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LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 Copyright  2000 Rev. 1.1, 2000-12-01 /G09/G0A /G0D /G09 /G09/G09 /G0A A MICROSEMI COMPANY

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 Copyright  2000 Rev. 1.1, 2000-12-01 INTRODUCING LX1710/1711 AUDIO MAX Thank you for your interest in the latest generation of AudioMAX products. The enclosed LXE1710 evaluation board is a fully functional mono amplifier designed to demonstrate the “new and improved” Switching Class-D Power Amplifier IC from Linfinity Microsemi. The LX1710/1711 is a completely new controller design with superior performance over the LX1720 stereo controller IC. Key improvements include better SNR, lower noise floor, and reduced THD therefore resulting in a much “quieter” and “cleaner” sounding amplifier. The evaluation board has been configured with easy-to-use terminal block connections for power supply/battery hook up and speaker connections. An RCA jack or separate audio +/- pins allow a quick interface to your audio source. Jumpers are also provided to enable/disable the amplifier (Sleep control) and to turn off the audio input (Mute control). With minimal setup, the user can be listening to the amplifier in a matter of a few minutes. Both the LX1710 and LX1711 operate from a single supply voltage. The LXE1710 evaluation board can /G01/G02/G02/G03/G04/G04/G03/G05/G01/G06/G07 /G01 /G09/G0A/G0B/G0B/G0C/G0D /G0E/G03/G0C/G06/G01/G0F/G07 /G10/G11/G03/G04 /G12/G13 /G06/G03 /G14/G15/G13 /G16/G17/G18/G02/G17 /G0B/G11/G03/G05/G0A/G02/G07/G09 /G19/G15/G1A /G18/G1B/G06/G03 /G1C/G1D /G01/G1B/G05 /G0F/G11/G07/G01/G06/G07/G11 /G06/G17/G01/G1B /G1E/G1F/G1A /G18/G1B/G06/G03 /G19/G1D/G20/G21/G17 e LX1711 can handle a higher supply voltage (7V to 25V) and provides greater than 50W continuous output power /G18/G1B/G06/G03 /G1C/G1D/G20/G21/G17/G07 /G07/G0E/G01/G0C/G0A/G01/G06/G18/G03/G1B /G01/G04/G0B/G0C/G18/G10/G18/G07/G11 /G22/G03/G01/G11/G05 /G17/G01/G09 /G22/G07/G07/G1B /G05/G07/G09/G18/G0F/G1B/G07/G05 /G10/G03/G11 /G01 /G1C/G1D /G0C/G03/G01/G05/G20/G21/G17/G07 /G03/G0A/G06/G0B/G0A/G06 /G10/G18/G0C/G06/G07/G11 /G02/G01/G1B /G22/G07 /G07/G01/G09/G18/G0C/G0D /G04/G03/G05/G18/G10/G18/G07/G05 /G06/G03 change frequency response for other load optimization. Thank you again for your interest in the new “quieter”, high efficiency Class-D Audio Amplifier from Linfinity Microsemi. Please let us know what you think and stay tuned for future product releases to our AudioMAX family of products. Regards, Linfinity Microsemi http://www.linfinity.com (714) 898-8121

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 Copyright  2000 Rev. 1.1, 2000-12-01 TABLE OF C ONTENTS Input Compensation Output Stage Filter Stage

Application Information

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 Copyright  2000 Rev. 1.1, 2000-12-01 Part Number Product Description LX1710CDB AudioMAX High Fidelity Controller IC VDD = 7V to 15V, Switching Class-D Mono Power Amplifier IC, 28-Pin SSOP Package. LX1711CDB AudioMAX High Power Controller IC VDD = 7V to 25V, Switching Class-D Mono Power Amplifier IC, 28-Pin SSOP Package. LXE1710 LX1710 AudioMAX Evaluation Board Fully Operational Mono Audio Amplifier. LX1710/1711 AUDIO MAX E VALUATION B OARD FEATURES AND C IRCUIT D ESCRIPTION

