4 research outputs found
๋ฉ๋ชจ๋ฆฌ ์ธํฐํ์ด์ค๋ฅผ ์ํ ๋ฉํฐ ๋ ๋ฒจ ๋จ์ผ ์ข ๋จ ์ก์ ๊ธฐ ์ค๊ณ
ํ์๋
ผ๋ฌธ (๋ฐ์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ปดํจํฐ๊ณตํ๋ถ, 2020. 8. ๊น์ํ.๋ณธ ์ฐ๊ตฌ์์ ๋ฉ๋ชจ๋ฆฌ ์ธํฐํ์ด์ค๋ฅผ ์ํ ๋ฉํฐ ๋ ๋ฒจ ์ก์ ๊ธฐ๊ฐ ์ ์๋์๋ค. ํ๋ก์ธ์์ ๋ฉ๋ชจ๋ฆฌ ๊ฐ์ ์ฑ๋ฅ ์ฐจ์ด๊ฐ ๋งค๋
๊ณ์ ์ฆ๊ฐํจ์ ๋ฐ๋ผ, ๋ฉ๋ชจ๋ฆฌ๋ ์ ์ฒด ์์คํ
์ ๋ณ๋ชฉ์ ์ด ๋๊ณ ์๋ค. ์ฐ๋ฆฌ๋ ๋ฉ๋ชจ๋ฆฌ ๋์ญํญ์ ๋๋ฆฌ๊ธฐ ์ํด PAM-4 ๋จ์ผ ์ข
๋จ ์ก์ ๊ธฐ๋ฅผ ์ ์ํ์๊ณ , ๋ฉํฐ ๋ญํฌ ๋ฉ๋ชจ๋ฆฌ๋ฅผ ์ํ duobinary ๋จ์ผ ์ข
๋จ ์ก์ ๊ธฐ๋ฅผ ์ ์ํ์๋ค.
์ ์๋ PAM-4 ์ก์ ๊ธฐ์ ๋๋ผ์ด๋ฒ๋ ๋์ ์ ํ์ฑ๊ณผ ์ํผ๋์ค ์ ํฉ์ ๋์์ ๋ง์กฑํ๋ค. ๋ํ ์ ํญ์ด๋ ์ธ๋ํฐ๋ฅผ ์ฌ์ฉํ์ง ์์ ์์ ๋ฉด์ ์ ์ฐจ์งํ๋ค. ์ ์๋ ZQ ์บ๋ฆฌ๋ธ๋ ์ด์
์ ์ธ๊ฐ์ ๊ต์ ์ ์ ๊ฐ์ง๊ณ ์์ด ์ก์ ๊ธฐ๊ฐ ์ ํํ ์ํผ๋์ค์ ์ ํ์ ์ธ ์ถ๋ ฅ์ ๊ฐ๊ฒ ํ๋ค. ํ๋กํ ํ์
์ 65nm CMOS ๊ณต์ ์ผ๋ก ์ ์๋์๊ณ ์ก์ ๊ธฐ๋ 0.0333mm2์ ๋ฉด์ ์ ์ฐจ์งํ๋ค. ์ธก์ ๋ 28Gb/s์์์ eye๋ 18.3ps์ ๊ธธ์ด์ 42.4mV์ ๋์ด๋ฅผ ๊ฐ๊ณ , ์๋์ง ํจ์จ์ 0.64pJ/bit์ด๋ค. ZQ ์บ๋ฆฌ๋ธ๋ ์ด์
๊ณผ ํจ๊ป ์ธก์ ๋ RLM์ 0.993์ด๋ค.
