NAU8223 3.1W Stereo Filter-Free Class-D Audio Amplifier 1 Description The NAU8223 is a stereo high efficiency filter-free Class-D audio amplifier, which is capable of driving a 4 load with up to 3.1W output power. This device provides chip enable pin with extremely low standby current and fast start-up time of 3.4ms. It has five selectable gain settings (i.e. 0dB, 6dB, 12dB, 18dB and 24dB), which can be controlled by a single gain pin. The NAU8223 is ideal for the portable applications of battery drive, as it has advanced features like 87dB PSRR, 91% efficiency, ultra low quiescent current (i.e. 2.1mA at 3.7V for 2 channels) and superior EMI performance. It has the ability to configure the inputs in either single-ended or differential mode. NAU8223 is available in Miniature QFN-20 package and TSSOP-20 package. Key Features Low Quiescent Current: * 2.1mA at 3.7V for 2 channels * 3.2mA at 5V for 2 channels 5 Selectable Gain Settings: * 0dB / 6dB / 12dB / 18dB / 24dB Powerful Stereo Class-D Amplifier: * 2ch x 3.1W (4 @ 5V, 10% THD+N) * 2ch x 1.26W (4 @ 3.7V, 1% THD+N) * 2ch x 1.76W (8 @ 5V, 10% THD+N) * 2ch x 0.76W (8 @ 3.7V, 1% THD+N) Low Output Noise: 20 VRMS @0dB gain 87dB PSRR @217Hz Low Current Shutdown Mode Click-and Pop Suppression Applications Notebooks / Tablet PCs Personal Media Players / Portable TVs MP3 Players Portable Game Players Digital Camcorders Figure 1: NAU8223Block Diagram NAU8223 Datasheet Rev 1.3 Page 1 of 23 July, 2012 2 Pinout 2.1 NAU8223 QFN 20 (TOP VIEW) NAU8223Datasheet Rev 1.4 Page 2 of 23 August, 2013 2.2 TSSOP 20 (TOP VIEW) NAU8223Datasheet Rev 1.4 Part Number Dimension Package Package Material NAU8223YG 4mm x 4mm QFN-20 Pb-Free NAU8223WG 4.4mm x 6.5mm TSSOP-20 Pb-Free Page 3 of 23 August, 2013 3 Pin Descriptions QFN TSSOP Name Type 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 9 10 11 12 13 14 15 16 17 18 19 20 1 2 3 4 5 6 7 8 - OUTRP VDD NC EN INR IPR GS VDD VSS IPL INL NC NC VDD OUTLP VSS OUTLN VDD OUTRN VSS Ex-Pad Analog Output Supply NC Digital Input Analog Input Analog Input Analog Input Supply Supply Analog Input Analog Input NC NC Supply Analog Output Supply Analog Output Supply Analog Output Supply Analog Input Functionality Right Channel Positive BTL Output Power Supply No Connect Chip Enable (High = Enable; Low = PD) Right Channel Negative Input Right Channel Positive Input 5 Selectable Gain Setting (0dB / 6dB / 12dB / 18dB / 24dB) Power Supply Ground Left Channel Positive Input Left Channel Negative Input No Connect No Connect Power Supply Left Channel Positive BTL Output Ground Left Channel Negative BTL Output Power Supply Right Channel Negative BTL Output Ground Thermal Tab (must be connected to VSS, QFN-20 package, only) Notes 1. Pins designated as NC (Not Internally Connected) should be left as no-connection Table 1: NAU8223 Pin description NAU8223Datasheet Rev 1.4 Page 4 of 23 August, 2013 4 Electrical Characteristics Conditions: EN = VDD = 5V, VSS = 0V, Av = 12dB ZL = , Bandwidth = 20Hz to 22kHz, TA = 25 oC Parameter Symbol Comments/Conditions Min Typ Max Units Power Delivered Output Power (per channel) Pout ZL = 4 + 33H THD + N = 10% ZL = 4 + 33H THD + N = 1% ZL = 8 + 68H THD + N = 10% ZL = 8 + 68H THD + N = 1% Parameter Chip Enable (EN) Voltage Enable High Voltage Enable Low Input Leakage Current Thermal and Current Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis Short circuit Threshold Gain Setting Voltage Gain Differential Input Resistance NAU8223Datasheet Rev 1.4 Symbol VEN_H VEN_L VDD = 5.0V VDD = 3.7V VDD = 5.0V VDD = 3.7V VDD = 5.0V VDD = 3.7V VDD = 5.0V VDD = 3.7V Comments/Conditions VDD = 2.5V to 5.5V VDD = 2.5V to 5.5V 3.1 1.57 2.46 1.26 1.76 0.95 1.41 0.76 Min Typ Units 0.4 +1 V V A o 130 15 2.1 ILIMIT RIN Max 1.4 -1 AV W Tie GS to VSS GS Connect VSS through 100k 5% Tie GS pin to VDD GS Connect VDD through 100k 5% Floating Node AV = 24dB AV = 18dB AV = 12dB AV = 6dB AV = 0dB Page 5 of 23 C C A o 24 18 12 6 dB 0 35 70 140 280 558 k August, 2013 Electrical Characteristics (continued) Conditions: EN = VDD = 5V, VSS = 0V, Av = 12dB, ZL = , Bandwidth = 20Hz to 22kHz, TA = 25 oC Parameter Symbol Comments/Conditions Min Typ Max Units Normal Operation Quiescent Current Consumption IQUI Shut Down Current Oscillator Frequency Efficiency Start Up Time Output Offset Voltage Common Mode Rejection Ratio IOFF fOSC Tstart VOS CMRR Click-and-Pop Suppression DC PSRR AC PSRR* Power Supply Rejection Ratio VDD = 3.7V VDD = 5V EN = 0 2.1 3.17 0.1 300 91 3.4 1 80 -72 fIN = 1kHz Into Shutdown (ZL=8) A Weighted VDD = 2.5V to 5.5V VRIPPLE = 0.2Vpp@217Hz** VRIPPLE = 0.2Vpp@1KHz VRIPPLE = 0.2Vpp@10KHz fIN = 1kHz, ZL = 8 + 68H *Measured with 0.1uF capacitor on VDD and Battery supply Symbol Comments/Conditions dBV 98 dB 87 dB 74 54 Channel Crosstalk Parameter 4 mA mA A kHz % msec mV dB -101 dB ** Measured with 2.2uF input capacitor. Min Typ Max Units Noise Performance Av = 0dB (A-weighted) Av = 6dB (A-weighted) Av = 12dB (A-weighted) Av = 18dB (A-weighted) Av = 24dB (A-weighted) 20 21 27 36 52 VRMS The following setup is used to measure the above parameters NAU8223Datasheet Rev 1.4 Page 6 of 23 August, 2013 Absolute Maximum Ratings Condition Min Max Units -0.50 +5.50 V Industrial operating temperature -40 +85 C Storage temperature range -65 +150 C Analog supply CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely influence product reliability and result in failures not covered by warranty. Operating Conditions Condition Symbol Min Typical Max Units Analog supply range VDD 2.50 3.7 5.50 V Ground VSS NAU8223Datasheet Rev 1.4 Page 7 of 23 0 V August, 2013 6 Special Feature Description The NAU8223 offers excellent quantity performance as high efficiency, high output power and low quiescent current. It also provides the following special features. 6.1 Gain Setting The NAU8223 has a GS pin, which can control five selectable gain settings (i.e. 0dB / 6dB / 12dB / 18dB / 24dB). 6.2 GS Pin Configuration Internal Gain (dB) GS tie to VSS 24 GS connect to VSS through 100k 5% resistor 18 GS tie to VDD 12 GS connect to VDD through 100k 5% resistor 6 Floating (open node) 0 Device Protection The NAU8223 includes device protection for three operating scenarios. They are 1. 2. 3. 6.2.1 Thermal Overload Short circuit Supply under voltage Thermal Overload Protection When the device internal junction temperature reaches 130C, the NAU8223 will disable the output drivers. When the device cools down and a safe operating temperature of 115C has been reached for at least about 47mSec, the output drivers will be enabled again. 6.2.2 Short Circuit Protection If a short circuit is detected on any of the pull-up or pull-down devices on the output drivers for at least 14uSec, the output drivers will be disabled for 47mSec. The output drivers will then be enabled again and check for the short circuit. If the short circuit is still present, the output drivers are disabled after 14uSec. This cycle will continue until the short circuit is removed. The short circuit threshold is set at 2.1A. 6.2.3 Supply under Voltage Protection If the supply voltage drops under 2.1V, the output drivers will be