Transcript Mixed-Signal ASIC for Rover Environmental Monitoring System

AMICSA 2008: REMS ASIC
Mixed-Signal ASIC for Rover Environmental
Monitoring System
Cascais, Portugal 2nd September 2008
Stefania Chicca – Aurelia Microelettronica
Franco Bigongiari – Aurelia Microelettronica
Jesus Lopez Soto – EADS Astrium Crisa
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AMICSA 2008: REMS ASIC
PRESENTATION CONTENTS
Rover Environmental Monitoring System
• REMS ASIC Presentation
• REMS ASIC Functional Overview
• ASIC Analog interface
• Internal Analog to Digital Converter
• Test Activity: temperature tests and comments on test results
• Qualification activity: actual status and qualification flow
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REMS ASIC
AMICSA 2008: REMS ASIC
MMars Mission in 2009 funded by NASA/Spanish
Government
TTo investigate the past and present habitability at
the surface of Mars
AAurelia is subcontractor of CRISA-EADS Astrium
Front-end ASIC for wind,
temperature and humidity
sensors
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AMICSA 2008: REMS ASIC
REMS ASIC GENERAL BLOCK DIAGRAM
MIXED MODE FRONT END (WIND SENSORS)
DATA
REGISTER
D
feedback
ANALOG
FRONT
END
MUX & ADC
M
U
X
ON CHIP
CALIBRATION
anti alias
& ADC
UART
DATA
&
CONF
RS422
RS422
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AMICSA 2008: REMS ASIC
REMS ASIC building blocks
•
12 PC sigma-delta channels to interface with wind sensors
•
3 channels to measure the threshold temperature of sigma delta channels
•
4 channels to amplify the thermopile signals
•
1 channel to amplify the air temperature sensor signal
•
1 channel to measure the temperature for thermopile calibration purposes
•
1 channel to heat two of the thermopile sensors
•
7 channels to amplify the temperature PT signals
•
1 external channel
•
Power on reset generator
•
Voltage reference circuit
•
Bias section to provide current bias to the sensors and to the internal circuitry
•
16 bit sigma delta A/D converter
•
Clock receiver on RS-422 Physical Layer and internal clock divider
•
Logic Control Unit, Configuration Registers, Output Data Registers
•
UART with RS-422 transmitter/receiver
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AMICSA 2008: REMS ASIC
REMS ASIC Block Diagram & Interface
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REMS ASIC
AMICSA 2008: REMS ASIC
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AMICSA 2008: REMS ASIC
REMS ASIC ENVIRONMENT & TECHNOLOGY
The REMS ASIC has been designed for a storing temperature ranging from –135°C to
+125°C and an operating temperature ranging from –55°C to 90°C
The ASIC will be warmed up to the minimum operating temperature by an external
heater prior to power up
Latch up immunity is provided by XFAB 1.0um CMOS SOI-HV technology
TID level requirement of 7Krad(Si) is not a concern for the selected technology:
irradiation tests operated in the frame of other activities showed applicability up to
50Krad
Single event upset mitigation is performed inside the digital section to avoid loss of
functionality
ASIC die size: 62.8 mm2
Assembled in CQFP100 package
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AMICSA 2008: REMS ASIC
REMS ASIC SENSOR INTERFACE
RTemp interface: 7 Pt 1000 sensors are interfaced by the ASIC: internal controlled-current biasing is
supplied to the sensor only during signal acquisition to limit self-heating: an internal multiplexer
multiplexes the channels to the internal ADC and the biasing current to the sensor which is being
acquired
Air_Temp interface: 1 Pt 1000 sensor for measuring the Mars atmosphere temperature and 1 Pt 1000
sensor for measuring the infrared radiation source to calibrate the infrared temperature sensors
Thermopile interface: 3 infrared sensors, whose conditioning chain inside the ASIC offers several
programmable gains up to 2048
