TECHNICAL NOTE Audio Accessory ICs Karaoke/Surround Digital Echo BU9253AS/FS, BU9262AFS ●Description The Karaoke/Surround Digital Echo IC incorporates a digital delay circuit, an input/output mixing circuit, supporting Karaoke echo and surround system, all in a single chip. BU9253AS/FS has functions required by Karaoke echo system, and BU9262AFS has various functions required for surround / echo system. ●Features ＜BU9253AS/FS＞ 1) Digital delay time : 131ms (fCLK = 375kHz) 2) Built-in mixing circuit for adding original sound and echo sound 3) Echo mix ratio settable by DC voltage 4) Built-in amplifier circuit for structuring input/output secondary LPF 5) Microphone mute function (mute of mixing sound of original sound + echo sound) 6) Built-in CR oscillation circuit ＜BU9262AFS＞ 1) Digital delay time : 8-stage setting from 9.2ms to 192ms 2) Built-in input/output mixing circuit 3) Built-in feedback, delay volume circuit 4) Built-in input/output LPF 5) Serial interface 6) Auto mute circuit built in (action at power on, mode switching) 7) Built-in auto reset circuit at power on ●Applications Radio cassette recorder, mini-component and karaoke systems. ●Product lineup Parameter Supply voltage Oscillation frequency Current consumption Operating temperature range Package Digital delay Echo level BU9253AS 4.0V～5.5V 375kHz 6mA -10～+70℃ SDIP18 Fixed Fixed BU9253FS 4.0V～5.5V 375kHz 6mA -10～+70℃ SSOP-A16 Fixed Fixed BU9262AFS 4.5V～5.5V 2MHz 20mA -10～+70℃ SSOP-A32 Variable Variable Ver.B Oct.2005 ●Absolute maximum ratings ＜BU9253AS＞ Parameter Symbol Supply voltage VCCMAX Terminal voltage VIN Power dissipation PD Storage temperature TSTG * Reduce by 6.0 mW/°C over 25°C Ratings 7.0 -0.3 ～ VCC+0.3 600* -55 ～ +125 Unit V V mW ℃ ＜BU9253FS＞ Parameter Symbol Supply voltage VCCMAX Terminal voltage VIN Power dissipation PD Storage temperature TSTG * Reduce by 5.0 mW/°C over 25°C Ratings 7.0 -0.3 ～ VCC+0.3 500* -55 ～ +125 Unit V V mW ℃ ＜BU9262AFS＞ Parameter Supply voltage Terminal voltage Power dissipation Storage temperature Symbol VCC VIN PD TSTG Ratings 0.3 ～ 7.0 VSS – 0.3 ～ VCC + 0.3 800* -55 ～ +125 Unit V V mW ℃ * Reduce by 8.0 mW/°C over 25°C Note: This IC is not designed to be radiation-resistant. Note: Operation is not guaranteed. ●Operating conditions ＜BU9253AS/FS＞ Parameter Supply voltage Operating temperature Operating frequency Symbol VCC Ta fC Limits 4.0 ～ 5.5 -10 ～ +70 375 Unit V ℃ kHz ＜BU9262AFS＞ Parameter Operating supply range Operating temperature Operating frequency Symbol VCC Ta fC Limits 4.5 ～ 5.5 -10 ～ +70 2 Unit V ℃ MHz 2/16 ●Electrical characteristics ＜BU9253AS/FS＞ （Ta=25℃, VCC=5.0V, fC=375kHz, fin=1kHz, VI=-10dBV, ECHO VR pin=VCC, MUTE pin=VCC, unless otherwise specified.） Limits Parameter Symbol Unit Min Typ Max Circuit Current ICC － 6 12 mA Voltage Gain 1 GV1 -5.6 -3.5 -1.4 dB Voltage Gain 2 GV2 -1 0 -1 dB Output distortion 1 THD1 － 1.5 3 % Output distortion 2 THD2 － 0.02 0.1 % VNO1 － -80 -60 dBV VNO2 － -90 -80 dBV VOM1 1.4 1.7 － Vrms VOM2 1.4 1.7 － Vrms VH 3.8 － 5.0 V VM 1.6 － 2.8 V VL 0 － 0.7 V fC － 375 － kHz Output noise voltage 1 Output noise voltage 2 Maximum output voltage 1 Maximum output voltage 2 MUTE control voltage Oscillation frequency 3/16 Condition No signal input Delay side total gain IN→OUT Through side total gain IN→OUT、ECHO VR pin=GND Delay side Through side ECHO VR pin=GND Delay side Rg=1kΩ Through side Rg=1kΩ、ECHO VR pin=GND Delay side THD=10% Through side THD=1%、ECHO VR pin=GND H mode hold voltage MUTE pin DC M mode hold voltage MUTE pin DC L mode hold voltage MUTE pin DC ＜BU9262AFS＞ (Ta = 25℃, VCC = 5V, VIN = 