MP7752 18V, 2x15W Stereo BTL fix frequency Inductorless Class D Audio Amplifier The Future of Analog IC Technology DESCRIPTION FEATURES MP7752 is an analog input inductorless Class D Audio Amplifier which can drive stereo speakers in bridge-tied-load configuration. It is one of MPS’ products of fully integrated audio amplifiers which dramatically reduce solution size by integrating the following: • • • 240mΩ power MOSFETs Startup / Shutdown pop elimination Short circuit protection circuits Advanced EMI performance Inductorless while passing EMC test The MP7752 utilizes a stereo BTL structure capable of delivering 15W per channel into 8Ω speakers at 16V power supply. MPS Class D Audio Amplifiers exhibit the high fidelity of a Class AB amplifier at high efficiencies. The MP7752 includes an internal circuit which allows the system automatic shutdown after the absence of the audio signal. This feature is used for energy-using products and for battery operated applications. It also has an adjustable power limit function. The PLIMIT circuit sets a limit on the output peak-to-peak voltage. The limiting is done by limiting the duty cycle to fixed maximum value. This limit can be thought of as a "virtual" voltage rail which is lower than the supply connected to PVCC. • • • • • • • • • • • • • 5V to 18V Operation from a Single Supply ±5A Peak Current Output Output Power: 9.5W/channel at 12V, 8Ω Load, 10%THD 15W/Channel at 16V, 8Ω Load, 10%THD 90% Efficiency with 8Ω Load, 10%THD, 1kHz, 12V Supply Voltage 240mΩ power MOSFETs Startup / Shutdown pop elimination Short circuit protection circuits Inductorless Topology Advanced EMI performance All Switches Current limited Internal Under Voltage Protection Internal Thermal Protection TSSOP-28 EP package Adjustable power limiter Automatic shutdown with zero input signal detect Fault Output Flag APPLICATIONS • • • TV DVD Receiver Active Speaker All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. The MP7752 is available in TSSOP-28 EP package. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 1 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL APPLICATION MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 2 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER ORDERING INFORMATION Part Number* MP7752GF Package TSSOP-28 EP Top Marking See Blow * For Tape & Reel, add suffix –Z (e.g. MP7752GF–Z) TOP MARKING MPS: MPS prefix: YY: year code; WW: week code: MP7752: part number; LLLLLLLLL: lot number; PACKAGE REFERENCE TSSOP-28 EP MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 3 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Supply Voltage VCC ..................... –0.3V to +20V VSW ........................................... –1V to VCC + 1V VEN, V/FAULT, VGAIN, VInAbsence – 0.3V to VCC + 0.3V BS Voltage VBST ............. VSW – 0.3V to VSW + 6V VPLIMIT ............................. – 0.3V to VAVCC + 0.3V VINXX .............................................– 0.3V to 6.5V AGND to PGND ......................... –0.3V to +0.3V (2) Continuous Power Dissipation (TA = +25°C) ………………………………………………...3.9W Junction Temperature .............................. 150°C Lead Temperature ................................... 260°C Storage Temperature .............. –65°C to +150°C TSSOP-28 EP .…… .… .…. .…32 Recommended Operating Conditions (3) (4) θJA θJC 6 °C/W Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ (MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. Supply Voltage VIN ............................. 5V to 18V Operating Junction Temp. (TJ) . -40°C to +125°C MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 4 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER ELECTRICAL CHARACTERISTICS (5, 6) VCC = 18V, VEN = 5V, TJ = -40°C to 125°C, unless otherwise noted. Parameters Symbol Condition Standby Current Quiescent Current Output Offset Voltage SW On Resistance IQSTBY IQ VOS RdsON Short Circuit Current Closed Loop Gain G EN Enable Threshold Voltage Typ Max Units VEN = 0V,NIN=PIN=Float VEN = 5V, no load, no LC filter VI = 0 V, Gain = 36 dB, Tj = 25°C 130 20 200 40 µA mA 20 65 mV IO = 500mA, TJ = 25°C Sourcing and Sinking, TJ = 25°C GAIN0 = L, GAIN1 = L GAIN0 = H, GAIN1 = L GAIN0 = L, GAIN1 = H GAIN0 = H, GAIN1 = H VEN Rising 0.24 VEN Falling VEN = 5V VUVP Rising VUVP Falling EN Enable Input Current Under Voltage Protection AVCC Operating Voltage VDR Operating Voltage VINN/INP Common Mode Voltage Thermal Shutdown Trip Point VGAIN Falling Ω 4 5 6 19 25 31 35 20 26 32 36 1.3 21 27 33 37 2.0 0.4 4 5 5 2.3 VGAIN Rising GAIN0/GAIN1 Threshold Turn-on Time Turn-off Time Switching frequency Input signal absence sensitivity Min A dB V 0.9 12 4.6 4.3 5.5 5.5 2.5 6 6 2.7 V µA V V V V V 1.6 2 V 25 5 0.6 1.1 V 260 2 13 0.2 325 5 ms us kHz mV tON tOFF TJ Rising Thermal Shutdown Hysteresis 360 8 150 °C 20 °C Notes: 5) The device is not guaranteed to function outside its operating rating. 