disabled while the NAU8223 control circuitry still operates. This will avoid the battery supply to drag down too low before the host processor can safely shut down the devices on the system. If the supply drops further below 1.0v the internal power on reset activated and puts the entire device in power down state. NAU8223Datasheet Rev 1.4 Page 8 of 23 August, 2013 6.3 Power up and Power down Control When the supply voltage ramps up, the internal power on reset circuit gets triggered. At this time all internal circuits will be set to power down state. The device can be enabled by setting the EN pin high. Upon setting the EN pin high, the device will go through an internal power up sequence in order to minimize `pops' on the speaker output. The complete power up sequence will take about 3.4mSec. The device will power down in about 30uSec, when the EN pin is set low. It is important to keep the input signal at zero amplitude or enable the mute condition in order to minimize the `pops' when the EN pin is toggled. . NAU8223Datasheet Rev 1.4 Page 9 of 23 August, 2013 7 Typical Operating Characteristics Conditions: EN = VDD = 5V, VSS = 0V, Av = 12dB, ZL = , Bandwidth = 20Hz to 22kHz, TA = 25 oC, unless otherwise noted Efficiency Vs Output Power (VDD = 3.7V) 100 90 80 70 60 50 40 30 20 10 0 100 90 80 70 60 50 40 30 20 10 0 Efficiency(%) Efficiency(%) Efficiency Vs Output Power (VDD = 5.0V) ZL=4+33uH ZL=8+68uH 0 1 2 3 Output Power(W) ZL=4+ 33uH ZL=8 +68uH 0 4 THD+N vs Frequency (VDD = 3.7V, ZL= 8 + 68uH) 1 1.5 Output Power(W) THD+N vs Frequency (VDD = 4.2V, ZL= 8 + 68uH) 1 1 Pout 0.2W Pout 0.4W 0.1 Pout 0.2W Pout 0.6W THD+N(%) THD+N(%) 0.5 0.01 0.1 0.01 0.001 0.001 20 200 2000 20000 Frequency(Hz) NAU8223Datasheet Rev 1.4 20 200 2000 20000 Frequency(Hz) Page 10 of 23 August, 2013 2 THD+N vs Pout (VDD = 3.7V, ZL = 8 + 68uH) THD+N vs Frequency (VDD = 5V, ZL= 8 + 68uH) 100 Pout 0.2W Pout 1.2W 0.1 f 100Hz f 1kHz f 6kHz 10 THD+N (%) THD+N(%) 1 0.01 1 0.1 0.01 0.001 20 200 2000 0.001 20000 0 Frequency(Hz) 0.5 1 1.5 Pout (W) THD+N vs Pout (VDD = 5V, ZL=8 + 68uH) 100 100 10 10 THD+N (%) THD+N (%) THD+N vs Pout (VDD = 4.2V, ZL= 8 + 68uH) 1 f 100Hz f 1kHz f 6kHz 0.1 0.01 1 f 100Hz f 1kHz f 6kHz 0.1 0.01 0.001 0.001 0 0.5 NAU8223Datasheet Rev 1.4 1 Pout (W) 1.5 2 0 1 2 Pout (W) Page 11 of 23 August, 2013 3 THD+N vs Frequency (VDD = 3.7V, ZL= 4 + 33uH) THD+N vs Frequency (VDD = 4.2V, ZL= 4 + 33uH) 1 1 0.1 THD+N(%) THD+N(%) Pout 0.2W Pout 0.8W 0.01 Pout 0.2W Pout 1W 0.1 0.01 0.001 20 200 2000 20000 0.001 20 Frequency(Hz) 2000 20000 Frequency(Hz) THD+N vs Frequency THD+N vs Pout (VDD = 3.7V, ZL= 4 + 33uH) (VDD = 5V, ZL= 4 + 33uH) 1 100 Pout 1.5W Pout 2W 10 0.1 THD+N (%) THD+N(%) 200 0.01 1 f = 100Hz f = 1kHz f = 6kHz 0.1 0.01 0.001 0.001 20 200 NAU8223Datasheet Rev 1.4 2000 Frequency (Hz) 20000 0 1 2 Pout (W) Page 12 of 23 August, 2013 3 THD+N vs Pout (VDD = 5V, ZL= 4 + 33uH) 100 100 10 10 THD+N (%) THD+N (%) THD+N vs Pout (VDD = 4.2V, ZL= 4 + 33uH) 1 f = 100Hz f = 1kHz f = 6kHz 0.1 1 0.1 0.01 0.01 0.001 0.001 0 1 2 f = 100Hz f = 1kHz f = 6kHz 0 3 1 2 Pout (W) Pout (W) Gain 0dB Gain 6dB Gain 12dB Gain 18dB Gain 24dB Gain vs Frequency 30 25 Crosstalk vs Frequency 0 Left to Right Right to Left -20 Level (dB) 20 Gain (dB) 3 15 10 5 0 -40 -60 -80 -100 -5 -120 -10 20 200 2000 20000 200 2000 20000 Frequency (Hz) Frequency (Hz) NAU8223Datasheet Rev 1.4 20 Page 13 of 23 August, 2013 4 AC PSRR vs Frequency 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 PSRR @Gain 0dB, 1KHz 2.5 3.5 4.5 5.5 PSRR (dB) PSRR (dB) AC PSRR vs Supply