| 1. |
- Hedayati, Raheleh, et al.
(författare)
-
A 500 degrees C 8-b Digital-to-Analog Converter in Silicon Carbide Bipolar Technology
- 2016
-
Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383 .- 1557-9646. ; 63:9, s. 3445-3450
-
Tidskriftsartikel (refereegranskat)abstract
- High-temperature integrated circuits provide important sensing and controlling functionality in extreme environments. Silicon carbide bipolar technology can operate beyond 500 degrees C and has shown stable operation in both digital and analog circuit applications. This paper demonstrates an 8-b digital-to-analog converter (DAC). The DAC is realized in a current steering R-2R configuration. High-gain Darlington current switches are used to ensure ideal switching at 500 degrees C. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) at 25 degrees C are 0.79 and 1.01 LSB, respectively, while at 500 degrees C, the DNL and INL are 4.7 and 2.5 LSB, respectively. In addition, the DAC achieves 53.6 and 40.6 dBc of spurious free dynamic range at 25 degrees C and 500 degrees C, respectively.
|
|
| 2. |
- Hedayati, Raheleh, et al.
(författare)
-
A Monolithic, 500 degrees C Operational Amplifier in 4H-SiC Bipolar Technology
- 2014
-
Ingår i: IEEE Electron Device Letters. - : IEEE. - 0741-3106 .- 1558-0563. ; 35:7, s. 693-695
-
Tidskriftsartikel (refereegranskat)abstract
- A monolithic bipolar operational amplifier (opamp) fabricated in 4H-SiC technology is presented. The opamp has been used in an inverting negative feedback amplifier configuration. Wide temperature operation of the amplifier is demonstrated from 25 degrees C to 500 degrees C. The measured closed loop gain is around 40 dB for all temperatures whereas the 3 dB bandwidth increases from 270 kHz at 25 degrees C to 410 kHz at 500 degrees C. The opamp achieves 1.46 V/mu s slew rate and 0.25% total harmonic distortion. This is the first report on high temperature operation of a fully integrated SiC bipolar opamp which demonstrates the feasibility of this technology for high temperature analog integrated circuits.
|
|
| 3. |
- Hedayati, Raheleh, 1984-, et al.
(författare)
-
High Temperature Bipolar Master-Slave Comparator and Frequency Divider in 4H-SiC Technology
- 2017
-
Ingår i: Materials Science Forum. - Switzerland : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 897, s. 681-684
-
Tidskriftsartikel (refereegranskat)abstract
- This paper demonstrates a fully integrated master-slave emitter-coupled logic (ECL)comparator and a frequency divider implemented in 4H-SiC bipolar technology. The comparator consists of two latch stages, two level shifters and an output buffer stage. The circuits have been tested up to 500 °C. The single ended output swing of the comparator is -7.73 V at 25 °C and-7.63 V at 500 °C with a -15 V supply voltage. The comparator consumes 585 mW at 25 °C. The frequency divider consisting of two latches shows a relatively constant output voltage swing over the wide temperature range. The output voltage swing is 7.62 V at 25 °C and 7.32 V at 500 °C.
|
|
| 4. |
- Hedayati, Raheleh, et al.
(författare)
-
Wide Temperature Range Integrated Amplifier in Bipolar 4H-SiC Technology
- 2016
-
Ingår i: 2016 46TH EUROPEAN SOLID-STATE DEVICE RESEARCH CONFERENCE (ESSDERC). - : IEEE. - 9781509029693 ; , s. 198-201
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a high temperature integrated amplifier implemented in bipolar 4H-SiC technology. A 40 dB negative feedback voltage amplifier has been designed using the structured design method to overcome the temperature variation of device parameters. The amplifier performance degrades as the temperature increases from room temperature up to 500 degrees C. The measured gain is reduced from 39 dB at room temperature to 34 dB at 500 degrees C, and the 3-dB bandwidth decreases from 195 kHz to 100 kHz. The measured power-supply-rejection-ratio (PSRR) is reduced from -78 dB to -62 dB, while the output voltage swing decreases from 8 V to 7 V.
|
|
| 5. |
- Hedayati, Raheleh, et al.
(författare)
-
Wide Temperature Range Integrated Bandgap Voltage References in 4H–SiC
- 2016
-
Ingår i: IEEE Electron Device Letters. - : IEEE. - 0741-3106 .- 1558-0563. ; 37:2, s. 146-149
-
Tidskriftsartikel (refereegranskat)abstract
- Three fully integrated bandgap voltage references (BGVRs) have been demonstrated in a 4H-SiC bipolar technology. The circuits have been characterized over a wide temperature range from 25 degrees C to 500 degrees C. The three BGVRs are functional and exhibit 46 ppm/degrees C, 131 ppm/degrees C, and 120 ppm/degrees C output voltage variations from 25 degrees C up to 500 degrees C. This letter shows that SiC bipolar BGVRs are capable of providing stable voltage references over a wide temperature range.
|
|
| 6. |
- Kargarrazi, Saleh, et al.