200mVrms, fin = 1kHz, fC = 2MHz, Rg = 600Ω, unless otherwise specified.) Parameter Circuit current [Digital delay] Input/Output Gain Symbol ICC AV1 THD1 THD2 Output distortion THD3 THD4 VNO1 VNO2 Output noise voltage VNO3 VNO4 Maximum output voltage VMX1 [Delay volume “DSIG output”] Input//Output Gain AV5 Output distortion THD5 Output noise voltage VNO5 Maximum output voltage VMX5 Maximum attenuation ATT5 [Feedback volume] Input/Output Gain AV6 Maximum attenuation ATT6 [Line amplifier] Input/Output Gain AV7 Output distortion THD6 Output noise voltage VNO6 Maximum output voltage VMX6 Channel separation AVCS Input impedance ZI [Digital unit] Input“H”voltage VIH Input“L”voltage VIL Pull-up resistance Rd [Serial data] Clock width twCK Latch width twLT Data setup tdsu Data hold th Latch setup tlsu Min. － Limits Typ. 20 Max. 40 -3 － － － － － － － － 0.7 0 0.6 1.0 1.2 1.5 -90 -87 -85 -83 1.0 3 1.2 2.0 2.4 3.0 -75 -72 -70 -68 － dB % % % % dBV dBV dBV dBV Vrms tDL = ～48ms、30kHz LPF tDL = 96ms、30kHz LPF tDL = 144ms、30kHz LPF tDL = 192ms、30kHz LPF tDL = ～48ms、DIN－AUDIO tDL = 96ms、DIN－AUDIO tDL = 144ms、DIN－AUDIO tDL = 192ms、DIN－AUDIO THD = 10%、30kHz LPF 0 － － 1.1 － 3 0.17 -100 1.4 -90 6 0.34 -90 － -60 dB % dBV Vrms dB DLYVOL = MAX. 30kHz LPF DELAY OFF、DIN－AUDIO THD = 10%、30kHz LPF DLYVOL = MIN. DIN－AUDIO -6 － -3 -90 0 -60 dB dB FBVOL = MAX. FBVOL = MIN. DIN－AUDIO -3 － － 1.2 － 24 0 0.01 -100 1.8 -90 35 3 0.03 -90 － -65 － dB % dBV Vrms dB kΩ 30kHz LPF DELAY OFF、DIN－AUDIO THD = 10%、30kHz LPF f = 400Hz、DIN－AUDIO 3.8 － 12 － － 25 － 1.2 50 V V kΩ 2.0 2.0 1.0 1.0 1.0 － － － － － － － － － － us us us us us 4/16 Unit mA Condition No signal input ●Reference data ＜BU9253AS/FS＞ Ta=25℃ 6.0 5.5 5.0 4.5 4.0 375 370 365 360 4.0 10 MIX OUT VOLTAGE : VOUT [dBv] 4.0 3.5 Mute 2.5 2.0 1.5 1.0 Mute & OSC stop 0.5 0.0 VCC=5V / Ta=25℃ 10 -30 -40 -50 -60 -70 -80 0.0 VCC=5V / Ta=25℃ 20 10 10 OUTPUT LEVEL : VOUT [dB] OUTPUT LEVEL : VOUT [dB] VCC=5V / Ta=25℃ 1.0 2.0 3.0 4.0 ECHO VR VOLTAGE : VR [V] -20 -30 10K 100K 1M -20 -30 1M -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 OUTPUT CURRENT : IOUT [mA] Fig.10 LPF operation amplifier output performance THD=３% 4.0 3.5 3.0 1.0 VCC=5V / Ta=25℃ 5.5 5 5.0 4 3 2 1 10.0 100.0 OUTPUT LOAD : RLOAD [kΩ] Fig.9 Through side output load drive characteristic 6 VCC=5V / Ta=25℃ THD=1% 4.5 4.0 3.5 3.0 2.5 0 0 10.0 4.5 10M OUTPUT LEVEL : VOUT [Vpp] 1 100K 10K Fig.8 MIX operation amplifier frequency characteristic OUTPUT VOLTAGE : VOUT [V] 2 5.0 INPUT FREQUENCY : FIN [Hz] VCC=5V / Ta=25℃ 1.0 INPUT FREQUENCY: FIN [kHz] 2.5 1K 6 3 -15 VCC=5V / Ta=25℃ -10 Fig.7 LPF operation amplifier frequency characteristic 4 -10 5.5 INPUT FREQUENCY : FIN [Hz] 5 -5 VCC=5V / Ta=25℃ 0 10M 0 Fig.6 A/D frequency characteristic -40 -40 5 -20 0.1 5.0 Fig.5 ECHO VR characteristic -10 5.5 Fig.3 Total gain characteristic -20 5.5 0 4.5 5.0 INPUT VOLTAGE : VCC [V] 0 20 1K Delay side -6 4.0 OUTPUT LEVEL:VOUT[Vpp] 4.5 5.0 INPUT VOLTAGE : VCC [V] -4 5.5 -10 Fig.4 Mute pin threshold OUTPUT VOLTAGE : VOUT [V] 4.5 5.0 INPUT VOLTAGE : VCC [V] -90 4.0 -2 Fig.2 Oscillation frequency VCC=5V / Ta=25℃ 3.0 0 -8 5.5 OUTPUT GAIN : VOUT[dB] 4.5 5.0 INPUT VOLTAGE : VCC [V] Fig.1 Current consumption MUTE THRESHOLD : MTH [V] Through side 380 355 4.0 Ta=25℃ 2 OUTPUT GAIN : GV [dB] 6.5 4.5 Ta=25℃ 385 OSC FREQUENCY : fC [kHz] OUTPUT CURRENT : ICC [mA] 7.