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 •Karaoke functions on stereo systems, portable stereos and VCRs •1)Features Single-chip IC with vocal fader, to erase vocals from 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). 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. •Absolute maximum ratings (Ta = 25°C) Parameter Power supply voltage Power dissipation DIP16 SOP16 Symbol Limits Unit VCC 18 V 1000∗1 Pd mV 550∗2 Operating temperature Topr – 40 ~ + 85 °C Storage temperature Tstg – 55 ~ + 125 °C ∗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 Conditions Symbol Min. Typ. Max. Unit Power supply voltage∗1 VCC 5.4 — 10 V Ta = – 40°C ~ + 85°C Power supply voltage∗1 VCC 5.4 — 13 V Ta = – 40°C ~ + 60°C Power supply voltage∗2 VCC 4.0 — 15 V Ta = 25°C ∗1 BA3837 and BA3837F ∗2 BA3838F 1 Multimedia ICs BA3837 / BA3837F / BA3838F •Block diagram C B A ROUT LP LP LP RIN 16 15 14 13 12 11 10 9 – + – + LOGIC – + R L+R SW2 SW1 – + + – L–R + L + – 2 + – 1 2 3 4 5 6 7 8 VCC MIC LOUT FK TK LIN BIAS GND Multimedia ICs BA3837 / BA3837F / BA3838F •Pin descriptions Pin No. Pin name 1 VCC Equivalent circuit Function 1 VCC 2 VCC 51k 2 2 Mixing input pin for microphone sound MIC IN VCC VCC 20k 20k 3 LOUT 3 Lch output pin 1 VCC 2 VCC 51k 4 4 Input pin for key controller signals FK BA3837 / BA3837F VCC VCC 5 5 TK Output pin for key controller signals BA3838F VCC VCC 5 400 3 Multimedia ICs Pin No. BA3837 / BA3837F / BA3838F Pin name Equivalent circuit Function 1 VCC 2 VCC 51k 6 6 LIN L signal input pin VCC VCC 51k 7 BIAS Signal bias circuit pin 7 51k 8 GND 1 VCC 2 VCC 51k 9 9 RIN R signal input pin 11 VCC 10.4k 10 LPF1 10.4k LPF time constant pin 10 VCC 10.4k 10.4k 11 LPF2 11 LPF time constant pin 10 4 Multimedia ICs Pin No. BA3837 / BA3837F / BA3838F Pin name Function Equivalent circuit 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 •BA3837 / F (unless otherwise noted, Ta = 25°C, Vcc = 10V, f Parameter Symbol Min. Typ. Max. IN = 1kHz, VIN = 150mV, RL = 100kΩ) Unit Conditions IQ 1.6 2.4 3.3 mA Maximum output voltage Vom 2.3 2.8 — Vrms L / R gain GVT 10 14 17 dB Through mode Low frequency gain GVF 10 14 17 dB fin = 50kHz, vocal fader mode Microphone gain GVM 5 8 11 dB Crosstalk CT 54 70 — dB fIN = 1kHz Mute attenuation MU 73 80 — dB fIN = 1kHz 33 — dB Vocal fader mode % Through mode, BW : 400Hz - 30kHz Quiescent current Vocal suppression rate Through mode THD = 1%, through mode — SV 28 THD — Noise level VN — 15 22 µVrms Rg = 0, DIN AUDIO Input impedance RIN 35 50 65 kΩ LIN, RIN, MICIN, FK Control pin threshold (high) VthH 4.7 — — V — Control pin threshold (low) VthL — — 0.3 V — Output switching DC differential ∆DC — 7 26 mV Maximum output voltage differential between L, R and TK modes Total harmonic distortion 0.02 0.07 䊊 Not designed for radiation resistance. Mode table (A = pin14, B = pin15, C = pin16) A B C LOUT ROUT TK 0 0 0 MUTE MUTE MUTE 0 0 1 VF VF VF 0 1 0 L L L 0 1 1 L R L 1 0 0 MUTE MUTE MUTE 1 0 1 KC KC VF 1 1 0 KC KC L 1 1 1 KC KC L+R 0 : 0V Mode Mute — Vocal fader mode — Sound multiplexing mode — Through mode — Mute Vocal fader mode Sound multiplexing mode L+R 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. 