• Fully Assembled Mono Evaluation Board with LX1710 Class-D Controller IC
• Improved SNR and Noise Floor Performance
• Output Power of 25W typical (LX1710, 15VDD , /G01/G02/G03 /G05/G06 /G07/G08/G09/G0A/G0B/G0C
• Output Power of 54W typical (LX1711, 25VDD , /G01/G02/G03 /G05/G06 /G07/G08/G09/G0A/G0B/G0C
• Supports Full Audio Bandwidth
• /G0D/G0E/G0F/G10/G11/G10/G12/G13/G14 /G0F/G15 /G09/G16/G10/G17/G13 /G01/G02 /G18/G0E/G13/G19/G1A/G13/G16 /G1B/G15/G19/G14
• Terminal Block Connectors for Supply Voltage and Speaker Connection
• RCA Plug for Audio Input Signal The AudioMAX Evaluation Amplifier Board allows the user to quickly connect and evaluate the LX1710 Switching Class-D Mono Controller IC. Easy-to- connect terminal blocks and an RCA plug are provided for interfacing to Power, Speaker, and Audio Input connections. The single stage output filter has been configured to drive a 4/G02 /G1C/G15/G19/G14 /G19/G1D/G14 /G1E/G1F/G0E/G0E/G15/G16/G0F /G20/G1F/G1C/G1C audio bandwidth amplification (See Application section LC filter design for component selection, calculations, and suggested inductor and capacitor values for other loads). The LXE1710 Evaluation Board operates from a single supply voltage. The Class-D Amplifier Controller IC requires a minimal number of external components to create a complete amplifier solution. See LXE1710 Evaluation Board Schematic and Bill of Materials for circuit specifics. A Class-D Amplifier is a “switching” amplifier that converts a low-level, analog audio input signal into a high power, pulse-width modulated (PWM) output. The switching frequency (500kHz typical but can be adjusted) is much higher than the audio bandwidth (20Hz to 20kHz), and is easily filtered out with a simple LC filter. The support circuitry can be generally grouped into three areas (input circuit, output power stage, and output filter). I NPUT C OMPENSATION The first group is the compensation network and control setting components. These resistors and capacitors set up the controller operating frequency, response characteristics, and comparator ramp fundamental to Class-D operation. O UTPUT STAGE The next section is the output stage. The controller IC generates a PWM output by controlling external FETs connected in a full bridge configuration. The full bridge configuration is connected between the single supply voltage (PVDD) and ground (PGND) with the output of the bridge driving the LC filter stage. Because the FETs are either fully “on” or fully “off”, Class-D topology is extremely efficient (up to 85% typical), circuit power dissipation is minimal, and maximum power is delivered to the speaker. The bridge output also drives the RC low pass filter, which provides the feedback for the control loop through the FBK+ and FBK- inputs. F ILTER STAGE The single stage, second order LC filter is used to remove the switching frequency. The frequency response and corner frequency can be easily adjusted for optimization of various loads. The LC evaluation board component values have been chosen for a 4/G02 /G1C/G15/G19/G14/G21 /G18/G13/G13 /G1E/G13/G22/G0F/G10/G15/G1D /G15/G1D /G1B/G23 /G20/G10/G1C/G0F/G13/G16 /G14/G13/G1E/G10/G24/G1D for component selection.

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 Copyright  2000 Rev. 1.1, 2000-12-01 Q UICK START G UIDE The LXE1710 Evaluation Board is a fully functional, Class-D Amplifier. Connection to a single supply voltage (VDD from either a battery or power supply), speakers, and your audio source is all that is required to begin evaluating the amplifier and listening to music. The following outlines the necessary connections and control jumpers. 1) Verify contents of Evaluation Kit: The easy-to- use amplifier is all contained on a single board. Visually inspect to see if the board or any components were damaged during shipping. All components are located on the top side of the PCB except for the decoupling capacitor, C17. A copy of the LX1710/1711 Datasheet should also be enclosed or a PDF version can be downloaded from the Microsemi.com website (http://www.microsemi.com/datasheets/MSC1580.PDF). 2) Power and Ground Connections: The voltage supply and ground connections are made through terminal block TB1. Connect your “+” (+7V to +15V) power supply or battery to the +V input of TB1. Connect your supply or battery ground to the GND input of TB1. Please ensure the correct positive and ground connections are made before turning on the power supply. 3) Speaker Connection: The amplifier is designed /G0F/G15 /G14/G16/G10/G17/G13 /G19 /G1E/G10/G1D/G24/G1C/G13 /G01/G02 /G1E/G0E/G13/G19/G1A/G13/G16/G21 /G23/G15/G1D/G1D/G13/G22/G0F /G1E/G0E/G13/G19/G1A/G13/G16 “+” and “-“ to the +OUT and –OUT input of terminal block TB2 respectively. The amplifier can be used to drive other speaker loads but frequency response may not be optimal. See LC filter design section for recommended inductor and capacitor modifications. 4) Audio Input Connection: Connect your audio source to the RCA Jack CN1, Audio In. For other type interfaces, the audio input signal can also be connected to the amplifier board using the J3 (In- and In+) location. Strip Line Plugs can be inserted into J3 for connectivity. 5) Jumper Selection Controls: The “on/off” or enable to the module is controlled with the SLEEP/ signal. Jumper J1 connects the SLEEP/ to “on” or “ off”. SLEEP/ is an active Low control. Jumper J2 connects the MUTE control which enables/disables the audio input to the amplifier. MUTE is an active High signal. See table below. 6) Power Source: If a power supply is being used, make sure it is set to the correct voltage level and turn the power supply on. 7) Audio Source: Make sure the audio source signal is set to a minimum level. Start or “play” audio source and adjust source volume to desired level. 8) Listen to AudioMAX: If the amplifier is not operating properly, verify preceding steps or contact Linfinity for technical assistance (714) 898-8121. Jumper toward OFF Jumper toward ON Jumper floating J1 Jumper: SLEEP/ Amplifier enabled (SLEEP/ is OFF) Amplifier disabled (SLEEP/ is ON) Amplifier disabled (SLEEP/ is ON) J2 Jumper: MUTE Audio Input enabled (MUTE is OFF) Audio Input disabled (MUTE is ON) Audio Input enabled (MUTE is OFF) /G01/G02/G03/G04/G05 /G07/G08 Jumper Settings To Power Supply +V 7V-15V for LX1710 7V-25V for LX1711 To Speaker + To Speaker - To Power Supply Ground Optional Audio In - Optional Audio In + To Audio Source