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 OUTPUT CURRENT : IOUT [mA] Fig.11 MIX operation amplifier output performance 5/16 1.0 10.0 100.0 OUTPUT LOAD : RLOAD [kΩ] Fig.12 Delay side output load drive characteristic ●Reference data ＜BU9262AFS＞ VCC=5V / Ta=25℃ 20 15 10 10 0 0 OUTPUT GAIN : VOUT[dB] Ta=25℃ OUTPUT GAIN : VOUT[dB] -10 -20 -30 -40 -50 10 4.5 4.7 4.9 5.1 5.3 5.5 INPUT VOLTAGE : VCC [V] VCC=5V / Ta=25℃ -40 -50 -60 -20 -10 -20 -30 0 10 VCC=5V / Ta=25℃ LEVEL : DBO [dBV] fIN=10kHz fIN=1f00Hz -20 -30 -40 -50 -60 -70 -80 -20 0.001 -20 10M -30 -40 100K OUTPUT THD : THD2 [%] 100 10 VIN=1kHz fIN=10kHz fIN=1f00Hz fIN=100Hz 0.1 0.01 -20 10M VIN=1kHz 5 10 Fig.22 Input level vs distortion ratio characteristic 1 10 Fig.23 Input level vs distortion ratio characteristic 2 6/16 -5 0 VCC=5V / Ta=25℃ Cutoff=３kHz/Sampling=2MHz/24 10 1 VIN=1kHz VIN=100Hz VIN=100Hz 0.1 -35 -30 -25 -20 -15 -10 -5 0 5 INPUT LEVEL: VIN [dB] -10 Fig.21 MIX VOL distortion characteristic 100 10 VIN=100Hz -15 INPUT LEVEL: RIN [dB] VCC=5V / Ta=25℃ Cutoff=３kHz/Sampling=2MHz/12 1 Beginning at the top 1 Fig.20 MIX VOL frequency characteristic VCC=5V / Ta=25℃ Cutoff=7kHz/Sampling=2MHz/6 0 Fig.18 Line amplifier distortion characteristic INPUT FREQUENCY: FIN [Hz] Fig.19 MIX VOL linearity -5 VCC=5V / Ta=25℃ -20 1K -10 10 -10 -50 10 0 -15 INPUT LEVEL: LIN [dB] 0 AMPLITUDE : DBI [dBV] 0.1 -35 -30 -25 -20 -15 -10 -5 0 INPUT LEVEL: VIN [dB] 100K fIN=100Hz 0.01 OUTPUT DISTORTION : VOUT [%] OUTPUT GAIN : VOUT [dB] 0 -10 OUTPUT THD : THD1 [%] Beginning at the top VCC=5V / Ta=25℃ 10 10 -40 1K VCC=5V / Ta=25℃ Fig.17 Line amplifier frequency characteristic Fig.16 Line amplifier linearity -60 1K 10K 100K 100 INPUT FREQUENCY: FIN [Hz] INPUT FREQUENCY: FIN [Hz] AMPLITUDE : DBI [ dBV] -80 -40 Fig.15 FBVOL frequency characteristic -50 -80 -40 -30 0.1 -40 -70 -60 -20 10 OUTPUT DISTORTION : THD6 [%] OUTPUT GAIN : AV7 [dB] LEVEL : DBO [dBV] -30 1 10K 0 -20 100 1K 100 INPUT FREQUENCY: FIN [Hz] VCC=5V / Ta=25℃ 10 -10 -80 -10 Fig.14 PRE FILTER frequency characteristic Fig.13 Circuit current 0 VCC=5V / Ta=25℃ -50 10 OUTPUT THD : THD3 [%] OUTPUT CURRENT : ICC [mA] 25 0.1 -35 -30 -25 -20 -15 -10 -5 0 5 INPUT LEVEL: VIN [dB] 10 Fig.24 Input level vs distortion ratio characteristic 3 ●Pin description, Block diagram, Application circuit ＜BU9253AS/FS＞ ・BU9253AS pin assignment ・Description of terminal BU9253AS BU9253FS Pin No. Pin No. 1 1 Symbol CR MUTE NC VCC ADINTIN ADINTOUT ADLPFOUT 18 17 16 15 14 13 12 ADLPFIN 11 GND pin 2 2 ECHO VR 3 － NC1 Echo level DC control pin Not connected Analog unit DC bypath 4 3 BIAS 5 4 DAINT IN 6 5 DAINT OUT 7 6 DALPF IN 8 7 DALPF OUT 9 8 MIX OUT 10 9 MIX IN pin DA side integrator input pin 1 DA side integrator GND output pin 2 3 4 5 6 7 8 9 ECHOVR NC BIAS DAINTIN DAINTOUT DALPFIN DALPFOUT MIXOUT Fig.25 BU9253AS pin assignment DA side LPF input pin DA side LPF output pin Mixing output of original ・BU9253FS pin assignment sound and echo sound Original sound input pin CR MUTE VCC 16 15 14 ADINT IN ADINT OUT ADLPF OUT 13 ADLPF IN 12 11 10 5 6 7 11 10 ADLPF IN 11 ADLPF OUT 13 12 ADINT OUT 14 13 ADINT IN 15 14 VCC AD side LPF input pin AD side integrator output pin AD side integrator input pin VCC pin － NC2 17 15 MUTE Mute control pin 18 16 CR Oscillator CR pin Not connected 1 2 3 GND ECHO VR BIAS 4 DAINT IN DAINT OUT DALPF IN DALPF OUT Fig.26 BU9253FS pin assignment ・BU9253AS Block diagram, Application circuit VCC VC C + R7 20k C5 0.012u 100u IN C1 100p R3 22k VCC 0.1u C3 0.01u R4 10k R6 8.2k + C2 22u 17 16 15 14 MUTE 13 C4 4700p 12 + R5 20k 11 2.2u 10 - A/D + OSC A/D side LPF operation amplifier A/D側LPF用オペアンプ COUNTOR SRAM MIX D/A side LPF operation amplifier D/A側LPF用オペアンプ + D/A 2 3 VC C R8 2.2k 9 AD side LPF output pin 16 1 MIX IN of mixing amplifier 12 18 10 Function GND R2 39k MIXIN 4 + 5 - 6 7 C8 3300p 8 9 