6) Electrical Characteristics are for the IC only with no external components except bypass capacitors. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 5 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER OPERATING SPECIFICATIONS (7) Circuit of figure 5, VCC = 18V, Gain=20dB, VEN = 5V, RLOAD = 8Ω+66uH, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Units f = 1kHz, THD+N = 10%, VCC = 18V f = 1kHz, THD+N = 10%, VCC = 16V f = 1kHz, THD+N = 10%, VCC = 12V POUT = 5W, f = 1kHz, VCC = 12V 20 15 9.5 0.5 POUT = 15W, f = 1kHz, VCC = 18V 0.5 % Efficiency POUT = 9.5W + 9.5W, THD+N = 10%, VCC = 12 V, 1kHz, RLOAD = 8Ω 90 % Deadtime Cross Talk Noise Floor Signal-to-noise ratio IO=0.5A VO = 1 Vrms, f = 217Hz A-Weighted, 22 Hz to 22 kHz f = 1kHz, THD+N = 1%, A-Weighted 40 -110 115 100 nS dB μV dB Power Supply Rejection VRIPPLE=300mVPP, Inputs ac-coupled to AGND f = 1kHz -60 dB f = 217Hz -70 dB Power Output THD+ Noise W % Notes: 7) Operating Specifications are for the IC in Typical Application circuit. Not production tested. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 6 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL PERFORMANCE CHARACTERISTICS VCC = 12V, GAIN = 20dB, f = 1kHz, TA = 25°C, unless otherwise noted. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 7 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VCC = 12V, GAIN = 20dB, f = 1kHz, TA = 25°C, unless otherwise noted. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 8 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VCC = 12V, GAIN = 20dB, f = 1kHz, TA = 25°C, unless otherwise noted. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 9 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VCC = 12V, GAIN = 20dB, f = 1kHz, TA = 25°C, unless otherwise noted. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 10 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER PIN FUNCTIONS Pin # Name 1 EN 2 3 4 5 6 7 8 9 10 11 12 13 14 15, 16 17 Description Enable input. Drive EN high to turn on the Amplifier 1A/1B/2A/2B, low to turn them off. Fault Output. A low output at FAULT indicates that the IC has detected an over temperature or over current condition. This output is open drain. IN1A Positive audio input for channel 1. Biased at 2.5V. IN1B Negative audio input for channel 1. Biased at 2.5V. GAIN0 Gain selection bit. GAIN1 Gain selection bit. AVCC Internal analog reference, 5.5V, need connect a bypass capacitor from AVCC to AGND. AGND Analog ground. Gate Drive Supply Bypass. VDR powers the internal circuitry, internal MOSFET gate VDR drive. Bypass VDR to AGND with a 0.1μF to 10μF capacitor. Power limit and anti-clipping feature control. PLIMIT Connect a resistor divider from AVCC to GND to set power limit. Connect directly to AVCC for no power limit. IN2B Negative audio input for channel 2. Biased at 2.5V. IN2A Positive audio input for channel 2. Biased at 2.5V. InAbsence Open drain output used to report the input signal absence. Delay Time control for input signal absence report function. This holding time can be Cap_D adjusted with external capacitor. Connect this pin to AGND to disable automatic shutdown with zero signal input function. Power supply input for channel 2. Bypass PVCC2 to PGND2 with a 1μF X7R capacitor (in PVCC2 addition to the main bulk capacitor), placed close to the PVCC2 and PGND2 pins. High-side MOSFET bootstrap input for Amplifier 2A. A capacitor from BST2A to SW2A BST2A supplies the gate drive current to the internal high-side MOSFET. /FAULT 18 SW2A 19 PGND2 20 SW2B 21 BST2B 22 BST1B 23 SW1B 24 25 PGND1 SW1A 26 BST1A 27, 28 PVCC1 MP7752 Rev. 1.0 8/15/2014 Switched