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 Copyright  2000 Rev. 1.1, 2000-12-01 SCHEMATIC VDD PVDD CP RPWM CPWM VREF V25 GND SLEEP MUTE INAMPOUT INPUT+ INPUT- EAOUT EAIN FAOUT STATUS CLOCK PGND CN FBK+ FBK- IS- R5 34.8K R1 56.2K R2 10K C11 4.7µF 470nF C14 470nF 150pF 18pF R8 10K R9 10K C26 330pF 1µF 1µF C16 100pF MUTE SLEEP V IN7V to 15V C22 .1µF R11 10 ohm 10 ohm R10 10 ohm R12 10 ohm .1µF 50V RS1 .0347C17 220µF 25V C12 .1µF C10 4.7µF R13 15 ohm L1 15µH L2 15µH C20 .68µF C21 .68µF C19 .47µF C18 .47µF 24.3K 220pF 24.3K 220pF LX1710 NC NC AUDIO INPUT NC NC3 0.1µF 35V C13 2.2µF + /G02/G03/G04/G05/G06/G05/G07 – Evaluation Board Schematic

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 Copyright  2000 Rev. 1.1, 2000-12-01 ELECTRICAL C HARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C<TA<70°C. For test circuit, see LXE1710 Evaluation Board Schematic diagram. PARAMETER SYMBOL TEST C ONDITIONS M IN. TYP . M AX U NITS Supply Voltage LX1710 VDD 7 15 V Supply Current IDD VIN=15V, PO =38W, RL/G01/G02/G03/G04 THD+N=1% 3 A Quiescent Current IQ V IN=15V, No Input 43 mA VIN=15V, RL/G01/G06/G03/G04 /G07/G08/G09/G0A/G0B/G01/G0C/G0D/G04 10Hz to 22kHz 14 W VIN=15V, RL/G01/G0E/G03/G04 /G07/G08/G09/G0A/G0B/G01/G0C/G0D/G04 10Hz to 22kHz 25 W Output Power PO VIN=15V, RL/G01/G02/G03/G04 /G07/G08/G09/G0A/G0B/G01/G0C/G0D/G04 10Hz to 22kHz 38 W VIN=15V, fIN=1kHz, PO =10W 82 % Efficiency VIN=15V, fIN=1kHz, PO =20W 85 % fIN=1kHz, PO =1W 0.05 % Total Harmonic Distortion Plus Noise THD+N fIN=20Hz to 20kHz, PO=1W 0.3 % Signal-To-Noise Ratio SNR 81 dBV Power Supply Rejection Ratio PSRR VIN=15V, VRIPPLE =1VRMS , 10Hz to 10kHz -70 dB

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8 Copyright  2000 Rev. 1.1, 2000-12-01 PERFORMANCE G RAPHS /G04/G08/G08/G09/G0A/G09/G04/G0B/G0A/G0C /G0D/G0E/G0F /G10/G11/G12/G13/G11/G04/G08/G08/G09/G0A/G09/G04/G0B/G0A/G0C /G0D/G0E/G0F /G10/G11/G12/G13/G11 /G12 /G13/G10/G14/G04/G15/G12 /G13/G10/G14/G04/G15 /G10/G11/G12/G13/G11/G12 /G13/G10/G14/G04/G15 /G0D/G0E/G0F /G0E/G11/G13/G10/G11/G12/G13/G11/G12 /G13/G10/G14/G04/G15 /G0D/G0E/G0F /G0E/G11/G13 /G13/G02/G0C /G0D/G10/G02/G12/G16/G17/G04/G13/G02/G0C /G0D/G10/G02/G12/G16/G17/G04 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 0 5 10 15 20 25 30 Output Power (W) Efficency (%) /G01/G02 61 1 1 6 2 1 2 6 Supply Voltage (VIN) Output Power (W) VIN = 15V fIN=1kHz RL/G25/G01/G02 THD+N=1% /G08/G15/G04/G18/G11/G04/G0B/G0A/G0C /G15/G04/G0E/G13/G10/G0B/G0E/G04/G08/G15/G04/G18/G11/G04/G0B/G0A/G0C /G15/G04/G0E/G13/G10/G0B/G0E/G04 /G12/G19/G1A/G1B/G0B /G0D/G0E/G0F /G10/G11/G12/G13/G11/G12 /G13/G10/G14/G12/G19/G1A/G1B/G0B /G0D/G0E/G0F /G10/G11/G12/G13/G11/G12 /G13/G10/G14 /G04/G15/G04/G15 -20 +20 -15 -10 +10 +15 -0.08 -0.59 Voltage Amplification (dBr) 10 80k 50 100 200 500 1k 2k 5k 10k 50k 17.88k 18.2 Frequency (Hz) 0.001 100 0.002 0.005 0.01 0.02 0.1 0.5 0.26 0.04 THD + N (%) 50m 30 100m 200m 500m 2 5 10 20 24.56 1.13 Output Power (W) VIN=15V RL/G25/G01/G02 R O =1W RMS VIN=15V fIN=1kHz RL/G25/G01/G02

