Smart Sensor ASIC for Nuclear Power Monitoring David Kerwin, Aeroflex Colorado Springs Ken Merkel, Aeroflex Colorado Springs Olivier Rouxel, Dimac Red S.R.L. www.aeroflex.com/HiRel Presented at ANIMMA - June 2013 1 www.aeroflex.com Outline: Smart Sensor ASIC ▼ Block Diagram ▼ Features ▼ Neutron Test Results ▼ Gamma Total Ionizing Dose (TID) Results ▼ Temperature Results ▼ Summary 2 Smart Sensor ASIC www.aeroflex.com/HiRel Sensor Load EXC_OUT_P EXC_OUT_N Reference Generator Excitation Generator EXT_CLK Clock Reference PLL_CNTL[1:0] RBIAS VREF_P/N Smart Sensor IC Block Architecture DAC_VREF_P/N UT08SC14ADV045HT Smart Sensor ASIC Block Diagram Loop Filter Clock Generator MAIN_CLK VREF_CM EXC_CLK ADC_SAMPLE_CLK ADC_MOD_CLK Digital Core ∆-Σ ADC SPI Port C 3 Excitation Generator/ Mux SPI Port A SPI Port A GND_PROG CORE_RESET SPI Port C RESET TESTRESET TESTEN POR SPI Port B LVDS_EN Signal Conditioning Control/ Status Registers SPI Port B Sensors (8 differential channels) Control/Status to/from analog OTEP ROM www.aeroflex.com/HiRel UT08SC14ADV045HT Smart Sensor ASIC ▼ Complete Instrumentation System: – Includes circuitry to excite and precisely measure the response from 11 sensor types on 8 separate channels. – Supported Sensors: ▼ Resistance Thermometer, Thermocouple, Linear Variable Differential Transformer (LVDT), Strain Gauge/Load Cell, Inductive and Transformer-based Position, Absolute and Relative Pressure Sensors, Hall Effect Probe, Photodiode, Accelerometer, Tachometer, and other types of Sensors. – Excitation generator includes a 14-bit digital-to-analog converter (DAC) with a high current, high-voltage differential output. – Eight high-voltage differential signal inputs are provided, with configurable signal conditioning. – 14-bit 45 kSps delta-sigma analog-to-digital converter (ADC) 4 www.aeroflex.com/HiRel UT08SC14ADV045HT Smart Sensor ASIC ▼ Complete Instrumentation System: – Data I/O: ▼ Digital data word transmitted through a Low-Voltage Differential Signaling, Serial Peripheral Interface (LVDS SPI) port. ▼ A second LVDS SPI port is used for configuration, control, parameter trim, and access to internal registers. – Clock Generation: ▼ A clock generator block generates the necessary internal clocks from a low-frequency reference. – Voltage Regulators: ▼ 5 Internal regulators derive necessary supply voltages and references from +/-6V (Va6p and Va6n) and +3.3V (Vd3) power supply inputs. www.aeroflex.com/HiRel UT08SC14ADV045HT Smart Sensor ASIC ▼ Complete Instrumentation System: – Non-volatile Memory (NVM): ▼ Aeroflex Radiation Hardened One-Time Electrically Programmable Read-Only Memory (RH OTEP ROM) provides storage for reference trim data, configuration data, and user configurable program storage. – Applications: 6 ▼ Nuclear Power Instrumentation Monitoring ▼ Spacecraft Telemetry ▼ Radiation Oncology Equipment Motor/Motion Control ▼ Nuclear Waste Monitoring www.aeroflex.com/HiRel Key Performance and Environmental Parameters ASIC Specification Excitation Output Sensor Inputs Signal Channel A/D Converter Typical channel mismatch Requirement 14-bit DAC with differential voltage-mode output up to 20Vp-p, up to 140mA. Sine/square/triangle or arbitrary function outputs. 8 multiplexed differential high-impedance user inputs; input range -5V < Vin < +5V Programmable gain range 0.18 to 100, 15 kHz bandwidth, includes anti-alias filter 14-bit, 3rd-order delta-sigma, 45kSps 0.04% to 100°C, 0.07% to 200°C Operating Environment Requirement Gamma Ray Total ionizing Dose (TID) 100 krad(Si) at a dose rate of 2.8 mrad(Si)/sec Neutron Induced Upset (NIU) Neutron induced Latch-Up (NIL) Temperature 7 < 1E-11 errors/bit/day Immune (5E11 neutrons/cm2, peak energy < 2 MeV) 200 °C max. operating www.aeroflex.com/HiRel Neutron Induced Upset (NIU) Test Results ▼ ▼ ▼ ▼ ▼ Five Smart Sensor ASICs were tested at Sandia National Laboratory (SNL) Annular Core Research Reactor (ACRR). Scan chains (≥ 95% coverage) were run at 2 MHz. Lowest operational supply voltages used (95% of nom.). Average neutron fluence: 6.9E11 n/cm2 No scan chain errors before, during or after irradiation → No Neutron Induced Upset (NIU) SNL’s