NJM2776 Headphone Amplifier for Portable Audio ■ GENERAL DESCRIPTION The NJM2776 is a low voltage headphone amplifier for portable audio applications. The NJM2776 operates directly for one battery supply with + + independent power supply terminals (V 1 and V 2). Also it provides shock-noise less standby mode. The NJM2776 is suitable for portable MD, portable CD and others. ■ FEATURES ● Operating Voltage ■ PACKAGE OUTLINE NJM2776RB2 + + + V 1(from step-up converter) =1.8 to 4.5V (however, V 1 > V 2) + + + V 2(from battery) =0.9 to 4.5V (however, V 1 > V 2) + + + ● Low Operating Current ICC4(V 1 side)=200µA typ. (V 1=2.3V, V 2=1.2V, No signal) + + + ICC3(V 2 side)=350µA typ. (V 1=2.3V, V 2=1.2V, No signal) + + + ● Supply Current in Standby mode ICC2(V 1 side)=25µA typ. (V 1=2.3V, V 2=1.2V) + + + ICC1(V 2 side)= 6µA typ. (V 1=2.3V, V 2=1.2V) ● Output Power Exceeds PO=8.5mW typ. (RL=16Ω, THD=10%) ● Shock-noise less Standby mode ● Bipolar Technology ● Package Outline TVSP10 ■ PIN CONFIGURATION AND BLOCK DIAGRAM V +2 1 10 GND OUT 1 2 9 OUT 2 IN 1 3 8 IN 2 + STANDBY TC 4 V +1 5 - - BIAS + 7 STANDBY 6 VREF 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. + V2 OUT1 IN1 STADBY_TC + V1 VREF STANDBY IN2 OUT2 GND REG VREF AMP -1- NJM2776 ■ ABSOLUTE MAXIMUM RATINGS (Ta=25°C) PARAMETER SYMBOL + Supply Voltage V Power Dissipation PD Operating Temperature range Topr Storage Temperature Range Tstg RATINGS 5 (note) 320 -20 to +75 -40 to +125 UNIT V mW °C °C ■ RECOMMENDED OPERATING CONDITIONS PARAMETER SYMBOL TEST CONDITION + V1 Operating Voltage Range + V2 + MIN. 1.8 0.9 TYP. 2.3 1.2 MAX. 4.5 4.5 UNIT V + ■ ELECTRICAL CHARACTERISTICS (Ta=25°C, V 1=2.3V, V 2=1.2V, VIN=-30dBV (31.6mVrms), f=1kHz, RL=16Ω, Active mode, unless otherwise specified) ●Power Supply TEST CONDITION PARAMETER SYMBOL MIN. TYP. MAX. UNIT pin + + Operating Current ICC0 V 1=0V V2 1.0 + ICC1 V2 6.0 10.0 Standby mode + µA ICC2 V1 25 35 + ICC3 V2 350 750 No signal + ICC4 V1 200 400 + ICC5 V2 2.5 PO=0.1mW+0.1mW mA + 200 V1 ICC6 Reference Voltage No signal 0.50 0.60 0.65 V VR E F ●Amplifier PARAMETER Closed loop Gain Output Power Total Harmonic Distortion Output Noise Voltage Channel Separation Mute Level Supply Voltage Rejection Ratio SYMBOL GV PO THD V NO MUTE PSRR1 SYMBOL V IH V IL ■ MODE SWITHCH FUNCTION ●STANDBY (7PIN) PARAMETER CONTROL SIGNAL Standby L, open Active H -2- THD=10% P O =1mW A-Weighted Standby mode 1kHz Band Pass + V 1=1.8V + 0.1Vrms + V 2=0.9V + V 1=1.8V + V 2=0.9V + 0.1Vrms TYP. 11.5 8.5 0.20 -100 MAX. 12.5 0.50 -96 UNIT dB mW % dBV (10.0) (15.8) (µV) 44 55 - dB - -100 -80 