MM1376

MITSUMI IC for Headphone Stereos MM1376 IC for Headphone Stereos Monolithic IC MM1376 Outline This IC was developed for use in 3V headphone stereos, and combines all the basic audio circuitry for headphone stereos on a single chip. Recently hearing impairment caused by the high volumes of headphone stereos has become a problem, and there has been strong demand for functions for limiting loud volumes in the sets themselves. This IC incorporates an ALC circuit and has functions to hold the output from the headphone to a fixed level; it also eliminates the ordinary electronic governor circuit in order to accommodate trends toward thinner sets, as seen in the adoption of BSL motors. Package 1. Configuration: Pre-and power amps, ALC circuit 2. Internal tape selector: A selector switch allows the user to select between normal and metal tapes. 3. Internal OCL circuit: No need for large-capacitance output capacitor 4. Preamp off function: Preamp alone can be turned off for connection to radio etc. 5. MM1376CF amp gain takes Dolby noise reduction into account Package SOP-22 Pin Assignment 1 2 3 4 22 21 20 19 18 17 16 15 14 13 12 5 6 1 2 3 4 5 6 7 8 9 10 11 SOP-22 7 8 9 10 11 COM1 Preamp non-inverted input Preamp inverted input Metal switching output Preamp output Power input Rectifier pin ALC control Power output COM2 GND1 12 13 14 15 16 17 18 19 20 21 22 Power output VCC Ripple filter Preamp off Tape selector Power input Preamp output Metal switching output Preamp inverted input Preamp non-inverted input GND2 Absolute Maximum Ratings Item Operating temperature Storage temperature Power supply current Power consumption Symbol TOPR TSTG VCC Pd Ratings -10~+65 -40~+125 -0.3~+7.5 350 Units °C °C V mW MITSUMI IC for Headphone Stereos MM1376 Recommended Operating Conditions Item Operating temperature Operating voltage Symbol TOPR VOPR Ratings -10~65 2.0~5.0 Units °C V Electrical Characteristics Item Consumption current Preamp unit Open-circuit gain Closed-circuit gain I Closed-circuit gain II (Except where noted otherwise, Ta=25°C, VCC=3V, f=1kHz, RL1=10kΩ, RL2=16Ω) Measurement conditions VIN=0V Min. Typ. Max. Units 6 14 72 22 mA dB 36 34.5 33 28 0.5 150 100 dB dB Vrms % µVrms dB dB -60 28 34 2 1.5 200 250 dBm Normal Metal Normal Metal Vo=-10dBm, f=1kHz Vo=-10dBm, f=5kHz THD=10% VOUT=-10dBm Rg=2.2k, BPF (400~30kHz) Rg=2.2kΩ, VOUT=-10dBm VCC=3V, VR=-20dBm, fR=100Hz Rg=2.2kΩ VIN=100mVrms, Pre off CF DF 31 29.5 28 23 0.30 30 20 50 45 33.5 32 30.5 25.5 0.45 0.05 75 45 70 55 -80 Maximum output voltage Total harmonic distortion ratio Output noise voltage Normal Metal Crosstalk between channels Ripple rejection Output voltage with preamp off ALC (off) + power amp Voltage gain Voltage gain difference between channels Maximum output current Total harmonic distortion ratio Crosstalk between channels Output noise voltage POUT=5mW 24 30 -2 30 35 26 32 0 50 0.5 45 85 135 dB dB mW % dB µVrms dB THD=10%, RL=16Ω POUT=5mW POUT=5mW Rg=0Ω, BPF (400~30kHz) VCC=3V, VR=-20dBm fR=100Hz, Rg=0Ω CF DF CF DF Ripple rejection Input resistance ALC (on) + power amp Power amp output voltage ALC initiation input voltage ALC width ALC total harmonic distortion Noise of preamp+power amp+ALC 35 35 19 45 40 24 -30 -56 -62 29 -26 kΩ dBm dBm dB VIN=-40dBm CF DF Input width for output from start of up to +4dB VIN=-40dBm Rg=2.2kΩ (Pre amp), Noise of preamp+power amp CF DF -34 30 40 0.5 1.5 2.8 1.5 6 6 % mVrms MITSUMI IC for Headphone Stereos MM1376 Application Circuits Characteristics Preamp Gain- Frequency 60.0 55.0 50.0 45.0 40.0 volt 35.0 dB 30.0 25.0 lin 20.0 15.0 10.0 5.0 0. 1.0 ALC + power amp (32 dB) VIN-VOUT RL=16ohm 10 0 -10 ALC OFF Normal Metal VOUT (dBV) -20 -30 -40 -50 ALC ON (ADJUST) ALC ON (max.) -60 -80 -70 -60 -50 -40 -30 -20 -10 10.0 100.0 1.0k 10.0k 100.0k 1.0x 10.0x 0 Frequency (log) VIN (dBV)