LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE LX1725 15W X 2 30W BTL CLASS-D AUDIO AMPLIFIER AN-35 User Information Application Engineer: Jeff Jiang ® TM Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE TABLE OF CONTENTS Key Features & Applications .................................................................................................................3 Block Diagram .......................................................................................................................................4 Output LC Filter Design .........................................................................................................................5 BTL Output With Filter Less ..................................................................................................................6 LX1725 System Configuration...............................................................................................................6 Thermal Design .....................................................................................................................................7 PCB Design Guidelines .........................................................................................................................8 Design of PCB Land Pattern For Package Terminals ...........................................................................8 Exposed Pad PCB Design.....................................................................................................................9 Thermal Pad VIA Design .......................................................................................................................9 Evaluation Kit Quick Guide..................................................................................................................10 Evaluation Kit Schematic............................................................................................................ 11 & 12 Evaluation Boards ...................................................................................................................... 13 & 14 Bill of Materials ........................................................................................................................... 15 & 16 Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE KEY FEATURES 11Wx2 @ 8Ω THD+N<1% | 15Wx2 @ 8Ω THD+N<10% 25W BTL @ 8Ω THD+N<1% 32W BTL @ 8Ω THD+N<10% High Efficiency: >90% @8Ω Full Audio Band: 20Hz~20KHz Low Distortion:<0.1% @1KHz, 8Ω | <0.4% @20~20KHz, 8Ω High Signal-to-Noise Ratio: >85dB non A-Weighted Split/Single Power Supply Wide Supply Voltage Range: ±6V ~ ±15V or 12V ~ 30V Low quiescent current <20mA Turn ON/OFF POP Free STANDBY/MUTE Feature Programmable gain 14/20/26dB Built-in over current Protection Built-in Under Voltage Lockout Thermal shut down Power Limiting Based on Die Temperature (gain fold back) Synchronization APPLICATIONS LCD TV, PDP Sets CD/DVD Combo Player Combo DVD 5.1 Amplifier Home theater system Computer Speaker System Game Machine PART SPECIFIC INFORMATION Part Number Product Description LX1725ILQ -40 to +85 TJ(°C) 32-Pin MLPQ Package 15W + 15W Stereo Class-D Amplifier (Filter less 30W Mono BTL) TABLE 1 – PART INFORMATION IC EVALUATION BOARDS LX1725ILQ LX1725D EVAL Dual Supply Stereo Evaluation Board LX1725ILQ LX1725S EVAL Single Supply Stereo Evaluation Board TABLE 2 – EVALUATION BOARD INFORMATION Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE IC BLOCK DIAGRAM STBY V5V VREF OVP & OTP & UVLO & Reference VPOS VNEG FAULT FLAG SYNC COSC VPOS OSC MASTER High Side Driver Level Shift MUTE INM VCOM - MUTE Mute + INP - ILIMITT + RILIM - + Fault + Timer - - + VREF VPOS VNEG ILIMITB + EAOUT OUT + - VCOM