Voltage 6.5 PSRR @ Gain 0dB 20 200 2000 20000 Frequency (Hz) Supply Voltage (V) NAU8223Datasheet Rev 1.4 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 Page 14 of 23 August, 2013 SupplyVoltage vs SupplyCurrent 3.5 3 Supply Current(mA) 2.5 2 1.5 1 0.5 0 2.5 NAU8223Datasheet Rev 1.4 3.5 4.5 Supply Voltage (V) 5.5 Page 15 of 23 August, 2013 OUTLP 15 VDD NAU8223 Stereo Class D NC QFN 20-Pin NC 14 INL 11 1 OUTRP 2 VDD 3 NC 4 EN 5 INR VSS 20 VSS 19 OUTRN 18 VDD 17 OUTLN 16 Application diagram 6 8.1 Application Information 13 12 IPR 7 GS 8 VDD 9 VSS 10 IPL 8 P.S. GS Pin - The 100k resistors are optional. GS can be floating for internal gain setting = 0dB. Please refer Section 2.1 (Gain Setting) for the detailed explanation. NAU8223Datasheet Rev 1.4 Page 16 of 23 August, 2013 8.2 Component selection Coupling Capacitors An ac coupling capacitor (Cin) is used to block the dc content from the input source. The input resistance of the amplifier (Rin) together with the Cin will act as a high pass filter. So depending on the required cut off frequency the Cin can be calculated by using the following formula Where is the desired cut off frequency of the High pass filter. Input Cin Amplifier Output Rin(Input Resistance) Bypass Capacitors Bypass capacitors are required to remove the ac ripple on the VDD pins. The value of these capacitors depends on the length of the VDD trace. In most cases, 10uF and 0.1uF are enough to get the good performance. 8.3 Layout considerations The NAU8223 QFN package uses an exposed pad on the bottom side of the package to dissipate excess power from the output drivers. This pad must be soldered carefully to the PCB for proper operation of the NAU8223. This pad is internally connected to Vss. A typical layout is shown below. NAU8223Datasheet Rev 1.4 Page 17 of 23 August, 2013 The PCB has to be designed in such a manner that it should have nine vias in 3x3 grid under NAU8223. The vias should have hole size of 12mil and a spacing of 30mils. The pad size of the vias is 24mils. The vias on the top side of the board should be connected with a copper pour that has an area of 2mm x 2mm, centered underneath the NAU8223. The nine vias should connect to copper pour area on the bottom of the PCB. It is preferred to pour the complete bottom side of the board with Vss. Also good PCB layout and grounding techniques are essential to get the good audio performance. It is better to use low resistance traces as these devices are driving low impedance loads. The resistance of the traces has a significant effect on the output power delivered to the load. In order to dissipate more heat, use wide traces for the power and ground lines. 8.4 Class D without filter The NAU8223 is designed for use without any filter on the output line. That means the outputs can be directly connected to the speaker in the simplest configuration. This type of filter less design is suitable for portable applications where the speaker is very close to the amplifier. In other words, this is preferable in applications where the length of the traces between the speaker and amplifier is short. The following diagram shows this simple configuration. NAU8223 outputs connected to speaker without filter circuit 8.5 Class D with filter In some applications, the shorter trace lengths are not possible because of speaker size limitations and other layout reasons. In these applications, the long traces will cause EMI issues. There are two types of filter circuits available to reduce the EMI effects. These are ferrite bead and LC filters. Ferrite Bead