power output for Amplifier 2A (the positive output of channel 2). Power ground for Amplifier 2A/2B. Switched power output for Amplifier 2B (the negative output of channel 2). High-side MOSFET bootstrap input for Amplifier 2B. A capacitor from BST2B to SW2B supplies the gate drive current to the internal high-side MOSFET. High-side MOSFET bootstrap input for Amplifier 1B. A capacitor from BST1B to SW1B supplies the gate drive current to the internal high-side MOSFET. Switched power output for Amplifier 1B (the negative output of channel 1). Power ground for Amplifier 1A/1B. Switched power output for Amplifier 1A (the positive output of channel 1). High-side MOSFET bootstrap input for Amplifier 1A. A capacitor from BST1A to SW1A supplies the gate drive current to the internal high-side MOSFET. Power supply input for channel 1. Bypass PVCC1 to PGND1 with a 1μF X7R capacitor (in addition to the main bulk capacitor), placed close to the PVCC1 and PGND1 pins. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 11 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER FUNCTIONAL BLOCK DIAGRAM Functional Block Diagram (only one channel) MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 12 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER OPERATION The MP7752 is a fully integrated Class D stereo BTL audio amplifier. Because of the switching Class D output stage, power dissipation in the amplifier is drastically reduced when compared to Class A, B or A/B amplifiers while maintaining high fidelity and low distortion. The MP7752 includes a delay circuit which allows the IC continues to hold the flag after the absence of the audio signal. This holding time can be adjusted with external capacitor. 1. The amplifier has fully differential outputs and inputs. The differential input is useful to minimize the common-mode noise (any noise that appears on both input lines of the channel). This device can still be used with a single-ended input. The MP7752 includes eight high-power MOSFETs wherein for each half-bridge channel the output driver stage uses two N-Channel MOSFETs to deliver the pulses to the magnetic bead and capacitor output filter which in turn drives the load. To fully enhance the high-side MOSFET, the gate is driven to a voltage higher than the source by the bootstrap capacitor between OUTxx and BSTxx pins. While the output is driven low, the bootstrap capacitor is charged from power supply through an internal circuit. The gate of the high-side MOSFET is driven high from the voltage at Bootstrap Supply, forcing the MOSFET gate to a voltage higher than power supply voltage and allowing the MOSFET to fully turn on, reducing power loss in the amplifier. The gain of the MP7752 is set by the input terminals, GAIN0 and GAIN1. The actual gain settings are controlled by ratios of the input and feedback resistors Enable Function The MP7752 EN input is an active high enable control. To enable the MP7752, drive EN with a 2.0V or higher voltage. To disable the amplifier, drive it below 0.4V. While the MP7752 is disabled, the PVCC operating current is around 250μA and the output driver MOSFETs are turned off. The input absence flag will be high initially when power on. After device enabled, the internal circuit start to detect the input signal. MP7752 will then hold the output report and normal operation for a delay time which can be adjusted by the Capacitor value @ pin 14. Then MP7752 will turn off the all MOSFETs and pull low the input absence output, until the input signal detected again. Figure 1a: enable on with no signal detected 2. The input absence flag output will be or maintain high when input signal is detected. The delay circuit will only be activated when the input signal absence. MP7752 will then hold the output report for a delay time which can be adjusted by the Capacitor value @ pin 14. Then MP7752 will turn off the all MOSFETs and pull low the input absence output, until the input signal detected again. Input signal Absence detect The MP7752 includes an internal circuit which allows the system automatic shutdown after the absence of the audio signal. This feature is used for energy-using products and for battery operated applications. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 13 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER given maximum input voltage and speaker impedance. POUT ⎛⎛ ⎞ ⎞ RL ⎜⎜ ⎟ × VP ⎟ ⎝ RL + 2 × R S ⎠ ⎠ =⎝ 2 × RL 2 for unclipped power Where: RS is the total output series resistance (including Rdson and the resistance of output filter. Figure 1b: enable on with audio signal present RL is the load resistance. Adjustable Power Limit VP is the peak amplifier of the output voltage. Power limit and anti-clipping feature control. The voltage at pin 10 can used to limit the power to levels below that which is possible based on the supply rail. Connect a resistor divider from AVCC to GND to set power limit. Connect directly to AVCC for no power limit. VP = 9 x PLIMIT voltage if 8 x PLIMIT < PVCC And An external reference may also be used if tighter tolerance is required. Also add a 1μF capacitor from pin 10 to ground. Input signal=1Vrms Plimit=1.74V=11.24W Plimit=1.44V=10W Plimit=0.8V=5W Figure 2. PLIMT Circuit Operation The PLIMIT circuit sets a limit on the output peak-to-peak voltage. The limiting is done by limiting the duty cycle to fixed maximum value. This limit can be thought of as a "virtual" voltage rail which is lower than the supply connected to PVCC. This "virtual" rail is 9 times the voltage at the PLIMIT pin. This output voltage can be used to calculate the maximum output power for a MP7752 Rev. 1.0 8/15/2014 POUT @10%THD ≈ 1.25 × unclipped POUT Table 2: Power Limit Typical Operation Output Voltage (Vp-p) Output Power (10% THD) 0.80V 14.9 5.0W 0.80V 14.9 5.0W 1.44V 23.6 10.0W 1.44V 23.6 10.0W Test PLIMIT Condition Voltage VDD=12V, Vin=1Vrms, Load=8Ω, Gain=20dB VDD=16V, Vin=1Vrms, Load=8Ω, Gain=20dB VDD=16V, Vin=1Vrms, Load=8Ω, Gain=20dB VDD=18V, Vin=1Vrms, Load=8Ω, Gain=20dB Gain Setting The gain of the MP7752 is set by the input terminals, GAIN0 and GAIN1. The actual gain settings are controlled by ratios of the internal input and feedback resistors, details please see the below table. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 14 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER Table 2: Gain Setting GAIN0 GAIN1 Typ. GAIN Typ. Input Impedance (dB) (kΩ) 0 1 0 0 0 1 20 26 32 75 50 30 1 1 36 20 A fault on any channel will cause the FAULTB pin to pull low. A fault on either channel will cause the all outputs to go into high impedance. When the fault goes away, the MP7752 will resume normal operation. Over-Temperature Shutdown Thermal monitoring is also integrated into the MP7752. If the die temperature rises above 150°C, all switches turn off. The temperature must fall below 130°C before normal operation resumes, with the same power-up sequence used to prevent popping noise. Short Circuit Performance The MP7752 has internal overload and short circuit protection. The currents in both the highside and low-side MOSFETs are measured. Upon detection of short circuit, all MOSFETs of the over current full bridge channel will go into high impedance for a fixed duration before resuming normal operation. After the fixed duration and the short circuit condition is removed, the MP7752 will restart with the start up sequence that is used for normal starting to prevent a pop from occurring. Figure 3: Fault Timing Chart Fault Output The MP7752 includes an open drain, active low fault indicator output on the /FAULT pin. A fault triggers if either the current limit or thermal shutdown is tripped. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 15 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER APPLICATION INFORMATION COMPONENT SELECTION Delay time for input signal absence report The Recovery time is defined as follows. Tdelay = 1.6 × 108 × CR [ sec ] Choosing the Output EMI Filter The magnetic bead-capacitor filter converts the pulses at SW to the output voltage that drives the speaker. Both PVCC line and output current flow needed magnetic beads to prevent large radiation from high slew-rate pulse. The larger impedance of the magnetic bead, the better EMI performance can be approach. Input Coupling Capacitor The input coupling capacitor transmits the AC signal from the source to the MP7752 while blocking the DC voltage. Choose an input coupling capacitor such that the corner frequency (fIN) is less than the passband frequency. The