VREF Level Shift VGND Low Side Driver VNEG + - VGND VCOM FB Figure 1 – Simplified Block Diagram Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX1725 CLASS-D AUDIO AMPLIFIER OUTPUT LC FILTER DESIGN Class-D audio amplifiers basically are Pulse width modulation (PWM) amplifiers; these types of amplifier require low pass filtering of the output to demodulate the PWM carrier. Some applications also utilize the filter as a way to achieve an impedance transformation that draws less power supply current than is delivered to the load. These filters can be as simple as a single inductor; to multiple LC nodes depending on the application. In some applications the load will have enough inductance to act as its own filter called filter less configuration which uses the speaker’s own inductance as a low pass filter. PWM filters are normally a low pass configuration, many different types of low pass filters exist. The Butterworth filter (flat response in the pass band and good roll off beyond the cutoff frequency) is the most common filter used in class-D amplifier applications. while the value of the capacitor across the load stays the same. Therefore, from system design the half bridge will save two inductors and capacitors which reduces the system cost and PCB area. Aside from the primary advantage of reduced system cost, the half filter also decreases the quiescent current. In the half bridge filter each output sees the full inductance value, which effectively reduces the rate of change in the inductor current, providing less power loss in the filter. Although this filter attenuates the differential signal, which reduces the magnetic field radiation. Figure 4 is the frequency response based on the different load: Frequency Response at Different Impedance 5 -3 Initial considerations of LC filter design basically includes cut-off corner frequency, usually 1/10 ~ 1/5 of the switching frequency FSW; the poles of filter, which are decided by the bridged supply voltage (supply voltage) and desired voltage ripple cross the load. Normally two pole LC filter is used in the design. Consider deciding the L and C value, there are two types of LC low pass filter: Single-ended and Bridged (Figure 2, 3). 8ohm, Q=0.96 0 Output (dB) APPLICATION INFORMATION APPLICATION NOTE 6ohm, Q=0.72 -5 4ohm, Q=0.48 -10 -15 -20 L=47uF, C=680nF -25 10 50 100 500 1k 5k 10k 50k 100k 20k Frequency (Hz) Figure 4 – Frequency Response at different load Figure 5 shows the Frequency response of different LC values based on 4Ω / 8Ω. 5 L 4ohm L=22µH, C=820nF 0 -3 C Output (dB) -5 Figure 2 – Half bridged LC filter L/2 8ohm L=47µH, C=470nF -10 -15 -20 C -25 L/2 C 10 50 100 500 1k 5k 10k 20k 50k 100k Frequency (Hz) Figure 5 – Frequency at different LC value Figure 3 – Full bridged LC filter For the half bridge LC filter configuration, if the cut-off frequency to remain unchanged (compaired to full bridge); the value of the inductor is doubled Copyright © 2005 Rev. 1.1, 2005-11-04 Suggested impedance: LC value at Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 different speaker Page 5 LX1725 CLASS-D AUDIO AMPLIFIER Table 3 shows best LC value combination for 4Ω, 6Ω, and 8Ω load. Suggested LC value table Speaker (Ω) Inductor (µH) 4 6 8 Capacitor (µF) 22 47 47 Table 3 0.82 0.68 0.47 For Bridge-Tied-Load (BTL) configuration, keep the capacitor value same, and split the inductor L value to half, added on the output stage. BTL OUTPUT WITH FILTER LESS When using the power amplifier in a mono BTL application the inputs of both channels must be connected in parallel and the phase of one of the inputs must be inverted. In principle the loudspeaker can be connected between the outputs