BA3837

Multimedia ICs Vocal fader IC BA3837 / BA3837F / BA3838F The BA3837, BA3837F and BA3838F are ICs with an internal secondary active LPF for vocal cancellation functions and mixing amplifier functions with high degrees of vocal cancellation. Three control pins are used to switch between modes: the key controller input mode, through mode, vocal fader mode, sound multiplexing mode and mute mode. By offering these functions on a single chip, these ICs can significantly reduce the number of external components. •Applications on stereo systems, portable stereos and VCRs Karaoke functions •Features IC with vocal fader, to erase vocals from 1) Single-chip commercially available recordings. 2) Internal secondary active LPF for high degrees of vocal cancellation (high synchronization rejection). 3) Three control pins for switching between 4 modes: through, vocal fader, sound multiplexing and mute. 4) Key controller input and internal switches. 5) Low noise and low distortion. 6) Internal microphone mixing amplifier. 7) Available in two packages: DIP 16-pin and SOP 16pin (BA3838F is available in SOP 16-pin only). •Absolute maximum ratings (Ta = 25°C) Parameter Power supply voltage Power dissipation DIP16 SOP16 Symbol VCC Pd Topr Tstg Limits 18 1000∗1 550∗2 – 40 ~ + 85 – 55 ~ + 125 Unit V mV °C °C Operating temperature Storage temperature ∗1 Reduced by 10 mW for each increase in Ta of 1°C over 25°C. ∗2 Reduced by 5.5mW for each increase in Ta of 1°C over 25°C. •Recommended operating conditions (Ta = 25°C) Parameter Power supply voltage∗1 Power supply voltage∗1 Power supply voltage∗2 Symbol VCC VCC VCC Min. 5.4 5.4 4.0 Typ. — — — Max. 10 13 15 Unit V V V Conditions Ta = – 40°C ~ + 85°C Ta = – 40°C ~ + 60°C Ta = 25°C ∗1 BA3837 and BA3837F ∗2 BA3838F 1 Multimedia ICs BA3837 / BA3837F / BA3838F •Block diagram C 16 B 15 A 14 ROUT 13 LP 12 – + LP 11 LP 10 RIN 9 –+ LOGIC –+ R L+R SW2 –+ – L–R + L +– +– + SW1 1 VCC 2 MIC 3 LOUT 4 FK 5 TK 6 LIN 7 BIAS 8 GND 2 Multimedia ICs BA3837 / BA3837F / BA3838F •Pin descriptions Pin No. 1 Pin name VCC VCC 1 VCC 2 51k Equivalent circuit Function 2 2 MIC IN Mixing input pin for microphone sound VCC VCC 20k 20k 3 LOUT 3 Lch output pin VCC 1 VCC 2 51k 4 4 FK Input pin for key controller signals BA3837 / BA3837F VCC VCC 5 5 TK BA3838F VCC VCC Output pin for key controller signals 5 400 3 Multimedia ICs BA3837 / BA3837F / BA3838F Pin No. Pin name Equivalent circuit Function VCC 1 VCC 2 51k 6 LIN 6 L signal input pin VCC VCC 51k 7 BIAS 7 51k Signal bias circuit pin 8 GND VCC 1 VCC 2 51k 9 RIN 9 R signal input pin 11 VCC 10.4k 10.4k 10 LPF1 10 LPF time constant pin VCC 10.4k 10.4k 11 LPF2 11 10 LPF time constant pin 4 Multimedia ICs BA3837 / BA3837F / BA3838F Pin No. Pin name Equivalent circuit Function VCC VCC VCC 20k 12 LPF3 12 LPF output pin 20k VCC VCC 13 ROUT 20k 13 R output pin VCC 14 CONTA 14 Mode switching pin A VCC 15 CONTB 15 Mode switching pin B VCC 16 CONTC 16 Mode switching pin C 5 Multimedia ICs BA3837 / BA3837F / BA3838F •Electrical characteristics noted, Ta = 25°C, Vcc = 10V, f BA3837 / F (unless otherwise Parameter Quiescent current Maximum output voltage L / R gain Low frequency gain Microphone gain Crosstalk Mute attenuation Vocal suppression rate Total harmonic distortion Noise level Input impedance Control pin threshold (high) Control pin threshold (low) Output switching DC differential Not designed for radiation resistance. IN = 1kHz, VIN = 150mV, RL = 100kΩ) Conditions Through mode THD = 1%, through mode Through mode fin = 50kHz, vocal fader mode — fIN = 1kHz fIN = 1kHz Vocal fader mode