Datasheet

SPECIFICATIONS AND ORDERING INFORMATION
for operation as a differential 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
100mV referred to input, from a 400 V input signal
within 100ns. 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 amplier’s inverting
(-) input. In this mode, the DA1855A can be used to very
accurately measure relatively small signals that are riding
on large AC or DCcomponents. Due to the precision of
the voltage gener ator, an oscilloscope, when used with the
DA1855A, can make voltage measurements that are much
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 amplier’s DC balance.
Specications
Main Specications
Bandwidth > 100 MHz
Electrical Characteristics
Rise time (typical) < 3.5 ns
Ordering Information
Product Description Product Code
Differential Ampliers
1 Ch, 100 MHz Differential Amplier 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 M
Ω Passive Attenuator for DXC Series Probes DA101*
2 Ch,100 MHz Differential Amplier 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 retrot)
*Must be used with DA Series Differential Ampliers
Customer Service
Teledyne LeCroy oscilloscopes and probes are designed, built, and tested
to ensure high reliability. In the unlikely event you experience difculties,
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
© 2010 by Teledyne LeCroy, Inc. All rights reserved. Specications, prices, availability, and delivery subject to change
without notice. Product or brand names are trademarks or requested trademarks of their respective holders.
DA1855A-DS-01nov13
1-800-5-LeCroy
teledynelecroy.com
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