N2870A-Series and N2894A passive
probes set a new standard for “high performance” probing of up to 1.5 GHz. These
general purpose probes and accessories are a great choice if you are looking for
high quality at a very reasonable price.
Table 1 Probe Models
Model Band width
(-3 dB)
Attenuation
Ratio
Input C Input R
(scope +
probe)
Max Input
Vol tage
(AC RMS)
Scope Input
Coupling
Scope
Comp
Range
N2870A 35 MHz 1:1 39 pF
(+scope)
1 MΩ55 V CAT II 1 MΩ—
N2871A 200 MHz 10:1 9.5 pF 10 MΩ400 V CAT Ia
300 V CAT IIb
1 MΩ10 - 25 pF
N2872A 350 MHz 10:1 9.5 pF 10 MΩ400 V CAT Ia
300 V CAT IIb
1 MΩ10 - 25 pF
N2873A 500 MHz 10:1 9.5 pF 10 MΩ400 V CAT Ia
300 V CAT IIb
1 MΩ10 - 25 pF
N2874A 1.5 GHz 10:1 1.8 pF 500 Ω8.5 V CAT Ic50 Ω—
N2875A 500 MHz 20:1 5.6 pF 20 MΩ400 V CAT Ia
300 V CAT
IIb
1 MΩ7-20 pF
N2876A 1.5 GHz 100:1 2.2 pF 5 kΩ21 V CAT Ic50 Ω—
N2894A 700 MHzd10:1 9.5 pF 10 MΩ400 V CAT Ia
300 V CAT IIb
1 MΩ10 - 25 pF
a Measurement Category I, 1250 V transient overvoltage
bMeasurementCategoryII
c Measurement Category I, 0 V transient overvoltage
d 700 MHz bandwidth available with InfiniiVision 4000X/6000X with 1 GHz or higher bandwidth models only

Introduction
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 5
Faithful Reproduction of Signals
These probes offer bandwidths of 35 MHz, 200 MHz, 350 MHz, 500 MHz, 700 MHz,
and 1.5 GHz along with various attenuation ratios to address a wide range of mea-
surement needs. For general purpose probing, the N2873A’s superior 10 MΩinput
resistance, 9.5 pF of low input capacitance, and low inductance ground connection
keep probe loading low enough to achieve high signal integrity measurements. The
1.5 GHz passive probe offers an even lower input capacitance for measuring faster
edges more accurately, making it a good low-cost alternative to an active probe. All
of these probes are automatically recognized when connected to Keysight
InfiniiVision and Infiniium Series oscilloscopes.
Easy Access to Signals
The compact design along with a 2.5 mm probe tip diameter provide better visibility
of the circuit under test when compared to the conventional 5 mm or 3.5 mm
probes. This makes it easier to probe today’s fine pitched ICs and components. To
learn more about probe tips and accessories, refer to “Accessories" on page 10.
Inspecting the Probe
• Inspect the shipping container for damage.
Keep the damaged shipping container or cushioning material until the contents
of the shipment have been checked for completeness and the probe has been
checked mechanically and electrically.
• Check the accessories.
If the contents are incomplete or damaged, notify your Keysight Technologies
Sales Office.
• Inspect the instrument.
If there is mechanical damage or defect, or if the probe does not operate
properly or pass performance verification tests, notify your Keysight
Technologies Sales Office.
If the shipping container is damaged, or the cushioning materials show signs of
stress, notify the carrier as well as your Keysight Technologies Sales Office. Keep
the shipping materials for the carrier’s inspection. The Keysight Technologies office
will arrange for repair or replacement at Keysight Technologies’ option without
waiting for claim settlement.

Introduction
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
6
Cleaning the Probe
Disconnect the probe and clean it with a soft cloth dampened with a mild soap and
water solution. Make sure the probe is completely dry before reconnecting it to an
oscilloscope.
Handling the Probe
Handle the probe with care to avoid injury, especially when it is fitted with the extra
thin and sharp spring contact tip.
CAUTION
The probe cable is a sensitive part of the probe and, therefore, you
should be careful not to damage it through excessive bending or pulling.
You should also avoid any mechanical shocks to this product in order to
guarantee accurate performance and protection.

