Performance of the CMP16E chip
(Data from ASIC Chip Test Stand at Fermilab, Feb. - Mar. 2000)

blue_ball.gif Introduction.

The ASIC 16-channel chips CMP16E (Sep. 1999 submission, a total of 30 ) installed on the anode front end boards AD16 have been tested on the ASIC chip test stand at Fermilab during Feb. - Mar., 2000. The parameters of the CMP16E chips are in N.Bondar's talk at the EMU meeting in Florida. After preliminary test, 6 chips from the 30 were rejected as bad. Here we present the results of measurements of the

threshold, noise, gain, discriminator offset, time resolution and slewing time for the remaining 24 chips. The identification numbers of the corresponding AD16 boards are: 15 - 28, 30, 31, 36, 38 and 39 - 44. Since the board has only one chip installed on it, we refer to the board numbers as the chip numbers.

blue_ball.gif Conditions.

The shape of the input test pulse is shown here. The amplitude of the test pulse is a linear function of the DAC code with a zero offset. Two calibrations were used, having at DAC=4000 the maximum amplitude value of 668 mV and 722 mV for chips 15-28 and 30-44 correspondingly (chips 30-44 were tested later with different calibration settings). The injection capacitance was Cinj =1.6 pF.

Attenuators of 6, 10 and 20 dB were used to adjust the interval of the input signal amplitudes. The threshold was controlled by JTAG, measured in mV. A usual, the threshold goes down as the JTAG value increases (Qthr=0 at JTAG=1600 mV and Qthr=17.5 fC at JTAG=1500 mV). For all data the detector capacitance Cdet was set to 180 pF.

blue_ball.gif The threshold, noise, gain and discriminator offset measurements (Fig. 1).

- The threshold (Qthr) and the noise for each channel have been measured at three JTAG settings (JTAG = 1100, 1300 and 1500 mV) and attenuation of 10 dB. Results are presented for JTAG = 1500 mV (page 1 in Fig. 1)). The gain and the offset are obtained from a fit to the Qthr at all three JTAGs (pages 12,17 in Fig. 1). The means and widths of the distributions for all chips together, as well as widths of the

channel residuals (pages 8,19 in Fig. 1), are given in the Table below. Chips 16, 20, 23, 31, 38 and 40 (total of 6 out of 24, see page 21 in Fig. 1) have too big a difference between the maximum and minimum values of the parameter within the chip (each chip has 16 channels). See also page 22 in Fig. 1. There, the minimum, maximum and mean values are plotted for each chip.

blue_ball.gif The time resolution and its variation (Fig. 2).

The time resolution was measured at JTAG=1500 mV and attenuation of 6 dB (25 fC < Qin < 535 fC). Data are available for chips 16, 17, 19-22 and 26-27, a total of 8 chips. The time resolution was calculated for each channel of the measured chip as the RMS of the

time distribution for that channel. Page 1 in Fig. 2 presents the RMS at Qin=100 fC and the variation of the RMS, which was defined as Max(RMS) - Min(RMS) in the interval of 50 fC < Qin < 500 fC.

blue_ball.gif The mean time and slewing time (Fig. 3).

The data were taken at JTAG=1500 mV and attenuation of 6 dB and 20 dB. Two attenuators were needed to take into account the pulser slewing time contribution. Data are available for chips 15, 17-19, 21-22 and 24-28, a total of 11 chips. The measured parameters are the mean of the time distribution for each channel at Qin=100 fC and,

the slewing time which was defined as Max(mean)-Min(mean) in the interval of 40 fC < Qin < 535 fC for each channel (page 1 in Fig. 3). In general, the channels within one chip are very similar, except for chips #19 and #21 (see page 7 in Fig. 3).

blue_ball.gif Tables.

- Threshold, noise, gain and discriminator offset.
Mean and sigma are from the Gaussian fit.
ParameterMean SigmaPage # in Fig. 1
Threshold, fC17.5 4.21
Threshold (residual), fC - 1.8 8
Noise, fC1.4 0.2 1
Noise (residual), fC - 0.1 8
Gain, mV/fC8.0 0.7 17
Gain (residual), mV/fC - 0.2 19
Discriminator offset, mV-31.6 31.3 17
Discriminator offset (residual), mV - 14.0 19

- Time resolution, mean time and slewing time.
Mean and sigma are from the Gaussian fit.
ParameterMean SigmaComment
Time resolution (RMS), ns 0.6 0.1 page 1, Fig.2
Time resolution (RMS), residual, ns - 0.06 page 4, Fig.2
Mean time, ns 100.3 1.0 page 1, Fig.3
Mean time, residual, ns - 0.5 page 4, Fig.3
Slewing time, ns 1.2 0.2 page 1, Fig.3
Slewing time , residual, ns - 0.2 page 4, Fig.3
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Last modified: Mon Oct 2 15:00:00 CST 2000