NJU8757 ANALOG SIGNAL INPUT 2.5W STEREO Class-D POWER AMPLIFIER GENERAL DESCRIPTION PACKAGE OUTLINE The NJU8757 is an analog signal input stereo class-D power amplifier. The NJU8757 incorporates BTL amplifiers, which eliminate AC coupling capacitors, and it is capable of driving up to 2.5W/channel into RL=4ohms with simple external LC low-pass filters. The NJU8757 includes PWM modulators, an output short protector, a low voltage detector and a pop noise reduction function. Class-D operation achieves high power-efficiency, which achieves longer battery life for battery powered applications, thus the NJU8757 is suited for multimedia speaker, PC, etc. NJU8757V NJU8757KN2 7 8 9 10 11 12 13 14 15 16 OUTLN VDDL NC NC NC NC BLOCK DIAGRAM VDD 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 1 2 3 4 5 6 NC 28 NC 1 COM INLN VSS MUTEb INRP VDDL INRN OUTLP STBYb VSSL VSSL VDDR OUTRP OUTLN VSSR OUTRN VDDR NC NC NC NC INRN STBYb VDDR OUTRP VSSR VSSR OUTRN NC VDDL NC NC NC VDDR NC 2-Channel Analog Differential Input 2-Channel BTL Outputs:2.5W/ch at 5V into 4 ohms NC NC Standby(Hi-Z), Mute Control NC VDD Built-in Low Voltage Detector INLP Built-in Short Protector for each channel INLN Built-in Pop noise reduction MUTEb Operating Voltage:2.7 to 5.25V VDDL CMOS Technology OUTLP VSSL Package Outline:SSOP32, QFN28-N2 INLP NC VDD COM VSS NC INRP PIN CONFIGURATION FEATURES VSS VDDL Pulse INLP Pre INLN Amplifier OUTLP Width VSSL Modulator VDDL OUTLN Short Protection COM INRN INRP Pulse Pre Width Amplifier Modulator VSSL VDDR OUTRP VSSR VDDR OUTRN Short Protection Soft Start Control Logic MUTEb Ver.2008-08-27 VSSR Low Voltage Detector STBYb -1- NJU8757 PIN DESCRIPTION SSOP32 4 5 6 No. QFN28-N2 26 28 1 SYMBOL I/O VDD INLP INLN I I FUNCTION Power Supply : VDD=5.0V L-channel Positive input L-channel Negative input Mute control 7 2 MUTEb I Low : Mute ON High : Mute OFF 8,12 3,9 VDDL L-channel Power Supply : VDDL=5.0V 9 4 OUTLP O L-channel positive output 10 5,6 VSSL L-channel Power GND 11 7 OUTLN O L-channel negative output 21,25 13,19 VDDR R-channel Power Supply : VDDR=5.0V 22 15 OUTRN O R-channel negative output 23 16,17 VSSR R-channel Power GND : VSSR=0V 24 18 OUTRP O R-channel positive output Standby control 26 20 STBYb I Low : Standby ON High : Standby OFF 27 21 INRN I R-channel Negative input 28 22 INRP I L-channel Positive input 29 24 VSS Power GND : VSS=0V 30 25 COM I Analog common Note 1) The relations of "VSS= VSSL= VSSR=0V" and "VDD= VDDL=VDDR" must be maintained. Note 2) MUTEb and STBYb must be connected to VDD, when these pins are not used. -2- Ver.2008-08-27 NJU8757 NJU3555 FUNCTIONAL DESCRIPTION (1) Signal Output The OUTLP/LN and OUTRP/RN generate respectively L-channel and R-channel PWM output signals, which will be converted to analog signal via external 2nd-order or higher LC filter. A switching regulator with a high response against a voltage fluctuation is the best selection for the VDDL and VDDR, which are the power supply for output drivers. To obtain better THD+N performance, the stabilization of the power is required. (2) Standby By setting the STBYB pin to "L", the standby mode is enabled. In the standby mode, the entire functions of the NJU8757 enter a low-power state, and the output pins(OUTLP/LN and OUTRP/RN) are high impedance. (3) Mute By setting the MUTEB pin to "L", the Mute function is enabled. In the Mute mode, the output pins(OUTLP/LN and OUTRP/RN) output square wave(Duty: 50%). (4) Low Voltage Detector When the power supply voltage drops down to below VDD(MIN), the internal oscillation is halted for prevention to generate unwanted frequency, and the output pins(OUTLP/LN and OUTRP/RN) become in high impedance. (5) Short Protection The short protector, which protects the NJU8757 against high short-circuit current, turns off the output drivers of L-channel and R-channel independently. About 8 seconds after the protection, the NJU8757 returns to normal operation. When only single-channel shorted, the other channel operates normally unless shorted. However If power supply voltage exceeds operating voltage range, both of short protectors may work