OUT 22u C6 0.01u VR1 10k R9 10k 0.47u C7 0.01u Fig.27 Application circuit 7/16 R10 4.7k R11 15k + 2.2u 8 MIX OUT ●Pin description, Block diagram, Application circuit ＜BU9262AFS＞ ・Description of terminal No. 1 2 3 ・Block diagram Symbol NC TESTB SCK Function 1 Not connected 2 Test negative logic input pin (normally “H” input) 3 Serial clock input 4 SLT Serial latch input 5 SI Serial data input 7 CLKI Oscillation input pin 9 8 NC Not connected 10 9 DSOUT Delay source output 11 10 TESTOUT Test output pin (normally “L” output) 12 11 LPF1I1 13 LPF1I2 14 ADI 17 DAI 18 DAO 19 LPF2I1 20 LPF2I2 21 LPF2O 22 VOIN 24 DSIG VREF 27 ＋ Output 出力 ミキシング mixing 26 ＋ Reference 基準電圧 voltage ＋ 25 24 23 Test mode output テストモード出力 Reset リセット 22 FBVOL 21 LPF LPF 20 19 ADC 16 ADO 23 LPF capacitor external pin LPF1O GND 28 RAM 15 16 29 クロック Clock 8 15 30 セレクタ 7 Oscillation output pin 14 Serial シリアル control コントロール 回路 circuit 6 CLKO 13 Input mixer 入力ミキサ selector 5 6 12 31 コントロール 4 32 DLYVOL Test mode negative logic input テストモード 負論理入力 Control Processing 処理 18 DAC 17 ADC capacitor connection pin Fig.28 Block diagram GND pin ・Pin assignment DAC capacitor connection pin NC 1 32 M IX IN T EST B 2 31 M IC IN SCK 3 30 VC C S LT 4 29 LC IN SI 5 28 R C IN C LK O 6 27 FB O U T C LK I 7 26 LC O U T NC 8 25 RCOUT DSOUT 9 24 VR E F T EST O U TESTOUT 10 23 D S IG LP F1I1 11 22 VO IN LPF capacitor external pin Delay signal / volume input pin Delay signal output Analog reference voltage 25 RCOUT Rch output 26 LCOUT Lch output 27 FBOUT Feedback signal output 28 RCIN Rch input LP F1I2 12 21 LP F2O 29 LCIN Lch input LP F1O 13 20 LP F2I2 30 VCC Power source pin AD I 14 19 LP F2I1 31 MICIN Microphone input (microphone amplifier output connected) AD O 15 18 D AO Mix signal input GND 16 17 D AI 32 MIXIN Fig.29 Pin assignment ・Application circuit ＋ 47u 0.1u 1 2 DLYVOL 32 Test mode negative logic input テストモード 負論理入力 31 ＋ MIC IN 1u SERIAL CLOCK 3 SERIAL LATCH 4 SERIAL DATA Input mixer 入力ミキサ selector Serial シリアル control コントロール circuit 回路 30 セレクタ 29 5 28 6 27 ＋ ＋ Lch IN 1u Rch IN 1u R 2MHz クロック Clock R 7 8 26 ＋ Output 出力 mixing ミキシング ＋ 25 ＋ ＋ 0.33u R 1M Lch OUT 2.2u Rch OUT 2.2u 9 1u NP 10 Reference 基準電圧 voltage ＋ 12 0.01u 2200p 23 テスト出力 Test output 11 FBVOL RAM 47u 0.1u 2200p LPF 20 19 ADC 0.01u DSIG ＋ 2.2u 21 14 15 ＋ 22 LPF 13 24 Processing 18 処理 DAC 16 0.01u 17 Fig.30 Application circuit 8/16 0.01u ●Description of operations ＜BU9253AS/FS＞ ・OSC(Oscillator) Clock is generated by connecting external RC circuit. Clock is used for the delay counter. ・Mute control circuit (MUTE) By input voltage of the mute terminal, 3 statuses, that is, mute, mute release (operating), and clock stop & mute can be selected. ・COUNTER This counter is for generating delay time. It can generate delay time about 131ms at oscillation frequency Fclk = 375kHz. ・SRAM SRAM with 8Kbit capacity for generating the delay. ・A/D side LPF operation amplifier LPF can be structured by external RC, and band limit of signal to be input to A/D is available. ・A/D This digitalizes output signal of AD side LPF, and outputs it to SRAM. ・D/A side LPF operation amplifier LPF can be structured by external RC, and band limit of signal to be output to D/A is available. ・D/A This converts delayed audio digital data input from SRAM into analog signal. ・Mixing amplifier (MIX) This circuit is used for mixing delayed signals and (original sound) signals input from MIX IN. ＜BU9262AFS＞ ・Serial control circuit This serial I/F circuit is for setting each register. It can be controlled by serial 16bit data. It reads in SI at the rise of SCK, and latches