NJM2792 Quad Boost Amplifier GENERAL DESCRIPTION The NJM2792 is a quad boost amplifier designed for car audio system. It expands the frequency characteristics by high slew rate. It can swing 14V peak-to-peak output voltage at 9V. It consists of four channel non-inverting amplifier with the gain of 8dB. It is suitable for car audio system and other boost amplifier system. FEATURES Operating Voltage Operating Current Boost output Function Maximum Output Voltage Supply Voltage Rejection Ratio Total Harmonic Distortion Noise Output Voltage Bipolar Technology Package Outline PACKAGE OUTLINE NJM2792V (6 to 11V) (12mA typ. ) + (VO=14Vpp:@V =9V) (4.5Vrms typ., @ f=100kHz ) (50dB typ. ) (0.003% typ. ) (5Vrms typ. ) SSOP20 BLOCK DIAGRAM LIFT AMP CLS SIGNAL AMP LF-IN LF-OUT SIGNAL AMP LR-IN RF-IN RR-IN LR-OUT SIGNAL AMP RF-OUT SIGNAL AMP LIFT AMP RR-OUT CLS -1- NJM2792 PIN CONFIGURATION No. Symbol 1 L-GND 2 L-CIN 20 L-CONT RL-OUT 19 3 FL-OUT RL-FB 18 4 FL-FB RL-IN 17 5 FL-IN V+ 16 6 REF RR-IN 15 7 FR-IN RR-FB 14 8 FR-FB RR-OUT 13 9 FR-OUT R-CIN 12 10 R-COUT R-GND 11 Function No Symbol 11 R-GND Function 1 L-GND Ground for Left Channel Ground for Right Channel 2 L-COUT Capacitor for - Level Shift Left Channel 12 R-CIN 3 FL-OUT Output for Front Left Channel 13 RR-OUT Output for Rear Right Channel 4 FL-FB - Input for Front Left Channel 14 RR-FB - Input for Rear Right Channel 5 FL-IN + Input for Front Left Channel 15 RR-IN 6 REF Reference Voltage 16 V+ Capacitor for + Level Shift Right Channel + Input for Rear Right Channel Power Supply 7 FR-IN + Input for Front Right Channel 17 RL-IN + Input for Rear Left Channel 8 FR-FB - Input for Front Right Channel 18 RL-FB - Input for Rear Left Channel Output for Rear Left Channel 9 FR-OUT Output for Front Right Channel 19 RL-OUT 10 R-COUT Capacitor for - Level Shift Right Channel 20 L-CIN -2- Capacitor for + Level Shift Left Channel NJM2792 ABSOLUTE MAXIMUM RANGES PARAMETER (Ta=25C) RANGE UNIT + V +15 V PD 550 NOTE: EIA/JEDEC STANDARD Test board (76.2x114.3x1.6mm, 2layer, FR-4) mounting mW Operating Temperature Topr -40 to +85 C Storage Temperature Tstg -40 to +125 C Supply Voltage Power Dissipation SYMBOL + ELECTRICAL CHARACTERRISTIC (V =9V,Ta=25C) PARAMETER TEST CONDITION SYMBOL MIN. TYP. MAX. UNIT 6.0 9.0 11.0 V - 12.0 18.0 mA - 7.8 - V 7.5 8.0 8.5 dB DC CHARACTERRISTIC + Operating Voltage V Operating Current ICC Output Voltage No Signal VODC AC CHARACTERRISTIC (f=1kHz , Vo=1Vrms, RL=10k) Voltage Gain Av Channel Separation 1 CS1 RS=600 , VO=1Vrms, f = 1kHz, 70 80 - dB Channel Separation 2 CS2 RS=600 , VO=1Vrms, f = 1kHz, - 100 - dB Channel Balance BAL - - 0.5 dB Front channel vs. Rear channel L channel vs. R channel Roll-off Low Frequency fRL -1dB - 5 - Hz Roll-off High Frequency fRH -1dB 100 - - kHz Input Resistance RIN 44 60 76 k Output Resistance ROUT - 2 - Maximum Output Voltage 1 VOM1 THD=0.1%, f = 1kHz 5.0 5.2 - Vrms Maximum Output Voltage 2 VOM2 THD=1%, f = 100kHz - 4.5 - Vrms Noise Output Voltage VNO Rs=0 , A-Weighting - 5 10 Vrms f=1kHz , VO=3Vrms, A-Weighting - 0.003 0.01 % - 0.01 - % 55 - - dB - 50 - dB THD1 Total Harmonic Distortion Supply Voltage Rejection Ratio THD2 SVR1 SVR2 f=17Hz to 20kHz , VO=3Vrms, A-Weighting Rs=0, f=1kHz , VRP=100mVrms Rs=0, f=20Hz to 20kHz , VRP=100mVrms -3- NJM2792 TERMINAL DESCRIPTION PIN NO. SYMBOL FUNCTION 2 10 L-COUT R-COUT Capacitor for - Level Shift Left Channel Capacitor for - Level Shift Right Channel 2PIN, 10PIN 12k 12 20 R-CIN L-CIN 3 9 13 19 FL-OUT FR-OUT RR-OUT RL-OUT Capacitor for + Level Shift Right Channel Capacitor for + Level Shift Left Channel 12PIN, 20PIN Output for Front Left Channel Output for Front Right Channel Output for Rear Right Channel Output for Rear Left Channel 3PIN, 9PIN, 13PIN, 19PIN 8.5k 4 8 14 18 FL-FB FR-FB RR-FB RL-FB - Input for Front Left Channel - Input for Front Right Channel - Input for Rear Right Channel - Input for Rear Left Channel 5 7 15 17 FL-IN FR-IN RR-IN RL-IN + Input for Front Left Channel + Input for Front Right Channel + Input for Rear Right Channel + Input for Rear Left Channel 5PIN, 7PIN, 15PIN, 17PIN 300 2k 60k -4- TERMINAL DC VOLTAGE EQUIVALENT CIRCUIT (V+-1.4)x0.09 [V] + V -0.7 [V] (12,20PIN) + V -1.4 [V] (3,9,13,19PIN) 8.5k 300 2k 4PIN, 8PIN, 14PIN, 18PIN (V+-1.4)x0.4 [V] NJM2792 TERMINAL DESCRIPTION PIN NO. SYMBOL FUNCTION 300 6 REF TERMINAL DC VOLTAGE EQUIVALENT CIRCUIT Reference Voltage 44k 44k 24k 24k 46k 46k 6PIN (V+-1.4)x0.6 [V] 300 -5- NJM2792 APPLICATION CIRCUIT 1 CLS 220F L-GND L-CIN Lift Amp 2 22F 3 + FL-OUT 22k 10F 5 36k RL-OUT 24k Signal Amp + 20 1.5nF L-COUT 33k FL-FB 4 RL=10k + FL-IN 60k RL-FB 60k Signal Amp Front-Left 19 22F + 33k 18 RL=10k 22k RL-IN 17 Rear-Left + 10F 44k 24k 46k V+ 16 REF 6 47F + 100nF 44k 24k 46k 10F + 7 Front-Right + 22F 33k 9 10 Rear-Right RR-IN Signal Amp 8 60k FR-IN 22k RL=10k 60k FR-FB FR-OUT 10F 15 Signal Amp 24k 36k 22k RR-FB RR-OUT R-CIN R-COUT 14 33k 13 12 Lift Amp RL=10k + 22F 1.5nF + R-GND -6- + 11 CLS 220F NJM2792 APPLICATION NOTE OPERATING PRINCIPLE Figure 1 is block diagram of NJM2792. A right channel and a left channel of figure are the same compositions. Only the reference voltage terminal and the power-supply voltage terminal are common between channels. One channel is composed of two signal amplifiers, one lift amplifier, the reference voltage, and the bias. The signal amplifier is non-reverting amplifier which gain(+8dB) is set by external resistances. However, to + + achieve the function of the boost, the output bias point is set near V [=V -1.4]. And, the power-supply voltage of the signal amplifier is supplied from the lift amplifier output. + The lift amplifier lifts the power-supply voltage of the signal amplifier more than V by the charge pump mechanism. However, unlike a charge pump, the lift amplifier lifts up voltage only when an input signal swings + above center. The output bias point of the lift amplifier is set near GND[=(V -1.4)*0.09]. When the input signal + swings below center, the power