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MN6627551 Problem report

MN6627551 Problem report. 2004. 3. 5. MN6627551 ES3 RF module oscillation phenomenon.

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MN6627551 Problem report

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  1. MN6627551 Problem report 2004. 3. 5

  2. MN6627551 ES3 RF module oscillation phenomenon (1)We found out that oscillation wave form come out from RFOUT and ARF.(2)This phenomenon is easy to happen in higher temperature and higher voltage.(3)This phenomenon is easy to happen at high EQ BST setting. In case of high temp., The following waveform comes out. 10MHz～20MHz 200mVp-p～400mVp-p 0.1uF 0.1μF ARF RFOUT CAGC RFIN A EQ AGC － B ＋ C 12dB/24dB D RFDET NRFDET VREF We found out the following phenomenon.When voltage level of CAGC swing over to GND level, it means that AGC Gain become big, then oscillation waveform come out.

  3. MN6627551 ES3 RF module oscillation phenomenon <Expected problems>1.In case of no input status (Laser ON & Stand-by), oscillation phenomenon is easy to happen since AGC gain become big.. *During playback, this phenomenon is difficult to happen since AGC gain become small. ( We have never seen this phenomenon during playback. )2.There are some possibility that NRFDET is misjudged (NRFDET = L) due to oscillation.3.In case that laser is on ( when RF add amp & AGC start working ), oscillation waveform comes out from RFOUT port for 300us duration transitionally. It should be no problem if this phenomenon is settled before starting disc detection and focus search. *There are some possibility to mis-judge the S-shape level when noise overlap on the FE signal.. However normally this noise is shut down by LPF. <Influence due to RFDET mis-judgement>1.In case of Focus pull in There are some possibility to lock the pick up since focus servo is kept on even though Focus pull in failed.2.In case that Focus is not on There are some possibility to lock the pick up since focus servo is kept on.

  4. MN6627551 ES3 RF module oscillation phenomenon We found out the countermeasure as below. Please evaluate deeply in your side about page 7 referring the following circuit diagram. * We will describe the same circuit diagram in the product spec. VREF RCAGC=100 kΩ CRFOUT=100 pF 0.1μF 0.1μF ARF RFOUT RFIN CAGC A EQ AGC － B ＋ C 12dB/24dB D RFDET NRFDET VREF

  5. Countermeasure for this oscillation and that margin Temp characteristic with external 100pF C and various R. (VCC3.7V RF gain HI EQ x1 speed EQ boost MAX) Effect of external C and R in worst condition (VCC3.7V 100℃ RF gain HI EQ x1 speed EQ boost MAX) Temp drop EQ boost drop EQ speed up Recover: No oscillation or can recover from oscillation after disturbance Osc: Keep oscillation or start oscillation after disturbance CRFOUT up EQ boost drop EQ speed up

  6. Lower limit amplitude of AGC input (RFIN) 0.1μF 100kΩ 0.1uF 100pF RFIN RFOUT ARF CAGC A EQ AGC － B ＋ C 12dB/24dB D VREF 100k ohm is connected ARF Min amplitude of RFIN which is boosted by AGC become bigger if 100k ohm is connected. Evaluation result of Min amplitude of RFIN which is boosted by AGC with AVDD=3.7V, 3.3V, 2.9V, high temp and normal temp is over 360mVpp. 1Vpp 100mVpp 360mVpp RFIN input amplitude

  7. MN6627551 ES3 RF module required confirmation issues <Confirmation issues>Please evaluate the following issues after adding the external component on CAGC and RFOUT port.* We haven’t see the phenomenon in Panasonic evaluation board. But please evaluate deeply in your side since pick up ,mechanism and etc are different between our evaluation board and your set or board.1.AGC response confirmation Please check the playability with discs which is related to RF-AGC response. Ex. Scratch, BDO, Finger Print, etc.Due to adding resister on CAGC, response of RF-AGC (especially amplification) become quicker.2..AGC dynamic range confirmation Please check if AGC D range (amplitude of ARF output) is enough with discs which RFOUT signal is the smallest like low reflection CD-RW disc.Due to adding resister on CAGC, upper limitation of D range become lower. (We think that this is no problem in normal use condition.)3.Playability confirmation Please check the playability at high speed setting if you are using high speed setting., especially with discs which have big jitter like CD-RW. Due to adding C on RFOUT, RF band is limited.

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