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 9 Copyright  2000 Rev. 1.1, 2000-12-01 /G07/G08/G09 /G0A /G0B /G17/G1E/G21 /G0D/G1F/G0F/G0E/G1F/G0F /G26/G15/G27/G13/G16 /G28/G01/G02/G03 /G05/G1A/G08/G12/G0C LX1710 Filter Implementation, 1-stage vs. 2- stage 0.001 100 0.002 0.005 0.01 0.02 0.05 0.1 0.2 0.5 0.55626 0.12572 Percent (%) 50m 30 100m 200m 500m 1 2 5 10 20 25.04 1.15 Watts(W) 2-Stage 1-Stage FILTER D ESIGN TRADEOFFS (1-STAGE VS . 2-STAGE ) A 1-stage or 2-stage filter may be used depending on your application and performance targets. The main tradeoff in this selection is price (number of components, component costs, PCB area) vs. performance. The primary advantage of the single stage filter is lower cost whereas the main benefit to a 2-stage filter is that it will provide steeper attenuation. This allows the corner frequency to be selected further outside of the audio band (to minimize the effects of impedance variations in the passband) and still provide adequate RF attenuation. Single Stage Filter Advantages

• Low Cost: The 1-stage LC filter uses one half the number of inductors/capacitors resulting in a substantial cost savings over a 2-stage design. Key parameters such as THD+N, frequency response, and nose performance do not change significantly.
• Power Loss: Since current will flow in two inductors and not four, the inductor power loss will be less in the single stage design. The overall amplifier will have a wider dynamic range and improved efficiency.
• Filter Design: This easy-to-design filter can limit audio signal changes within +/- 3dB across the audio band with impedance vari/G19/G1D/G22/G13 /G20/G16/G15/G11 /G29/G02 /G0F/G15 /G19/G0E/G0E/G16/G15/G2A/G10/G11/G19/G0F/G13/G1C/G2B /G2C/G02/G21 /G09/G1F/G13 /G0F/G15 a steeper rolloff with the 2-stage filter, impedance changes could result in a +/- 6dB change.
• THD: There are minimal differences between the 1-stage and 2-stage implementations with other parameters such as THD+N as seen in the above graph. Single Stage Filter Disadvantages
• EMI and Switching Frequency: For the 1- stage, the switching frequency must be higher than 400kHz to ensure the corner frequency will provide adequate amplifier performance in the high end of the audio frequency range. If f S < 400kHz, then fC < fS /10 = 40kHz which is too close to the desired audio band. A higher oscillation frequency could translate into greater MOSFET switching losses, slightly lower efficiency, and increased EMI effects. With a 2-stage 4th order filter, the switching frequency f S can be reduced to 120kHz. If fS = 120kHz, then fC = fS /3 = 40kHz. The lower oscillation frequency could help minimize EMI issues. LC F ILTER D ESIGN The output filter helps to reconstruct the amplified audio signal and filter out the switching frequency. The design of the filter depends on the type of attenuation and frequency response desired at the output. The output filter designed into the LXE1710