(författare)
-
500 degrees C Bipolar SiC Linear Voltage Regulator
- 2015
-
Ingår i: IEEE Transactions on Electron Devices. - : IEEE Press. - 0018-9383 .- 1557-9646. ; 62:6, s. 1953-1957
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we demonstrate a fully integrated linear voltage regulator in silicon carbide NPN bipolar transistor technology, operational from 25 degrees C up to 500 degrees C. For 15-mA load current, this regulator provides a stable output voltage with <2% variation in the temperature range 25 degrees C-500 degrees C. For both line and load regulations, degradation of 50% from 25 degrees C to 300 degrees C and improvement of 50% from 300 degrees C to 500 degrees C are observed. The transient response measurements of the regulator show robust behavior in the temperature range 25 degrees C-500 degrees C.
|
|
| 7. |
- Kargarrazi, Saleh, et al.
(författare)
-
A monolithic SiC drive circuit for SiC Power BJTs
- 2015
-
Ingår i: 2015 IEEE 27TH INTERNATIONAL SYMPOSIUM ON POWER SEMICONDUCTOR DEVICES & IC'S (ISPSD). - : IEEE. - 9781479962617 ; , s. 285-288
-
Konferensbidrag (refereegranskat)abstract
- Silicon Carbide (SiC) is an excellent candidate for high temperature electronics applications, thanks to its wide bandgap. SiC power BJTs are commercially available nowadays, and it is demanding to drive them efficiently. This paper reports on the design, layout specifics, and measurements results of a SiC drive integrated circuit (IC) designed for driving SiC power BJTs. The circuit has been tested in different loading conditions (resistive and capacitive), at switching frequencies up to 500kHz, and together with a commercial power BJT. The SiC drive IC is shown to have a robust operation over the entire temperature range from 25 degrees C to 500 degrees C.
|
|
| 8. |
- Kargarrazi, Saleh, et al.
(författare)
-
A study on positive-feedback configuration of a bipolar SiC high temperature operational amplifier
- 2016
-
Ingår i: Solid-State Electronics. - : Elsevier. - 0038-1101 .- 1879-2405. ; 116, s. 33-37
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the design and implementation of an integrated operational amplifier in bipolar SiC, and elaborates on its operation in positive-feedback configuration. The opamp is studied in different feedback setups: closed-loop compensated amplifier, comparator with hysteresis (Schmitt trigger), and as a relaxation oscillator. Measurement results suggest a stable closed-loop opamp with similar to 40 dB gain, a Schmitt trigger with constant threshold levels over a wide temperature range, and a relaxation oscillator tested up to 540 kHz. All the setups were tested from 25 degrees C up to 500 degrees C.
|
|
| 9. |
- Kargarrazi, Saleh, et al.
(författare)
-
Design and characterization of 500°c schmitt trigger in 4H-SiC
- 2015
-
Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. - 9783038354789 ; 821-823, s. 897-901
-
Tidskriftsartikel (refereegranskat)abstract
- Two versions of Schmitt trigger, an emitter-coupled and an operational amplifier (opamp)-based, are implemented in 4H-SiC bipolar technology and tested up to 500 °C. The former benefits the simplicity, smaller footprint, and fewer number of devices, whereas the latter provides better promise for high temperature applications, thanks to its more stable temperature characteristics. In addition, the measurements in the range 25 °C - 500 °C, shows that the opamp-based version provides negative and positive slew rates of 4.8 V/μs and 8.3 V/μs, ~8 and ~3 times higher than that of the emitter-coupled version, which are 1.7 V/μs and 1 V/μs.
|
|
| 10. |
- Lanni, Luigia, et al.
(författare)
-
500 degrees C Bipolar Integrated OR/NOR Gate in 4H-SiC
- 2013
-
Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 34:9, s. 1091-1093
-
Tidskriftsartikel (refereegranskat)abstract
- Successful operation of low-voltage 4H-SiC n-p-n bipolar transistors and digital integrated circuits based on emitter coupled logic is reported from -40 degrees C to 500 degrees C. Nonmonotonous temperature dependence (previously predicted by simulations but now measured) was observed for the transistor current gain; in the range -40 degrees C - 300 degrees C it decreased when the temperature increased, while it increased in the range 300 degrees C-500 degrees C. Stable noise margins of similar to 1 V were measured for a 2-input OR/NOR gate operated on -15 V supply voltage from 0 degrees C to 500 degrees C for both OR and NOR output.
|
|
