BA6387K Optical disc ICs Preservo amplifier for CD players BA6387K The BA6387K is a preservo amplifier for CD players. By using this paired with a ROHM DSP, a servo and main signal system can be configured with few external components and low power consumption. !Applications CD players !Features 1) Internal RF and AGC circuits. 2) Internal APC circuit. 3) Internal auto asymmetry circuit. 4) Internal disc defect detector. 5) Internal focus protect function against disc defects. !Absolute maximum ratings (Ta = 25°C) Symbol Limits Unit Power supply voltage Parameter VCC 9 V Power dissipation Pd 400* mW Operating temperature Topr -25~+75 ˚C Storage temperature Tstg -55~+125 ˚C * Reduced by 4mW for each increase in Ta of 1˚C over 25˚C. !Recommended operating conditions (Ta = 25°C) Parameter Power supply voltage Symbol Limits Unit VCC 2.4~5.5 V BA6387K Optical disc ICs 19 18 45µ 20k 25 39k 14 + + + − 28 30p 160k − + 160k 30p D DEFECT 0.6V − 27 20k 20k 39k 44.7k − − + + 2k 15 20k 10k 20k 60k BL BS MIRR + 2k PS PL 20k 10k 44.7k 20k − + − A C 16 DET BLOCK 2k 26 EFM − + 60k 20k + 2k 17 18 − B ASY 20 CAGC 21 BLH 22 PLH 23 VCC 24 RFI RFO RF- !Block diagram − 13 FOK SCRATCH CONTROL HOLD BLOCK FOK 10k FEB FE FOK 29 12 LOOP ON + 0.2V − E 10k + 2k − + + − 50k 18 TEO 13.3k 5p 12p + 5 6 PD 4 LD 3 CAPC AGND 2 7 R/H MUTE High=off FO F SC 2.64k 260k 1 10 9 − 1M 402k 32 PL 20k + − 100k 12p 2k BL 20k 50k − TE 20k 10k 20k 31 11 TEO 5p + RAMP OSC GAIN 6dB FI FE' FOCUS SWITCH − 30 FON FOCUS BIAS − + 100k 100k VB 8 BA6387K Optical disc ICs !Pin descriptions Pin No. Pin name Function F input 17 ASY Auto-asymmetry control input F output 18 CAGC For capacitor for AGC constant Analog GND 19 BLH For capacitor for bottom long F gain adjustment feedback 20 PLH For capacitor for peak long For capacitor for APC phase compensation 21 VCC Power supply 22 RFI RF output capacity coupling reinput APC amplifier input 23 RFO RF summing amplifier output R/H For capacitor for ramp wave/ loop off 24 RF- RF summing amplifier feedback input 9 SC For resistor for scratch depth adjustment 25 B B input 26 A A input 10 TE Tracking error output 27 C C input 11 FON Focus on control 28 D D input Focus OK comparator output 29 FEB Pin No. Pin name 1 F 2 FO 3 AGND 4 FI 5 CAPC 6 LD APC amplifier output 7 PD 8 Function Focus error bias input 12 FOK 13 FE Focus error output 1 30 VB Bias amplifier output 14 DEFECT Defect signal output 31 FE' Focus error output 2 15 MIRR Mirror signal output 32 E 16 EFM EFM signal output E input BA6387K Optical disc ICs !Electrical characteristics (unless otherwise noted, Ta = 25°C and VCC = 2.5V) Parameter Quiescent current Symbol Min. Typ. Max. Unit Conditions IQ - 8.7 12.7 mA - 〈Bias amplifier〉 Bias voltage VB 1.12 1.25 1.38 V Maximum output high level voltage IOH 3.0 - - mA Bias fluctuation below 200mV Maximum output low level voltage IOL 3.0 - - mA