[hspice]行为级DAC波形不理想，怎么修正，求助！！！

xiecooller

最上面的输出有刺

1.28us处的放大

输出本应是严格阶梯状的,出现在在输入信号上升下降时
下面是网表

1. ****Start ideal 8-bit DAC Subcircuit************************************
   
2. .subckt DAC8bit VDD VREFP VREFM trip Vout B7 B6 B5 B4 B3 B2 B1 B0
   
3. *Change input logic signals into logic 0s or 1s
   
4. X7 trip B7 B7L Bitlogic
   
5. X6 trip B6 B6L Bitlogic
   
6. X5 trip B5 B5L Bitlogic
   
7. X4 trip B4 B4L Bitlogic
   
8. X3 trip B3 B3L Bitlogic
   
9. X2 trip B2 B2L Bitlogic
   
10. X1 trip B1 B1L Bitlogic
    
11. X0 trip B0 B0L Bitlogic
    
12. E1 VOUT 0 VOL='(v(VREFP)-v(VREFM))/256*(v(B7L)*128+v(B6L)*64+v(B5L)*32+v(B4L)*16+v(B3L)*8+v(B2L)*4+v(B1L)*2+v(B0L)*1+1/256)'
    
13. .ENDS
    
14. .subckt Bitlogic  trip BX BXL
    
15. Vone one 0 DC 1.0
    
16. Xa2 one BXL BX trip SW
    
17. .ENDS
    
18. ******会不会是下面这个模块不合适？**********.SUBCKT SW 1 2 3 4Gswitch 1 2 VCR PWL (1)  3 4 0V,10G 200pV ,1E-5
    
19. R1 2 0 10G
    
20. .ENDS
    
21. ***main body*********
    
22. VDD VDD 0 DC 1.0
    
23. R2 VDD 0 10G
    
24. VREFP VREFP 0 DC 1.0
    
25. VREFM VREFM 0 DC 0.0
    
26. VTRIP TRIP 0 DC 0.0
    
27. VB7 B7 0 DC 0 pulse(1.0 0 0 200p 200p 1279.8n 2560n)
    
28. VB6 B6 0 DC 0 pulse(1.0 0 0 200p 200p 639.8n 1280n)
    
29. VB5 B5 0 DC 0 pulse(1.0 0 0 200p 200p 319.8n 640n)
    
30. VB4 B4 0 DC 0 pulse(1.0 0 0 200p 200p 159.8n 320n)
    
31. VB3 B3 0 DC 0 pulse(1.0 0 0 200p 200p 79.8n 160n)
    
32. VB2 B2 0 DC 0 pulse(1.0 0 0 200p 200p 39.8n 80n)
    
33. VB1 B1 0 DC 0 pulse(1.0 0 0 200p 200p 19.8n 40n)
    
34. VB0 B0 0 DC 0 pulse(1.0 0 0 200p 200p 9.8n 20n)
    
35. Xa1  VDD VREFP VREFM trip Vout B7 B6 B5 B4 B3 B2 B1 B0 DAC8bit
    
36. R1 VOUT 0 10G
    
37. .OPTION LIST NODE POST
    
38. .OP
    
39. .option runlvl=0
    
40. .TRAN 200p 2.6u
    
41. .PRINT DC  v(Vout)
    
42. .END
    

复制代码

xiecooller

期待大家的帮助，谢谢！！！

xiecooller

越高位变化时，毛刺越明显
修改后：
.SUBCKT SW 1 2 3 4Gswitch 1 2 VCR PWL (1)  3 4 0V,10G 200pV ,1E-5
R1 2 0 1E-4
.ENDS
波形没有明显变化

tjulibolibo

mmmmmmmm

windwithgone

回复 1# xiecooller

Set runlvl=6 to get the most accuracy but at the cost of reduced simulation speed!

edwardk

学习中。。。。

wuzl423

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