supply of the signal amplifier is supplied from V through the diode. + Figure 2 shows the signal operation and the voltage. V /CIN/OUT/COUT shows terminal voltage. The NJM2792 can output more than the power-supply voltage when power-supply voltage of the signal amplifier (CIN) is more than the output voltage. The NJM2792 does not have standby function and mute function. The stability operation is after the capacitor of the reference voltage terminal is charged at power supply on. 1 2 CoFL 22F Output 3 + L-GND Lift Amp L-CIN 36k FL-OUT RL-OUT Input 19 C2 1.5nF + Output 18 R2FL 22k 5 CoRL 22F R1RL RL-FB 33k 24k 4 + 20 L-COUT R1FL 33k FL-FB CiFL 10F Voltage CLS-L 220F + Signal Amp 60k 60k FL-IN R2RL 22k Signal Amp RL-IN 17 CiRL 10F COUT + time Input Rear-Left Front-Left V+ CIN OUT Figure 2: Signal operation 44k 24k 46k Bias REF V+ 6 CREF 47F 16 + 44k CoFR 22F Output + 24k 7 FR-IN Signal Amp 60k 8 Input + R1FR FR-FB 33k 9 10 FR-OUT Bias CoRR 22F Rear-Right Front-Right R2FR 22k CiFR 10F 46k 60k C1 100nF RR-IN Signal Amp 15 + Output R2RR 22k 14 24k 36k R-COUT RR-FB R1RR 33k RR-OUT R-CIN 13 CiRR 10F + Input C3 1.5nF 12 Lift Amp + R-GND 11 CLS-R 220F Figure 1: Block diagram and application circuit -7- NJM2792 OPERATING PRECAUTIONS 1. External parts 1.1 Bypass capacitor for power supply Bypass capacitor (C1) for the power supply should use the capacitor of wide temperature range and high-frequency characteristic. Connect the capacitor near the IC for low interconnection resistance. 1.2 Feedback resister Set the gain to 8dB with feedback resister R1 and R2 of each channel. The use of high-value resisters causes increase of the output noise voltage. However, R1+R2 cannot use low-value resisters because of the load resistance of the signal amplifier. The resistances of the example of application circuit are the recommend value. 1.3 Input coupling capacitor The low frequency of the input signal is cut with the high-pass filter that composes of input coupling capacitor and input impedance (about 60k). The cut-off frequency at capacitor value (10uF) of application circuit is about 0.3Hz. 1.4 Output coupling capacitor The low frequency of the output signal is cut with the high-pass filter that composes of output coupling capacitor (Co) and load resistance. The cut-off frequency lowers when the large capacitor value (Co). When the load resistance is 10k, the cut-off frequency of application circuit is about 0.8Hz. 1.5 Bypass capacitor for reference voltage The bypass capacitor (CREF) for the reference voltage influences the turn-on time and SVR. When CREF is large, SVR is improved, but turn on time becomes long. 1.6 Boost capacitor When the boost capacitor (CLift) is large, the distortion of the low frequency decreases. 1.7 Bypass capacitor for CIN terminal Bypass capacitor (C2/C3) of the CIN terminal absorbs fluctuation of the CIN terminal. The capacitances of the example of application circuit are the recommend value. 