Bias fluctuation below 200mV VOFRF -1.02 -0.90 -0.78 V GRF 21.0 24.0 27.0 dB V8 = 0.8V, SG5 = 30mVP-P, 1kHz Maximum output high level amplitude VOHRF 0.90 1.10 - V Simultaneous AC and BD input Maximum output low level amplitude VOLRF - -1.10 -0.90 V Cutoff frequency FCRF - 6 - MHz VOFFE -80 0 80 mV dB SG5 = 30mVP-P, 1kHz SG6 = 30mVP-P, 1kHz - 〈RF amplifier〉 Output offset voltage Voltage gain * V9 = VB + 0.25V, VB-0.05V * -3dB point 〈FE amplifier〉 Output offset voltage Voltage gain AC GFEAC 26 29 32 Voltage gain BD GFEBD 26 29 32 dB -3 0 3 dB Voltage gain difference ∆GFE * Measurement with AC and BD input Maximum output high level amplitude VOHFE 0.90 1.10 - V Maximum output low level amplitude VOLFE - -1.10 -0.90 V V9 (V10) = VB ± 0.15V Frequency characteristics FCFE 19 22 25 dB SG5 (SG6) = 60mVP-P, 60kHz Output offset voltage VOFTE -80 0 80 mV Voltage gain E GTEE 27 30 33 dB SG1 = 30mVP-P, 1kHz GTEF 27 30 33 dB SG2 = 30mVP-P, 1kHz -3 0 3 dB 0.90 1.10 - V * 〈TE amplifier〉 Voltage gain F Voltage gain difference ∆GTE Maximum output high level amplitude VOHTE Maximum output low level amplitude VOLTE - -1.10 -0.90 Frequency characteristics FCTE 19 22 25 * V1 = VB + 0.1V * V V2 = VB + 0.1V * dB SG1 (SG2) = 60mVP-P, 60kHz 〈FOK comparator〉 Input pin 22 Threshold voltage VTHFK -0.42 -0.30 -0.18 V Output high level voltage VOHFK 2.0 - - V V7 = VB-0.42V V7 = VB-0.18V * Output low level voltage VOLFK - - 0.5 V Maximum operating frequency FMXFK 45 - - kHz Output offset voltage VOFAS -60 - 60 mV Voltage gain 1 G1AS 3 6 9 dB Input pin 22, 80mVP-P, 1kHz Voltage gain 2 G2AS 8.5 11.5 14.5 dB Input pin 17, 80mVP-P, 1kHz Maximum output high level amplitude VOHAS 0.90 1.10 - V V7 = VB ± 0.8 Maximum output low level amplitude VOLAS - -1.10 -0.90 V V6 = VB ± 0.4 - 〈Asymmetry amplifier〉 * * BA6387K Optical disc ICs Parameter Symbol Min. Typ. Max. Unit Output voltage 1 VO1AP 1.90 Output voltage 2 VO2AP - Reference voltage VAPR Frequency characteristics FAP Conditions 2.30 - V 230mV input at pin 7 1.0 1.4 V 170mV input at pin 7, I2 = 1mA 190 200 210 mV -5 -1 3 dB SG7 = 40mVP-P, 500Hz 〈APC〉 - 〈AGC〉 Reference voltage 1 VAGC1 0 - 100 mV V8 = 0.8V, RFO = 1.2VP-P Reference voltage 2 VAGC2 180 195 210 mV V8 = 0.8V, RFO = 0.7VP-P Attack time RATT 70 100 130 kΩ Recovery time RRCV 0.7 1.0 1.3 MΩ VOHMR 2.0 - - V Output low level voltage VOLMR - - 0.5 V - Minimum operating frequency FMNMR - - 600 Hz - Maximum operating frequency FMXMR 30 - - kHz - Minimum input operating voltage VMNMR - - 0.2 VP-P - Maximum input operating voltage VMXMR 1.2 - - VP-P - Output high level voltage VOHDF 2.0 - - V Output low level voltage VOLDF - - 0.5 V - Minimum operating frequency FMNDF - - 1 kHz - Maximum operating frequency FMXDF 2 - - kHz - Minimum input operating voltage VMNDF - - 0.5 VP-P - Maximum input operating voltage VMXDF 1.2 - - VP-P - VSC 0.13 0.20 0.27 V - - Measurement of internal R 〈Mirror detector〉 Output high level voltage RL = 15kΩ 〈Defect detector〉 Scratch depth RL = 15kΩ 〈Ramp wave generator circuit〉 ISIRA 220 340 460 ms High level limit voltage VLHRA 80 124 168 mV Low level limit voltage VLLRA -168 -124 -80 mV IIFON 10.4 13.5 16.6 µA - VTHFO 1.10 1.45 1.80 V - tOFLO 4.0 6.6 10.0 ms - Period FEO output value * 〈FON pin〉 Inflow current Input threshold voltage 〈Loop on unit〉 Loop off delay time 〈FZC comparator〉 Input sensitivity level VFZH 320 400 480 mV - Zero cross sensitivity level VFZL 120 200 280 mV - * Standards are with VB reference. ** When FON is LOW, 8 voltage is VB. ** The ramp wave begins at the bottom. ** The loop will not turn on when the ramp wave is at the bottom. ** Pin 8 is charged rapidly when the loop turns on. BA6387K Optical disc ICs !Measurement circuit SW11 V ∼ VCC OFF A N A I1 SW10 C OFF C B B B O SG4 ∼ A SW3 V7 V V 20k T 1µ A SW9 A 3300p 3300p SW12 91k SW21 V11 10k 10k A SW4 B OFF C ∼ 23 22 21 20 19 18 17 RFO RFI VCC PLH BLH CAGC ASY A 27k B 25 B 26 27 V6 EFM 16 A MIRR 15 V ∼ L C DEFECT 14 V ∼ 15k SW23 15k 10k 27k SW13 27k SG6 OFF A B 27k D FE 13 29 FEB FOK 12 SW17 30 VB FON 11 31 FE' TE 10 J V ∼ V ∼ I SW16 SW18 82k A B 33k OFF V A H LD PD R/H SW22 CAPC 32 FI Q AGND V FO P F I2 SW25 100k BA6387K SW14 f1 f SW24 28 C 1 2 3 4 5 6 7 8 E V12 V ∼ 9 SC SW6 G 62k 10k 22k V SW26 13k 62k SW20 A SW1 A B C 26k B SG1 ∼ A A SW2 A A B B B A SW19 V10 K SW7 SW15 ∼ V ∼ SW8 C V9 M 10k ∼ 24 RF- SG3 V8 SG5 D C A C SG2 E V F 1µ C V4 B V1 B SW5 A V3 V ∼ C V2 470p 1µ 4.7 I2 V V 1k 47 U Fig.1 V 1µ ∼ SG7 S V5 BA6387K Optical disc ICs !Circuit operation (1) RF amplifier, FOK comparator 20k 24 0.01µ 23 22 − + 20k 45µ 10k 10k 20k 60k 20k + + 20k 2k 28 − − 25 2k 60k − − 26 12 2k + + 27 0.6V 2k Fig.2 RF and FOK block RFO is shifted downwards from VB by 0.9V. However, the resistance between pins 23 and 24 is set to 20kΩ and if this resistance is changed use external components to adjust the shift back to 0.9V. Have the feedback resistance 10kΩ or greater. If the DC component of RF rises 0.3V, then FOK becomes high. BA6387K Optical disc ICs (2) FE amplifier and focus search 30p ON + 160k 160k + LOOP ON OFF 20k 20k − 44.7k 11 FOK I / 10 ON 60k − 25 OFF 2k 28 2k I 65k 44.7k + 30p 13 − 10k R11 − ×3 + I 60k − 26 2k 27 2k 8 + 1µF 29 31 Fig.3 Focus error block The voltage for focus search is obtained by the charging and discharging of the capacitor attached to pin 8. The charging current is I / 10 and the discharging current is I. The FEO output amplitude (VSERCH) at this time is determined by the formula given below. VSERCH = ± I × 15kΩ × 2 (VB reference) Moreover, from Fig.3, I can be approximated by the formula given below. I= VCC - 1.4 65k + R11 × 1 3 Set R11 so that I becomes 2µA or greater. Apply biasing to the focus error signal from pin 29. If no adjustment occurs, pin 29 = VB . The timing charts when the focus loop turns ON or OFF are given on the next page. BA6387K Optical disc ICs (1) LOOP ON timing When FOK turns high, the fall of FE’ is detected and the FOCUS LOOP turns ON. 0.2V 0.4V FE' (pin31) pin8 FZC (internal) RFO (pin23) 0.3V FOK (pin12) FOCUS LOOP ON (internal) Fig.4 LOOP ON timing (2) LOOP OFF timing After FOK turns low, the FOCUS LOOP turns OFF after the delay T (s) shown in the figure below. RFO (pin23) 0.3V FOK (pin12) pin8 VB T FOCUS LOOP ON (internal) Fig.5 LOOP OFF timing T=14E3 ⋅ C ⋅ In (1+1.5 / VCC) [S] BA6387K Optical disc ICs (3) APC block and AGC block 11 FON lagc=50µA MUTE High-off 20k 20k − BL 20k 13.3k Tr1 + PL 20k 100k V1 − 2.64k V-I 1M + 18 5 6 1µF 4.7 1µF 1k 200 10µH PD LD 1µF Fig.6 APC and AGC blocks The initial setting for V1 is 1.2V. When PL-BL (the RF AC amplitude) exceeds a certain value (VAGC), then AGC lowers V1 and suppresses the laser power. The value of VAGC is (50µA × 20k) = 1V. When defect turns high, Tr1 turns OFF. When FON (pin 11) is low, the LD output (pin 6) becomes high. 7 BA6387K Optical disc ICs (4) DET block + 15 − vsc + 37k 88k − RFO Bottom hold (long) Bottom hold (short) Peak hold (long) Peak hold (short) Charging current 0.1µA Charging current 1µA Discharging current 0.1µA Discharging current 1µA 19 200 R9 9 30p 17.8p 1.2V 20 3300p 3300p Fig.7 DET block Peak hold (long) (PL) Bottom hold (long) (BL) Peak hold (short) (PS) Bottom hold (short) (BS) PL-VSC BL + (PL - BL) ⋅ 37k ⋅ (37k + 88k) Mirror Defect Fig.8 Defect and mirror generation When defect is high, the bottom hold (long) charging current is 50µA. The scratch depth (VSC) can be adjusted by changing the resistance at pin 9. VSC = 12 R9 + 200 × 4k The peak hold voltage will not go below (GND + 0.9V) and the bottom hold voltage will not go below (VCC – 0.9V). 14 BA6387K Optical disc ICs !Application example 33µ 3300p 22 21 20 19 18 17 BLH CAGC ASY 3300p 23 PLH 26 24 VCC B 0.47µ RFI 25 100k 1µ RFO 27k B 0.01µ RF- 20k EFMI EFM 16 A MIRR 15 27 C DEFECT 14 28 D FE 13 27k A EFMO MIRR 27k C FE 27k D To DSP DEF BA6387K FOK 50k 29 FEB FOK 12 30 VB FON 11 10µ FON 33k TE FE' 31 FE' 32 E TE 10 SC 9 F FO AGND FI CAPC LD PD R/H 62k E 1 2 3 4 5 6 7 8 22k 62k F 1µ 22k 20k 10 10µH 200 PD 1µ 1k LD Fig.9 1µ BA6387K Optical disc ICs !Electrical characteristics curves 50 50 180 180 GAIN 0 0 PHASE -180 -50 1k 10k 100k 1M 10M -180 -50 100 100M 10k 100k FREQUENCY : f (Hz) Fig.10 RF amplifier frequency characteristics Fig.11 FE amplifier frequency characteristics 50 180 0 0 PHASE -180 -50 100 1k 10k 100k FREQUENCY : f (Hz) Fig.12 TE amplifier frequency characteristics !External dimensions (Units : mm) 9.0±0.3 7.0±0.2 17 16 32 9 1.45±0.1 0.05 1 0.8 8 0.4±0.1 QFP32 0.4 9.0±0.3 7.0±0.2 24 25 0.15±0.1 0.15 1M PHASE (deg) GAIN GAIN (dB) 1k FREQUENCY : f (Hz) 1M PHASE (deg) 0 PHASE GAIN (dB) 0 PHASE (deg) GAIN (dB) GAIN