data at the rise of SLT. No. D0 D1 D2 D3 D4 Mode Remarks Delay time Delay time setting "Refer to the separate table." INPUT select “ISEL” ( D3、D4 ) = ( L、L )：L＋R ( L、L )：L－R ( L、H )：MIC ( H、H )：CLK OFF D7 D8 D9 D10 D11 D12 D13 Delay out “DOSW” ( D5、D6 ) = ( L、L )：FWD (L, R in phase) ( L、L )：REV (R in opposite phase) ( L、H )：MIC MIX ( H、H )：NORMAL H : output ON L : output OFF Delay volume “DLYVOL” Delay signal / volume setting "Refer to the separate table." Feedback volume “FBVOL” Feedback / volume setting "Refer to the separate table." D14 Latch control (D5, D6) = (L, H) : latch Others are not latch D5 D6 OUTPUT select “OSEL” 9/16 ・Delay time control circuit This circuit controls delay time. -8 delay time can be selected by register. D0 L H L H L H L H D1 L L H H L L H H D2 L L L L H H H H Delay time (Sampling frequency) 9.2msec (2MHz / 6) 15.4msec (2MHz / 6) 21.1msec (2MHz / 6) 30.0msec (2MHz / 6) 48.0msec (2MHz / 6) 96.0msec (2MHz / 12) 144.0msec (2MHz / 18) 192.0msec (2MHz / 24) LPF cutoff frequency 7kHz 3kHz ・Delay signal volume circuit This is the delay signal volume circuit. 8 volume setting can be selected by register. D8 L H L H L H L H D9 L L H H L L H H D10 L L L L H H H H DLYVOL +3dB 0dB -3dB -6dB -9dB -12dB -15dB -∞dB ・Feedback volume circuit This is the feedback volume circuit. 8 feedback volume setting can be selected by register. D11 L H L H L H L H D12 L L H H L L H H D13 L L L L H H H H FBVOL -3dB -5dB -7dB -9dB -11dB -13dB -15dB -∞dB ・Input mixer･selector circuit This mixes MIC IN, LCIN, RCIN, VOIN signals, and selects the output path by selector. LCIN ＋ ＋ － VOIN ＋ ISEL FBVOL LCOUT OSEL #3 RCOUT ＋ RCIN MRCIN OSEL #2 ＋ ADC Delay ディレイ DAC ＋ OSEL #1 － DLY VOL DOSW Fig.31 Input mixer selector circuit 10/16 DSIG ・Output/ input LPF circuit This is the LPF circuit connected to the ADC input unit and the DAC output unit. Delay time setting can be select by internal resistor. Delay amount 48.0msec or below 96.0msec or below Switch S1 S2 Resistance value 4.8kΩ* 11.3kΩ* *Internal resistance precision is ±30%. Pins 12, 20 12、20ピン Pins 11, 19 11、19ピン Pins 13, 21 13、21ピン R1 R2 S1 R1 R2 R1 R2 S2 (注)11ピンでは外付け容量結合になります Note: In Pin 11, is an external capacity connection Fig.32 Input LPF / Output LPF circuit ・Auto mute circuit Delay output is muted during power on and delay time switching. ●Timing chart ＜BU9262AFS＞ ・Serial interface specification SI D0 D12 D13 D14 D15 D1 SCK SLT Fig.33 Serial interface specification ・Serial timing SCK twCK tdsu twCK th tdsu SI twLT SLT Fig.34 Serial timing 11/16 ●Description of external components < BU9253AS/FS > (Refer to Fig. 27.) ・Echo level Echo signal level is determined by the gains of A/D side operation amplifier and the D/A operation amplifier, since there is no gain in A/D → SRAM → D/A. Path in applied circuit example, Gain at A/D side : R4 ÷ R5 = 10K ÷ 20K = 0.5 Gain at D/A side : R11 ÷ R9 = 15K ÷ 10K = 1.5 When the original signal is defined as 1, the echo signal level becomes the feedback ratio. Echo signal feed back ration = 0.5 x 1.5 = 0.75 = 75% ・Echo level setting method Echo level can be set by adjusting DC voltage by VR1. It does not change in low voltage range, therefore, R8 is added, and it can be adjusted by VR pot. ・Clock frequency and delay time Clock frequency and delay time are as the following equations. Sample frequency = clock frequency ÷ 6 Delay time = (1 ÷ sample frequency) x 8192 (SRAM 8192 bits) As an example, when clock frequency is 375kHz, then sample frequency is 375kHz ÷ 6 = 62.5kHz. Therefore, the delay time is: Delay time = (1 ÷ 62500) x 8192 = 131ms Clock frequency