together. The short-protector operates at following accidents. * Short * Short * Short * Short * Short * Short between OUTLP and OUTLN between OUTLP and VSSL between OUTLN and VSSL between OUTRP and OUTRN between OUTRP and VSSR between OUTRN and VSSR Note 3) The detectable current and the period for the protection depend on the power supply voltage and ambient temperature. Note 4) The short protector is not effective for a long term short-circuit but for an instantaneous accident. Continuous high-current may cause permanent damage to the NJU8757. Ver.2008-08-27 -3- NJU8757 ABSOLUTE MAXIMUM RATINGS (Ta=25C) PARAMETER SYMBOL CONDITIONS RATING UNIT OUTLP-VDDL,OUT LN-VDDL OUTRP-VDDR,OUT RN-VDDR -0.3 to + 5.5 VDD Supply Voltage With Schottky barrier diode VDDL V OUTLP-VDDL,OUT LN-VDDL VDDR OUTRP-VDDR,OUT RN-VDDR -0.3 to + 5.0 Without Schottky barrier diode Input Voltage Vin -0.3 to VDD+0.3 V Junction Temperature Tj -40 to +125 C Ambient Temperature Ta -40 to +85 C Storage Temperature Tstg -40 to +125 C PDS2 2 layers(EIAJ) SSOP32 1.0 PDS4 4 layers(EIAJ) SSOP32 1.5 Power Dissipation W PDQ2 2 layers(EIAJ) QFN28-N2 0.75 PDQ4 4 layers(EIAJ) QFN28-N2 1.8 Note 5) All voltage are relative to "VSS= VSSL= VSSR=0V" reference. Note 6) The LSI must be used inside of the "Absolute maximum ratings". Otherwise, a stress may cause permanent damage to the LSI. Note 7) Refer to "Typical Application Circuit" for the Schottky barrier diode. Note 8) Power Dissipation The class-D amplifiers operate with high power efficiency and low dissipation power compared to general analog-amplifiers. In theory, the NJU8757 actualize quite high output-power such as 2.5W/channel at 5V operation into 4 ohms load, and total power is supposed to be 5.0W. For this reason, it looks as if the NJU8757 exceeds the absolute maximum rating of the power dissipation. However, in practice, the effective output-power of usual music sound is only about 1/5 to 1/10 of its maximum output power, thus it may never exceed the absolute maximum rating. The maximum power dissipation in the system is calculated, as shown below. Pdmax(W) = (Tjmax(C) - Ta(C)) /ja Pdmax: Maximum Power Dissipation, Tjmax: Junction Temperature = 125C Ta: Ambient Temperature, ja: Thermal Resistance of package. ja = 100C / W ,2 layers(EIAJ) SSOP32 ja = 66.7C / W ,4 layers(EIAJ) SSOP32 ja = 133.3C / W ,2 layers(EIAJ) QFN28-N2 ja = 55.6C / W ,4 layers(EIAJ) QFN28-N2 Power dissipation of the NJU8757 itself is calculated, as shown below. Pd(W) = PO(W) X RO() / RL() + PdIC(W) Pd: Power Dissipation, PO: Output Power, RO: Internal Resistance(output driver) RL: Load Resistance, PdIC: Power internal circuit -4- Ver.2008-08-27 NJU8757 NJU3555 ELECTRICAL CHARACTERISTICS PARAMETER VDD,VDDP,VDDN Supply Voltage Input Voltage Drain-Source On-state Resistance (Low-side) Drain-Source On-state Resistance (High-side) Operating Current (Standby) Operating Current (No signal input) Startup Time (Ta=25C, VDD= VDDL= VDDR=5.0V, Input Signal=1kHz, Input Signal Level=200mVrms, Frequency Band=20Hz~20kHz, Load Impedance=4, LC Filter(L=10H, C=1F) CONDITIONS SYMBOL MIN TYP MAX UNIT OUTLP-VDDL,OUT LN-VDDL OUTRP-VDDR,OUT RN-VDDR VDD1 2.7 5.0 5.25 With Schottky barrier diode V OUTLP-VDDL,OUT LN-VDDL OUTRP-VDDR,OUT RN-VDDR VDD2 2.7 4.5 Without Schottky barrier diode VIH 0.7VDD VDD V MUTEb,STBYb VIL 0 0.3VDD V OUTLP=0.01V,OUTLN=0.01V OUTRP=0.01V,OUTRN=0.01V RDSL - 0.4 - OUTLP=VDDL-0.01V,OUTLN=VDDL-0.01V OUTRP=VDDR-0.01V,OUTRN=VDDR-0.01V RDSH - 0.4 - - IST - 0.1 1 A No Filter, No Load IDD - 7.5 10 mA 180 35 280 22.9 360 1 50 25 - ms MUTEb=L TON INRP,INLP RINP Input Resistance INRN,INLN RINN MUTEb,STBYb=5V or 0V ILK Input Leakage INRP,INLP=5V or 0V ILKP Current ILKN INRN,INLN=5V or 0V Voltage Gain No Filter, No Load AV Note 9) Startup Time : It is a time until the output driver is worked from the STBYb ON. Ver.2008-08-27 k A dB -5- NJU8757 (Ta=25C, VDD= VDDL= VDDR=5.0V, Input Signal=1kHz, Input Signal Level=200mVrms, Frequency Band=20Hz~20kHz, Load Impedance=8, LC Filter(L=22H, C=0.47F) PARAMETER CONDITIONS SYMBOL MIN TYP MAX UNIT Output Power Efficiency THD+N=10% Eeff8 87 % THD+N