dB 46 52 dB TEST CONDITION V IN =High Level V IN =Low Level STATUS IC is non-active. IC is active. MIN. 10.0 5.0 - CS PSRR2 ●Mode Control PARAMETER High Level Input Voltage Low Level Input Voltage TEST CONDITION 70 77 - MIN. 1.2 0.0 TYP. - MAX. + V1 0.3 UNIT V NJM2776 ■ TERMINAL DESCRIPTION PIN No. SYMBOL EQUIVALENT CIRCUIT VOLTAGE NOTE V+2 2,9 15K OUT1, OUT2 OUT 0.6V 5K VREF GND V+1 3,8 IN1, IN2 IN 0.6V 20K VREF GND V+1 4 88k STANDBY_TC 1.2V 680 400 STANDBY_TC GND V+2 V+1 100 6 VREF VREF 0.6V GND -3- NJM2776 PIN No. SYMBOL EQUIVALENT CIRCUIT VOLTAGE V+1 680 7 STANDBY STANDBY 120k 300k GND -4- - NOTE NJM2776 ■ APPLICATION CIRCUIT V +2 GND C1 22µF C10 C2 330µF 330µF R1 C3 10Ω 0.22µF IN 1 C4 0.47 µF STANDBY TC ＮＪＭ２７７６ OUT 1 OUT 2 C9 0.22µF R2 10Ω IN 2 C8 0.47 µF Active STANDBY C5 0.33µF Standby V +1 C6 22µF V +1 VREF C7 22µF Note) Recommended the capacitors C1, C3, C6 and C9 are featuring higher frequency efficiency to prevent the oscillation. -5- NJM2776 ■ APPLICATION NOTE 1. Procedure for Supplying Power + + Supply the power to first V 2(Battery side) and then V 1(Step-up Converter side). 2. Input Dynamic Voltage Range The reference voltage is fixed at 0.6V. Therefore input dynamic voltage range is not proportion to the power supply voltage. The input signal over dynamic range makes distortion. For prevent the distortion, adjust the maximum input signal level. 3. Charge Sequence Pop noise may not be happened with mode switch operation once output voltage becomes reference voltage. The "Charge Sequence" may shorter the time for power up initialization. Charge Sequence: To set mode switch from standby to active during power up initialization, activate rapid charge circuit for stabilizing the output voltage. -6- NJM2776 ■ TYPICAL CHARACTERISTICS Operating Current vs. Operating Voltage Operating Current vs. Operating Voltage V+1=2.3V, Ta=25o C, Active + V 2=1.2V, Ta=25 oC, Active 2000 1000 800 1000 Operating Current [µA] Operating Current [µ A] 1500 V +2 600 + V2 400 + V1 500 + 200 V1 0 0 1 2 3 4 5 0 6 0 0.5 + V+1=2.3V, Ta=25o C, Standby 50 25 40 20 Operating Current [µ A] Operating Current [µ A] V 2=1.2V, Ta=25 C, Standby + V1 20 0 + V2 0 1 2 3 4 V+1 15 10 V+2 5 5 0 6 0 Operating Voltage (V+1) [V] 0.5 1 2 2.5 Operating Current vs. Temperature + + V 1=2.3V, V 2=1.2V, Active + V 1=2.3V, V 2=1.2V, Standby 600 40 35 500 30 Operating Current [mA] Operating Current [µ A] 1.5 Operating Voltage (V+2) [V] Operating Current vs. Temperature + 2.5 Operating Current vs. Operating Voltage o 10 2 Operating Voltage (V 2) [V] Operating Current vs. Operating Voltage 