of the two single-ended demodulation filters. Also the LX1725 output stage is configured as a filter less push-pull driver. With zero input voltage, the duty cycle at each output is around 50% and the signals are in-phase with each other. In this case, there is basically no differential voltage across the speaker. When the input signal goes positive, the duty cycle at OUT1 increases above 50% and the duty cycle at OUT2 decreases below 50%. This causes a net positive current to flow into the speaker. A negative input voltage causes the OUT2 duty cycle to increase and the OUT1 duty cycle to decrease, which causes a net negative current to flow into the speaker. The differential voltage across the speaker has a fundamental frequency of twice the switching frequency. The speaker itself serves as the low pass filter, which then recreates the audio signal. This type of modulation can be described as driving VPOS-VNEG, VNEG and VNEG-VPOS across the speaker, which is why it is referred to as 3-Level modulation. The filter can be completely eliminated if the speaker is inductive at the switching frequency. The main trade off to eliminating the filter is that the power from the switching waveform is dissipated in the speaker, which leads to a higher quiescent current, IQQ. The speaker is both resistive and reactive, whereas an LC filter is almost purely reactive. The switching waveform, driven directly into the speaker, may damage the speaker, however this is not as significant because the speaker cone movement is proportional to 1/f2 for frequencies Copyright © 2005 Rev. 1.1, 2005-11-04 APPLICATION NOTE beyond the audio band. Therefore, the amount of cone movement at the switching frequency is insignificant. But damage could occur to the speaker if the voice coil is not designed to handle the additional power. Eliminating the filter also causes the amplifier to radiate EMI from the wires connecting the amplifier to the speaker. Therefore, the filter less application is not recommended for EMI sensitive applications, or long speaker wire application. LX1725 SYSTEM CONFIGURATIONS The power supply of LX1725 can be dual or single supply with supply voltage range: ±6V ~ ±15V dual or 12V ~ 30V single. So there are 4 different system configurations: Split Supply / Stereo, Split Supply / BTL, Single Supply / Stereo and Single Supply / BTL. The dual supplies condition is very simple, just connect “VPOS” to positive supply, “VNEG” to negative supply and “VCOM” connected to GND. For the single supply condition, the “VCOM” voltage must be half of VPOS for device internal reference and feedback, you can either use a zener diode to climb the VPOS down to the half if the “VPOS” voltage is fixed (Figure 6). 24V R1 VCOM C1 + D1 Figure 6 – VCOM voltage generation circuit (zener) D1 is a 12V zener diode, R1 is for limiting the current through the zener diode, C1 is a bypassing capacitor to eliminate any ripple on the VCOM, it also can be useful for “de-pop” when the system used for stereo configuration or a pair of resistors also can be used for voltage divider to divide the POS into half to feed into VCOM. Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE C1 in Figure 7 is VCOM slow start-up control capacitor, its value should be calculated as: VPOS R2 C1 > (RL x C) / R1 VCOM C1 RL – Speaker load impedance; R C – The AC coupling capacitor value; R1 – VCOM current limit resistor; Figure 7 – VCOM Voltage Generate Circuit (Resistor) VPOS When LX1725 is used as single supply stereo mode, a AC coupling capacitor must be added in series with speaker to cancel the DC offset caused by VCOM (Figure 8). MUTE VCOM OUT C13 POR + L1 0~50% Figure 9 – VCOM start up