USB 하드웨어 디자인 가이드
- GND, 샤시에 FB
- 15 Ohm Termination resistor
- ESD 인증에 문제가 있을 경우 protection device – NXP IP4220CE6
- Common mode choke – Murata plw3216s900sq2t1
- 2개의 USB 신호쌍은 parallel 하게하며, 간극은 최대 150 mil을 넘지 않도록
- 신호선의 최대 길이는 18인치를 넘지 않도록
HBM, MM, CDM 3가지 모델이 있으며, 각각의 테스트에 해당하는 테스트 회로와 입력 stress 파형의 조건이 다르다.
파형은 rise time (Tr), delay time(Td), 입력 전류 최대치(Ipeak) 가 각각 다르다.
아래 각각의 파형에 기준치가 기록이 되어 있다.
1. HBM (Human Body Model)
Two examples of industry standards that define MM ESD testing are JEDEC’s JESD22-A115 and ESD Association’s ESD STM5.2: Electrostatic Discharge Sensitivity Testing — Machine Model.
Two examples of industry standards that define CDM ESD testing are JEDEC’s JESD22-C101 and ESD Association’s ESD STM5.3.1: Electrostatic Discharge Sensitivity Testing — Charged Device Model
4. ESD Sensitivity Classfication Levels
Table 1. ESDS Component Sensitivity Classification – Human Body Model
(Per ESD STM5.1-1998*)
Class | Voltage Range |
---|---|
Class 0 | < 250 volts |
Class 1A | 250 volts to < 500 volts |
Class 1B | 500 volts to < 1,000 volts |
Class 1C | 1000 volts to < 2,000 volts |
Class 2 | 2000 volts to < 4,000 volts |
Class 3A | 4000 volts to < 8000 volts |
Class 3B | > = 8000 volts |
Table 2. ESDS Component Sensitivity Classification – Machine Model
(Per ESD STM5.2-1999*)
Class | Voltage Range |
---|---|
Class M1 | < 100 volts |
Class M2 | 100 volts to < 200 volts |
Class M3 | 200 volts to < 400 volts |
Class M4 | > or = 400 volts |
Table 3. ESDS Component Sensitivity Classification – Charged Device Model
(Per ESD STM5.3.1-1999*)
Class | Voltage Range |
---|---|
Class C1 | <125 volts |
Class C2 | 125 volts to < 250 volts |
Class C3 | 250 volts to < 500 volts |
Class C4 | 500 volts to < 1,000 volts |
Class C5 | 1,000 volts to < 1,500 volts |
Class C6 | 1,500 volts to < 2,000 volts |
Class C7 | =>2,000 volts |