Therm_heater interface: an heater circuit able to provide up to 100mA is integrated into the ASIC to
calibrate in flight the infrared sensors
R_therm_cal interface: it is organized to bias and measure a PT 1000 resistor and it is used for
calibration purposes
WD_CON wind interface: 3 wind transducers treated inside the ASIC as sigma-delta channels
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AMICSA 2008: REMS ASIC
WD_COND SENSORS CHANNELS
• 3 groups, 4 sensors each
sense X 12 Channels
• each sensor is treated by a SD, that
drives (with a current Inx) an
external heater (Rheater) to keep
Rx-sensor temperature at a given
value (fixed by Rref, 1Rref/group)
• internal adjusting on Rref bias
current is provided in 64 steps
Q
WD_OUT
counter
D
comp
CK
WD_Rx_IN_n
n=0..11
auto zeroed
pre-amplifier
WD_Ref_IN_n
n=0,1,2
controls from
UART
WD_Ref_RTN_n
n=0,1,2
CK1
internal analog
ground, 2.5V
to
UART
WD_Total
counter
duty cycle
limiter
sensor bias X (12 +1REF) Channels
DUTY
power force X 12 Channels
biasing
interval
modulator
from UART
CFG 6 bit
RSW
Inx
controls from
UART
MUX n to 1
• bias currents for Rx and Rref are
multiple of an unique current
reference
to
UART
Imx
bias [n]
WD_Heater_RTN_n
n=0,1,2
REF_BIAS
• the drops on the 3 Rref resistors
are amplified and converted by the
ADC
• all the heaters are activated in
parallel
WD_Heater_OUT_n
n=0..1
Low Gain Sensor Amp X 3 Channels to ADC
to
MUX
WD_Rref_Sensing+_n
REF_OUT
amp
WD_Rref_Sensing-_n
n=0,1,2
• force and sense pins on Rref are
separated
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AMICSA 2008: REMS ASIC
IR_COND Thermopile channels
III stage:
programmable gain
256, 500, 2000 by
acting on capacitor
ratio
II stage:
only used for offset
cancellation purposes
I stage:
programmable gain 8
to 128 by acting on
feedback DAC
V25
Track & Hold
V25
C
+
+ -
-
-
-
+
V25
IA
V25
+
+
-
-
+
C
V25
V25
internally connected
to 2.5V
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AMICSA 2008: REMS ASIC
Pt, Air_temp, IR_CAL, REF_Amp Channels
AVDD
active only
during ADC
acquisition
R_TEMP_N_Sensing+
+
10K
-
analog ground 2
amp
+
Temperature
to ADC
- +
analog ground 1
+
buffer
R_TEMP_N_Sensing-
-
Single-ended to differential conversion (with 2.5V common mode)
common mode range:
analog_ground 1 = 1V
analog_ground 2 = 1.5V
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AMICSA 2008: REMS ASIC
REMS ASIC DIGITAL SECTION
The digital section contains:
 RS422 receiver
 RS422 Transmitter
 Control Unit
The control unit decodes the command and prepares the answer, manages the
acquisition from wind sensor channels and stores the data coming from ADC.
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AMICSA 2008: REMS ASIC
REMS ASIC DIGITAL SECTION
Data-TX
TX Shift
Registers
and
Control
UART
Counters
for 12 Wind
Sensor
Channels
Configuration Registers Output
Reset Request Output
ADC MUX Selector (5 bits)
Analogue Data
Dump Enable
CONTROL
UNIT
Command Echo
RX Shift
Registers
and
Control
Wind Sensor Data
Dump Enable
Data-RX
Commands
Decoder
and
Handling
Unit
Data
Handling
Unit
Converted Analogue Data
(16 bits)
RSW and Duty
From 12 Wind
Sensor
Comparators
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AMICSA 2008: REMS ASIC
REMS ASIC A/D CONVERSION
X
1/4
z-1
1-z-1
z-1
1-z-1
1/3
1/4
Fig. -1: ADC z-domain representation
II order sigma delta ADC
Y
Internal Analog to Digital II
order sigma-delta converter is
integrated with programmable
conversion time: the converter
provides an analog antialiasing active filter before
conversion and a digital filter
on converted samples after
decimation down to 400Hz
cutoff frequency: the noise
filtering is achieved internally
to the ASIC in this way (no
need for software-processing
the converted data).
Decimation filter
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AMICSA 2008: REMS ASIC
REMS ASIC TEST ACTIVITY
A dedicated test
setup has been
developed in
Labview environment
to allow automatic
testing.
