IEEE 802.3af DTE Power via MDI. When PSE is periodically detecting.

Transcription

1 IEEE802.3af, May 2002 IEEE 802.3af DTE Power via MDI When PSE is periodically detecting. Probing signal spectrum measurements and more. Ad hoc A.I. 6.3! Yair Darshan, PowerDsine! Aacknowledgments to Shimon Cohen, PowerDsine

2 Test objectives! To determine the signal spectrum limitations for zero data errors at the following operating modes: " AC disconnect detection probing signal " Resistor Detection probing signal! To confirm the calculated results as analyzed in A.I

3 Background! In some implementations AC disconnect signal required to be applied to the port most of the time! Resistor Detection uses min 2 point measurements which is very low frequency ac signal constrained by other circuit parameters! Resistor detection may run continuously generating up to 30Vpp low frequency signal across the the port " PSE is trying to detect other PSE/Non-compliant PD! The target of the following work is to support the theoretical analysis conclusion that confirm that no data degradation is expected and we have huge margin. 3

4 Strategy for evaluating the spectrum limits! Worst case signal amplitude : 30Vp during Resistor Detection! Min Rise time / Fall time : Need to be confirmed " Currently specified 0us min.! Max frequency : Not specified in IEEE802.3af " From EMI point of view # No issue (for the suggested spec at ad-hoc item.2) " Out of band of EMI standards " Close to zero noise, as demonstrated in March 2002 " Required to be met by vendor. " Confirm again in this tests 4

5 Test setup-common Mode noise measurements # PSE PSE 2 TX+ TX+ 00ohm R=Vsource / 5mA Probing Signal Source RX+ RL RX + 00ohm 00ohm RX- TX- TX- RX- 00ohm Common Mode Common Mode 5

6 Test setup-differential Mode Measurements #2 TX+ TX+ 00ohm 00ohm R=Vsource/5mA Probing Signal RX+ RL RX + differentials Mode 00ohm differentials Mode 00ohm RX- TX- TX- RX- 6

7 Test setup Data Error Measurement # 3 TX+ TX+ R=Vsource/5mA RL RX+ RX + RX- TX- TX- RX- Port A IN Port B Out SMB600 Analyzer 7

8 Test setup Data Error Measurement # 4 TX+ TX+ R=Vsource/5mA RX+ R=0, 0.K, 0.5K, 5K, 75K Probing Voltage source RX + RX- TX- TX- RX- Port A IN Port B Out SMB600 Analyzer 8

9 Test method! Running Sine wave from 0Hz to 5MHz to evaluate the following worst case values:! DM noise/vsource ratio! CM noise/vsource ratio! The V_port vs. Frequency envelope which above it, data errors>0 9

10 Data Error tests- test # -Cable length = 05meter -Frequency range: MHz to 5MHz -Amplitude=69Vpp, test setup limitation! Results for 69Vp_p with MHz signal Events Rates Events Rates 2-07 LN-300 A 2-07 LN-300 A 2-08 LN-300 A 2-08 LN-300 A Tx Frames 339,796,590 48,80 339,796,566 48,80 Rx Frames 339,796,590 48,80 339,796,567 48,80 Rx Bytes 2,746,98,772 9,523,883 2,746,980,268 9,523,884 Collisions CRC Errors Alignment Errors OverSize Frag/UnderSize

11 Tests # 2, 3, 4! Same results as test #, no errors were observed for the following conditions:! 25Vp, 5MHz! 2Vp, 0MHz! 8Vp, 5MHz! Voltage levels are limited by setup and not limited by data error.

12 Conclusions! Data integrity is kept, with large margin for the following conditions:! 69Vpp/MHz through 5K min! Any practical cable length! Loads from zero to 75K! For dual voltage source or single voltage source ( setups 3 and 4) 2

13 CM test results m CAT5 Freq 00HZ KH 0K 00K M 2M 5M 8M 0M 3M 5M Test Results [mvpp] CABLE=M Rs=5k RL=500 Source Amplitude [Vpp] Results RL=5K Results RL=70K Results mv=noise floor limitation 3

14 CM test results 20m CAT5 Freq 00HZ KH 0K 00K M 2M 5M 8M 0M 3M 5M Test Results [mvpp] CABLE=20M Rs=5k Source Amplitude [Vpp] RL=500 Results RL=5K Results RL=70K Results mv=noise floor limitation 4

15 DM test results m CAT5 Freq Test Results [mvpp] CABLE=M Rs=5k RL=500 Source Amplitude [Vpp] Results RL=5K Results RL=70K Results 00HZ KH 0K 00K M 2M 5M 8M 0M 3M 5M mv=noise floor limitation 5

16 DM test results 20m CAT5 Freq Test Results [mvpp] CABLE=20M Rs=5k Source Amplitude [Vpp] RL=500 Results RL=5K Results RL=70K Results 00HZ KH 0K 00K M 2M 5M 8M 0M 3M 5M mv=noise floor limitation 6

17 PHY noise requirements! According to Fred Schindler data summarized from IEEE802.3 The following Common Mode noise is permitted. ) 0B-TX, 802.3, Common-mode rejection, p276 The PHY must tolerate: A common mode voltage of 25Vpp, <=500KHz, edge rates no slower than 4nS (20% to 80%). This must not contribute more than 2.5nS edge jitter to the transmitted signal. 2) 00B-TX, ANSI X , Common-mode rejection The PHY must tolerate: Vpp sine wave, 0MHz to 25MHz. There is another section that covers cross talk:..3 They are only concerned with cross talk above MHz. 3) 000B-TX, 802.3ab, , Common-mode rejection They are only concerned with cross talk above MHz. 7

18 DM noise / V_port attenuation DATA spectrum starts here IEEE802.3af probing signals spectrum ends here RL=70K,m RL=5K,m RL=500,m RL=70K,20m RL=5K,20m RL=500,20m Attenuation Noise floor limitation Frequency[MHz] 8

19 CM noise / V_port attenuation IEEE802.3af probing signals spectrum ends here RL=70K,m RL=5K,m RL=500,m RL=70K,20 m RL=5K,20 m RL=500, 20 m Attenuation Noise floor limitation Frequency[MHz] DATA spectrum starts here

20 Specifying IEEE802.3af probing signal spectrum for 60Vpp port signal 20 NO EMI Limits range 000B-TX No Limit range 00 B-TX limit 0B-TX limit Measured Source Input Voltage level[dbmv] Source Signal 0B-TX limits 00B-TX limits W.C Measured (CM&DM noise) Noise floor limitation 0 00HZ KH 0K 00K M 2M 5M 8M 0M 3M 5M Frequency[MHz] we are here Data spectrum 20

21 Summary! Suggested probing signal spectrum: " Amplitude: 30V max as defined by IEEE802.3af " Rise/Fall time: currently 0us specified, meets data error free requirements " Changing to dv/dt<0.v/us # No EMI " Frequency: up to 500Hz! Periodically detecting (Signature or Disconnect) with the suggested probing signal spectrum is not generating data errors nor EMI.! Suggested probing signal spectrum meets IEEE802.3 limits with huge margins 2