Through mode, BW : 400Hz - 30kHz Rg = 0, DIN AUDIO LIN, RIN, MICIN, FK — — Maximum output voltage differential between L, R and TK modes Symbol IQ Vom GVT GVF GVM CT MU SV THD VN RIN VthH VthL ∆DC Min. 1.6 2.3 10 10 5 54 73 28 — — 35 4.7 — — Typ. Max. 2.4 2.8 14 14 8 70 80 33 3.3 — 17 17 11 — — — Unit mA Vrms dB dB dB dB dB dB % µVrms kΩ V V mV 0.02 0.07 15 50 — — 7 22 65 — 0.3 26 Mode table (A = pin14, B = pin15, C = pin16) ABC 000 001 010 011 100 101 110 111 0 : 0V 1 : 5V VF : vocal fader output KC : signal passed through key controller (1) Microphone output is not muted during muting (ABC = 000 or 100). (2) Gain and relative phase: See block diagram. 1. L / R input and output in the through mode are synchronous with a gain of 14dB. 2. L / R input and TK output in the key controller mode are synchronous with a gain of 8dB. 3. FK input and L / R output in the key controller mode are synchronous with a gain of 6dB. 4.MIC input and L / R output are negative phase with a gain of 8dB. LOUT MUTE VF L L MUTE KC KC KC ROUT MUTE VF L R MUTE KC KC KC TK MUTE VF L L MUTE VF L L+R Mute Mode Key controller mode — — — — Vocal fader mode Sound multiplexing mode Through mode Mute Vocal fader mode Sound multiplexing mode L+R • • • • 6 Multimedia ICs BA3837 / BA3837F / BA3838F BA3838F (unless otherwise noted, Ta = 25°C, Vcc = 10V, fIN = 1kHz, VIN = 150mV, Rl = 100Ω) Parameter Quiescent current Maximum output voltage L / R gain Low frequency gain Microphone gain Crosstalk Vocal suppression rate Total harmonic distortion Noise level Input impedance Control pin threshold (high) Control pin threshold (low) Output switching DC differential Not designed for radiation resistance. Symbol IQ Vom GVT GVF GVM CT SV THD VN RIN VthH VthL ∆DC Min. 1.9 2.3 10 10 5 54 28 — — 35 4.7 — — Typ. 2.7 2.8 14 14 8 70 33 0.02 15 50 — — 7 Max. 3.6 — 17 17 11 — — 0.07 22 65 — 0.3 46 Unit mA Vrms dB dB dB dB dB % µVrms kΩ V V mV fIN = 1kHz Vocal fader mode Through mode THD = 1%, through mode Through mode Conditions fin = 50kHz, vocal fader mode — Through mode, BW : 400Hz - 30kHz Rg = 0, DIN AUDIO, through mode LIN, RIN, MICIN, FK — — Maximum output voltage differential between L, R and TK modes Mode table (A = pin14, B = pin15, C = pin16) ABC 000 001 010 011 100 101 110 111 0 : 0V 1 : 5V VF : vocal fader output KC : signal passed through key controller LOUT R VF L L KC KC KC KC ROUT R VF L R KC KC KC KC TK R VF L L R VF L L+R Mode Sound multiplexing mode (ROUT) Vocal fader mode Sound multiplexing (LOUT) Through mode Sound multiplexing (R) Vocal fader mode Sound multiplexing mode (L) L+R Key controller mode — — — — • • • • ∗ Gain and relative phase: See block diagram. 1. Gain of L / R input and output in the through mode: 14 dB (synchronous) 2. Gain of L / R input and TK output in the key controller mode: 8dB (synchronous) 3. Gain of FK input and L / R output in the key controller mode: 6dB (synchronous) 4. MIC input and L / R output are negative phase with a gain of 8dB. 7 Multimedia ICs BA3837 / BA3837F / BA3838F •Measurement circuit (BA3838F) 4.7V A A A 0.3V C7 0.22µ 0.047µ C6 C5 + 16 C 15 B 14 A 13 Rout 12 LP 11 LP 10 LP 9 RIN 10µ VCC 1 MICIN 2 Lout 3 FK 4 TK 5 LIN 6 BIAS 7 GND 8 + + C2 10µ 10µ + C3 + C4 22µ A 10µ C1 V + 10µ MEASUREMENT FK MIC L R AUDIO ANALYZER 600Ω OSC 51k 100k V Fig. 1 8 Multimedia ICs BA3837 / BA3837F / BA3838F •Application example (BA3838F) µ – CON 51k 51k 51k 1µ + 1µ + 1µ + 0.22µ 0.047µ 10µ + 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 TAPE, CD LD, etc. 10µ + 10µ POWER AMP + + 22µ Key – con MICROPHONE + MICROPHONE Fig. 2 9 Multimedia