time sequence THERMAL DESIGN Thermal Protection C18 LX1725 has thermal gain fold back (power limiting) and shuts down depended on the junction temperature as described in “Function Description” on Page 11. Heatsink Requirement Calculation: To calculate the heatsink thermal resistance requirement, the following equation maybe used: Figure 8 – Single-supply half-bridge output In this configuration, the output will give a higher cut-off corner frequency in the lower frequency response than dual supply because that AC coupling capacitor, the corner frequency calculation as: R TH(J − A) = TJ(MAX) − TA PDISS where: TJ(MAX) = 150°C is the maximum junction temperature which can not be exceeded. F = 1/2πRLC Pdiss depends on the LX1725 efficiency (η), RL – Speaker load impedance; for example: C – The AC coupling capacitor value; Because usually the AC coupling capacitor value is quite big (normally 220µF ~ 4700µF) for obtaining a lower frequency response, this will cause another problem – turn ON/OFF “POP” noise due to the slow discharge of the capacitor. Slow charge the capacitor is one of the approaches to cancel this “POP” noise, basically the VCOM start slowly up to half of VPOS to make the output duty cycle slowly start from zero to 50% (Figure 9). When the AC coupling capacitor charge time is slower than its discharge time, there will not be discharge at all, the “POP” noise will be gone. Copyright © 2005 Rev. 1.1, 2005-11-04 POUT = 10W+10W into 8Ω speaker, η = 90%, TA = 70°C So, Pdiss = 20W x (1/0.9-1) = 2.2W RTH(j-a) = (150-70) / 2.2 = 36.4°C/W From the thermal resistance of LX1725 on Page 2, Θja = 30.7°C/W < RTH(j-a) So, no extra heatsink required. POUT=15W+15W into 4Ω speaker, η = 82%, TA = 70°C So, Pdiss = 30W x (1/0.82-1) = 6.6W Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 LX1725 CLASS-D AUDIO AMPLIFIER RTH(j-a) = (150-70) / 6.6 = 12.1°C/W From the thermal resistance of LX1725 on Page 2, Θja = 30.7°C/W > RTH(j-a) So, extra heatsink with at least 12.1°C/W thermal resistance required. Thermal Considerations This calculation shows that the LX1725 can drive 10 W of continuous RMS power per channel into an 8-Ω speaker up an ambient temperature of 70°C without extra heatsink required. Take a comparison of 2-layer PCB vs. 4-layer PCB. the 2–layer PCB layout was tightly controlled with a fixed amount of 2 oz. copper on the bottom layer of the PCB. 25 thermal vias of 13 mil (0.33mm) diameter were drilled under the PowerPad and connected to the bottom layer. The top layer only consisted of traces for signal routing. A 1.0in x 1.0 in square 2 oz. Copper can give you about 27 C/W thermal resistance. Since for 2-layer board, there are some traces also run on the bottom layer, you can not expect laying a big square of copper area, 27°C/W is enough thermal resistance for LX1725 drive two 8ohm speakers. If 4Ω speakers are driven, because of higher power dispassion (described above), a at least 12°C/W heatsink is needed (Figure 10). The 4–layer PCB layout was also tightly controlled with a fixed amount of 2 oz. copper in middle VNEG or GND layer (depended on the dual supply or single supply configuration). The top layer only consisted of traces for signal routing. The middle layers were left blank. 