2735DC
AND 2735PC 16-CHANNEL WIRE CHAMBER CARD
- Compact, Low Power
- Two Versions: For Drift and Proportional Chambers
- Appropriate for Chamber Mounting
- -2 µA Minimum Threshold, Remotely Settable
- Simple and Reliable: Uses Surface Mount Technology
- Negative or Positive Versions
- Protected Against HV Discharge
FOR USE WITH WIRE CHAMBERS IN PARTICLE, HEAVY ION, OR MEDICAL PHYSICS
APPLICATIONS
The Model 2735DC is an amplifier/discriminator optimized with short timeconstants for low slewing
applications. It is intended for drift chamberswith high resolution timing requirements and also useful
for multiwire proportionalchambers with short signal fall times. The low threshold of -2 µA can
be achieved with chamber-mounted opera tion without oscillations or multiple pulsing on threshold
-level signals provided that signal fall times are lessthan approximately 30 nsec. The 2735DC is also
appropriate for leading-edgetriggered, drift chamber readout without the above shape restrictions on
the chamber signals. The slower version, the 2735PC, is optimized for theslower timing of multiwire
proportional chambers but is otherwise identicalto the 2735DC.
Both cards accept 16
negative inputs via a printed circuit edge connector.A positive version is also available (MOD 100).
The inputs are protectedagainst discharges of up to 3 kV from 250 pF. The threshold of the 16 channels
can be commonly adjusted via a control voltage at the power connector orat the output connector. The
latter allows the cards to be programmed fromthe Model 2731A or Model 2730 PCOS III Receiver
modules.
The use of multichannel custom integrated circuits and surface-mount packaging
has resulted in simplicity and hence reliability and economy. The main componentsof the cards are
the custom monolithics TRA402S Amplifier and model MVL407SComparator. The use of these circuit
elements results in high sensitivityand a power dissipation of less than 375 mW per channel. The
positive versionis achieved by a jumper option. The TRA402S front-end amplifier was designed
for wire chamber inputs. Its low impedance, current-sensitive inputs areuniquely suited to chamber
applications, providing no extensive pulse integrationas characteristic of FET designs. This offers
high rate capability and optimumsensitivity to charge pulses from wire chambers.
The card offers a high impedance test input on the power connector. Applicationof a triangular
waveshape or pulse at this point injects a signal into allchannels simultaneously. This allows the
card to be tested in place.
The outputs are differential ECL, suitable for driving
twisted-pair cable.They are presented at a standard 34-pin header. The output duration is equal
to the time over threshold with a 7 nsec minimum.
SPECIFICATIONS
Model 2735DC
Conditions: V+ = 5.0 V, V- = 5.2 V, T = 25° C, Threshold = 1 V
corresponding to -2 µA.
Input Pulse (Neg): 5 nsec rise time, 30 nsec decay time constant.
Channels: 16.
Input Impedance: 150 ohm.
Input Offset Voltage: -0.7 V.
Input Coupling: Must be externally AC coupled, unless driven froma high
impedance source.
Input Protection: Protected against discharge of up to 3 kV from250 pF.
Threshold Control Voltage Input:
0.5 to 10 V, +500 mV/µA (±20%+100 mV/µA). Applied via power connector or output
connector. Current drawn is 12 mA at 10 V.
Minimum Threshold: -2 µA (typically -1 µA bench test).
Interchannel Isolation: > 45 dB for 10 nsec rise time. Betterfor slower signals.
Opposite Polarity Pulse Rejection: > 30 µA.
Propagation Delay: 15 nsec at 2 x threshold; 11.5 nsec at 20 x threshold.
Slewing (2x to 20x Threshold): 2.5 nsec.
Double Pulse Resolution: 20 nsec at 5 x threshold for 5 nsec; wideinput pulses.
Outputs: Complementary ECL outputs with on-board pull-down resistors,capable
of driving twisted-pair cables of 100 to 120 ohm impedance.
Output Pulse Width: Equal to time over threshold, except for effectsof hysteresis
and shaping time constant.
Minimum Output Pulse Width: 5 nsec at 2 x threshold.
Test Input: Via power connector. Minimum dV/dt for 2 µA input,approximately
20 mV/nsec; recommended width, 100 nsec.
Input Connector: 36-contact PC card-edge connector (0.254 cm centers),mates
with Viking 3VGH18/1JND5, LeCroy 455660036 (wire wrap); or Viking3VH18/1JV5 (solder tail).
Power Connector: 20-contact PC card-edge connector (0.254 cm centers).Mates
with LeCroy CK20P.
Output Connector: 34-pin header. Mates with LeCroy CK34.
Dimensions: 12.0 cm x 9.1 cm overall.
Power Requirements: 0.52 A at +5 V (+4.75 to +5.25 V); 0.68 A at-5.2 V
(-4.75 to -5.5 V).
Weight: 55 grams.
Model 2735PC
Conditions: V+ = 5.0 V, V- = 5.2 V, T = 25° C, Threshold = 1 V
corresponding to -2 µA.
Input Pulse (Neg): 5 nsec rise time, 100 nsec decay time constant.
Channels: 16.
Input Impedance: 150 ohm.
Input Offset Voltage: -0.7 V.
Input Coupling: Must be externally AC coupled, unless driven froma high
impedance source.
Input Protection: Protected against discharge of up to 3 kV from250 pF.
Threshold Control Voltage Input:
0.5 to 10 V, +500 mV/µA (±20%+100 mV/µA). Applied via power connector or output
connector. Currentdrawn is 12 mA at 10 V.
Minimum Threshold: -2 µA (typically -1 µA bench test).
Interchannel Isolation: > 45 dB for 10 nsec rise time. Betterfor slower signals.
Opposite Polarity Pulse Rejection: > 30 µA.
Propagation Delay: 20 nsec at 2 x threshold; 12 nsec at 20 x threshold.
Slewing (2x to 20x Threshold): 8 nsec.
Double Pulse Resolution: 35 nsec at 5 x threshold for 8 nsec; wideinput pulses.
Outputs: Complementary ECL outputs with on-board pull-down resistors,capable
of driving twisted-pair cables of 100 to 120 ohm impedance.
Output Pulse Width: Equal to time over threshold, except for effectsof hysteresis
and shaping time constant.
Minimum Output Pulse Width: 8 nsec at 2 x threshold.
Test Input: Via power connector. Minimum dV/dt for 2 µA input,approximately
20 mV/nsec; recommended width, 100 nsec.
Input Connector: 36-contact PC card-edge connector (0.254 cm centers),mates
with Viking 3VGH18/1JND5, LeCroy 455660036 (wire wrap) or Viking 3VH18/1JV5(solder tail).
Power Connector: 20-contact PC card-edge connector (0.254 cm centers).Mates
with LeCroy CK20P.
Output Connector: 34-pin header. Mates with LeCroy CK34.
Dimensions: 12.0 cm x 9.1 cm overall.
Power Requirements:
0.52 A at +5 V (+4.75 to +5.25 V); 0.68 A at-5.2 V (-4.75 to -5.5 V).
Weight: 55 grams.
Ordering Information
Negative Input: 2735DC or 2735PC.
Positive Input: 2735DC/MOD100 or 2735PC/MOD100.
(Positive versionavailable for quantities of > 250).
Copyright© October 1994. LeCroy is a registered trademark of
LeCroy Corporation.
All rights reserved. Information in this publication supersedes all earlierversions.
Specifications and prices subject to change without notice.