Safety Information
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 7
Safety Information
WARNING
To avoid personal injury and to prevent fire or damage to this product or
products connected to it, review and comply with the following safety
precautions. Be aware that if you use this probe assembly in a manner
not specified, the protection this product provides may be impaired.
WARNING
Handle Probe Tips / Accessories Carefully. Some of the probe tips /
accessories are very sharp (the spring tips and ground spring, for
example). You should handle these with care to avoid personal injury.
WARNING
Use Only Grounded Instruments. Do not connect the probe’s ground lead
to a potential other than earth ground. Always make sure the probe and
the oscilloscope are grounded properly.
WARNING
Connect and Disconnect Properly. Connect the probe to the oscilloscope
and connect the ground lead to earth ground before connecting the
probe to the circuit under test. Disconnect the probe input and the probe
ground lead from the circuit under test before disconnecting the probe
from the oscilloscope.
WARNING
Observe Probe Ratings. Do not apply any electrical potential to the probe
input which exceeds the maximum rating of the probe. Make sure to
comply with the voltage versus frequency derating curve on page 9.
WARNING
Keep Away From Live Circuits. Avoid open circuitry. Do not touch
connections or components when power is present.

Safety Information
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
8
WARNING
Indoor Use Only. Do not operate in wet/damp environments. Keep
product surfaces dry and clean.
WARNING
Do Not Operate With Suspected Failures Refer to qualified service
personnel.
WARNING
Do Not Operate in an Explosive Environment.

Low-Frequency Compensation
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 9
Low-Frequency Compensation
The N2871A, N2872A, N2873A, N2875A, and N2894A can be adjusted for low fre-
quency (LF) compensation. The N2870A, N2874A, and N2876A cannot be adjusted.
The probe should be adjusted for LF com-
pensation when it is connected to an oscil-
loscope input for the first time. LF
compensation matches the probe cable
capacitance to the oscilloscope input
capacitance. This matching assures good
amplitude accuracy from DC to the upper
bandwidth limit frequencies. A poorly com-
pensated probe clearly influences the over-
all system performance (probe and
oscilloscope) and introduces measurement errors resulting in inaccurate readings
and distorted waveforms. To perform the LF compensation:
To perform the LF compensation:
1 Connect the probe to the oscilloscope’s front-panel calibration output (a square
wave label is usually seen near this output).
2 Use the supplied trimmer tool to adjust the LF compensation to an optimum
square wave response as shown in this picture.
Figure 1 LF Compensation

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
10
Accessories
The probe comes with the accessories listed in Table 2. For a broader range of
available accessories, order the accessory kits described in “Available Accessories" on
page 17.
Table 2 Supplied Accessories
Accessory Quantity N2871A,
N2872A,
N2873A,
N2875A,
N2894A
N2870A N2874A,
N2876A
Spring-loaded probe tips 2 
Rigid probe tips 2 
Ground blade 2.5 mm 1 
Ground spring 2.5 mm 1 
Sprung hook 2.5 mm 1 
Short sprung hook 2.5 mm 1 
Ground lead 15 cm 1 
Copper pads 2 
IC cap 2.5 - 0.5 mm green 1 
IC cap 2.5 - 0.65 mm blue 1 
IC cap 2.5 - 0.8 mm gray 1 
IC cap 2.5 - 1.0 mm brown 1 
IC cap 2.5 - 1.27 mm black 1 
BNC adapter 2.5 mm 1 
Insulating cap 2.5 mm 1 
Protection cap 2.5 mm 1 

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 11
Replacing Rigid, Solid Probe Tip, and Spring-Loaded Probe Tips
The solid tips and spring-loaded tips are replaceable. Spring
loaded probe tips offer a method of probing signals that is
less susceptible to vibration or movement than traditional
rigid tips. Many users find it easier to use this type of tip. The
spring loaded tips work when they are either partially or fully
compressed and are protected against over compression
damage.
To change the probe tip, use pliers to grip the tip
and pull it straight out of its contact socket along
the axis of the probe. Do not grip the plastic insula-
tor or the housing with the pliers because the tip
could be crushed (see Figure 2). This could result in
being unable to remove the tip and/or damaging
the probe. Once the probe tip is removed, the new
tip can be inserted with pliers into the contact socket along the axis of the probe. In
order to insert the probe tip completely into the housing, carefully press the probe
tip against a hard surface.
Trimmer tool 1 
Color coding rings 3x4 colors 
User’s Guide 1 
Accessory Quantity N2871A,
N2872A,
N2873A,
N2875A,
N2894A
N2870A N2874A,
N2876A