25 thermal vias of 13 mils (0.33mm) diameter were drilled under the PowerPad and connected to the middle layers (Figure 11). Exposed PAD LX1725 Via holes PCB TOP APPLICATION NOTE to enhance capability. the package power dispassion PCB DESIGN GUIDELINES One of the key efforts in implementing the MLP package on a pc board is the design of the land pattern. The MLP has rectangular metallized terminals exposed on the bottom surface of the package body. Electrical and mechanical connection between the component and the pc board is made by screen printing solder paste on the pc board and reflowing the paste after placement. To guarantee reliable solder joints it is essential to design the land pattern to the MLP terminal pattern, exposed PAD and Thermal PAD via. There are two basic designs for PCB land pads for the MLP: Copper Defined style (also known as Non Solder Mask Defined (NSMD)) and the Solder Mask Defined style (SMD). The industry has had some debate of the merits of both styles of land pads, and although we recommend the Copper Defined style land pad (NSMD), both styles are acceptable for use with the MLP package. NSMD pads are recommended over SMD pads due to the tighter tolerance on copper etching than solder masking. NSDM by definition also provides a larger copper pad area and allows the solder to anchor to the edges of the copper pads thus providing improved solder joint reliability. DESIGN OF PCB LAND PATTERN FOR PACKAGE TERMINALS As a general rule, the PCB lead finger pad (Y) should be designed 0.2-0.5mm longer than the package terminal length for good filleting. The pad length should extended 0.05mm towards the centerline of the package. The pad width (X) should be a minimum 0.05mm wider than the package terminal width (0.025mm per side), refer to figure 11. However, the pad width is reduced to the width of the component terminal for lead pitches below 0.65mm. This is done to minimize the risk of solder bridging. PCB Bottom Heatsink (option) Part Figure 10 – 2-Layer PCB thermal design The 4-Layer PCB’s middle layers act as a heatsink copper, A 3in x 3in square copper can give close to 20°C/W thermal resistance, could cover 3W power dispassion which allows almost 30W output power. Since there are no traces running in the middle layers, you can lay as big metal copper for heatsink as you can (of cause limited by PCB size) Copyright © 2005 Rev. 1.1, 2005-11-04 Part Lead 0.05mm Y2 Solder PCB Pad PCB 0.20mm Y1 (X1) Min: 0.025mm Per side for lead pitches > 0.65mm Figure 11 – PC Board Land Pattern Geometry for MLP Terminals Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE EXPOSED PAD PCB DESIGN ~0.85mm The construction of the Exposed Pad MLP enables enhanced thermal and electrical characteristics. In order to take full advantage of this feature the exposed pad must be physically connected to the PCB substrate with solder. The thermal pad (D2th) should be greater than D2 of the MLP whenever possible, however adequate clearance (Cpl > 0.15mm) must be met to prevent solder bridging. If this clearance cannot be met, then D2th should be reduced in area. The formula would be: D2TH >D2 only if D2TH < Gmin - (2 x Cpl). ~0.025mm ~0.355mm D2th ~5.15mm 1.2mm Gmin ~6.00mm 0.305mm Ø 0.3mm THERMAL PAD VIA DESIGN There are two types of on-board thermal PAD design, one is using thermal vias to sink the heat to the other layer with metal traces. Based on Jedec Specification JESD 51-5, the thermal vias should be designed like 12. Another one is the no via thermal PAD which is using the same side copper PAD as heatsink, this type of thermal PAD is good for two layer board, since the bottom side is filled with all other kinds of trace also, it’s hard to use the whole plane for the heatsink. But you still can use vias to sink the heat to the bottom layer by the metal traces, then layout a NMSD on which a metal heatsink is put to sink the heat to the air. Micro Lead Quad Package Land Pattern Zmin ~7.45mm 5.00mm Figure 13 – Recommended Land Pad with Vias for LQ32 (7mm²) Zmin= D + aaa + 2(0.2) (where pkg body tolerance aaa=0.15) (where 0.2 is outer pad extension) Gmin= D-2(Lmax)-2(0.05) (where 0.05 is inner pad extension) (Lmax=0.50 for this example) D2th max = Gmin-2(CpL) (where CpL=0.2) Land Pattern for Four Layer Board with Vias Figure 12 – Comparison of land pattern theory For LX1701 with MLPQ-4x4 16Lds package, which has ΘJA =38.1°C/W by package itself, with maximum 2W (@4Ω) output it only has 300mW power dispassion (assuming 85% efficiency), which only has 11.4°C temperature rise. So the non-via type thermal PAD is suggested. Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 9 LX1725 CLASS-D AUDIO AMPLIFIER 4. Standby Selection: JP5 is the jumper selection for standby. Close to “STBY” will force the evaluation board into the zero current mode. EVALUATION KIT QUICK GUIDE PCB DESIGN GUIDELINES The LX1725 Evaluation Board is a fully functional stereo class-D amplifier with dual or single-supply, simply connected to power supply, two speakers and any audio input sources, you can start evaluating the amplifier right way. Board Settings: 1. Power and Ground Connections: The terminal TB3 is for the power supply connection. For dual supply version (LX1725D), VPOS is connected to the positive polarity of the power supply (6V ~ 15V), VNEG is connected to the negative polarity of the power supply (-6V ~ -15V) and V5V is simply connected to a 5V supply, the GND is connected to the ground of the power supply. For single supply version (LX1725S), VPOS is connected to the positive polarity of the power supply or battery (12V ~ 30V), V5V is simply connected to a 5V supply, the GND is connected to the negative polarity of the power supply or battery. 2. Speaker Connections: TB1 and TB2 are the speaker outputs. TB1 is for the CH1 output and TB2 is for CH2 output. Connect speaker “+” and “-“ to “OUT1+ / OUT2+” and “OUT2- / OUT2-“ of TB1 / TB2. For the BTL (Bridged-Tied-Load) configuration, just simply connect the speaker “+” to “OUT1+” of TB1 and connect the speaker “-” to “OUT2-” of TB2. Please pay attention that this evaluation board is designed for the maximum power 30W, so 8ohm load is suggested for BTL configuration under full rail of supply voltage, if 4Ω load is applied, 18V (±9V) rail supply voltage is suggested. 3. Audio input connections: J1, J2 and RCA1, RCA2 (only for 2-layer board) are the audio input connections, simply apply positive of audio source into “IN1+ / IN2+” and negative into “IN1- / IN2-”. When audio inputs are differential, the header connectors (J1 and J2) are suggested. JP1 and JP2 jumpers are the option for input signal grounding if the input has different ground with the evaluation board (for example, the battery operated audio device), default is “OPEN”. Copyright © 2005 Rev. 1.1, 2005-11-04 APPLICATION NOTE 5. “Master/Slave” selections: JP6 is a selection for “MNORMAL” (Master Normal), “MQUICK” (Master Quick start for production test purpose), “SQUICK” (Slave Quick start for production test purpose), “SNORMAL” (Slave Normal) 4 different combinations. Default is “MNORMAL”, “SNORMAL” is for synchronization application, please refer to “Function Description” on Page 10. 6. “MUTE / GAIN” Selection: JP7 is a multilevel jumper selection for “MUTE” and 14/20dB gain switch, default is 20dB. One thing must be paid attention, the “MUTE” and “STBY” start up sequence is very important for the turn ON/OFF “POP” noise, maybe you can hear the “POP” noise when you turn ON / OFF the board because there is no timing sequence circuit on the board. You should close the jumper to “MUTE” of JP7 and “STBY” of JP5 when you turn the power supply, then close to “NORMAL” of JP5 to enable the system, final remove the “MUTE” of JP7, to eliminate the “POP” noise. 