desence,sensitivity calculation with and without external LNA, Noise figure calculation with and without external LNA and IIP3 calculation with and without external LNA

1. B2 Desence
Lesson Learn
Jay Chang

2. VALUE1_VALUE2_VALUE3_VALUE4
AVAGO default: NM_2.7n_0.5p_22p
Chuck: NM_22p_0.5p_2.7n
Case 1: NM_22p_NM_2.7n (solve BC1 output power ?)
Case 2: NM_22p

3. B2 PAE

4. B2 Gain

5. AVAGO default
NM_2.7n_0.5p_22p

6. Chuck
NM_22p_0.5p_2.7n

7. Case 1(Thru)
NM_22p_NM_22p

8. Case 2(Thru and let mid-channel 50 Ω)
NM_22p_8.2n_22p

9. Case 3(try to turn left to PAE optimized, but useless)
NM_22p_5.6n_22p

10. Case 4(try to let BC1 output power bigger and keep Chuck’s topology)
NM_22p_NM_2.7n

11. Case 5(WCDMA B2 mid-channel sensitivity has 1dB better)
NM_3.5n_NM_22p

12. Case 6(PAE optimized)
8.2n_3n_1p_22p

13. NM_22p_NM_22p
default
Cu

14. Butterworth Pi LC HPF
RAL122 = 22p
5.6n_1.8p_5.6n_22p6.2n_22p

15. Butterworth Pi LC HPF
http://www.calculatoredge.com/electronics/bw%2
0pi%20high%20pass.htm

16. RAL124 = NM
Butterworth Tee LC HPF
http://www.calculatoredge.com/electronics/bw%2
0tee%20high%20pass.htm

17. RAL122 = 22p
Chebyshev Pi LC HPF
http://www.calculatoredge.com/electronics/ch%2
0pi%20high%20pass.htm
7.5n_2.2p_7.5n_22p

18. Chebyshev Tee LC HPF
RAL124 = NM
http://www.calculatoredge.com/electronics/ch%2
0tee%20high%20pass.htm
NM_3.5p_5.6n_3.5p

19. 10[ ] 174 10logSensitivity dBm BW loss RxNF C N     
Technology GSM CDMA WCDMA TD-SCDMA LTE
BW [MHz] 0.2 1.23 3.84 1.28 9
C/N [dB] 4.75 -2 -9.5 -5.5 -1
RxNF [dB] 2.3-3.5 2.3-3 2.3-3 2.3-3 2.3-3
loss = total loss before LNA.
RxNF = receiver noise figure (ex: WTR3925)
80-NH379-121
80-NH379-42
32 4
1
1 1 2 1 2 3
11 1
...total
FF F
F F
G G G G G G
 
    
1 2 31 1 2
1 2 3 4
1 1
...
3 3 3 3 3total
G G GG G G
IIP IIP IIP IIP IIP
    
我們已知 用火XD

20. Type Trace ASM iLNA others
Stage Stage1 Stage2 Stage3 Stage4
NF [dB] 3 1 0.85 4
Gain [dB] -3 -1 15 -4
NF 2 1.26 1.22 2.51
Gain 0.5 0.79 31.62 0.4
10
1.26 1 1.22 1 2.51 1
2 3.19
0.5 0.5 0.79 0.5 0.79 31.62
10log (3.19) 5.04 [dB].
total
total
F
F
  
    
  
 
我們先假設一種情況 w/o eLNA
w/o eLNA

21. Type ASM eLNA Trace iLNA others
Stage Stage1 Stage2 Stage3 Stage4 Stage5
NF [dB] 1 0.85 3 0.85 4
Gain [dB] -1 15 -3 15 -4
NF 1.26 1.22 2 1.22 2.51
Gain 0.79 31.62 0.5 31.62 0.4
10
1.22 1 2 1 1.22 1 2.51 1
1.26 1.59
0.79 0.79 31.62 0.79 31.62 0.5 0.79 31.62 0.5 31.62
10log (1.59) 2.02 [dB].
total
total
F
F
   
     
     
 
比較最好的情況w/ eLNA
w/ eLNA

22. 代入理論公式太麻煩, 看能不能省去甚麼…
我們發現, LNA後方Stage會因分母有LNA的Gain, 其值會變很小因此省略計算
10
1.26 1 1.22 1 2.51 1
2 3.08
0.5 0.5 0.79 0.5 0.79 31.62
10log (3.08) 4.88 [dB].
total
total
F
F
  
