Transcript HINP32C Southern Illinois University Edwardsville VLSI Design Research Laboratory Washington University in Saint Louis Nuclear Reactions Group.

HINP32C
Southern Illinois University
Edwardsville VLSI Design
Research Laboratory
Washington University in Saint
Louis Nuclear Reactions Group
University Cooperation
Dr. George L. Engel,Muthu Sadavisam,Mythreyi Nethi
Department of Electrical and Computer Engineering
VLSI Design Research Laboratory
Southern Illinois University Edwardsville
Jon Elson, Dr. Lee Sobotka, Dr. Robert Charity
Department of Chemistry
Nuclear Reactions Group
Washington University in Saint Louis
General Description
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HINP32C is a 32 channel integrated
circuit (IC) for use in a series of
experiments in low and intermediate
energy nuclear physics.
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The IC will be fabricated in the AMIS
0.5 mm, N-well CMOS, double-poly,
triple-metal, high-resistance process
through MOSIS.
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The die is 6 mm x 6 mm.
Overview
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Need for HINP32C
IC specifications / features
How does it all work?
Expected performance
Where do we go from here?
Need for HINP32C
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Need for high density signal
processing in low and intermediate
energy nuclear physics community is
widespread
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No commercial chip was found to do
exactly what we wanted. Necessary
for the “experimenter” to be in the
“designer’s seat”
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Timing, self-triggering, and on chip
sparsification non-existent or
inadequate
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Gain ranges beyond 50 MeV not
available
Sample Applications
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Spectroscopy of low lying particle unstable
states
by
resonance
decay
correlation
techniques
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Inverse (d,p) scattering experiments designed to
study shell structure and pairing in n-rich nuclei
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Inverse (p,d) reactions examining the n single
particle structure of secondary unstable beams
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Particle-particle correlation experiments at
intermediate
energy
designed
to
refine
temperature determinations and to image source
characteristics
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Si arrays for detecting  particles and CZT and
Ge arrays for detecting  ray’s.
Initial Specifications
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100 MeV full range with 25 keV (FWHM)
resolution
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Time resolution of 500 ps (FWHM) for a
monoenergetic 5 MeV a-particle
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Capable of processing either polarity
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Data sparsification: User selection of
either hit channels or all to be read out
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High level of debug capability
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Compatibility with modern pipeline
ADC’s
Implemented
Features
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Two gain modes: 100 MeV or 500 MeV
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Capable of processing either polarity
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Variable peaking time: 1 ms – 2 ms
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Channel by channel disable of on-chip
CFDs
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Analog multiplicity output (and logical OR)
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Data Sparsification: User selection of
either hit channels or all to be read out
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Two time measurement ranges: 250 ns or 1
ms
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Automatic reset of time-to-voltage and
peak sampling circuits unless vetoed by
user with variable decision time (300 ns –
30 ms)
Channel Block Diagram
reset
Reset Logic
time (Volts)
q (Coulombs)
Pseudo
CFD
TVC
CSA
energy (Volts)
Slow shaper
Peak sampler
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CSA
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Each channel consists of a charge sensitive amplifier
(CSA) with two gain modes: 100 MeV and 500 Mev fullscale.
The CSA output (30 ns risetime, 50 mse falltime) is split
to feed energy and timing branches each of which
produce sparsified pulse trains with synchronized
addresses for off-chip digitization with a pipelined ADC
Noise slope: 3 e / pF
Noise at 0 pF : 2475 e Noise at 75 pF: 2600 e
Resolution: 25 - 30 keV
Slow Shaper
Response of Shaper
Output Voltage (V)
2.7
2.65
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The energy leg consists of a
third-order,
tranconductance-C
shaping filter with a fast return to
baseline, < 20 ms, and variable
peaking time: 1 ms - 2 ms.
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This slow-shaper is followed by a
continuous-time peak sampling
circuit. Energy resolution is 2530 keV in the 100 MeV (FS) mode.
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This slow-shaper is followed by a
continuous-time peak sampling
circuit
2.6
2.55
2.5
2.45
20
25
30
35
Time (us)
Noise plot for CSA & Shaper
3000
Electrons
2900
2800
2700
2600
2500
2400
0
20
40
60
80
100
Capacitance (pF)
120
140
160
CFD
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The timing leg consists of a pseudo
constant fraction discriminator (CFD)
composed of a leading edge and a zerocross discriminator.
The zero-crossing
discriminator has its offsets dynamically
nulled.
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A 6-bit DAC is used to correct offsets
associated with the leading-edge circuit as
well as to set CFD threshold levels. When
the CFD fires it starts a time-to-voltage
conversion (TVC).
CFD Walk Plot
51. 0
Propagation Delay (ns)
50. 5
50. 0
49. 5
49. 0
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48. 5
48. 0
47. 5
47. 0
1. 00E+04
1. 00E+05
1. 00E+06
1. 00E+07
1. 00E+08
Input Electrons
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A fast logical ‘OR’ signal and an analog
output proportional to the number of
channels that were hit are available for use.
The logical ‘OR’ and the analog multiplicity
output are also automatically reset unless
vetoed by the user.
The energy leg consists of a third-order,
tranconductance-C shaping filter with a fast
return to baseline (20 ms) and variable
peaking time (1 ms - 2 ms).
TVC
The TVC circuit has two measurement ranges:
250ns and 1 ms. The conversion is stopped by a
common stop signal applied to all channels.
The TVC circuit as well as the peak sampling
circuit is automatically reset after a variable
delay time (300 ns – 30 ms) reference to when the
CFD fires, unless vetoed by the user.
The intrinsic time resolution on-chip is 150 ps in
the 250 ns range mode.
Common Circuits
A common channel provides biasing for the
32 processing channels and contains readout
electronics.
A 48-bit configuration register allows the user
to selectively disable CFD outputs on a
channel by channel basis, select test modes,
select processing for either positive or
negative CSA pulses, select CSA gain mode,
TVC measurement range, and assign an 8-bit
ID to the chip.
The chip only responds when an externally
applied chip address matches the ID stored in
the chip's configuration register.
Power Breakdown
Supply Current Distribution for Single Channel
BIAS
0.829%
Total Current is 6.7mA
CSA
26.965%
CFD
41.047%
SHAPER
15.655%
TVC
0.225%
RESET_LOGIC
0.150%
Area Breakdown
Area Chart for single channel
sample peak
13%
tvc
3%
csa
17%
reset logic
2%
cfd
25%
shaper
40%
Where do we go from here?
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HINP16C is presently being
tested!
The testing process will take
several months
If HINP16C succeeds then we
will move on to HINP32C
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ADDITIONAL PROJECTS
Peak sampler with digital assist
Lower-noise version of shaper?
Multiple sampling PSD chip
Microchip
designed
at
SIUE