7. “SYNC / FLAG”: “SYNC” is used for synchronization of multi devices (refer to “Function Description on Page 10.), “FLAG” is the system mode indicator, indication the system fault conditions, logic level output, can be applied to any logic level controlled device to make the further actions. 8. “Filterless”: “Filterless” can only be used for BTL output configuration, applied for both dual supply and single supply conditions. Simply short the L1/L2 and remove the C18/C19 to drive the speaker directly. Aslo, tie “IN1+” with “IN2+” and “IN1-“ with “IN2-“. BTL configuration refers to “Board Settings” 2. Speaker Connections on this page. 9. “High Gain” Mode. Which give (default is open) you 0dB extra gain. If the jumper is closed to “+6dB” position it will boost gain output by 6dB. Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 10 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE EVALUATION KIT SCHEMATIC DUAL SUPPLY R110 10K V5V C7 1µF 35V IN1IN1+ V5V C8 1µF 35V C6 0.1µF 35V SYNC SYNC FLAG FLAG R1 50K C12 1µF 35V C101 0.1µF 35V C11 220pF VPOS1 STBY C103 10µF 35V RILIM C18 0.68µF 50V VNEG1 Part LX1725 VNEG VNEG2 VREF OUT2 COSC VPOS2 C19 0.68µF 50V L2 47µH C15 0.1µF 35V OUT2+ OUT2- C106 10µF 35V MASTER MASTER MUTE VGND VNEGA OUTREF2 IN2P IN2N EAOUT2P VNEGA VPOS C9 1µF 35V IN2IN2+ C10 1µF 35V VNEGA V5V MUTE V5V C5 10µF 35V V5V GND_SIGNAL R103 6K 1% VPOS VPOS PGND VNEG OUT1+ OUT1- L1 47µH C14 0.1µF 35V OUT1 EAOUT2N VNEG VPOS STBY VCOMA C100 0.1µF 35V V5V AGND VCOM V5V HIGAIN OUTREF1 EAOUT1N EAOUT1P VPOSA VPOS JP2 Jumper IN1N IN1P JP1 Jumper C1 470µF 35V C2 470µF 35V R105 4K 1% R104 5K 1% MUTE MNORMAL MASTER MQUICK 20dB SQUICK C3 0.1µF 35V R107 6K 1% MUTE 14dB R106 3K 1% SNORMAL C4 0.1µF 35V VNEG V5V R102 10K OPTION V5V FLAG SYNC R101 10K OPTION FLAG SYNC STBY SW1 SPDT Note: This is a typical a 8Ω load design. Other than 8Ω please refer to “Table 3” on page 6 to change L.C. value. Figure 14 – Application Schematic (Stereo, Split Supply) Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 11 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE EVALUATION KIT SCHEMATIC SINGLE SUPPLY R118 10K V5V C7 1µF 35V IN1IN1+ VCOM V5V C8 1µF 35V C6 0.1µF 35V VCOM VPOS VCOM V5V HIGAIN OUTREF1 EAOUT1N VPOSA EAOUT1P R108 0Ω OPTION IN1N IN1P JP1 Jumper STBY VCOMA C100 0.1µF 35V VCOM SYNC SYNC FLAG FLAG R1 50K C12 1µF 35V C11 220pF OUT2 COSC VPOS2 R121 10K C15 0.1µF 35V C106 10µF 35V MASTER MUTE VGND VNEGA IN2P IN2N OUTREF2 MASTER L2 47µH C19 0.68µF 50V OUT2+ OUT2- C16 470µF 50V R122 10K VPOS R110 1.2K 1/2W OPTION V5V R112 51K R101 10K OPTION VCOM V5V MUTE C17 47µF 50V R111 1K 1/2W OPTION V5V C5 10µF 35V D104 1N5242 STBY SW1 SPDT V5V GND_SIGNAL R103 6K 1% VPOS VPOS PGND PGND OUT1+ OUT1- VPOS C9 1µF 35V C10 1µF 35V C13 470µF 50V C18 0.68µF 50V R120 10K VNEG2 VREF VCOM V5V AGND C14 0.1µF 35V VNEG1 Part LX1725 RILIM VNEGA IN2IN2+ L1 47µF OUT1 EAOUT2P C101 0.1µF 35V STBY VPOS1 EAOUT2N JP2 Jumper VPOS R119 10K C103 10µF 35V C1 100µF 35V C3 0.1µF 35V R105 4K 1% R104 5K 1% MNORMAL SNORMAL MUTE 14dB MQUICK SQUICK R107 6K 1% MUTE MASTER 20dB R106 3K 1% R102 10K OPTION V5V FLAG SYNC FLAG Note: This is a typical 8Ω load design. Other than 8Ω load, please refer to “Table 3” on page 6 to change L.C. value. SYNC Figure 15 – Application Schematic (Stereo, Single Supply) Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 12 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE LX1725 EVALUATION BOARDS DUAL SUPPLY Figure 16 Bottom Layer Top Layer Inner Layer 2 Inner Layer 3 Bottom Silk Top Silk Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 13 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE LX1725 EVALUATION BOARDS (CONTINUED) SINGLE SUPPLY Figure 17 Bottom Layer Top Layer Inner Layer 2 Inner Layer 