filter The ferrite bead filters are used to reduce the high frequency emissions. The typical circuit diagram is shown in the figure. NAU8223 outputs connected to speaker with Ferrite Bead filter NAU8223Datasheet Rev 1.4 Page 18 of 23 August, 2013 The characteristic of ferrite bead is such that it offers higher impedance at high frequencies. For better EMI performance select ferrite bead which offers highest impedance at high frequencies, so that it will attenuate the signals at higher frequencies. Usually the ferrite beads have low impedance in the audio range, so it will act as a pass through filter in the audio frequency range. LC filter The LC filter is used to suppress the low frequency emissions. The following diagram shows the NAU8223 outputs connected to the speaker with LC filter circuit. RL is the resistance of the speaker coil. NAU8223 outputs connected to speaker with LC filter Standard Low pass LCR filter The following are the equations for the critically damped ( = 0.707) standard low pass LCR filter 2 is the cutoff frequency 0.707 1 2 The L and C values for differential configuration can be calculated by duplicating the single ended configuration values and substituting RL = 2R. NAU8223Datasheet Rev 1.4 Page 19 of 23 August, 2013 8.6 NAU8223 EMI performance The NAU8223 includes a spread spectrum oscillator for reduced EMI. The PWM oscillator frequency typically sweeps in a range of 300 kHz +/- 15 kHz in order to spread the energy of the PWM pulses over a larger frequency band. In addition, slew rate control on the output drivers allows the application of `filter less' loads, while suppressing EMI at high frequencies. The below graph shows the EMI performance of NAU8223 with ferrite beads and speaker cable length of 30cm. NAU8223Datasheet Rev 1.4 Page 20 of 23 August, 2013 9 9.1 Package Dimensions QFN20L 4X4 MM^2, Pitch:0.50 MM TOP VI EW 15 BOTTOM VI EW 11 16 20 1 NAU8223Datasheet Rev 1.4 11 10 10 6 6 5 16 20 5 Page 21 of 23 15 1 August, 2013 9.2 TSSOP20L 4.4X6.5 MM^2, Pitch:0.65 MM NAU8223Datasheet Rev 1.4 Page 22 of 23 August, 2013 10 Ordering Information Nuvoton Part Number Description NAU8223 _G Package Material: G = Pb-free Package Package Type: Y = 20-Pin QFN Package W = 20-Pin TSSOP Package Version History VERSION DATE PAGE DESCRIPTION Preliminary Revision Updated typical characteristics Updated Pin No. Added application diagrams Rev1.0 March, 2012 P.8, P.9 Rev1.1 March, 2012 P.2, P.10 Rev1.2 May, 2012 NA Updated Electrical Characteristics Rev1.3 July, 2012 P.4, P.5, P.10-P.18 Added Application information section Added/Modified Typical operating Characteristics Updated Electrical Characteristics Rev1.4 August, 2013 P.4, P.5, P.22,P.23 Added TSSOP20 Package information section Table 1: Version History Important Notice Nuvoton products are not designed, intended, authorized or warranted for use as components in systems or equipment intended for surgical implantation, atomic energy control instruments, airplane or spaceship instruments, transportation instruments, traffic signal instruments, combustion control instruments, or for other applications intended to support or sustain life. Furthermore, Nuvoton products are not intended for applications wherein failure of Nuvoton products could result or lead to a situation wherein personal injury, death or severe property or environmental damage could occur. Nuvoton customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Nuvoton for any damages resulting from such improper use or sales. NAU8223Datasheet Rev 1.4 Page 23 of 23 August, 2013