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 10 Copyright  2000 Rev. 1.1, 2000-12-01 evaluation board is a second order, LC type filter as shown below. Tradeoffs between performance and component cost must be considered when determining the complexity or type of filter selected. OUT+ OUT- L 15µH L 15µH C 0.68µF C 0.68µF R Its Laplace Transform function is: ω ω ωω RCQ LC SQS C S LCSRCS C S 1Where 11H(S) 222 The Class-D amplifier evaluation board design has a pass-band of 20Hz to 20kHz to support the audio frequency range and is configured to utilize a switching or oscillator frequency f s = 500kHz. Depending on the application, this oscillator frequency may be adjusted (see section on Oscillator Configuration) to optimize amplifier performance or modified for other considerations such as EMI effects. Further requirements of the filter are that the pass band attenuation of switching frequency f s should be lower than 40dB and the corner frequency of the LC filter should be set higher than 20kHz to avoid attenuating audio signals in the desired audio band by more than 1dB. A speaker DC impedance o/G20/G01/G02 /G27/G10/G0F/G2D /G19/G1D /G20 C = 50kHz corner frequency are defined for the evaluation board. The Q (selectivity factor or ratio of the center frequency divided by the bandwidth) of the filter must also be considered when designing a filter. Too high a Q will result in a boost of the audio signal across the audio band whereas a low Q will cause too much attenuation of the signal. A Q value of 0.707 provides the required audio response and is used in the calculation below. Board Evaluation in the used is µF68.0 µ56.0)50000)(2(4 707.0 )f2( ==== C FR Q R QC C ππω To Compute the Inductor Value: Board Evaluation in the used is µH15 µ9.14 )µ68(.)]50000)(2[( )f2( 222 ==== L H CC L C ππω LXE1710 Evaluation Board Frequency Response -15 +15 -12.5 -10 -7.5 -2.5 +2.5 +7.5 +10 +12.5 Voltage Amplification (dBr) 10 80 k 20 50 10 20 50 1k 2k 5k 10 k k kFrequency (Hz) /G01/G02 /G03/G02 /G04/G02 Frequency response of the audio amplifier was /G11/G13/G19/G1E/G1F/G16/G13/G14 /G1F/G1E/G10/G1D/G24 /G17/G19/G16/G10/G15/G1F/G1E /G1E/G0E/G13/G19/G1A/G13/G16 /G1C/G15/G19/G14 /G10/G11/G0E/G13/G14/G19/G1D/G22/G13/G1E /G29/G02/G03 /G01/G02/G03 /G19/G1D/G14 /G2C/G02/G21 /G07/G2D/G13 /G24/G16/G19/G0E/G2D/G1E /G17/G13/G16/G10/G20/G2B /G0F/G2D/G19/G0F /G0F/G2D/G13 /G20/G10/G1C/G0F/G13/G16 /G22/G19/G1C/G22/G1F/G1C/G19/G0F/G10/G15/G1D/G1E /G27/G13/G16/G13 /G2E/G19/G1E/G13/G14 /G15/G1D /G19 /G01/G02 /G1E/G0E/G13/G19/G1A/G13/G16/G21 /G07/G2D/G13 /G2C/G02 /G19/G1D/G14 /G29/G02 /G22/G1F/G16/G17/G13/G1E /G14/G10/G1E/G0E/G1C/G19/G2B /G19 /G29/G14/G2F /G2E/G15/G15/G1E/G0F /G19/G1D/G14 /G19 –4dB attenuation respectively. Therefore, to improve frequency response performance for other loads, the value of Q must be increased/decreased by changing the capacitor. Since a different value C will affect the corner frequency, values for L and C must be recalculated. Below are recommended inductor and capacitor values for 2/G02/G03 /G01/G02/G03 /G19/G1D/G14 /G2C/G02 /G1C/G15/G19/G14/G1E /G20/G15/G16 /G0F/G2D/G10/G1E single stage LC filter design. Capacitor C (µF) Inductor L (µH) /G01/G02 1.0 10 /G03/G02 0.68 15 /G04/G02 0.47 22 /G01/G02/G03/G04/G05 /G09/G08 Filter Component Values Please note: These recommended values are guidelines for speaker loads. Actual speakers have varying impedances, which may require revised filter calculations and optimization. Furthermore, your application may have different design goals than those chosen for the LX1710 evaluation board

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 11 Copyright  2000 Rev. 1.1, 2000-12-01 MOSFET S ELECTION As seen in previous sections, the user can design the output filter of the amplifier to meet performance or costs targets. In addition, the amplifier’s power stage (selection of MOSFETs) can be selected depending on these tradeoffs. The efficiency of the amplifier circuit can be approximated by the following equation. CROSSLINDPDSNDS L IN OUT PRRRRI RI P P ++++== ])(2[ 2 Where RL = DC Resistance of Speaker RNDS = n-channel MOSFET on-resistance RPDS = p-channel MOSFET on-resistance RIND = DC Resistance of Inductor PCROSS = MOSFET Switching Loss The overall efficiency is a function of primarily the MOSFETs and output filter inductors. The “Inductor” section’s contribution will be considered later. The MOSFET Power loss is a function of the on-resistance and gate charge. /G01/G02/G03/G04/G05/G06/G07/G06/G08/G09/G02/G0A/G05/G0B /G04 /G01/G02 /G0D AR PI WP RRIP O PDSNDSDS 5.24 25Then 4at 25If )](2[LossPower MOSFET 2 === +== The LX1710 Evaluation Board is designed using FDS4953 p-channel and FDS6612A n-channel MOSFETS. WP RR DS PDSNDS 095.0 ,03.0 2 =+= Ω=Ω= MOSFET power loss is proportional to on-resistance. /G0E/G0F/G08/G09/G10 /G11/G09/G08/G05 /G12/G13/G09/G14/G15/G05/G0B /G16 /G04 /G0D nfCVP SCROSS 2Loss Switching MOSFET == Where C = Input Capacitance V = Supply Voltage fS = Switching Frequency n = Number of MOSFETS Assume C = 1000pF V = 15VDC f S = 500kHz MOSFET switching loss is proportional to total gate charge, supply voltage, and switching frequency. There are a few other important parameters to consider when selecting the output power components besides the on-resistance and gate charge of the MOSFETs. The drain-source voltage must provide ample margin for circuit noise and high speed switching transients. Since the amplifier configuration requires output bridge operation at the supply voltage, the MOSFETs should have a drain-source voltage of at least 50% greater than the supply voltage. The power dissipation of the MOSFETs should also be able to dissipate the heat generated by the internal losses and be greater than the sum of P DS and PCROSS . Linfinity recommends that in selecting MOSFETs, RDS /G30 /G31/G21/G05/G31/G02 /G19/G1D/G14 /G32 g <10nC. The table below provides several MOSFET options. FDS6612A FDS4953 Si4532ADY IRF7105 n-channel p-channel n-channel p-channel n-channel p-channel Drain-Source On-Resistance RDS(ON)@VGS = +/-10V Drain-Source Voltage VDSS (V) 30 -30 30 -30 25 -25 Total Gate Charge Q g (typical) (nC) 9 8 8 10 9.4 10 Manufacturer Fairchild Fairchild Vishay Siliconix Vishay Siliconix International Rectifier International Rectifier /G01/G02/G03/G04/G05 /G0A/G08 MOSFET Component Options

