The A250F and A250F/NF are high density versions of the Amptek A250 Charge Sensitive Preamplifier.

The A250F includes the input FET (IFN152).

The A250F/NF does NOT include the input FET, online it must be added externally.

A250F

A250F – with Internal FET

The A250F is a high density version of the Amptek A250 Charge Sensitive Preamplifier.

The A250F includes the input FET (IFN152).

a250f configuration

A250F Pin Configuration

Pin 1 Input
Pin 2 FET Drain
Pin 3 Ground and Case
Pin 4 -Vs (-6 V Typical)
Pin 5 +Vs (+6 V Typical)
Pin 6 Output

NOTES

  1. The internal feedback resistor Rf = 1 Gohm
  2. The internal feedback capacitor Cf = 0.25 pF
    Sensitivity (gain) = 175 mV/MeV (Si)
    4 V/pC
    0.64 µV/electron
  3. For lower sensitivity applications, Cf can be increased externally
  4. The internal 1 kohm resistor from Pin 2 to Pin 5 provides the FET with a drain current of IDS = 2.75 ma
    IDS can be increased by adding an external resistor (R < 1 kohm) from Pin 2 to Pin 5

A250F/NF

A250F/NF – with External FET

The A250F/NF is a high density version of the Amptek A250 Charge Sensitive Preamplifier.

The input FET is not included and must be added externally.

a250fnf configuration

A250F/NF Pin Configuration

Pin 1 Feedback
Must be connected to Gate of the FET.
Pin 2 Input
Must be connected to Drain of the FET.
Pin 3 Ground and Case
Pin 4 -Vs (-6 V Typical)
Pin 5 +Vs (+6 V Typical)
Pin 6 Output

NOTES

  1. The internal feedback resistor Rf = 1 Gohm
  2. The internal feedback capacitor Cf = 0.25 pF
    Sensitivity (gain) = 175 mV/MeV (Si)
    4 V/pC
    0.64 µV/electron
  3. For lower sensitivity applications, Cf can be increased externally
  4. The external 1 kohm resistor from Pin 2 to Pin 5 provides the FET with a drain current of IDS = 2.75 ma
    IDS can be increased by reducing R < 1 kohm

PC250F Test Board

PC250F Test Board for the A250F or the A250F/NF

pc250f layout
Dimensions: 1.75 in X 1.75 in (4.5 cm X 4.5 cm)

pc250f schematic

Mechanicals

a250f and a250f/nf mechanicals

Weight: 1.6 g with leads cut to 0.100 in (2.5 mm).