is determined by R2, C1 connected to CR terminal (pin 18 in BU9253AS, pin 16 in BU9253FS). When C, R are changed, oscillation frequency changes, but the delay time is kept fixed. ・LPF frequency characteristic When the band width is set too narrow, echo voice becomes worse, and when band width is set wide, A/D cannot be converted, and S/N becomes worse. Band width of applied circuit example is 2kHz. ・A/D, D/A external capacitors C3, C6 Feedback is set by resistance and capacitor so that output follows even when input signal level and frequency of A/D, D/A change. Variation in the externally attached capacitor can influence the sound quality. A small capacitor can generate noise, while a capacitor that is too large will attenuate. In applied circuit example, 0.01uF is selected to avoid influence upon LPF. ・Mute Can be controlled by input voltage of MUTE pin. It takes more than one SRAM cycle for switching between mute → mute release (L → M → H). It is necessary for initializing SRAM and insuring stable status before changing operating modes. MIX OUT output is muted, so original sound and echo sound output is stopped. MUTE pin H M L Mode Mute release (operating) Mute Clock stop & mute In the applied circuit example, MUTE is set by R3, C2. In the specifications, voltage range of M is 1.6V ~ 2.8V, therefore, it is necessary to change R3,C2, and set the time of 1.6V ~ 2.8V over 131ms. In consideration of fluctuation, C2 = 22uF, R3 = 22kΩ. When MUTE pin is controlled by the microcontroller, select M range to 1.6V ~ 2.8V and keep M level over 131ms. ・Maximum signal input When original signal and echo are in phase and mixed, both the signals are added to reach maximum output. In order not to clip this signal, the maximum output at power source voltage of 5V is about 4Vpp. When echo feedback ratio is 0.75, then maximum signal input becomes about 1.0Vpp. Vout MAX＝1／(1－A)×Vin ＝1／(1－0.75)×Vin＝4Vpp ∴Vin＝1Vpp 12/16 ・LPF and echo system gain When the ratio of original signal and echo is changed, R5, R6, R9, R11 are also changed, and the characteristics of LPF change too. Therefore, it is necessary to change all the constants of LPF. In the case, to precisely measure the ratio of original signal and echo, remove R7, input signal around 500Hz without the influence of LPF from MIX IN, and compare it with the output of DALPF OUT. R4 R11 fc = C4 C8 R5 R9 IN 2 π C 4 C 5 R 4R 5 R6 R10 C 5R 4R 5 1 Q= R 4R 5 + － C5 C7 1 R 4R 5 C4 R6 QQgenerally about 0.7 0.7ぐらい は一般的に OUT A1 = ＋ R4 R5 A2 = R11 R9 Echo signal amplitude ratio エコ－信号増幅率 = A1 × A 2 = Fig.35 LPF and echo system gain R 4 × R11 R5 × R9 ・Clock oscillation As for C,R, tolerance should be below 5%. Note: If measurement is made by attachment a probe oscilloscope it might load the oscillator and reduce the oscillation frequency. * The set values in this document are for reference only. In the actual set, characteristics may change according to board layout, wiring, types of parts used, and therefore, in actual use, carry out sufficient verification with the actual devices. 13/16 ●Cautions on Use 1) Absolute maximum ratings An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down the devices, thus making impossible to identify breaking mode, such as a short circuit or an open circuit. If any over rated values will expect to exceed the absolute maximum ratings, consider adding circuit protection devices, such as fuses. 2) Operating conditions Characteristics are guaranteed under the conditions of each specified parameter. 