B2 desence

B2 DesenceLesson Learn

Jay Chang

VALUE1_VALUE2_VALUE3_VALUE4

AVAGO default: NM_2.7n_0.5p_22pChuck: NM_22p_0.5p_2.7n

Case 1: NM_22p_NM_2.7n (solve BC1 output power ?)Case 2: NM_22p

B2 PAE

B2 Gain

AVAGO defaultNM_2.7n_0.5p_22p

ChuckNM_22p_0.5p_2.7n

Case 1(Thru)NM_22p_NM_22p

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

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

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

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

Case 6(PAE optimized)8.2n_3n_1p_22p

NM_22p_NM_22p

default

Cu

Butterworth Pi LC HPF

RAL122 = 22p

5.6n_1.8p_5.6n_22p6.2n_2.7p_6.2n_22p

Butterworth Pi LC HPF

http://www.calculatoredge.com/electronics/bw%20pi%20high%20pass.htm



RAL124 = NM

Butterworth Tee LC HPF

http://www.calculatoredge.com/electronics/bw%20tee%20high%20pass.htm



RAL122 = 22p

Chebyshev Pi LC HPF

http://www.calculatoredge.com/electronics/ch%20pi%20high%20pass.htm

7.5n_2.2p_7.5n_22p



Chebyshev Tee LC HPF

RAL124 = NM

http://www.calculatoredge.com/electronics/ch%20tee%20high%20pass.htm

NM_3.5p_5.6n_3.5p



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-NH379-12180-NH379-42

32 41

1 1 2 1 2 3

11 1 ...totalFF FF F

G GG GG G

1 2 31 1 2

1 2 3 4

1 1 ...3 3 3 3 3total

GG GG GGIIP IIP IIP IIP IIP

我們已知用火 XD

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 12 3.190.5 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

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 11.26 1.590.79 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

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 12 3.080.5 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 11.26 1.540.79 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

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 .

LTE B2 FE ASM Duplexer LNA Rx SAW DPDT Trace loss Loss before WTR Rx NF Rx BW CN SensitivityTyp 1.24 0.68 1.9 　　 0.4 0.5 4.72 2.3 9 -1 -98.44Max 1.62 0.83 3.5 　　 0.4 0.8 7.15 3 9 -1 -95.31

For SXMXLNA 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 SensitivityTyp 1.24 0.68 1.9 　　 0.4 0.5 4.72 2.3 3.84 -9.5 -110.64Max 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 SensitivityTyp 1.24 0.68 1.9 　　 0.4 0.5 4.72 2.3 1.23 -2 -108.08Max 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 SensitivityTyp 1.24 0.68 1.9 0.6 　　 0.5 4.92 2.3 9 -1 -98.24Max 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 SensitivityTyp 1.24 0.68 1.9 0.6 　　 0.5 4.92 2.3 3.84 -9.5 -110.44Max 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 SensitivityTyp 1.24 0.68 1.9 0.6 　　 0.5 4.92 2.3 1.23 -2 -107.88Max 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 .

Type FEL + ASM + Dup Trace eLNA Trace + RxSAW iLNA


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 NFAnd loss use max value to calculate

B2 FE ASM DuplexerTyp 1.24 0.68 1.9Max 1.62 0.83 3.5

32 41

1 1 2 1 2 3

610

11 1 ... 8.09 dB.

[ ] 174 10log 9 10 8.09 ( 1) 97.4

totalFF FF F

G GG GG G

Sensitivity dBm

照理說最爛 0dBm sensitivity 也有 -97.4 以上

Gain mode G0 Min Typ Max UnitVoltage conversion gain 49 53 57 dBV/V

PS WTR3925 LTE Gain mode 0 define by Voltage Conversion Gain need to translation to power gain

RxSAW1.83.1

10

10 10

10log

10log 20log 2

IFOUT

RFIN

IFOUT IFOUT

RFIN RFIN

VVCG

VP V

VCGP V

Type FEL + ASM + LPF + Dup + SP6T + Trace

eLNA Trace + RxSAW iLNA


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 NFAnd loss use max value to calculate

32 41

1 1 2 1 2 3

610

11 1 ... 6.34 dB.

[ ] 174 10log 9 10 6.34 ( 1) 99.1

totalFF FF F

G GG GG G

Sensitivity dBm

LTE B12_17 FE ASM LPF Duplexer SP6TTyp 0.73 0.45 0.56 1.65 0.4Max 0.98 0.55 0.56 2.35 0.5


PS WTR3925 LTE Gain mode 0 define by Voltage conversion gain need to translation to power gain

RxSAW1.62.5w/ eLNA

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 NFAnd loss use max value to calculate

32 41

1 1 2 1 2 3

610

11 1 ... 7.76 dB.

[ ] 174 10log 9 10 7.76 ( 1) 97.7

totalFF FF F

G GG GG G

Sensitivity dBm




RxSAW1.62.5w/o eLNA

這篇講到說升高 LNA 的 Vcc 有助於降低 LNA 的 NFA Single Chip Silicon Bipolar Receiver for GPS/GLONASS Applicationshttps://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 ?

https://www.maximintegrated.com/en/app-notes/index.mvp/id/640

https://www.maximintegrated.com/en/app-notes/index.mvp/id/640

接下來討論 IIP3

w/o eLNA 整體的 IIP3

Type Trace ASM iLNA others


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 33 26.5 [dBm].total

total

GG GG GGIIP IIP IIP IIP IIPIIP

w/o eLNA

Type ASM eLNA Trace iLNA others


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

13 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

GG GG GGIIP IIP IIP IIP IIP

IIP

比之前 degrade~15dB

Type FEL + ASM + LPF + Dup + SP6T + Trace

eLNA Trace + RxSAW iLNA


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 IIP3And loss use max value to calculate




RxSAW1.62.5

1 2 31 1 2

1 2 3 4

1 1 ...3 3 3 3 33 15.1 [dBm].total

total


w/ eLNA

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 IIP3And loss use max value to calculate




RxSAW1.62.5

1 2 31 1 2

1 2 3 4

1 1 ...3 3 3 3 33 [dBm].total

total


w/o eLNA

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 40 505

6

7

8

9

10

CascadeNF(dB) CascadeIIP3(dBm)

-60

-40

-20

0

Casca

de IIP

3 (dB

m)

Casca

de NF

(dB)

eLNA Gain (dB)

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 Max Input 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 Maximum input 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.

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 .

[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

To be continued…

B2 desence

Engineering

Transcript of B2 desence