30 1.5 + Operating Voltage(V 1) [V] + 1 400 V+2 300 200 + V1 + V1 25 20 15 + V2 10 100 5 0 -50 0 50 o Ta [ C] 100 150 0 -50 0 50 100 150 o Ta [ C] -7- NJM2776 ■ TYPICAL CHARACTERISTICS Reference Voltage vs. Operating Voltage Reference Voltage vs. Temperature V+1=2.3V, Ta=25o C V+1=2.3V, V +2=1.2V 1 700 600 Reference Voltage [mV] Reference Voltage [V] 0.8 0.6 0.4 500 400 300 200 0.2 100 0 0 0.5 1 1.5 2 0 -50 2.5 0 50 + 100 150 o Operating Voltage (V 2) [V] Ta [ C] Total Harmonic Distortion vs. Output Power Total Harmonic Distortion vs. Output Power V+1=2.3V, V +2=1.2V, f=1KHz, RL=16Ω, BW=400Hz-30kHz + + V 1=2.3V, V 2=1.2V, RL=16Ω, Ta=25 oC 10 BW f=10kHz:400-80kHz f= 1kHz:400-80kHz f=100Hz: 10-30kHz 10 Ta=-20oC Ta=75oC 1 THD+N [%] THD+N [%] Ta=25o C 0.1 1 f=10kHz f=100Hz 0.1 0.01 0.001 0.01 0.1 1 f=1kHz 0.01 0.001 10 0.01 Output Power [mW] 0.1 1 10 Output Power [mW] Power Dissipation vs. Output Power Output Power vs. Operating Voltage V +1=2.3V, V +2=1.2V, f=1kHz, RL=16Ω, BW=30kHz, Ta=25oC + V 1=2.3V, f=1kHz, THD=10%, RL=16Ω, BW=400-30kHz 50 14 12 40 Output Power [mW] o Ta=-20 C Ta=75oC 8 6 4 Operating Current [mW] Ta=25oC 10 THD=10% 30 20 10 2 0 0.5 1 1.5 2 2.5 + Operating Voltage (V 2) [V] -8- 3 0 0 2 4 6 Output Power [mW/ch] 8 10 NJM2776 ■ TYPICAL CHARACTERISTICS Channel Separation vs. Frequency Output Noise Voltage vs. Temperature V +1=2.3V, V +2=1.2V, Vin=-30dBV, RL=16Ω, Ta=25o C -60 100 -70 80 Channel Separation [dB] Output Noise Voltage [dBV] V +1=2.3V, V +2=1.2V, RL=16Ω, Rg=600Ω, A-Weighted -80 -90 60 40 20 -100 -110 -50 0 50 100 0 0.01 150 0.1 o Ta [ C] o V +1=2.3V, V +2=1.2V, Vin=-30dBV=0dB, f=1KHz, RL=16 Ω 1kHz Band pass STANDBY -30 -40 -40 -50 -50 Mute Level [dB] Mute Level [dB] Mute Level vs. Temperature + V 1=2.3V, V 2=1.2V, Vin=-30dBV=0dB, RL=16 Ω, Ta=25 C 1kHz Band pass, STANDBY -30 -60 -70 -80 -60 -70 -80 -90 -90 -100 -100 -110 0.01 0.1 1 10 -110 -50 100 0 100 150 Ta [ C] + + PSRR vs. frequency (V 1) PSRR vs. frequency (V 2) V +1=1.8V+0.1Vrms, V+2=0.9V, Rg=600Ω, RL=16Ω, Ta=25oC V +1=1.8V, V +2=0.9V+0.1Vrms, Rg=600Ω, RL=16Ω, Ta=25o C 100 80 80 60 60 PSRR [dB] 100 40 20 0 0.01 50 o Frequency [kHz] PSRR [dB] 10 Frequency [kHz] Mute Level vs. Frequency + 1 40 20 0.1 1 Frequency [kHz] 10 100 0 0.01 0.1 1 10 100 Frequency [kHz] -9- NJM2776 ■ TYPICAL CHARACTERISTICS Gain vs. STANDBY Control Voltage V +1=2.3V, V+2=1.2V, Vin=-30dBV, f=1kHz, RL=16 Ω 20 0 Ta=-20oC Ta=25o C Gain [dB] -20 Ta=75o C -40 -60 -80 -100 -120 -0.5 0 0.5 1 1.5 2 STANDBY Control Voltage [V] [CAUTION] The specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. - 10 -