On the right, the
output for an
infrared channel as a
function of the input
voltage is shown:
however, relevant
parameters are
downloaded directly
into datalog files.
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AMICSA 2008: REMS ASIC
REMS ASIC TEST RESULTS: INFRARED
CHANNELS
• Repeatability
of
parameters on different
samples
• Gain accuracy:
512,256,128,64,32 and
16 <2.5%.
2048: max 3%
8: max 2.8%
• The output range of
the channels is a valid
value for the input ADC
input range in all cases
but one, (2048  3.5V,
some saturation occurs
at full scale).
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AMICSA 2008: REMS ASIC
REMS ASIC TEST RESULTS: Pt 1000 channels
• Electrical
test emulates
sensor resistance
variation with
temperature by means of
a 16 bit DAC-provided
voltage
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AMICSA 2008: REMS ASIC
REMS ASIC TEST RESULTS: Pt 1000 channels
Gain Variation versus Temperature
gain
3,8
R0
Air_temp
R_therm
R0
Gain
Offset
INL
Air_temp
Gain
Offset
INL
R_therm
Gain
Offset
INL
T=90°C T=25°C
T=0°C
T=-20°C T=-40°C
3,5858
3,5772
3,6004
3,5872
3,5895
-3,6501
-3,5963
-3,5895
-3,5474
-3,5058
1,32
4,02
3,33
1,47
2,1
T=90°C T=25°C
T=0°C
T=-20°C T=-40°C
3,5935
3,599
3,598
3,6044
3,5948
-3,875 -3,85226
-3,8228
-3,7968
-3,7425
1,55
1,8
1,75
1,83
2,33
T=90°C T=25°C
T=0°C
T=-20°C T=-40°C
3,5962
3,6018
3,5963
3,5916
3,595
-3,8806
-3,8549
-3,8198
-3,7842
-3,7418
1,01
6,15
1,77
3,02
2,19
Gain and offset deviation over
temperature
R0
T=25°C vs T=-40°C T=25°C vs T=90°C
Gain Deviation
-0,34%
-0,24%
Offset Deviation
2,52%
-1,50%
Temperature °C
Air_temp
T=25°C vs T=-40°C T=25°C vs T=90°C
3,5
Gain Deviation
0,12%
0,15%
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Offset Deviation
2,85%
-0,59%
R_therm
T=25°C vs T=-40°C T=25°C vs T=90°C
Gain Deviation
0,19%
0,16%
Offset Deviation
2,93%
-0,67%
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AMICSA 2008: REMS ASIC
BIAS SECTION: CURRENTS STABILITY & MATCHING
T Room
Input Currents
(VDD=5V)
Ix Current
CH 0
CH 1
CH 2
CH 3
CH 4
CH 5
CH 6
CH 7
CH 8
CH 9
CH 10
CH 11
99,7
100,1
99,6
100,3
100,1
100,4
99,6
99,4
99,6
99,6
100,7
100,3
T=-55°C
Ix Full Scale Ix Zero Scale
95,7
96,1
96,4
95,97
96,05
96,6
95,6
95,38
95,43
94,88
97,23
96,08
104,1
103,7
103,9
104,4
104,8
104,2
103,5
103,6
103,6
103,5
104,3
103,9
T=90°C
IREF
Ix Current
Ix Full Scale
Ix Zero Scale
IREF
Ix Current
98
98
97,5
97,5
97,5
97,5
98
98
97,3
97,3
97,3
97,3
98,7
98,8
98,9
98,8
99,6
99,3
98,3
99,3
98,6
98,9
98,6
98,7
94,5
94,5
94,6
95,1
93,8
95,7
94,6
95
93,6
94,6
94,7
94
102,5
102,5
102,4
102,2
101,8
103,2
102
101,8
102,1
102,1
102
102,8
96,6
96,6
97,2
97,2
97,2
97,2
96,6
96,6
96,8
96,8
96,8
96,8
100
100,8
99,6
100,6
99,4
100,5
100,2
99,3
101,1
99,7
100,1
99,6
Ix Full Scale Ix Zero Scale
96,9
97,8
95,5
96
95,9
97
96,2
95,5
97,1
96,1
96,4
94,9
104,4
104,6
104,2
103,9
103,8
104
103,7
103,5
104
103,7
103,9
103,4
IREF
97,8
97,8
98
98
98
98
97,8
97,8
97,9
97,9
97,9
97,9
Ix (bias) versus channel number
101,5
Ix Current (uA)
101
100,5
T Room
100
T=-55°C
99,5
T=90°C
99
98,5
98
0
1
2
3
4
5
6
7
8
9
10
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channels
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AMICSA 2008: REMS ASIC
SCREENING FLOW
The screening has been performed on 210 parts according to
requirements NASA GSFC EEE-INST-002
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AMICSA 2008: REMS ASIC
SCREENING FLOW
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AMICSA 2008: REMS ASIC
SCREENING FLOW
 Big effort has been put to find a glue for die attach able to
survive at –135°C
 30 parts have been selected after screening and an extra
electrical characterization has been performed (the
measurements have been repeated between –55°C and
90°C with 10°C step).