3) Reverse polarity connection of the power supply Connecting the of power supply in reverse polarity can damage IC. Take precautions when connecting the power supply lines. An external direction diode can be added. 4) Power supply line Design PCB layout pattern to provide low impedance GND and supply lines. To obtain a low noise ground and supply line, separate the ground section and supply lines of the digital and analog blocks. Furthermore, for all power supply terminals to ICs, connect a capacitor between the power supply and the GND terminal. When applying electrolytic capacitors in the circuit, note that capacitance characteristic values are reduced at low temperatures. 5) GND voltage Ground-GND potential should maintain at the minimum ground voltage level. Furthermore, no terminals (except SWOUT) should be lower than the GND potential voltage including an electric transients. 6) Short circuit between terminals and GND or other devices Pay attention to the assembly direction of the ICs. Wrong mounting direction or shorts between terminals, GND, or other components on the circuits, can damage the IC. 7) Operation in a strong electromagnetic field Using the ICs in a strong electromagnetic field can cause operation malfunction. 8) Inspection with set PCB During testing, turn on or off the power before mounting or dismounting the board from the test Jig. Do not power up the board without waiting for the output capacitors to discharge. The capacitors in the low output impedance terminal can stress the device. Pay attention to the electro static voltages during IC handling, transportation, and storage. 9) Input terminals In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the parasitic element can cause interference with circuit operation, thus resulting in a malfunction and breakdown of the input terminal. Therefore, pay thorough attention not to apply a voltage lower than the GND to the input terminals. Furthermore, do not apply a voltage to the input terminals when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is applied, apply a voltage lower than the power supply voltage to the input terminals, or a voltage within the guaranteed value of electrical characteristics. 10) Ground wiring pattern The power supply and ground lines must be as short and thick as possible to reduce line impedance. Fluctuating voltage on the power ground line may damage the device. 11) External capacitor When using external ceramic capacitors, consider degradation in the nominal capacitance value due to DC bias and changes in the capacitance with temperature. 14/16 ●Product designation B U 9 2 5 3 A E Package type AS: SDIP18 FS: SSOP-A16 Part Number BU9253 B - S U 9 2 6 2 A Part Number BU9262A F 2 Package and forming specifications E2: Embossed tape and reel - S E 2 Package and forming specifications E2: Embossed tape and reel Package type FS: SSOP-A32 SDIP18 <Dimension> <Packing information> Container 19.4 ± 0.3 10 1 9 3.4 ± 0.2 0.51Min. 3.95 ± 0.3 6.5 ± 0.3 18 Tube Quantity 1000pcs Direction of feed Direction of products is fixed in a container tube. 7.62 0.3 ± 0.1 0° ∼ 15° 0.5 ± 0.1 1.778 (Unit:mm) ※Orders are available in complete units only. SSOP-A16 <Dimension> <Tape and Reel information> 1 8 2500pcs Direction of feed E2 (Correct direction: 1pin of product should be at the upper left when you hold reel on the left hand, and you pull out the tape on the right hand) 0.15±0.1 0.1 1234 1234 Direction of feed 1pin Reel 1234 1234 1234 1234 0.36±0.1 1234 0.8 0.3Min. 9 Embossed carrier tape Quantity 1234 6.2±0.3 1.5±0.1 4.4±0.2 0.11 6.6±0.2 16 Tape ※Orders are available in complete units only. （Unit:mm) SSOP-A32 <Dimension> <Tape and Reel