    
  
 
10
1.22 1 2 1 1.22 1 2.51 1
1.26 1.54
0.79 0.79 31.62 0.79 31.62 0.5 0.79 31.62 0.5 31.62
10log (1.54) 1.88 [dB].
total
total
F
F
   
     
     
 
做個table比較一下
NF 理論 NF 化簡
w/o eLNA 5.04 dB 4.88 dB
w/ eLNA 2.02 dB 1.88 dB

23. 化簡公式還要除, 還是覺得有點麻煩…看能不能更直觀 !!
直接將LNA input Stage的NF總和 [dB], 與從天線下來遇到的第一顆LNA自身的NF [dB], 兩個相加 
NFtot [dB] = LNA pre-loss [dB] + LNA NF [dB]
再做個table比較一下
NF 理論 NF 化簡 NF 直觀
w/o eLNA 5.04 dB 4.88 dB 4.85 dB
w/ eLNA 2.02 dB 1.88 dB 1.85 dB
w/o eLNA
w/ eLNA
差不多, 計算方便, 又直觀
But 與理論有些微誤差.

24. LTE B2 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.4 0.5 4.72 2.3 9 -1 -98.44
Max 1.62 0.83 3.5 0.4 0.8 7.15 3 9 -1 -95.31
For SXMX
LNA都先給他thru (w/o eLNA), 計算sensitivity
WCDMA B2 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.4 0.5 4.72 2.3 3.84 -9.5 -110.64
Max 1.62 0.83 3.5 0.4 0.8 7.15 3 3.84 -9.5 -107.51
BC1 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.4 0.5 4.72 2.3 1.23 -2 -108.08
Max 1.62 0.83 3.5 0.4 0.8 7.15 3 1.23 -2 -104.95
For SXMX
掛LNA (w/ eLNA), 計算sensitivity
由上頁知, NFtot [dB] = LNA pre-loss [dB] + LNA NF [dB]
Datasheet Infineon B2 LNA NF = 0.6-1.2, 再來我們忽略 RxSAW 與 DPDT 的NF.
LTE B2 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.6 0.5 4.92 2.3 9 -1 -98.24
Max 1.62 0.83 3.5 1.2 0.8 7.95 3 9 -1 -94.51
WCDMA B2 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.6 0.5 4.92 2.3 3.84 -9.5 -110.44
Max 1.62 0.83 3.5 1.2 0.8 7.95 3 3.84 -9.5 -106.71
BC1 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN Sensitivity
Typ 1.24 0.68 1.9 0.6 0.5 4.92 2.3 1.23 -2 -107.88
Max 1.62 0.83 3.5 1.2 0.8 7.95 3 1.23 -2 -104.15
所以LNA掛WTR附近是沒有作用的.

25. Type FEL + ASM + Dup Trace eLNA Trace + RxSAW iLNA
Stage Stage1 Stage2 Stage3 Stage4 Stage5
NF [dB] 5.95 0.8 1.2 0.4 3
Gain [dB] -5.95 -0.8 14.3 -0.4 35.12
NF 3.94 1.2 1.32 1.1 2
Gain 0.25 0.83 26.9 0.91 3250.87
那我們現在來計算一下LTE B2的NF
And loss use max value to calculate
B2 FE ASM Duplexer
Typ 1.24 0.68 1.9
Max 1.62 0.83 3.5
32 4
1
1 1 2 1 2 3
6
10
11 1
... 8.09 dB.
[ ] 174 10log 9 10 8.09 ( 1) 97.4
total
FF F
F F
G G G G G G
Sensitivity dBm
 
     
        
照理說最爛0dBm sensitivity也有-97.4以上
Gain mode G0 Min Typ Max Unit
Voltage conversion gain 49 53 57 dBV/V
PS WTR3925 LTE Gain mode 0 define by Voltage Conversion Gain need to translation to power gain
RxSAW
1.8
3.1
10
10 10
10log
10log 20log 2
IFOUT
RFIN
IFOUT IFOUT
RFIN RFIN
V
VCG
V
P V
VCG
P V

  

