The LRS Model 127E is a fast, versatile bipolar linear fan-in featuring unity gain, non- inverting operation, direct-coupled circuit design and freedom from duty cycle limitations and rate effects. The Model 127E operates as either a dual 8-fold linear fan-in or as a single 16-fold linear fan-in. With rise and fall times of < 2.5 ns, and an absolute delay of less than 4 ns, the Model 127E may be used to combine nanosecond pulses from as many as sixteen different sources. All inputs are terminated in 50Ohm. Output is linear to +/- 1 .0 volt, and limits at 1 .8 volts. Pulses may be applied separately or simultaneously to one or both channels; channel inputs and output at ground potential allow compatible interconnection between units. The current source output stage permits paralleling, by external cables, a large number of similar high-output impedance channels. The front-panel pushbutton MIXED switch connects Channel A output to Channel B out put. The output amplitude of each channel is the algebraic sum of the input amplitudes. Negligible stretching on overload allows use as a logic fan-in of NIM level inputs.

The LRS Model 127E is a member of the leading line of high-speed logic instrumentation in which modern circuit design, components, and packaging are combined in instruments of unusually broad usefulness to experimental physicists in both high and low-energy nuclear research.

The LRS Model 127E is also available as the Model 127EL with Lemo-type connectors in a NIM #1 width module.

 INPUT CHARACTERISTICS

 Number of Channels:              2.

 Inputs:                    8 per channel; direct-coupled. ( Unused
                        inputs need not be terminated.)

 Impedance:                   50 Ohm.

 Polarity:                   Positive or negative.

 Reflection Coefficient:            Less than 7% for inputs of 2 ns risetime.

 Input Protection:               A built-in diode limiter  provides  protection
                        against overload,  and  a  constant  impedance
                        up to+ 1 00 volts. DC overload  characteris-
                        tics are determined by the 250 mW dissipation
                        limit of the 50 Ohm terminating resistor.

 OUTPUT CHARACTERISTICS

 Outputs:                    One per channel; direct-coupled, current
                        source.

 Maximum Amplitude:               Linear region; +/- 20 mA.     1 .0 volts into 50 Ohm)
                        Limits at +/- 36 mA ( +/- 1 .8 volts into 50 Ohm).

 Rise and Fall Times:              < 2.5 ns, 10% to 90%, with outputs  termin-
                        ated in 50 Ohm.

 Gain:                     Input to output: 1 .0 into 50 Ohm ( 20 mA out per
                        volt of input).

 Duty Cycle Limitations:            None.


 D.C. Offset:                Adjustable with front-panel potentiometer.

 Output Stability:              Better than 0.7 mV/'C with 50 Ohm load.

 Stage Delay:                4 ns.

 Overload Recovery:             Approximately 1 ns with eight simultaneous
                       NIM level ( -800 mV) inputs.

 Non-Linearity:               Less than 1% over operating range of 0 to +/- 1 .5
                       volts.

 GENERAL

 Output Mixing:               A front-panel switch combines the outputs of
                       the two 8-input channels to provide one 1 6-in-
                       put channel.

 Packaging:                 Model 127E-RF shielded AEC/NIM #2 module;
                       dimensions 2.75 x 8.75 x 1 0 inches deep. BNC
                       connectors.

                       Model 127EL-RF  shielded  AEC/NIM  #1  module;
                       dimensions 1 .375 x 8.75 x 1 0 inches deep.
                       LEMO - type connectors.

 Power Requirements:             + 24 volts at 25 mA, + 1 2 volts at 1 65 mA, - 1 2
                       volts at 150 mA, and -24 volts at 25 mA.


 NOTE: Be sure to terminate unused output with 50 Ohm
      when operating in single-16 mode.