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 12 Copyright  2000 Rev. 1.1, 2000-12-01 INDUCTOR SELECTION The output filter inductors are key elements in the performance of the Class-D audio power amplifier. Inductor selection criteria also involves tradeoffs between performance (efficiency) and component costs. The critical specifications for the inductor are the DC resistance, DC current, and peak current ratings. The inductors should be able to handle the amplifier’s power as well as operate within its linear region. Saturating the inductors could decrease performance (increase THD) and even produce a short, which may damage either the circuit or the speaker. Other variables when selecting an inductor depend on the switching frequency of the designed amplifier. A higher switching frequency implies that the corner frequency of the LC filter is higher. With a higher f C , the inductor value is smaller. The amplifier’s application and design constraints will help determine whether the inductors are selected for size, power, or performance. Various inductors such as those that are shielded may also have different EMI effects and distortion performance. The overall efficiency (/G01 ) of the amplifier circuit is given in the previous MOSFET section. The inductor’s power loss contribution is a function of the inductor’s DC resistance, R IND . /G17/G02/G18/G19/G0A/G08/G0F/G14 /G1A/G12 /G04/G05/G06/G07/G06/G08/G09/G02/G0A/G05/G0B /G04 /G05/G06/G01 /G0D ))(2)(( LossPower Inductor 2 INDIND RIP == The LX1710 Evaluation board utilizes two 15µH radial leaded R.F. inductors from Inductor Supply, Inc. (ISI). When evaluating component options, inductors such as from Coilcraft can be used for other performance / price tradeoffs. See inductor table below. The efficiency approximation can now be completed. %2.90 2545.7.56.1 ])(2[ =+++= +++ ++++ LCROSSINDDS L CROSSLINDPDSNDS L IN OUT RIPPP RI PRRRRI RI P P The efficiency is a function of the power and switching loss in the MOSFETs and inductors. Manufacturer Part Number Inductance /G05/G06/G07/G08 Q min Test Frequency DC Resistance /G09/G0A/G0B /G05/G09/G02/G08 DC Current max (ARMS ) Self Resonant Frequency min (MHz) ISI RL622-150K 15.0 50 2.520MHz 56 2.50 12.0 Coilcraft DO5022P-153HC 15.0 100kHz 32 4.4 20 /G01/G02/G03/G04/G05 /G0B/G08 Inductor Component Options

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 13 Copyright  2000 Rev. 1.1, 2000-12-01 C APACITOR SELECTION The LC filter design section discusses filter options and the calculation of component values. However, the specification of capacitor type depends on the application in the circuit. The table provides descriptions and guidelines for capacitors in the AudioMAX amplifier board. Reference Designator Capacitor Comments C10, C11 FET gate drive These /G0E/G11/G12/G13/G14 /G15/G16/G17/G15/G16/G18/G19/G1A /G1B/G16/G1C/G16/G1B/G1D/G15/G1E/G1F/G20/G16/G1F/G21 /G1B/G22/G16/G1F/G23/G21 /G15/G1F/G16/G17/G20 /G24/G21/G1F /G1B/G16/G1C/G16/G1B/G1D/G15/G1E/G1F/G20/G24/G1E/G1F /G15/G22/G21 /G14/G25/G07 /G23/G16/G15/G21 /G26/G1F/G1D/G27/G21/G11 C3 C14 Audio input path These decoupling capacitors are used for the audio input +/- signals. C18, C19, C20, C21 Output filter The output filter metal film capacitors (low ESR, 5% tolerance) work well to set an accurate corner frequency at a low cost. C8, C12 FET bypass These metal film capacitors are used for the power supply bypass for the FETs. Place adjacent to the FETs or consider lower value ESR solutions depending on the PCB component placement. C22 LX1710 bypass The metal film capacitor is a high frequency bypass for the LX1710 IC. C9, C13 VDD, PVDD bypass These tantalum capacitors provide the bypass for the IC supply voltage and output driver supply voltage utilizing a minimal footprint area. C17 Output power stage The electrolytic filter capacitor smoothes out ripple current and should be placed close to the output FETs. C16 Oscillator frequency The timing capacitor (5% tolerance) sets the oscillator frequency. C6, C7 Feedback filter These (5%) capacitors are used in the RC filter to provide feedback for the control loop. C4, C5 Error amplifier These (5%) capacitors create the compensation network. Make sure the appropriate “temperature grade” is used to ensure stability. C1, C2 Voltage references The filter capacitors provide the bypass for the 5V and 2.5V references. C26 Audio input filter The RC filter minimizes high frequency noise to the amplifier. /G01/G02/G03/G04/G05 /G0C/G08 Capacitor Description

