
SPECIFICATIONS AND ORDERING INFORMATION
comparator or applied internally as a true differential offset
voltage. The PVG is also available for external use through
a rear panel connector.
The DA1855A operates from 90 to 250 VAC line without
line switching. High-performance differential probes
such as the DXC100 ÷10/÷100 high CMRR probes are
recommended.
Overdrive Recovery
With a ÷100 probe, the DA1855A settles to within
100mV referred to input, from a 400 V input signal
within 100ns. With attenuating probes, this allows
the in circuit measurement of dynamic saturation in switch
mode power converter switching devices.
Comparator Mode
The DA1855A becomes a differential comparator when
the internal PVG output is selected as the amplier’s
inverting (-) input. In this mode, the DA1855A can be used
to measure relatively small signals that are riding on large
AC or DCcomponents (within the precision and accuracy
limitations of the PVG). Therefore, an oscilloscope, when
used with the DA1855A, can make voltage measurements
that are much often more accurate than the oscilloscope is
capable of by itself. The output of the PVG is available for
external use via a rear panel connector.
True Differential Offset Mode
The DA1855A has built-in Precision Voltage Generator
can be used to generate a true differential offset while still
allowing both inputs to be used as differential inputs. The
offset range can be as high as ±50,000 divisions and the
generator has 5 1/2 digit resolution. This mode facilitates
making measurements such as changes to a transistor’s
base to emitter voltage caused by variations in temperature
and/or current. Used in this mode, the voltage generator
can be set to a value that will zero out the static value
of the junction’s on voltage. The DA1855A’s differential
measurement capability will reject any dynamic signal
common to both sides of the junction, and the oscilloscope
is left to measure only the changes in the junction voltage.
Autobalance
Each time either gain setting button is pressed, the
DA1855A automatically adjusts the amplier’s DC balance.
Specications
Main Specications
Bandwidth > 100 MHz
Electrical Characteristics
Rise time (typical) < 3.5 ns
Ordering Information
Product Description Product Code
Differential Ampliers
1 Ch, 100 MHz Differential Amplier DA1855A
with Precision Voltage Source
÷100 or ÷10 Selectable, 250 MHz DXC100A*
Passive Differential Probe Pair
÷1, 50 MHz Passive Differential Probe Pair DXC200*
÷100, 250 MHz 2.5kv, High Voltage Probe Pair DXC-5100*
(requires DA101 for full performance)
Ordering Information (cont’d)
Product Description Product Code
÷10 1 MΩ Passive Attenuator for DXC Series Probes DA101*
2 Ch,100 MHz Differential Amplier DA1855A-PR2
with Precision Voltage Source
DA1855A with Rackmount DA1855A-RM
DA1855A with Rackmount DA1855A-PR2-RM
(must be ordered at time of purchase, no retrot)
*Must be used with DA Series Differential Ampliers
Customer Service
Teledyne LeCroy oscilloscopes and probes are designed, built, and tested
to ensure high reliability. In the unlikely event you experience difculties,
our digital oscilloscopes are fully warranted for three years and our probes
are warranted for one year.
This warranty includes:
• No charge for return shipping • Long-term 7-year support
• Upgrade to latest software at no charge
© 2018 by Teledyne LeCroy, Inc. All rights reserved. Specications, prices, availability, and delivery subject to change
without notice. Product or brand names are trademarks or requested trademarks of their respective holders. da1855a-ds-07feb18
1-800-5-LeCroy
teledynelecroy.com
Local sales ofces are located throughout the world.
Visit our website to nd the most convenient location.