IBM 7220, Instruction Manual

Page: 112 / 155

A-2
Appendix A, SPECIFICATIONS
Current Input
Mode Low Noise or Wide Bandwidth
Full-scale Sensitivity
Low Noise 20 fA to 10 nA in a 1-2-5 sequence
Wide Bandwidth 20 fA to 1 µA in a 1-2-5 sequence
Dynamic Reserve > 100 dB (with no signal filters)
Frequency Response
Low Noise -3 dB at 500 Hz
Wide Bandwidth -3 dB at 50 kHz
Impedance
Low Noise < 2.5 k
Ω
at 100 Hz
Wide Bandwidth < 250
Ω
at 1 kHz
Noise
Low Noise 13 fA/
√
Hz at 500 Hz
Wide Bandwidth 130 fA/
√
Hz at 1 kHz
Gain Accuracy (midband)
Low Noise
≤
0.6 % typ
Wide Bandwidth
≤
0.6 % typ
Line Filter attenuates 50, 60, 100, 120 Hz
Grounding BNC shields can be grounded or floated via
1 k
Ω
to ground
Reference Channel
TTL Input (rear panel)
Frequency Range 1 mHz to 120 kHz
Analog Input (front panel)
Impedance 1 M
Ω
// 30 pF
Sinusoidal Input
Level 1.0 V rms**
Frequency Range 1 Hz to 120 kHz
Squarewave Input
Level 100 mV rms**
Frequency Range 300 mHz to 120 kHz
**Note: Lower levels can be used with the
analog input at the expense of increased phase
errors.
Phase
Set Resolution 0.01º increments
Accuracy 0.5º typ
Noise at 100 ms TC, 12 dB/octave
Internal Reference < 0.0001º rms
External Reference < 0.01º rms at 1 kHz