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 14 Copyright  2000 Rev. 1.1, 2000-12-01 G ATE R ESISTOR Series resistors (R6, R10, R11, R12) can be added to the gate of MOSFETs (Q1 to Q4) to control the switching transition times. This reduces signal distortion as seen in the THD+N vs. Output Power graph below. The slower switching speeds will however, increase power dissipation and therefore slightly decrease the overall efficiency of the amplifier. OUT+ VIN R12 10 Ω R11 10 Ω /G07/G2D/G13 /G1B/G33/G34/G05/G35/G05/G31 /G13/G17/G19/G1C/G1F/G19/G0F/G10/G15/G1D /G2E/G15/G19/G16/G14 /G1F/G0F/G10/G1C/G10/G12/G13/G1E /G05/G31/G02 /G24/G19/G0F/G13 resistors, which improves (decreases) the THD+N from 0.1% to 0.05% with a slight impact on efficiency of approximately 2%. The recommended gate resistor /G10/G1E /G20/G16/G15/G11 /G31 /G0F/G15 /G05/G36/G02/G21 O SCILLATOR C ONFIGURATION The oscillator is programmed by the external timing components RPWM and CPWM. For a nominal frequency of 333kHz, RPWM and CPWM should be set to 49.9kOhms and 100pF respectively. Note that in order to keep the slope of the PWM ramp voltage proportional to the supply voltage, both the ramp peak and valley voltages, and the charge and discharge currents are proportional to the supply voltage. This keeps the frequency relatively constant while keeping the slope of the PWM ramp proportional to the voltage on the VDD pin. For operating frequencies other than 333kHz, the frequency can be approximated by the following equation: nsCR PWMPWM 320))()(577.0( 1Frequency += M ULTI C HANNEL R EQUIREMENTS AND FREQUENCY SYNCHRONIZATION For applications that require more than a single channel, the oscillators of multiple LX1710/1711 controllers can be configured for synchronous operation. One unit, the master, is programmed for the desired frequency with the RPWM and CPWM as usual. Additional units will be slave units, and their oscillators will be disabled by leaving the RPWM pin disconnected. The CLOCK pin and the CPWM pin of the slave units should be tied to the CLOCK pin and the CPWM pin of the master unit respectively. In this configuration, the CLOCK pins of the slave units begin receiving instead of transmitting clock pulses. Also, the CPWM pins quit driving the PWM capacitor in the slave units. Note that for optimum performance, all slave units should be located within a few inches of the master unit. Gate Resistor Impact On THD+N 0.001 100 0.005 0.01 0.1 0.26978 0.04675 THD+N (%) 50m 30 100m 200m 500m 1 2 5 10 20 24.56 1.131 Output Power (W) No Gate Resistor W ith 10Ω Gate Resistor V IN = 15V fIN = 1kHz RL /G01/G0E/G03

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 15 Copyright  2000 Rev. 1.1, 2000-12-01 PCB LAYOUT R ECOMMENDATIONS Like most analog circuits, component placement, signal routing, and power/ground isolation can affect the overall performance of the design. The layout should utilize individual ground traces/planes for the audio amplifier whenever possible. The audio input and controller ground, FET ground, and output filter ground are routed using a “star” connection in the LXE1710 evaluation board. See PCB layer views. The power to the controller IC should be routed using separate traces that do not carry high current pulses from the switching circuit. In general, minimizing the high frequency, high power currents from flowing through the same copper as the audio signal references are recommended. Signal traces that could be sensitive to noise should be node to node connections (no “shared” traces). Stray capacitance at the controller pins RPWM, EAOUT, EAIN, and FAOUT can affect the circuit performance and components associated with these pins should be placed as close to the controller IC as possible.

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 16 Copyright  2000 Rev. 1.1, 2000-12-01 PRINTED C IRCUIT B OARD LAYOUT Silkscreen Layer CN1 : RCA Jack Audio In J3: Optional Connections Audio In +, Audio In - TB1 : Power Supply Terminal Block +V, GND J2: Mute Jumper J1: Sleep Jumper TB2 : Audio Output Terminal Block + OUT, - OUT

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 17 Copyright  2000 Rev. 1.1, 2000-12-01 PRINTED C IRCUIT B OARD Bottom Layer Top Layer

LXE1710 E VALUATION B OARD U SER G UIDE Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 18 Copyright  2000 Rev. 1.1, 2000-12-01 B ILL OF M ATERIALS /G1C/G09/G0E/G1C/G09/G0E /G0A/G04/G02/G02/G16/G0B/G04/G10/G11/G0E /G0A/G10/G1C/G13/G10/G0B/G04/G0B/G12/G0A/G04/G02/G02/G16/G0B/G04/G10/G11/G0E /G0A/G10/G1C/G13/G10/G0B/G04/G0B/G12 /G0E/G0E Line Item Part Description Manufacturer & Part # Case Reference Designators Qty