26. Type FEL + ASM + LPF +
Dup + SP6T + Trace
eLNA Trace + RxSAW iLNA
Stage Stage1 Stage2 Stage3 Stage4
NF [dB] 4.6 1.37 2.3 2.3
Gain [dB] -4.6 11.9 -2.3 35.12
NF 2
Gain 3250.87
那我們現在來計算一下LTE B12/17的NF
And loss use max value to calculate
32 4
1
1 1 2 1 2 3
6
10
11 1
... 6.34 dB.
[ ] 174 10log 9 10 6.34 ( 1) 99.1
total
FF F
F F
G G G G G G
Sensitivity dBm
 
     
        
LTE B12_17 FE ASM LPF Duplexer SP6T
Typ 0.73 0.45 0.56 1.65 0.4
Max 0.98 0.55 0.56 2.35 0.5
Gain mode G0 Min Typ Max Unit
Voltage conversion gain 49 53 57 dBV/V
PS WTR3925 LTE Gain mode 0 define by Voltage conversion gain need to translation to power gain
RxSAW
1.6
2.5
w/ eLNA

27. Type FEL + ASM + LPF + Dup + SP6T
+ Trace = loss before WTR
iLNA
Stage Stage1 Stage4
NF [dB] 5.46 2.3
Gain [dB] -5.46 35.12
NF 2
Gain 3250.87
那我們現在來計算一下LTE B12/17的NF
And loss use max value to calculate
32 4
1
1 1 2 1 2 3
6
10
11 1
... 7.76 dB.
[ ] 174 10log 9 10 7.76 ( 1) 97.7
total
FF F
F F
G G G G G G
Sensitivity dBm
 
     
        
LTE B12_17 FE ASM LPF Duplexer SP6T
Typ 0.73 0.45 0.56 1.65 0.4
Max 0.98 0.55 0.56 2.35 0.5
Gain mode G0 Min Typ Max Unit
Voltage conversion gain 49 53 57 dBV/V
PS WTR3925 LTE Gain mode 0 define by Voltage conversion gain need to translation to power gain
RxSAW
1.6
2.5
w/o eLNA

28. 這篇講到說升高LNA的Vcc有助於降低LNA的NF
A Single Chip Silicon Bipolar Receiver for GPS/GLONASS Applications
https://www.maximintegrated.com/en/app-notes/index.mvp/id/640
不過我們用MIPI控制的, 除非Layout, grounding沒走好造成IR drop否則應該是2.7V ?

29. 接下來討論IIP3
w/o eLNA 整體的 IIP3
Type Trace ASM iLNA others
Stage Stage1 Stage2 Stage3 Stage4
IIP3 [dBm] 100 80 5 -15.5
Gain [dB] -3 -1 15 -4
IIP3 [mW] 1010 108 3.16 0.028
Gain 0.5 0.79 31.62 0.4
1 2 31 1 2
1 2 3 4
1 1
...
3 3 3 3 3
3 26.5 [dBm].
total
total
G G GG G G
IIP IIP IIP IIP IIP
IIP
    
 w/o eLNA

30. Type ASM eLNA Trace iLNA others
Stage Stage1 Stage2 Stage3 Stage4 Stage5
IIP3 [dBm] 80 5 100 5 -15.5
Gain [dB] -1 15 -3 15 -4
IIP3 [mW] 108 3.162 1010 3.162 0.028
Gain 0.79 31.62 0.5 31.62 0.4
比較最好的情況w/ eLNA 整體的 IIP3
w/ eLNA
1 2 31 1 2
1 2 3 4
8 10
1 1
...
3 3 3 3 3
1
3 41.6 [dBm].
1 0.79 0.79 31.62 0.79 31.62 0.5 0.79 31.62 0.5 31.62
10 3.162 10 3.162 0.028
total
total
G G GG G G
IIP IIP IIP IIP IIP
IIP
    
  
     
   
比之前degrade~15dB

31. Type FEL + ASM + LPF +
Dup + SP6T + Trace
eLNA Trace + RxSAW iLNA
Stage Stage1 Stage2 Stage3 Stage4
IIP3 [dBm] 80 -2 100 -10
Gain [dB] -4.6 11.9 -2.3 35.12
IIP3 [mW]
Gain
那我們現在來計算一下LTE B12/17的IIP3
And loss use max value to calculate
LTE B12_17 FE ASM LPF Duplexer SP6T
Typ 0.73 0.45 0.56 1.65 0.4
Max 0.98 0.55 0.56 2.35 0.5
Gain mode G0 Min Typ Max Unit
Voltage conversion gain 49 53 57 dBV/V
PS WTR3925 LTE Gain mode 0 define by Voltage conversion gain need to translation to power gain
RxSAW
1.6
2.5
1 2 31 1 2
1 2 3 4
1 1
...
3 3 3 3 3
3 15.1 [dBm].
total
total
G G GG G G
IIP IIP IIP IIP IIP
IIP
    
