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A275 Pulse Amplifier

The A275 is a high performance hybrid differential op-amp developed as a pulse amplifier for instrumentation.

Its low power dissipation (15 mW), high slew rate (100 V/µs), and low input noise (4 nV/? Hz) make it ideal for use in a wide range of op-amp applications. The A275 is packaged in a standard 14 Pin hybrid DIP and is also available in a SIP as the A275F.

Features

  • Power 15 mW
  • Slew Rate 100 V/µs
  • Input Noise 4 nV/√Hz
  • Stable DC Operation
  • 200 MHz Gain-Bandwidth Product
  • High Reliability Screening
  • Unity Gain Stable

 

  • Specifications +


    Absolute Maximum Ratings

    Supply Voltage ±8 V
    Input Voltage ±VS
    Operating Temperature -55 °C to +125 °C
    Storage Temperature -65 °C to +150 °C
    Lead Temperature Range (Soldering, 10 sec.) +300 °C

    General

    Screening Amptek High Reliability
    Mean Time Between Failure (MTBF) 1.6/106  hrs @ +60 °C
    Package 14 Pin hybrid DIP, also available in a SIP as the A275F.
    Weight 3.8 g

    Electrical Characteristics

    VS = ±6 V, TA = +25 °C

    Parameter Symbol Conditions Min Typ Max Units
    Input Offset Voltage
    Uncompensated/Compensated    		 VOS 2 5/7 mV
    Input Offset Current IOS 0.1 0.6 µA
    Input Bias Current IB 1.5 4 µA
    Input Capacitance CIN 4 pF
    Differential Input Resistance RIN 44 kohm
    Common-Mode Input Resistance RIN >5 8 Mohm
    Common-Mode Rejection Ratio CMRR 90 95 dB
    Common-Mode Input Range IVR ±4.5 V
    Power Supply Rejection Ratio PSRR 60 dB
    Large-Signal Voltage Gain
    @5kHz
    @5kHz
    @10MHz
    @10MHz    		 ALFC
    ALF
    AHFC
    AHF    		 compensated
    uncompensated
    compensated
    uncompensated    		 64
    72
    16
    24    		 66
    74
    20
    28    		 dB
    Pulse Risetime (AV = 10) trc
    tr    		 compensated
    uncompensated    		 15
    9    		 22
    15    		 ns
    Output Voltage Swing VOP
    VON    		 positive
    negative    		 +4.2 +4.4
    -5.0    		 -5.5 V
    Open Loop Output Resistance RO 750 ohm
    Output Short-Circuit Current IOSC source
    sink    		 11
    -4    		 mA
    Slew Rate SRP
    SRN    		 positive
    negative    		 65
    35    		 100
    40    		 V/µs
    Input Noise Voltage Density eN 4 nV/√Hz
    Supply Current IS ±1.1 ±1.25 ±1.4 mA
    Power Consumption PD 15 mW

    Connection Diagram and Pin Out

    Pin Function
    1 Inverting input
    2 Non-inverting input
    3 Bias adjust to Pin 4, (R > 3 kohm) Frequency De-Compensation
    This resistor will increase the current to the input stage and increase the bandwidth
    4 -Vs direct
    5 -Vs through 50 ohms
    6 Compensation to Pin 7, (C = 0 to 5 pF)
    Frequency Compensation to decrease the bandwidth
    7 Case and Ground
    8 Output through 50 ohms
    9 Output direct
    10 +Vs through 50 ohms
    11 +Vs direct
    12,13,14 Compensation (leave open for gain < 10, short for gain > 10)

    The A275 is also available in a SIP package as the A275F.

  • Operating Notes +


    A275 gain & phase

    A275 pulse characteristics

    Upper: Input pulse
    First output: 3 pole
    Second output: 5 pole

    Circuit Layout Considerations

    Due to the high bandwidth of the A275, care should be taken in circuit layout. In general, ground plane construction is recommended. Input and output lines should be well separated and in most cases shielding will be necessary. Grounding the physical case of the A275 (in addition to Pin 7) to the ground plane can be used to avoid oscillations or electronic pick-up.

  • Applications +


    Connection to a solid state detector with 5 pole shaping and active baseline restoration

    General case for 3 and 5-pole response for different peaking times (TP)

  • PC275 Test Board +


    PC-275

    The A275 can be tested as a shaping amplifier by using the circuit shown below.
    The PC-275 Test Board accommodates three (3) A275s and a BLR1 and produces a 5-pole pulse with 1 µs risetime (2.3 µs peaking time).


    Figure 4. PC-275 layout. Dimensions: 3.5 in X 1.75 in (88.9 mm X 44.45 mm)


    Figure 5. The A250 connected to a solid state detector with 5-pole shaping and active baseline restoration (BLR1). The PC-275 Schematic begins at the output of A250.

  • Mechanicals +


  • Documentation +