The pc 25 test board may be used as an example of

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Unformatted text preview: ltra low noise of the A225, care should be taken in circuit layout. The PC-25 Test Board may be used as an example of appropriate layout technique. In general, ground plane construction is recommended. Input and output lines should be kept well separated and in most cases shielding will be necessary. Particular attention should be paid to the detector ground connection to avoid oscillation due to feedback. The supply voltage is internally decoupled. While this is normally adequate, in some applications external bypassing may be helpful. To facilitate noise minimization in certain applications, two separate ground connections are provided. Pin 4 is the ground connection for the input stage and is also connected to the case. Pin 5 is ground for the remainder of the circuit. In most applications Pin 4 and 5 may be connected to the same ground (preferably a ground plane under the unit) along with Pins 2,3,6,7,9,10 and 13. The A225 may also be used in applications where the input from the detector is positive by connecting Pin 5 (output ground) to a negative supply voltage instead of ground. This voltage can range from 0 to -10 V. A negative output pulse at Pin 8 will result from a positive input. The dynamic range in this case will be approximately 0.5 Volts greater than Pin 5. For example, with Pin 5 operated at -5 Volts, negative pulses of up to 5.5 Volts amplitude can be obtained. This mode of operation will result in increased operating current. The A225 is not specified in this mode and critical parameters should be verified by the user. Temperature: -55 to +125 ºC Operational Temperature Stability: 0.02% / ºC at 25 ºC typical ±2% from -25 to +75 ºC Screening: Amptek High Reliability Power Supply Package: 14 pin hybrid DIP (metal) Radiation Resistance: 100k rad(Si) Warranty: One year While specifications are given for operation at +5 V, the characteristics of the A225 are relatively unaffected by changes in supply voltage from +4 to +25 VDC. Parameters critical to a particular application should be checked at the actual operating voltage. Test Board: PC-25 For more information visit www.amptek.com OPERATING NOTES (Continued) Input In order to minimiz...
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