 
w/ eLNA

33. Type FEL + ASM + LPF + Dup + SP6T
+ Trace = before WTR
iLNA
Stage Stage1 Stage4
IIP3 [dBm] 80 -10
Gain [dB] -5.46 35.12
IIP3 [mW]
Gain
那我們現在來計算一下LTE B12/17的IIP3
And loss use max value to calculate
LTE B12_17 FE ASM LPF Duplexer SP6T
Typ 0.73 0.45 0.56 1.65 0.4
Max 0.98 0.55 0.56 2.35 0.5
Gain mode G0 Min Typ Max Unit
Voltage conversion gain 49 53 57 dBV/V
PS WTR3925 LTE Gain mode 0 define by Voltage conversion gain need to translation to power gain
RxSAW
1.6
2.5
1 2 31 1 2
1 2 3 4
1 1
...
3 3 3 3 3
3 [dBm].
total
total
G G GG G G
IIP IIP IIP IIP IIP
IIP
    
 
w/o eLNA

34. 1. 由此可知eLNA可以提升sensitivity, 但是連帶的也會降低linearity(IIP3變爛).
2. 其中IIP3 degrade = eLNA Gain.
eLNA Gain vs cascade NF & IIP3
1. eLNA的Gain對於sensitivity的改善其實是有極限的.
2. Transceiver整體IIP3的下降是來自於eLNA的Gain, Gain每多增加1dB, Transceiver整體的IIP3就會降1dB.
0 10 20 30 40 50
5
6
7
8
9
10
CascadeNF(dB)
CascadeIIP3(dBm)
-60
-40
-20
0
CascadeIIP3(dBm)
CascadeNF(dB)
eLNA Gain (dB)

35. System Band Test Item Ch Cell Power Lower Upper Unit Result Judgement
WCDMA 1 6.2 Sensitivity Level 9613 -106.7 None 0.1 % 0 PASS
WCDMA 1 6.3 MaxInput Level 9613 -25.7 None 0.1 % 0 PASS
System Band Test Item Ch Cell Power Lower Upper Unit Result Judgement
LTE-FDD 4 7.3 Reference sensitivity level;10MHZ; 20000 -96.3 95 None % 100 PASS
LTE-FDD 4 RSRP;10MHZ; 20000 -96.3 None None None 16 None
LTE-FDD 4 7.4 Maximuminput level;10MHZ; 20000 -25.7 95 None % 100 PASS
 Sensitivity: 是在測試BER能接受情況下, 所能接收的最小輸入訊號.
 Maximum Input Level: 顧名思義則是在測試BER能接受情況下, 所能接收的最大輸入訊號.
 以Dynamic Range(DR)來解釋, Sensitivity是在測DR的下限, 而Maximum Input Level則是在測DR的上限.
 整體來說Sensitivity, Maximum Input Level便是在量測整體Rx電路的P1dB.

36. 在來我們討論SAW Filter and Linearity的影響
換言之就是計算有SAW情況下的IIP3
因為若Receiver整體的IIP2跟IIP3越大(越線性), 其抑制IMD2跟IMD3的能力就越好.

37. [1] Guidelines for achieving best-in-class RX Diversity Performance in your Smartphone
Applications, Infineon
[2] Understanding and Enhancing Sensitivity in Receivers for Wireless Applications, TI
[3] Improving Receiver Sensitivity with External LNA, Maxim Integrated
[4] A Single Chip Silicon Bipolar Receiver for GPS/GLONASS Applications
[5] 80-NH379-121
[6] 80-NH379-42
[7] ATF-531P8 1900 MHz High Linearity Amplifier, AVAGO
[8] Integration of an External Low-noise Amplifier Improving the sensitivity of the Receiver, Atmel
[9] Increasing the Sensitivity of the TDA52xx Receivers, Infineon
[10] Signal Chain Noise Figure Analysis, TI
[11] Use Selectivity to Improve Receiver Intercept Point, Maxim
references

38. To be continued…