๋ฉ๋ชจ๋ฆฌ์ ์ฉ๋์ ๋๋ฆฌ๊ธฐ ์ํด ํ๋์ ํจํค์ง์ ์ฌ๋ฌ ๊ฐ์ DRAM ๋ค์ด๋ฅผ ์์ง์ผ๋ก ์๋ ํจํค์ง์ ๋ฉ๋ชจ๋ฆฌ์ ์ค์ ํจ๋ ๊ตฌ์กฐ์ ๊ฒฐํฉ๋์ด ์งง์ ๋ฐ์ฌ๋ฅผ ์ผ๊ธฐํ๋ ์คํ
์ ๋ง๋ ๋ค. ์ฐ๋ฆฌ๋ ์ด ๋ฌธ์ ๋ฅผ ์ํํ๊ธฐ์ํด ๋ฐ์ฌ ๊ธฐ๋ฐ duobinary ์ก์ ๊ธฐ๋ฅผ ์ ์ํ๋ค. ์ด ์ก์ ๊ธฐ๋ ๋ฐ์ฌ๋ฅผ ์ด์ฉํ์ฌ duobinary signaling์ ํ๋ค. 2ํญ ๋ฐ๋ ๊ฐ์กฐ ๊ธฐ์ ๊ณผ ์ฌ๋ฃจ ๋ ์ดํธ ์กฐ์ ๊ธฐ์ ์ด ์ ํธ ์๊ฒฐ์ฑ์ ๋์ด๊ธฐ ์ํด ์ฌ์ฉ๋์๋ค. NRZ eye๊ฐ ์๋ 10Gb/s์์ ์ธก์ ๋ duobinary eye๋ 63.6ps ๊ธธ์ด์ 70.8mV์ ๋์ด๋ฅผ ๊ฐ๋๋ค. ์ธก์ ๋ ์๋์ง ํจ์จ์ 1.38pJ/bit์ด๋ค.Multi-level transmitters for memory interfaces have been presented. The performance gap between processor and memory has been increased by 50% every year, making memory to be a bottle neck of the overall system. To increase memory bandwidth, we have proposed a PAM-4 single-ended transmitter. To compensate for the side effect of the multi-rank memory, we have proposed a reflection-based duobinary transmitter.
The proposed PAM-4 transmitter has the driver, which simultaneously satisfies impedance matching and high linearity. The driver occupies a small area due to a resistorless and inductorless structure. The proposed ZQ calibration for PAM-4 has three calibration points, which allow the transmitter to have accurate impedance and linear output. The ZQ calibration considers impedance variation of both the driver and the receiver. A prototype has been fabricated in 65nm CMOS process, and the transmitter occupies 0.0333mm2. The measured eye has a width of 18.3ps and a height of 42.4mV at 28Gb/s, and the measured energy efficiency is 0.64pJ/b. The measured RLM with the 3-point ZQ calibration is 0.993.
To increase memory density, the stacked die packaging with multiple DRAM die stacked vertically in one package is widely used. However, combined with the center-pad structure, the structure creates stubs that cause short reflections. We have proposed the reflection-based duobinary transmitter to mitigate this problem. The proposed transmitter uses reflection for duobinary signaling. The 2-tap opposite FFE and the slew-rate control are used to increase signal integrity. The measured duobinary eye at 10Gb/s has a width of 63.6ps and a height of 70.8mV while there is no NRZ eye opening. The measured energy efficiency is 1.38pJ/bit.CHAPTER 1 INTRODUCTION 1
1.1 MOTIVATION 1
1.2 THESIS ORGANIZATION 8
CHAPTER 2 MUTI-LEVEL SIGNALING 9
2.1 PAM-4 SIGNALING 9
2.2 DESIGN CONSIDERATIONS FOR PAM-4 TRANSMITTER 16
2.2.1 LEVEL SEPARATION MISMATCH RATIO (RLM) 17
2.2.2 IMPEDANCE MATCHING 19
2.2.3 PRIOR ARTS 21
2.3 DUOBINARY SIGNALING 24
CHAPTER 3 HIGH-LINEARITY AND IMPEDANCE-MATCHED PAM-4 TRANSMITTER 30
3.1 OVERALL ARCHITECTURE 31
3.2 SINGLE-ENDED IMPEDANCE-MATCHED PAM-4 DRIVER 33
3.3 3-POINT ZQ CALIBRATION FOR PAM-4 47
CHAPTER 4 REFLECTION-BASED DUOBINARY TRANSMITTER 57
4.1 BIDIRECTIONAL DUAL-RANK MEMORY SYSTEM 58
4.2 CONCEPT OF REFLECTION-BASED DUOBINARY SIGNALING 66
4.3 REFLECTION-BASED DUOBINARY TRANSMITTER 70
4.3.1 OVERALL ARCHITECTURE 70
4.3.2 EQUALIZATION FOR REFLECTION-BASED DUOBINARY SIGNALING 72
4.3.3 2D BINARY-SEGMENTED DRIVER 75
CHAPTER 5 EXPERIMENTAL RESULTS 77
5.1 HIGH-LINEARITY AND IMPEDANCE-MATCHED PAM-4 TRANSMITTER 77
5.2 REFLECTION-BASED DUOBINARY TRANSMITTER 84
CHAPTER 6 92
CONCLUSION 92
BIBLIOGRAPHY 94Docto