 On the 10 parts out of 30 have been performed further
electrical test between –55°C to –135°C to verify the
possibility to work at temperature near to mars
atmosphere.
 Only one part doesn’t work down to –65°C
 6 parts work correctly down to –135°C but the
parameters are out of specification
 3 parts work correctly down to –135°C with the
expected parameters
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AMICSA 2008: REMS ASIC
QUALIFICATION FLOW
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AMICSA 2008: REMS ASIC
QUALIFICATION FLOW
REMS ASIC is classified as
SCD Level 2 (SourceVendor Control Drawing)
according to EEE-INST002 Section M3,
Microcircuits, Monolithic:
as a consequence, the
qualification flow included
in EEE-INST-002 is
followed
(to allow screening
according to the reliability
standard MIL-PRF-38535,
Class Q, QML-38535).
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AMICSA 2008: REMS ASIC
THERMAL CYCLING PLAN
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AMICSA 2008: REMS ASIC
QUALIFICATION ACTIVITY: THERMAL CYCLES
D2009 (REF NO CYCLES)
115
-1,653
-1,730
-1,648
-1,719
-1,689
-1,645
-1,706
-1,731
-1,668
65,077
65,371
64,804
66,189
-1,614
OK
D2003 (6200 CYCLES)
110
-1,778
-1,716
-1,567
-1,567
-1,652
-1,669
-1,575
-1,586
-1,784
67,430
61,925
62,936
66,405
-1,644
OK
D2004 (6200 CYCLES)
125
-1,660
-1,654
-1,647
-1,758
-1,573
-1,607
-1,608
-1,678
-1,708
66,689
65,113
68,706
65,943
-1,685
OK
D2006 (6200 CYCLES)
120
-1,583
-1,728
-1,687
-1,699
-1,653
-1,796
-1,709
-1,665
-1,727
66,023
68,641
65,895
66,617
-1,687
OK
D2008 (6000 CYCLES)
105
-1,637
-1,641
-1,594
-1,664
-1,665
-1,666
-1,562
-1,772
-1,605
69,382
63,712
62,531
66,053
-1,683
OK
120
110
125
120
115
Reference Sample
6200 cycles
6200 cycles
6200 cycles
6000 cycles
No cycling
The ICC is constant during The ICC is increase lightly The ICC is increase lightly The ICC is constant during
The ICC is constant
the test,
during the test,
during the test,
the test,
during the test, NO
NO heating effect is
A little heating effect is
A little heating effect is
NO heating effect is
heating effect is observed
observed
observed
observed
observed
The gain are linear and
Some gain are not linear
The gain are linear and
The gain are linear and
The gain are linear and NO
NO changes of slope are and There are changes of some changes of slope are some changes of slope are
changes of slope are
observed
slope.
observed
observed
observed
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27
AMICSA 2008: REMS ASIC
CONCLUSION
 A mixed-signal ASIC for signal acquisition and data
conditioning has been presented
 The ASIC will be used in a meteorological package, to be
integrated in the Mars Science Laboratory Rover payload,
for being launched on 2009.
 The general architecture of ASIC has been presented and
some blocks have deeply discussed
 A summary of screening and qualification flow have been
shown.
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