IC for Headphone Stereos (bass boost) LAG668 MITSUMI IC for Headphone Stereos (bass boost) Monolithic IC LAG 668 Outline This IC was developed to provide bass boost functions without deviating from the basic design concept of Mitsumi's LAG665, which is highly regarded for applications in headphone stereos for overseas markets in particular. Bass boost functions are widely adopted in models for overseas markets as well. However, because of stringent cost constraints, there has been a need for an IC which is simple and inexpensive. This IC can provide bass boost functions simply by adding three resistors and one capacitor (per channel). Moreover, it has the same pinout as the LAG665, so that by making selective use of set features, a product lineup can be developed without changes to the printed circuit board. Features 1. Configuration: pre and power amps, motor control, E. VR, bass boost 2. Preamp off function convenient for use in models with radios 3. Independent motor control circuit 1. Motor noise is effectively suppressed 2. With motor on/off pin (motor can be stopped easily when radio is in use) 3. With fast forward pin 4. Bass boost frequency characteristic can be changed simply by changing the resistance multiplier. 5. Well-balanced E. VR circuit 1. L, R channels variable using a single VR 2. A-curve can be reproduced using B-curve VR 6. Few external components Package SOP-28B (LAG668F) SDIP-30A (LAG668D) Absolute Maximum Ratings Item Symbol Ratings Units Operating temperature TOPR -20~+65 °C Storage temperature TSTG -40~+125 °C Power supply current VCC max. -0.3~+7.5 V Power consumption Pd DIP : 750, SOP : 450 mW Operating voltage Vop +2.0~+5.0 V MITSUMI Electrical Characteristics IC for Headphone Stereos (bass boost) LAG668 (Except where noted otherwise, Ta=25°C) Item Symbol Measurement conditions Consumption current ICC VIN=0v, IM=0mA Preamp unit (Ta=25°C) Open-circuit gain Gvo VO=-10dBm, RL=infinite Closed-circuit gain Gvc VO=-10dBm Maximum output voltage Vom THD=10% Total harmonic distortion ratio THD VOUT=400mVrms Output noise voltage Vno VIN=0, Rg=2.2k, BPF (30~20kHz) Input impedance ZIN VOUT=-10dBm Crosstalk between channels C.T Rg=2.2k, VOUT=-10dBm Output voltage with pre off Vooff VIN=100mVrms Output resistance with pre off Rooff Input resistance on pre off Rioff Attenuator unit (Ta=25°C) Maximum input voltage Vi max. Maximum attenuation Va max. Vcont=min. Attenuation error Vaerr Vcont=max. Input impedance ZIN Control pin input resistance Zicot Power amp unit (Ta=25°C) Voltage gain Gv POUT=5mW Voltage gain difference Gv Vcont=max. between channels Maximum output power I Pom1 THD=10%, RL=32Ω Maximum output power II Pom2 THD=10%, RL=16Ω Total harmonic distortion ratio THD POUT=5mW Crosstalk between channels C.T POUT=5mW Output noise voltage Vn Rg=2.2k, Vcont=max. Ripple rejection RR VCC=3V, 100Hz, 100mVp-p Noise of preamp + power amp + B.B. Vnto VIN=0, Rg=2.2k, Vcont=max. 1 Motor control unit (Ta=25°C) Consumption current IMC Startup current IMS Reference voltage Vref Between RML-ADJ pins Reference voltage fluctuation I Vref1 VCC between 2.1 and 5.0 V Reference voltage fluctuation II Vref2 IM between 25 and 250 mA Reference voltage fluctuation III Vref3 Ta between -10 and 50°C Current coefficient K Current coefficient fluctuation I K1 VCC between 2.1 and 5.0 V Current coefficient fluctuation II K2 IM between 25 and 250 mA Current coefficient fluctuation III K3 Ta between -10 and 50°C Output voltage on forced on VCEsa IM=200mA, 14PIN=VCC Input resistance on forced on Rion Leakage current on forced off IML Input resistance on forced off Ricon Conditions unless stated otherwise Amp unit: VCC=3.0V, f=1kHz, RL=16Ω, Pre OFF=OPEN Motor unit: VCC=3.0V, IM=100mA, Motor unit: (Mitsumi model) Note 1: Bass boost circuit constants are based on application circuit diagrams. Note 2: Motor pin voltage fluctuations Min. 40 0.45 18 30 72 42 0.6 0.05 150 22 10 10 dB dB Vrms 0.5 % 300 µVrms kΩ dB -50 dB kΩ kΩ 44 0.2 66 Vrms dB dB kΩ kΩ 0 200 100 36 20 30 20 31 * * Typ. Max. Units 18 25 mA 500 0.72 32 38 40 dB 0 3 dB 28 0.5 30 1.0 37 3.0 2.0 3.0 5.0 0.80 0.05 0.01 0.01 38 0.5 0.05 0.02 5.6 33 2.0 6.0 mW mW % dB mVrms dB mVrms mA mA 0.87 V %/V %/mA %/°C 43 %/V %/mA %/°C 0.6 V kΩ 200 µA kΩ MITSUMI Block Diagram IC for Headphone Stereos (bass boost) LAG668 IC for Headphone Stereos (bass boost) LAG668 MITSUMI Application Circuits Power amp gain (dB) Bass Boost Power Amp Gain GV 40 GVH 35 3dB 30 B•B ON 25 3dB GVL B•B Off 15 101 102 f1 103 104 105 106 f2 Frequency (Hz) GV : Power amp gain GVH : Bass boost power amp gain (high level) GVL : Bass boost power amp gain (low level, or boost off) f1, f2: Cutoff frequencies GVH=GV+20Log GVL=GV+20Log f1= R3 ( R1+R3 ( (dB) R1 (dB) ( R2//R3 R2//R3+ R1 ( 1 2π ((R1//R3) +R2)C 1 f2= 2πR2C (Hz) (Hz) IC for Headphone Stereos (bass boost) LAG668 MITSUMI Characteristics (Bass boost) Power amp gain (dB) Recommended constants 40 R1=33kΩ GVH=37dB 35 R2=4.7kΩ GVL=20dB 30 R3=180kΩ f1=50Hz 25 C=0.1µF 20 15 101 f2=340Hz No R4 or C2 102 103 104 105 106 Frequency (Hz) Power amp gain (dB) Bass boost efficiency 40 R1=12kΩ GVH=37dB 35 R2=2.2kΩ GVL=20dB 30 R3=180kΩ f1=130Hz 25 C=0.1µF f2=720Hz 20 15 101 No R4 or C2 102 103 104 105 106 Frequency (Hz) Power amp gain (dB) Response for poor headphone and cassette head characteristics 40 R1=33kΩ GVH=37dB 35 R2=6.8kΩ GVL=23dB 30 R3=180kΩ f1=50Hz 25 C=0.1µF f2=230Hz 20 15 101 No R4 or C2 102 103 104 105 106 Frequency (Hz) Power amp gain (dB) Bass + treble boost 40 R1=33kΩ GVH=37dB 35 R2=4.7kΩ GVL=20dB 30 R3=180kΩ f1=50Hz 25 C=0.1µF f2=340Hz R4=20kΩ GVH=27dB 20 15 101 C2=390pF 102 103 104 Frequency (Hz) 105 106