SPECIFICATIONS

CAMAC Model 2285A 24 CHANNEL ADC

Input Sensing

Charge (current integrating).

ADC Resolution

12 bits.

Full Scale

- 400 pC +/- 10%.

Common Mode Properties

For +/- 100 mV, CMRR of 40 dB at 60 Hz, 30 dB at 1 kHz for source impedance > 50 Ohm.

Gain Variations

+/- 10% deviation from mean.

Input Impedance

50 Ohm +/- 5%; 0 to - 60 mA.

Input Protection

+/- 25 V for 1 usec transients.

Input Limitations

Maximum voltage for linear response, - 1.5 V. For 3 V maximum input linearity is degraded to typically +/- (1 % of reading + 0.5 pC).

Integral Linearity

Typically +/-(0.l% of reading of +0.25 pC); worst case +/- (0.25% of reading +0.5 pC) for signals of slew rate =< 2 mA/nsec. For signals of slew rate 4 mA/nsec linearity is degraded to typically +/- (1% of reading + 0.5 pC).

Differential Linearity

Typically 25%.

Residual Pedestal

Typically 50 pC(subtracted from data by processor) for a gate width of 200 nsec and a high source impedance.

Pedestal-Gate Width Coefficient

< +/- 50 fC/nsec for gate widths >100 nsec.

Temperature Coefficient

Typically +/- (0.1% of reading + 0.00025 pC T)/'C where At = gate width in nsec.

Long-Term Stability

+/- (0.25% of reading + 0.5 pc)/week at constant temperature and voltage.

Conversion Time

200 usec nominal + 22 usec per ADC module.

Operating Temperature

0 to 40'C.

ADC Isolation

> 60 dB, including the effects of one input connector.

Gate Input

One per module, rear panel input driven from nonregenerative driver (via ASB) in 2280 System Processor module.

Gate Width

50 nsec to 1500 nsec. In operation with wide gates, ADC conversion gain depends on pulse position in ADC gate time. This dependence is typically 0.6%/usec.

Gate Timing

The gate input to the 2280 System Process or must precede the analog inputs by >=50 nsec.

Fast Clear

May be executed any time. Settles from full scale to within 1 count (100 fC) in < 2 usec.

Digital Clear

A digital clear is automatically generated by a fast clear &gt;=6 usec after the gate. Requires 3 usec to settle.

Test Feature

Exercised by 2280 System Processor. All channels have a test pulse applied. The amplitude of the pulse is proportional to a DC level applied to the Test Input (0 to + 8 V), typically 47 pC/volt. Matching to nominal of the test pulse is +/- 10%. Requires a gate width of => 300 nsec.

Analog Outputs

Current outputs proportional to input (~0.5 mA/mA) available at each hybrid for summing by user. Risetime > 25 nsec, 10-90%. Three output buffers on rear panel allow option for additional current summing. Gate feed through is typically 80 mV (into 50 ohms) for 16 channels, recovered in 80 nsec.

Readout and Control

Requires one Model 2280/85 Processor per CAMAC crate.

Packaging

No. 1 RF-shielded CAMAC module conforming to ESONE Report EUR 4100 and IEEE Standard 583.

Power Requirement

770 mA at + 6 V 160 mA at + 24 V (plus 1.5 times average input current) 325 mA at - 6 V Oat -24V

Special Options

15-bit operation and variable gain. Specially modified System Processor (Model 2280/85/15) allows 15-bit conversion. Side panel accessed jumpers allow external voltage program- ming of ADC gain over the range 10 to 30 counts/pC. Voltage range + 6.3 V to 2.1 V. The model 2285A/15 is tested at both 12- and 15-bit operation and at both 10 and 30 fC per count. Model 2285A specifications include only 12-bit 10 count/pC gain operation.

CAUTION: Sensitivity should be selected to give a full scale of 1000 pC or less.

Analog Input Cable

LeCroy Model DK6/50-Length. 4 per module. Includes AMP 226298-6 six-pair ribbon coaxial cable with termination by AMP 226651-6 connectors at both ends, plus one AMP 87606-2 bulkhead-mounting 6-pair connector


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