ICs BA3837 / BA3837F / BA3838F •Operation notes in the diagram “Application example” (1) The example is recommended with confidence. However, be sure to comply with these precautions and verify characteristics during actual use. Also, when changing an attached circuit constant, be sure to allow sufficient margins by taking into account both static and transient characteristics, including variation in these ICs and the attached components. (2) The low pass filter cutoff frequency is determined by the internal circuitry and by C6 and C7 in Fig. 1. With the constant used in Fig. 1, the cutoff frequency (fc) is roughly 150Hz. This cutoff frequency can be changed by changing C6 and C7. When C6 is multiple a, and C7 is multiple b, respectively, the cutoff frequency is calculated thus: fc = 150 ab (Hz) C7 C6 The value of Q is: Q = 1 2 (Currently, Q 1) (3) For the gain and relative phase of the input pin (LIN, RIN, MICIN and FK) inputs and output pin (LOUT, ROUT and TK) outputs, refer to “Gain and relative phase,” on page 2 / 10. (4) Electrical characteristics are measured at a load resistance (R L) of roughly 100k Ω. As using an extremely low load resistance (below 10kΩ) will result in slight variation in maximum output voltage and total harmonic distortion, caution must be used when designing connections with the subsequent stage. (5) The pin 7 bias voltage is roughly Vcc / 2. Because this is also the input and output pin voltage, select coupling capacitor polarity according to relative potential and the characteristics of the components to which the coupling capacitor is to be connected. (6) When outputting L + R from LOUT and ROUT in an application in which the key controller is left unconnected, attach a 10µF electrolytic capacitor between pins 4 and 5, with pin 5 being positive (L + R mode: ABC = 111). (7) Connecting a capacitance load to pin 5 (TK) of BA3837 / F can worsen noise characteristics. When connecting a capacitance load higher than 10µF, insert 1kΩ in series (Figs. 1 and 2). The pin 5 output impedance is roughly 5Ω (1kHz). In the BA3838F it is roughly 400Ω (1kHz). (8) The vocal fader works by canceling out the synchronous component of the signal, leaving the low components in place. Consequently, the vocal fader may not be very effective with certain recordings. (9) In cases where output DC differential can cause noise when switching between modes, use a time constant for the timing of control pin switching, or take some other measure. (10) Operating supply voltage may vary according to ambient temperature. Using this IC outside the recommended supply voltage range may result in increased crosstalk or mute attenuation. •Electrical characteristic curves 5 5 VOCAL COMRESSION RATIO : SV (dB) 0 2 4 6 8 10 12 14 16 18 20 (mA) 4 (mA) 40 20 14 0 4 QUIESCENT CURRENT : IQ 3 QUIESCENT CURRENT : IQ 3 2 2 – 20 – 40 1 1 – 60 10 100 1K 10K 100K 0 2 4 6 8 10 12 14 16 18 20 POWER SUPPLY VOLTAGE : VCC (V) POWER SUPPLY VOLTAGE : VCC (V) FREQUENCY : f (Hz) Fig. 3 IQ vs. VCC characteristics (BA3837 / F) Fig. 4 IQ vs. VCC characteristics (BA3838F) Fig. 5 SV vs. frequency characteristics 10 Multimedia ICs BA3837 / BA3837F / BA3838F L,R OUTPUT TOTAL HARMONIC DISTORTION : THD (%) 10 1 0.1 0.01 0.001 – 40 – 30 – 20 – 10 0 10 INPUT LEVEL : VIN (dBV) Fig. 6 THD vs. VIN characteristics •External dimensions (Units: mm) BA3837 BA3837F / BA3838F 19.4 ± 0.3 16 9 6.5 ± 0.3 16 6.2 ± 0.3 4.4 ± 0.2 10.0 ± 0.2 9 0.51Min. 1 8 7.62 3.2 ± 0.2 4.25 ± 0.3 1 1.5 ± 0.1 8 0.11 0.3 ± 0.1 1.27 0.4 ± 0.1 0.3Min. 0.15 2.54 0.5 ± 0.1 0° ~ 15° DIP16 SOP16 0.15 ± 0.1 11