2. Load resistance The NJM2792 is a line amplifier of class-A output. Connect the load resistance 10k or more. 3. Amplifier gain The amplifier gain of NJM2792 is decided in the ratio of external resistance R1 and R2. The output bias point of the signal amplifier changes when the gain is changed. The gain setting of +8dB is the recommend value. 4. Low frequency characteristic The NJM2792 lifts the power-supply voltage of the signal amplifier by the lift amplifier. The electric power from the power supply is decided depending on external capacity (Clift). Therefore, the distortion of low frequency increases when the electric power is insufficient. Connect capacitor (Clift) of a large capacity value for the distortion decrease of a low frequency. -8- NJM2792 5. High frequency characteristic The high frequency characteristic of NJM2792 can output 4.5Vrms(typ.) at 100kHz. However, note a capacitive load that increases at the high frequency. Set the total load impedance (load capacitance + load resistance) to 10k or more if the flat high-frequency characteristic is necessary. Maximum Output Voltage vs. Frequency (V+=9[V], THD=1[%], No-Filter, Ta=25oC) Maximum Output Voltage[Vrms] 6 5 0pF 4 220pF 3 470pF 1000pF 2 1 0 10000 100000 Frequency [Hz] 6. Signal phase to the front/rear channel Input the in-phase signal to front/ rear channel of NJM2792. The reverse-phase signal input attenuates output signal amplitude. Input the signal different in only the signal level to front/rear channel. Output Voltage vs. Phase Difference V+=9V, THD=0.1%, Ta=25oC 7 10kHz 1kHz Output Voltage[Vrms] 6 5 100Hz 4 3 2 1 0 -180 -90 0 90 180 Phase Difference[deg] -9- NJM2792 7. Turn on time The NJM2792 application circuit connects the capacitance of 47uF with the reference voltage terminal. The signal amplitude is insufficient after turning on of the power supply by capacitor charge. The turn-on time is long at a large capacity value, and shortens at a small capacity value. Note the SVR characteristic when connecting small capacity value. Rise Time vs Reference Voltage Capacity. Output voltage 90% Waveform Rise Time 5 10 4.5 4 1 3 2.5 Rise Time [s] Voltage [V] 3.5 47uF 22uF 10uF 4.7uF 2.2uF 1uF 2 1.5 1 0.1 0.5 0.01 0 -0.2 0.3 0.8 1.3 1.8 Time [s] 47uF 22uF Power-supply Rejection Ratio [dB] 70 60 1uF 50 2.2uF 4.7uF 40 10uF 30 20 10 0 10 100 1000 Frequency [Hz] - 10 - 10 Reference Voltage Capacity [uF] Power-supply Rejection Ratio vs. Frequency 80 1 10000 100000 100 NJM2792 2-CHANNEL ONLY APPLICATION CIRCUIT Use combination of front-left and front-right or rear-left and rear-right. The reverse-phase signal input attenuates output signal amplitude. Input the signal different in only the signal level to front/rear channel. 