ACRR Smart Sensor Test PCB attached to Al holder 8 www.aeroflex.com/HiRel Neutron Induced Latch-Up (NIL) Test Results ▼ ▼ ▼ Five Smart Sensor ASICs were tested at Sandia National Laboratory’s ACRR Nuclear Reactor Used valve position detector (VPD) config. with max. output voltage swing (20V pk-pk), and highest operational supply voltages to test for latch-up. No Neutron Induced Latch-Up (NIL) observed! ▼ ▼ Average neutron fluence: 6.8E11 n/cm2 Worst case results: - Supply current increased +6.7% (+6V power supply). All other current increases ≤ 1.5% - ▼ NIL Test PCB All supplies returned to pre-irradiation values after removal from reactor Variation in sine wave replication was +/- 0.034% Signal chain integrity demonstrated during NIL test and measurement 9 www.aeroflex.com/HiRel Neutron Induced Latch-Up (NIL) Test Results A 60 Hz sine wave was generated and measured at the SPI-C port Pre-Rad Supply Currents Irradiation Supply Currents No noticeable increase in power supply currents during irradiation Sine wave measurement used 768 samples taken at fclock = 46.08 kHz The figure overlays the maximum and minimum excursions of the sampled sine wave in blue. Y-axis in units of integer LSBs for the internal 16-bit ADC. X-axis in units of time for a single 60 Hz sine wave with a 16.7 msec period (Sine wave“glitches” artifact of look up table entries in EXCGEN, not NIU or NIL) 10 www.aeroflex.com/HiRel Gamma TID Results – Standard Dose Rate ▼ ▼ ▼ ▼ Quiescent current (Iddq) was measured on 5 ICs following steppeddose irradiation to 300 krad(Si) using standard dose rate (SDR) gamma irradiation (169 rad(Si)/sec) at Aeroflex Colorado Springs Iddq measured at low and high power supply settings following SDR irradiation: +/- 6V => +/- 5.7 or +/- 6.3V, and 3.3V => 3.14 or 3.47V No increase in Iddq up to a total ionizing dose (TID) of 300 krad(Si) Demonstrates excellent control of MOSFET subthreshold leakage in SDR gamma radiation Iddq Results to 300 krad(Si) SDR Iddq +6V Supply Iddq -6V Supply Iddq 3V Supply 11 www.aeroflex.com/HiRel Gamma TID Results – Low Dose Rate Iddq Results to 100 krad(Si) LDR Iddq +6V Supply Iddq -6V Supply Iddq 3V Supply ▼ ▼ ▼ ▼ Iddq was measured at Aeroflex RAD on 5 ICs following steppeddose irradiation to 100 krad(Si) using low dose rate (LDR) gamma irradiation at 10 mrad(Si)/sec Iddq measured at low and high power supply settings following SDR irradiation: +/- 6V => +/- 5.7 or +/- 6.3V, and 3.3V => 3.14 or 3.47V No increase in quiescent current in TID up to 100 krad(Si) Demonstrates excellent control of MOSFET subthreshold leakage in gamma radiation at LDR 12 www.aeroflex.com/HiRel Temperature Results ▼ ▼ ▼ ▼ Three ASICs subjected to an Extended Abnormal Temperature (EAT) ramp for up to 960 hrs as defined below Complete characterization test performed at intervals marked by * Post-ramp results. All units passed all tests at room temperature (RT) and at low and high supply extremes. No functional failures observed at any temperature or at RT following thermal ramp exposure Parametric performance at high temperature generally tracks voltage reference. EAT Thermal Ramp vs. Time 13 www.aeroflex.com/HiRel Temperature Sweep Results ▼ Comprehensive characterization performed over 20 ≤ T ≤ 200 °C ▼ Absolute measurement accuracy ~1% at 180 °C, and ~5% at 200 °C - Tracks bandgap reference - Same reference used for excitation generator and ADC ▼ Relative/ratiometric error is ≤ 0.1% over entire temperature range ▼ Differential input leakage current < 10nA at 200 °C Signal Input Differential Leakage Current 14 Smart Sensor Parameters w.r.t. Temperature www.aeroflex.com/HiRel Summary ▼ Smart Sensor ASIC – Specifically designed for Nuclear Power Radiation Environment: ▼ > 100 krad(Si) in both Standard (SDR) and Low Dose-Rate (LDR) Gamma Radiation Environment ▼ High Tolerance to Neutrons: – Neutron Induced Latch-Up (NIL) Immune – No Neutron Induced Upset (NIU) ▼ High Temperature operation up to 200 ⁰C – High Functionality, Performance and Reliability in a Single ASIC: 15 ▼ 8 sensor inputs ▼ 14-bit ADC ▼ Programmable Gain ▼ 20Vpp DAC Output for sensor excitation www.aeroflex.com/HiRel