3 Bottom Silk Top Silk Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 14 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE LX1725D (DUAL SUPPLY) BILL OF MATERIALS 1 MISCELLANEOUS COMPONENTS Line Item Part Description Manufacturer & Part # 1 2 Stereo Class-D 20W Amplifier IC Inductor, 47µH MICROSEMI ISI LX1725CLQ RL622-470K 3 Header 2pin, .100” AMP 87220-2 4 5 6 7 8 9 Header 3pin .100” Header, Double Row, .100” 3x2 Header, Double Row, .100” 4x2 Shorting Jumpers SWT MS Toggle SPDT 3P 10TA810 PCB AMP AMP AMP 3M MOUNTAIN SWT MSC-IP 87220-3 Case MLPQ 929955-06 10TA810 ESG1725X3D4L Reference Designators U1 L1, L2 J1, J2, J3, JP1, JP2, TP1, TP2, TP4 JP8, TP3 JP7 JP6 JP6, JP7 SW1 Qty 1 2 8 2 1 1 2 1 1 CAPACITORS Line Item Part Description 1 Capacitor, Elect, VZ, 470µF, 25V 10x13 PANASONIC UVZ1E471MPD 2 Capacitor, Elect, VS 10µF, 35V PANASONIC ECE-V1VA100WR SMD 3 Capacitor, 0.1µF, 50V TDK C2012X7R1H104M 0805 4 5 6 Capacitor, 1µF, 50V Capacitor, 200pF, 50V Capacitor, 680nF, 25V TDK AVX VENKEL C3216X7R1C105M 06035A221JAT2A C1206X7R250-68KNE 1206 0603 1206 Part Description Case Reference Designators C1, C2 C5 C103, C106 C3, C4, C6, C12, C14, C15, C100, C101 C7, C8, C9, C10 C11 C18, C19 Qty 2 3 8 4 1 2 RESISTORS Line Item 1 2 3 4 5 6 Part Description Resistor, 3K, 1% Resistor, 4K, 1% Resistor, 5K, 1% Resistor, 6.04K, 1% Resistor, 10K, 5% Resistor, 50K, 5% Part Description SAMSUNG SAMSUNG SAMSUNG SAMSUNG SAMSUNG SAMSUNG RC1608F3001CS RC1608F4001CS RC1608F5001CS RC1608F6041CS RC1608J103CS RC1608J503CS Case Reference Designators Qty 0603 0603 0603 0603 0603 0603 R106 R105 R104 R103, R107 R101, R102, R110 R1 1 1 1 2 3 1 Orange Highlighted components for Test purpose only. Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 15 LX1725 CLASS-D AUDIO AMPLIFIER APPLICATION NOTE LX1725S (SINGLE SUPPLY) BILL OF MATERIALS 1 MISCELLANEOUS COMPONENTS Line Item Part Description Manufacturer & Part # 1 2 3 Stereo Class-D 20W Amplifier IC Inductor, 47µH SWT, SPDT 3P STD MICROSEMI ISI MOUNTAIN SWT LX1725CLQ RL622-470K MS 24L244 4 Header 2pin, .100” AMP 87220-2 5 6 7 8 9 Header 3pin .100” Header, Double Row, .100” 3x2 Header, Double Row, .100” 4x2 Shorting Jumpers PCB AMP AMP AMP 3M 87220-3 Case MLPQ 929955-06 Reference Designators U1 L1, L2 SW1 TB1, TB2, TB4, J1, J2, J3, JP1, JP2 TB3, JP8 JP7 JP6 JP6, JP7 Qty 1 2 1 8 2 1 1 2 Microsemi CAPACITORS Line Item Part Description Part Description Case 1 Capacitor, Elect, VS, 10µF 35V PANASONIC ECE-V1VA100WR SMD 2 Capacitor, 0.1µF, 50V TDK C2012X7RH104M 0805 3 4 5 6 7 8 Capacitor, 1µF, 50V Capacitor, 1000µF, 35V 12.5x25 Capacitor, 220pF, 50V Capacitor, 680nF, 25V Capacitor, ELEC VZ, 470µF, 25V, 13x10 Capacitor, 47µF, 35V, 5x11 TDK NICHICON AVX VENKEL NICHICON PANASONIC C3216X7R1C105M UVZ1H102MHH 06035A221JAT2A C1206X7R250-684KNE UVZ1E471MPD UVR1V470MDD 1206 0603 1206 Reference Designators C5, C103, C106 C3, C6, C12, C14, C15, C100, C101 C7, C8, C9, C10 C1 C11 C18, C19 C13, C16 C17, Qty 3 7 4 1 1 2 2 1 RESISTORS Line Item Part Description Part Description Case 1 2 3 4 5 Resistor, 0Ω, 5% Resistor, 3K, 1% Resistor, 4K, 1% Resistor, 5K, 1% Resistor, 6K, 1% SAMSUNG SAMSUNG SAMSUNG SAMSUNG SAMSUNG RC1608J000CS RC1608F3001CS RC1608F4001CS RC1608F5001CS RC1608F6001CS 0603 0603 0603 0603 0603 6 Resistor, 10K, 5% SAMSUNG RC1608J103CS 0603 7 Resistor, 50K, 5% Resistor, 1K, 5% CRCW2010-1KJNT1 9 Resistor SAMSUNG DALE NA RC1608J503CS 8 Reference Designators Qty 1 1 1 1 2 0603 R108 R106 R105 R104 R103, R107 R101, R102, R118, R119, R120, R121, R122 R1 2010 R110, R111 2 R112 1 7 1 Orange Highlighted components for Test purpose only. Copyright © 2005 Rev. 1.1, 2005-11-04 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 16