information> 1 16 2000pcs Direction of feed E2 (Correct direction: 1pin of product should be at the upper left when you hold reel on the left hand, and you pull out the tape on the right hand) 0.3Min. 17 Embossed carrier tape Quantity 15/16 1234 Direction of feed ※Orders are available in complete units only. （Unit:mm) 1234 1234 1pin 1234 1234 Reel 1234 0.36 ± 0.1 1234 0.8 0.15 ± 0.1 0.1 1234 1.8 ± 0.1 7.8 ± 0.3 5.4 ± 0.2 0.11 13.6 ± 0.2 32 Tape 16/16 Catalog No.05T411Be '06.4 ROHM C Appendix Notes No technical content pages of this document may be reproduced in any form or transmitted by any means without prior permission of ROHM CO.,LTD. The contents described herein are subject to change without notice. The specifications for the product described in this document are for reference only. Upon actual use, therefore, please request that specifications to be separately delivered. Application circuit diagrams and circuit constants contained herein are shown as examples of standard use and operation. Please pay careful attention to the peripheral conditions when designing circuits and deciding upon circuit constants in the set. Any data, including, but not limited to application circuit diagrams information, described herein are intended only as illustrations of such devices and not as the specifications for such devices. ROHM CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any third party's intellectual property rights or other proprietary rights, and further, assumes no liability of whatsoever nature in the event of any such infringement, or arising from or connected with or related to the use of such devices. Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or otherwise dispose of the same, no express or implied right or license to practice or commercially exploit any intellectual property rights or other proprietary rights owned or controlled by ROHM CO., LTD. is granted to any such buyer. Products listed in this document are no antiradiation design. The products listed in this document are designed to be used with ordinary electronic equipment or devices (such as audio visual equipment, office-automation equipment, communications devices, electrical appliances and electronic toys). Should you intend to use these products with equipment or devices which require an extremely high level of reliability and the malfunction of which would directly endanger human life (such as medical instruments, transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other safety devices), please be sure to consult with our sales representative in advance. It is our top priority to supply products with the utmost quality and reliability. However, there is always a chance of failure due to unexpected factors. Therefore, please take into account the derating characteristics and allow for sufficient safety features, such as extra margin, anti-flammability, and fail-safe measures when designing in order to prevent possible accidents that may result in bodily harm or fire caused by component failure. ROHM cannot be held responsible for any damages arising from the use of the products under conditions out of the range of the specifications or due to non-compliance with the NOTES specified in this catalog. Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact your nearest sales office. ROHM Customer Support System www.rohm.com Copyright © 2008 ROHM CO.,LTD. THE AMERICAS / EUROPE / ASIA / JAPAN Contact us : webmaster@ rohm.co. jp 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, Japan TEL : +81-75-311-2121 FAX : +81-75-315-0172 Appendix1-Rev2.0