1 Controller /G01/G02/G03/G04/G02/G03/G02/G05/G06 LX1710 SSOP 28 U1 1

2 N-Channel MOSFET /G07/G08/G02/G09/G0A/G0B/G02/G0C/G0D FDS6612A SO-8 Q2, Q4 2

3 P-Channel MOSFET /G07/G08/G02/G09/G0A/G0B/G02/G0C/G0D FDS4953 SO-8 Q1, Q3 2

4 Printed Circuit Board /G01/G02/G03/G04/G02/G03/G02/G05/G06 SGE2758 REV.X 1

5 Inductor, 15uH /G0E/G0F/G0E RL622-150K TH L1, L2 2

6 Phono Ja cks, 90° Nickel Plated, Wht /G10/G11/G12/G13/G14/G09 161-4214 TH CN1 1

7 Strip Line Plugs, Straight, Single Row .100" /G15/G16 CA-S36-24B-44 TH J1, J2 2

8 Shorting Jumpers, Open Top, Black /G10/G11/G12/G13/G14/G09 151-8030 TH J1 1

9 Terminal Block 2 pos 5mm /G17/G0C/G11/G0A/G18 /G10/G08/G13/G05/G14/G09 301-021-1000 TH TB1, TB2 2

/G0A/G16/G13/G16/G0A/G09/G12/G10/G15/G0E/G0A/G16/G13/G16/G0A/G09/G12/G10/G15/G0E Line Item Part Description Part Description Case Reference Designators Qty

1 Capacitor, COG, 18pF, 50V, 5% /G1A/G11/G1B/G08/G0A/G08/G1C 1206N180J500NT

/G16/G1D/G1E 12065C180JAT2A 1206 C5 1

2 Capacitor, COG, 150pF, 50V, 5% /G1A/G11/G1B/G08/G0A/G08/G1C 1206N151J500NT

/G16/G1D/G1E 12065C151JAT2A 1206 C4 1

3 Capacitor, COG, 220pF, 50V, 5% /G16/G1D/G1E 12065C221JAT2A 1206 C6, C7 2

4 Capacitor, X7R, 330pF, 50V, 10% /G1F/G08/G03/G08/G13/G11/G03/G02/G0A ECU-V1H331KBM 1206 C26 1

5 Capacitor, X7R, .47uF, 16V, 20% /G1A/G11/G1B/G08/G0A/G08/G1C 1206B474M160NT /G16/G1D/G1E 1206YC474MAT2A 1206 C3, C14 2

6 Capacitor, X7R, 1uF, 50V, 10% /G1A/G11/G1B/G08/G0A/G08/G1C 1206B105K500NT

/G16/G1D/G1E 12065C105KAT2A 1206 C1, C2 2

7 Capacitor, COG, 100pF, 50V, 5% /G1A/G11/G1B/G08/G0A/G08/G1C 0805N101J500NT

/G16/G1D/G1E 08055C101JAT2A 0805 C16 1 8 Capacitor Tant 0.1uF 35V 20% /G16/G1D/G1E TAJA104M035R 3216 C9 1 9 Capacitor Tant 2.2uF 25V 20% /G20/G14/G21/G14/G05 T491A225M025AS 3216 C13 1 10 Capacitor, Tant, 4.7uF, 16V, 20% /G20/G14/G21/G14/G05 T491A475M016AS /G16/G1D/G1E TAJA475M016R 3216 C10, C11 2 11 Capacitor Stacked MF 0.1uF 50V 5% /G1F/G08/G03/G08/G13/G11/G03/G02/G0A ECQ-V1H104JL TH C8, C12, C22 3 12 Capacitor Stacked MF 0.47uF 50V 5% /G1F/G08/G03/G08/G13/G11/G03/G02/G0A ECQ-V1H474JL TH C18, C19 2 13 Capacitor Stacked MF 0.68uF 50V 5% /G1F/G08/G03/G08/G13/G11/G03/G02/G0A ECQ-V1H684JL TH C20, C21 2

14 Capacitor, Elect 220uF, 25V, 20% /G22/G0C/G03/G08 RV-25V221MH10-R NT C17 1

/G15/G04/G0E/G09/G0E/G12/G10/G15/G0E/G15/G04/G0E/G09/G0E/G12/G10/G15/G0E Line Item Part Description Part Description Case Reference Designators Qty

1 Resistor, 10K, 5%, 1/4W /G16/G0F/G23 CR32J103T 1206 R2 1

2 Resistor, 24.3K, 1%, 1/4W /G16/G0F/G23 CR32F2432T 1206 R3, R4 2

3 Resistor, 10 Ohm, 5%, 1/8W /G16/G0F/G23 CR J100T 0805 R6, R10, R11, R12 4

4 Resistor, 10K, 5%, 1/8W /G16/G0F/G23 CR21J103T 0805 R8, R9 2

5 Resistor, 34.8K, 1%, 1/8W /G16/G0F/G23 CR21F3482T 0805 R5 1

6 Resistor,20K, 5%, 1/8W /G16/G0F/G23 CR J203T 0805 R7 1

7 Resistor, 56.2K, 1%, 1/8W /G16/G0F/G23 CR21F5622T 0805 R1 1

8 Resistor, 15 Ohm 5% 1W /G20/G24/G16 RM73B3A150J

/G25/G11/G0B/G21 MCR100JZHJ150 2512 R13 1 9 Resistor, Low Value Flat .0374 /G0E/G25/G15 LR2010-01-R0374-F 2512 RS1 1