1 2 CoFL 22F Output + 3 R1FL 33k 4 CiFL 10F Input L-GND Lift Amp FL-OUT 36k FL-FB 24k RL-OUT RL-FB Signal Amp 5 60k 60k FL-IN Signal Amp RL-IN 44k 47F 24k 46k Input + 18 17 V+ 16 44k 24k 46k 7 FR-IN Signal Amp 8 R1FR 33k 9 10 FR-FB FR-OUT C1 100nF Bias Rear-Right Front-Right R2FR 22k CiFR 10F 19 + + C2 1.5nF Bias 6 CoFR 22F Output + Rear-Left Front-Left REF CREF 20 L-COUT R2FL 22k + L-CIN CLif tL 220F 60k 24k 36k R-COUT 60k RR-IN 15 Signal Amp RR-FB RR-OUT R-CIN 14 13 C3 1.5nF 12 Lift Amp R-GND 11 + CLif tR 220F The application note doesn't guarantee the characteristic. Give due consideration to characteristic variation of external parts and IC. - 11 - NJM2792 TYPICAL CHARACTERISTICS Operationg Current vs. Operating Voltage (No signal, RS=0, RL=10k Operating Current vs. Ambient Temperature (No signal, RS=0, RL=10k 16.0 16.0 14.0 14.0 o 85 C 12.0 Operating Current [mA] Operating Current [mA] 12.0 10.0 o 25 C 8.0 o -40 C 6.0 10.0 + V =11V 8.0 V+=9V 6.0 V+=6V 4.0 4.0 2.0 2.0 0.0 0.0 0 2 4 6 8 10 12 14 -40 16 -20 0 Operating Voltage [V] DC Output Voltage vs. Operating Voltage (No signal, RS=0, RL=10k 40 60 80 100 120 DC Output Voltage vs. Ambient Temperrature (No signal, RS=0, RL=10k 16.0 16 14.0 14 12.0 12 DC Output Voltage [V] DC Output Voltage [V] 20 Ambient Temperature [ oC] 10.0 8.0 6.0 10 V+=11V 8 6 + V =9V 4 4.0 85oC 2.0 + 0.0 0 2 4 6 V =6V 2 25oC o -40 C 0 8 10 12 14 -40 16 -20 0 20 40 60 80 100 120 Ambient Temperature [ oC] Operating Voltage [V] Noise Output Voltage vs. Ambient Temperature (V+=9V, Rs=0, A-Weighting Filter) Voltage Gain vs. Frequency (V+=9V, RL=10k, Vo=1Vrms) 40.0 10.0 Noise Output Voltage [Vrms] 9.5 Voltage Gain [dB] 9.0 8.5 o -40 C 8.0 7.5 o 25 C 7.0 o 85 C 30.0 20.0 10.0 6.5 0.0 6.0 10 100 1000 Frequency [Hz] - 12 - 10000 100000 -40 -20 0 20 40 60 80 Ambient Temperature [ oC] 100 120 140 NJM2792 TYPICAL CHARACTERISTICS Maximum Output Voltage vs. RL 8 8 7 7 Maximum Output Voltage [Vrms] Maximum Output Voltage [Vrms] Maximum Output Voltage vs. Operating Voltage (RL=10k, f=1kHz, THD=0.1%, LPF=80kHz, Ta=25oC) 6 5 4 3 2 1 (V +=9V, f=1kHz, THD=0.1%, Ta=25oC) 6 5 4 3 2 1 0 0 3 4 5 6 7 8 9 10 11 12 13 0 1 2 3 4 5 6 RL [k] Operating Voltage [V] Channel Separation vs. Frequency (V +=9V, Rs=600, RL=10k, Ta=25oC) 8 9 10 11 THD+N vs. Output Voltage + o (V =9V, RL=10k, CLS=220F, LPF=80kHz, Ta=25 C) 10 140 diagonal channel Ex.) Front-L ch. vs. Rear-R ch. 120 1 100 80 Left ch. vs. Right ch. 60 Front ch. vs Rear Ch. THD+N [%] Channel Separation [dB] 7 40 0.1 10kHz 0.01 1kHz 20 0 10 100 1000 10000 100000 100Hz 0.001 0.01 1000000 0.1 Frequency [Hz] THD+N vs. Frequency + o (V =9V, RL=10k, Vo=3Vrms, LPF=80kHz, Ta=25 C) 10 10 THD+N vs. Frequency + (V =9V, RL=10k, CLS=220F, Vo=3Vrms, LPF=80kHz) 10 1 1 CLS=100F 0.1 85o C THD+N [%] THD+N [%] 1 Output Voltage [Vrms] CLS=220F 25oC 0.1 o -40 C 0.01 0.01 CLS=470F 0.001 0.001 10 100 1000 Frequency [Hz] 10000 100000 10 100 1000 10000 100000 Frequency [Hz] - 13 - NJM2792 TYPICAL CHARACTERISTICS Supply Voltage Rejection Ratio vs. Frequency (V +=9V, V RP=100mVrms, Rs=0, Ta=25oC) 80 70 60 SVR [dB] 50 40 30 20 10 0 10 100 1000 10000 100000 1000000 Frequency [Hz] [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. - 14 - Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: NJR: NJM2792V-TE2 NJM2792V-TE1