Po=0.5W THD+N8 0.02 % Output Power THD+N=10% Po8 1.5 W/ch S/N A-weight SNR8 83 dB Channel Separation 1kHz Echn8 78 dB Maximum Mute Attenuation 1kHz MAT8 85 dB Noise floor A-weight VN8 200 Vrms (Ta=25C, VDD= VDDL= VDDR=5.0V, Input Signal=1kHz, Input Signal Level=200mVrms, Frequency Band=20Hz~20kHz, Load Impedance=4, LC Filter(L=10H, C=1F) PARAMETER CONDITIONS SYMBOL MIN TYP MAX UNIT Output Power Efficiency THD+N =10% Eeff4 79 % THD+N Po=1W THD+N4 0.02 % Output Power THD+N=10% Po4 2.5 W/ch S/N A-weight SNR4 83 dB Channel Separation 1kHz Echn4 78 dB Maximum Mute Attenuation 1kHz MAT4 85 dB Noise floor A-weight VN4 200 Vrms Note 10) Test system of the output THD+N. The output THD+N is tested in the system shown in Figure1, where a 2nd-order LC LPF and another filter incorporated in an audio analyzer are used. Input Signal NJU8757 2nd-order LC LPF HPF 22Hz NJU8757 Test Board LPF 20kHz (AES17) THD+N Meter Audio Analyzer Figure 1. Output THD+N 2nd-order LPF : Refer to "Typical Application Circuit". Filters : 22Hz HPF + 20kHz LPF(AES17) -6- Ver.2008-08-27 NJU8757 NJU3555 TYPICAL APPLICATION CIRCUIT LC filter 10F 0.1F + RL() 4 8 VDD VSS 10F 1F + Refer to 11DQ04(Nihon Inter) VSSR INLP 2.2F INLN 2.2F INLN 10F + COM INRP INRN 2.2F 2.2F INLP INRP INRN OUTLP NJU8757 VDDR C(F) 1 0.47 Schottky barrier diode VDDL VSSL 10F 1F + L(H) 10 * 22 ** OUTLN OUTRP OUTRN L C L C L C L C RL Speaker RL Speaker Coil of LC filter RL=4 Refer to LQH55DN100M03(muRata) RL=8 Refer to LQH55DN220M03(muRata) MUTEb STBYb Figure2. Ver.2008-08-27 Application Circuit example -7- NJU8757 10F 0.1F + VDD Snubber Circuit VSS 10F 1F + RL[] 4 8 VDDL VSSL VDDR VSSR INLP 2.2F INLN 2.2F INLN 10F + COM INRP INRN 2.2F 2.2F INLP INRP INRN MUTEb STBYb Figure3. NJU8757 10F 1F + OUTLP CC RC OUTLN OUTRP CC RC OUTRN L[H] 10 22 L C L C L C L C C[F] 1 0.47 CS[pF] 220 150 RS[] 1.5 1.5 RL Speaker RL Speaker Recommended parts C RL=4 Refer to LQH55DN100M03(muRata) RL=8 Refer to LQH55DN220M03(muRata) Cs RL=4 Refer to RPE2C1H221J2K1A01B (muRata) RL=8 Refer to RPE2C1H151J2K1A01B (muRata) Application Circuit example Note 11) De-coupling capacitors must be connected between each power supply pin and GND. The capacity value should be adjusted on the application circuit and the operation temperature. It may malfunction if capacity value is small. Note 12) The power supply for VDDL and VDDR require fast driving response performance such as a switching regulator for better THD+N. Note 13) THD+N performance becomes worse by ripple if the capacity of De-coupling capacitor is small. Note 14) The transition time for MUTEb and STBYb signals must be less than 100s. Otherwise, a malfunction may be occurred. Note 15) It is necessary to connect the schottky barrier diode and snubber circuit to OUTLP, OUTLN, OUTRP and OUTRN terminal for terminal protection. (Recommended schottky barrier diode: Reverse Current is less than 10mA under the condition of Ta=150C,VDD=5V and Forward Voltage is about 0.55V under the condition of Ta=25C,IF =1A. Recommended Cs of snubber circuit: temperature compensating type, Rs: rated wattage is more than 1/4W. Note 16) Recommended Coil of LC filter: Rated current is more than 1700mA under the condition of RL=4and more than 800mA under the condition of RL=8 Note 17) The cutoff frequency of the LC filter influences the quality of sound. The Q factor of the LC filter must be less than "1". Otherwise, the operating current increase when the frequency of input signal is closed [CAUTION] The specifications on this databook are only to the cutoff frequency. given for information , without any guarantee Note 18) The above circuit shows only application example and does not as regards either mistakes or omissions. The application circuits in this databook are guarantee the any electrical characteristics. Therefore, please test described only to show representative usages of the product and not intended for the the circuit carefully to fit your application. guarantee or permission of any right including the industrial rights. -8- Ver.2008-08-27 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: NJR: NJU8757V-TE1 NJU8757KN1