6 Key controller mode • • • • Multimedia ICs BA3837 / BA3837F / BA3838F BA3838F (unless otherwise noted, Ta = 25°C, Vcc = 10V, fIN = 1kHz, VIN = 150mV, Rl = 100Ω) Parameter Symbol Min. Typ. Max. Unit Conditions IQ 1.9 2.7 3.6 mA Vom 2.3 2.8 — Vrms L / R gain GVT 10 14 17 dB Through mode Low frequency gain GVF 10 14 17 dB fin = 50kHz, vocal fader mode Microphone gain GVM 5 8 11 dB Crosstalk CT 54 70 — dB fIN = 1kHz Quiescent current Maximum output voltage Through mode THD = 1%, through mode — Vocal suppression rate SV 28 33 — dB Vocal fader mode Total harmonic distortion THD — 0.02 0.07 % Through mode, BW : 400Hz - 30kHz VN — 15 22 µVrms Noise level Rg = 0, DIN AUDIO, through mode RIN 35 50 65 kΩ VthH 4.7 — — V Control pin threshold (low) VthL — — 0.3 V — Output switching DC differential ∆DC — 7 46 mV Maximum output voltage differential between L, R and TK modes Input impedance Control pin threshold (high) LIN, RIN, MICIN, FK — 䊊 Not designed for radiation resistance. Mode table (A = pin14, B = pin15, C = pin16) A B C LOUT ROUT TK 0 0 0 R R R 0 0 1 VF VF VF 0 1 0 L L L Mode — Vocal fader mode — Sound multiplexing (LOUT) — — 0 1 1 L R L Through mode 1 0 0 KC KC R Sound multiplexing (R) 1 0 1 KC KC VF 1 1 0 KC KC L 1 1 1 KC KC L+R 0 : 0V 1 : 5V Key controller mode Sound multiplexing mode (ROUT) Vocal fader mode Sound multiplexing mode (L) L+R • • • • VF : vocal fader output KC : signal passed through key controller ∗ 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) A 4.7V A A 0.3V C7 0.22µ 0.047µ C6 C5 + 10µ 16 15 14 13 12 11 10 9 C B A Rout LP LP LP RIN LIN BIAS GND 6 7 8 VCC MICIN 1 2 Lout FK TK 3 4 5 + + C1 A 10µ + C2 10µ + C3 10µ C4 22µ V + 10µ 100k MEASUREMENT FK V R MIC AUDIO ANALYZER 600Ω OSC 51k Fig. 1 8 L Multimedia ICs BA3837 / BA3837F / BA3838F •Application example (BA3838F) µ – CON 51k 51k 51k 10µ + 1µ + 0.047µ + 1µ 1µ 0.22µ + 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 notes •(1)Operation The example in the diagram “Application example” (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. 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) The value of Q is: Q = 1 2 (Currently, Q ⱌ 1) C7 C6 (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 100kΩ. 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. •Electrical characteristic curves 3 2 1 2 4 6 8 10 12 14 16 18 20 POWER SUPPLY VOLTAGE : VCC (V) Fig. 3 IQ vs. VCC characteristics (BA3837 / F) VOCAL COMRESSION RATIO : SV (dB) (mA) 4 0 10 5 QUIESCENT CURRENT : IQ QUIESCENT CURRENT : IQ (mA) 5 4 3 2 1 0 2 4 6 8 10 12 14 16 18 20 POWER SUPPLY VOLTAGE : VCC (V) Fig. 4 IQ vs. VCC characteristics (BA3838F) 40 20 14 0 – 20 – 40 – 60 10 100 1K 10K FREQUENCY : f (Hz) Fig. 5 SV vs. frequency characteristics 100K L,R OUTPUT TOTAL HARMONIC DISTORTION : THD (%) Multimedia ICs BA3837 / BA3837F / BA3838F 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 10.0 ± 0.2 19.4 ± 0.3 9 0.3 ± 0.1 0.5 ± 0.1 0.11 7.62 2.54 9 1 8 1.27 0.4 ± 0.1 0.15 ± 0.1 8 16 4.4 ± 0.2 6.2 ± 0.3 1 1.5 ± 0.1 0.51Min. 3.2 ± 0.2 4.25 ± 0.3 6.5 ± 0.3 16 0.3Min. 0° ~ 15° 0.15 DIP16 SOP16 11