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
12
Figure 2 Proper Tip Removal Technique
Short Ground Blade and Ground Spring
The short ground blade is the best performing
ground connection available due to its low induc-
tance. To attach the ground blade, simply push it
over the probe tip and continue pushing until the
blade is inserted into the notch located on the probe
barrel, as shown in Figure 3. This will keep it from spinning around on the probe
while in use. You can also bend and form the blade to reach your grounding loca-
tion. In the picture, you can see that the ground blade was placed over the tip and
then an IC cap accessory was placed over the tip.
Figure 3 Blade inserted into the Probe Notch
The ground spring offers similar performance as the ground blade and depending
on the probing situation, may offer greater flexibility when making a ground con-
nection. The ground spring is also inserted over the probe tip in a similar manner. It
is mainly used for browsing as it is flexible and snaps back to original orientation
(unlike the ground blade that you can form) which allows you to connect it to your
grounding location and then move the probe tip around. It does have a slightly
larger inductance than the ground blade which may result in some decrease in per-
formance depending on the application.
WARNING
You should exercise caution when using these sharp probe tips to avoid
personal injury.

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 13
Sprung Hooks
You will see a gray line (shown as black in the picture
below) with an arrow pointing towards it on the barrel of
your N287XA Series probe. This is used as a marker to tell
you when you have pushed the sprung hook completely
onto the probe. When inserting the sprung hook onto the
probe barrel, push until you feel it lock onto the ridge (see
Figure 4). If you do not push the sprung hook to this point so it can engage and
“lock on” to the probe, the accessory may fall off or suffer a decrease in perfor-
mance. If the sprung hook is correctly attached then the gray marking line should
be covered when the hook is fully extended
Figure 4 Ridge Location on Probe
15 cm Ground Lead
This ground lead can be used to reach grounding loca-
tions that are farther away from the probing location
than can be reached by either the ground blade or
ground spring. However, the longer lead means it has
a larger inductance in the ground return path which
corresponds to a lower performance than these other
two grounding accessories.
BNC Adapter
Both the rigid and spring-loaded probe tips are compatible with
this adapter.

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
14
Copper Pads
These self adhesive copper pads can be attached on top of
an IC and connected to its ground pins to create a conve-
nient ground plane for the probe to connect to. When used
with the ground blade, this method provides an ideal
ground connection for probing signals with high frequency
content. However, to maximize the performance of this
setup, you need to connect the copper pad to as many
grounding locations as possible.
Figure 5 Copper Pad on IC
Insulator Cap
This cap fits over the probe tip and covers the ground barrel of the
probe, covering any potential shorting locations near the tip. This
enables you to probe in hot environments without having to worry
about shorts.
Channel Identification Rings
The channel identification rings can be used to keep track of which
probe is connected to which channel input on your oscilloscope. Place
one ring on the probe cable near the oscilloscope input and place
another ring of the same color near the probe head. This ensures that
you can pick up a probe and immediately know which channel it is con-
nected to without having to track the cable back to the oscilloscope channel input.

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 15
IC Caps
The IC caps fit over the probe tip and provide a convenient
self-aligning connection to an IC’s pins. This helps main-
tain contact on small fine pitch legs and prevents shorting
adjacent pins by preventing the probe tip from sliding
between the legs of the component.
The different colored IC caps correspond to different
pitches as listed in Table 2 on page 10.
Figure 6 shows how pitch is measured and how the caps
fit around the IC pins and where the probe tip comes
through the cap. IC caps are compatible with both the
rigid and spring loaded tips.
Figure 6 View of Top of IC with IC Cap Positioned Over IC Pin (not drawn to scale)

Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
16
PCB Adapter Kit
The PCB Adapter Kit is not included in the Standard
Accessories. However, the PCB Adapter Kit does not
include its own documentation so its features will be
documented in this User’s Guide. The PCB Adapter
sockets are designed to solder into a printed circuit
board (PCB) as test points to minimize ground inductance and maximize signal
fidelity.
The recommended PCB layout is shown in Figure 7. The PCB socket is compatible
with hand soldering and reflow processes. After soldering the socket - both the sig-
nal contact and ground contact - to the board, simply insert the probe. The PCB
adapter is compatible with either the rigid or spring-loaded probe tip.
Figure 7 Recommended PCB Layout

Available Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 17
Available Accessories
Accessories in Kits
The available accessories shown in this picture are listed in Table 3 on page 19 with
their associated accessory kits.

Available Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
18

Available Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide 19
Table 3 Accessory Quantity in Kits
Optional Accessory N2877A
Deluxe
Kit
N2879A
Fine Pitch
Kit
N2878A
General
Purpose Kit
N2885A
PCB Socket
Adapter Kit
Accessory
P/N
IC Cap 2.5 - 0.5 mm green 3 3 1 — 0960-2983
IC Cap 2.5 - 0.65 mm blue 3 3 1 — 0960-2984
IC Cap 2.5 - 0.8 mm gray 3 3 1 — 0960-2988
IC Cap 2.5 - 1.0 mm brown 3 3 1 — 0960-2989
IC Cap 2.5 - 1.27 mm black 3 3 1 — 0960-2986
Insulating Cap 2.5 mm 1 1 1 — 0960-2985
Protection Cap 2.5 mm 1 1 1 — 0960-2996
LF Compensation Trimmer Tool 1 — — — —
HF Compensated Ground Lead 22 cm 1 — — — 0960-2993
Ground Lead 22 cm to 4 mm banana plug 1 — — — —
Ground Lead 22 cm to 2 mm banana plug 1 — — — —
Ground Lead 11 cm to miniclip 1 — — — 0960-2977
Ground Lead 11 cm to 0.8 mm socket 1 — — — 0960-2978
Ground Spring 2.5 mm 3 3 — — 0960-2980
Self-adhesive Cu-pads
(2 x 2 cm)
10 10 10 — 0960-2908
Ground Blade 2.5 mm 3 3 1 — 0960-2982
Ground Lead 2.5 to mini Alligator Clip 1 — — — 0960-2991
Ground Lead 2.5 to 0.8 mm socket 1 — — — 0960-2994
Set of 5 Spring Tips Gold-plated 0.5 mm 1 1 1 — 0960-2981
Set of 5 Solid Tips CuBe 0.5 mm 1 1 1 — 0960-2979
Adapter 2.5 to 2 mm banana plug 1 — — — —
Adapter 2.5 to 0.8 mm socket 2 — — — 0960-2990
Dual Adapter 2.5 to 0.8 mm sockets 2 2 — — 0960-2898

Available Accessories
Keysight N2870A-Series and N2894A Passive Probes User’s Guide
20
Sprung Hook 2.5 mm 1 — 1 — 0960-2905
Short Sprung Hook 2.5 mm 1 — — — 0960-2907
Adapter 2.5 to 4 mm banana plug 1 — — — —
Pico Hook black 2 2 — — —
Pico Hook red 2 2 — — —
BNC Adapter 2.5 mm 1 — — — 0960-2987
PCB Adapter Kit 2.5 mm 1 10 — 25 —
QFP IC-Clips 13 mm long down o 0.5 mm
pitch (1 pair yellow/green)
22——0960-2992
QFP IC-Clips short down to 0.5 mm pitch
(1 pair yellow/green)
22——0960-2995
Ground Lead 15 cm 1 — 1 — 0960-2906
Channel Identification Rings, 4 colors 3 — 3 — —
2-leg Probe Positioner 1 1 — — N2786-6000
1
MicroSMDClip 12———
Optional Accessory N2877A
Deluxe
Kit
N2879A
Fine Pitch
Kit
N2878A
General
Purpose Kit
N2885A
PCB Socket
Adapter Kit
Accessory
P/N