corner frequency is calculated as: fIN = 1 2 × π × R IN × CIN The impedance of the input resister is different with the different gain setting. At the same gain setting, the input impedance from part-to-part may shift by ±20% due to shifts in the actual resistance of the input resistors. But please note that the gain variation from part-to-part is small. For design purposes, the input network should be designed assuming an input impedance of 16 kΩ, which is the absolute minimum input impedance of the MP7752. At the lower gain settings, the input impedance could increase as high as 90 kΩ. Power Source For maximum output power, the amplifier circuit requires a regulated external power source. A high power-supply voltage can deliver more power to a given load resistance, but a powersource voltage exceeding the maximum voltage of 18V can damage the MP7752. The MP7752’s power supply rejection is excellent, MP7752 Rev. 1.0 8/15/2014 though power-supply noise can pass to the output, so care must be taken to minimize power supply noise within the pass-band frequencies. Bypass the power supply with a large capacitor (typically aluminum electrolytic) along with two smaller 1μF and 1nF ceramic capacitors at the MP7752 VCC supply pins. PCB Layout Circuit layout is critical for optimal performance, low output distortion, and noise. Duplicate the EVB layout for best results. For layout changes, follow these guidelines. 1) Place the following components as close to the MP7752 as possible: Bootstrap Capacitors CBS supply the gate drive current to the internal HS-FET. Place CBS as close to BST pin and SW pin as possible. Power Supply Bypass Capacitors CBYP carry the transient current for the switching power stage. To avoid overstressing the MP7752 and excessive output noise, place CBYP as close to the PVCC pins as possible. 2) The magnetic bead-Capacitor filter converts the pulse train at SW to the output voltage that drives the speaker. Please keep the filter capacitor close to the magnetic bead. 3) Make sure that any traces carrying the switch node (SW) voltages are routed far from any input signal traces. If the trace must run near the SW trace near the input, shield the input with a ground plane between the traces. Physically separate each channel to prevent crosstalk. Route each power supply from the source to each channel individually, not serially. This prevents channel-to-channel coupling through the power supply input. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 16 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER Electro-Magnetic Interference (EMI) Considerations tested work well in series with PVCC and four SW outputs. Due to the switching nature of Class D amplifiers, care must be taken to minimize the effects of electromagnetic interference from the amplifier. However, proper component selection and careful attention to circuit layout can minimize the effects of the EMI due to the amplifier switching. The size of high-current loops that carry rapidly changing currents must be minimized: Make sure that the VCC bypass capacitors are as close to the MP7752 as possible. The magnetic beads are used for blocking radiated emissions from SW nodes. For the best EMI performance, use high current and high impedance magnetic bead. muRata NFZ2M series CLASS D EMI filter has been Nodes that carry rapidly changing voltage, such as SW, need to be made as small as possible. If sensitive traces run near a trace connected to SW, place a ground shield between the traces. MP7752 EVB passed CISPR22 CLASS B standard with stereo full power output. Figure 4: EMI Test Data of MP7752 EVB Test Condition: 10 meter EMI chamber, 1.2 meter twist speaker cable, MP7752 EVB stereo test. VDD=12V, LOAD=8ohm+66uH, POUT=9.5W X 2, 1 kHz Signal. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 17 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER TYPICAL APPLICATION CIRCUITS Figure 5: Typical Application Circuit MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 18 MP7752 – 18V, 2X15W STEREO FIX FREQUENCY INDUCTORLESS BTL CLASS D AUDIO AMPLIFIER PACKAGE INFORMATION TSSOP-28 EP NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP7752 Rev. 1.0 8/15/2014 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 19