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| www.fairchildsemi.com FAN7024 Features * * * * * * * * 675mW CMOS Mono Power Amplifier with Shutdown Description The FAN7024 is a bridge connected audio power amplifier capable of delivering 675mW of continuous average power to an 8 load with less than 0.3%(THD) from a 5V power supply. The FAN7024 requires few external components and operates on low supply voltage from 2.3V to 5.5V. Since the FAN7024 does not require output coupling capacitors, bootstrap capacitors, or snubber networks, it is ideally suited for low power portable systems that require minimum volume and weight. The FAN7024 features an externally controlled gain and low power consumption shutdown mode (0.1uA,typ.). Additional FAN7024 features include thermal shutdown protection, unity gain stability, and external gain set. 8MSOP 1 Continuous Average Power is 675mW (8) Low THD: Typical 0.3% @ Po=500mW PSRR@217Hz, Input Terminated : 60dB Do Not Need Output Coupling Capacitor or Bootstrap Capacitor Low Shutdown Current: Typical 0.1A Shutdown: High Active Click & Pop Suppression circuitry Built in TSD Circuit Typical Applications * Cellular Phone * PDA * Portable Audio Systems 10MLP 1 BOTTOM VIEW Internal Block Diagram 4 3 IN- VO1 5 IN+ 20K 20K BP 100K VDD/2 VO2 VDD BIAS & Shutdown 100K 2 8 6 1 SD 7 GND Rev. 1.0.0 (c)2003 Fairchild Semiconductor Corporation FAN7024 Pin Assignments VO2 GND VDD VO1 8 7 6 5 VO2 NC VDD NC 10 9 8 7 6 1 2 3 4 5 024 YWW 1 SD 2 BP 3 IN+ 4 IN- SD BP GND IN+ IN- VO1 8MSOP 10MLP(BOTTOM VIEW) Pin Definitions Pin Number 1(1) 2(2) 3(4) 4(5) 5(6) 6(8) 7(3) 8(10) Pin Name SD BP IN+ INVO1 VDD GND VO2 Pin Function Description ( ) : 10MLP Shutdown. Hold high to shutdown, hold low for normal operation Bypass. Tap to voltage divider for internal mid-supply bias Noninverting input Inverting input Power amplifier output1 Supply voltage input Ground connection for circuitry Power amplifier output2 2 FAN7024 Absolute Maximum Ratings (Note 2) Parameter Maximum Supply Voltage Input Voltage Power Dissipation Storage Temperature Junction Temperature Thermal Resistance Junction to Ambient Symbol VDD VIN PD TSTG TJ Rthja Value 6.0 -0.3 ~ VDD+0.3 Internally Limited -65 ~ +150 150 190 166 50 C/W Unit V V W C C 8MSOP 10MLP, Single-Layer 10MLP, Multi-Layer Remark Recommended Operating Conditions (Note 2) Parameter Operating Supply Voltage Operating Temperature Symbol VDD TOPR Min. 2.3 -40 Typ. Max. 5.5 85 Unit V C 3 FAN7024 Electrical Characteristics(Note1,2) (RL = 8, Ta = 25C, unless otherwise specified) Parameter Symbol Conditions Min. Typ. Max. Unit VDD = 5.0V, UNLESS OTHERWISE SPECIFIED Quiescent Power Supply Current Shutdown Current Output Offset Voltage Output Power Total Harmonic Distortion+Noise IDD ISD VOS PO THD+N VIN = 0V,IO = 0A VSD = VDD VIN = 0V THD = 1%(Max.), f = 1kHz PO = 500mWrms, Av=6dB, 20Hz 4 FAN7024 Typical Application Circuit RF 20K CI 0.39uF RI 4 20K IN- VO1 5 3 IN+ 20K 1uF 20K BP 8/16/32 100K VDD/2 VO2 VDD 20K BIAS & Shutdown 100K RL 2 CB VDD 8 6 CS 10uF 1 NC SD 7 GND External Components Descriptions Components 1. RI Functional Descriptions The inverting input resistor which sets the closed-loop gain in conjunction with Rf. This resistor also forms a high pass filter with CI at fc=1/(2RICI) The input coupling capacitor blocks the DC voltage at the amplifier's input terminals. Also creates a high pass with RI at fc=1/(2RICI). Refer to the section, Proper Selection of External Components, for an explanation of how to determine the value of CI. The feedback resistor which sets closed-loop gain in conjunction with RI. The supply bypass capacitor which provides power supply filtering. Refer to the Application Information section for proper placement and selection of the supply bypass capacitor. The bypass pin capacitor which provides half-supply filtering. Refer to the Proper Selection of External Components section for information concerning proper placement and selecting CB's value. 2. CI 3. RF 4. CS 5. CB 5 FAN7024 Performance Chracteristics 10 VDD=5V RL=8 Av=6dB BW < 80kHz 10 VDD=5V RL=16 Av=6dB BW < 80kHz 1 THD + N (%) 1 f = 20KHz THD + N (%) f = 20KHz 0.1 f = 1KHz 0.1 f = 20Hz f = 20Hz f = 1KHz 0.01 10m 50m 100m 500m 1 0.01 10m 50m 100m 500m 1 Output Power (W) Output Power (W) Figure 1. THD+N vs. Output Power Figure 2. THD+N vs. Output Power 10 VDD=5V RL=32 Av=6dB BW < 80kHz 10 VDD=3.3V RL=8 Av=6dB BW < 80kHz 1 1 THD + N (%) THD + N (%) f = 20KHz f = 20KHz 0.1 f = 20Hz 0.1 f = 1KHz f = 1KHz f = 20Hz 0.01 10m 50m 100m 500m 1 0.01 10m 50m 100m 500m 1 Output Power (W) Output Power (W) Figure 3. THD+N vs. Output Power Figure 4. THD+N vs. Output Power 10 VDD=3.3V RL=16 Av=6dB BW < 80kHz 10 VDD=3.3V RL=32 Av=6dB BW < 80kHz 1 1 f = 20KHz THD + N (%) THD + N (%) f = 20KHz 0.1 f = 1KHz 0.1 f = 20Hz f = 20Hz f = 1KHz 0.01 10m 50m 100m 500m 1 0.01 10m 50m 100m 500m 1 Output Power (W) Output Power (W) Figure 5. THD+N vs. Output Power Figure 6. THD+N vs. Output Power 6 FAN7024 Performance Characteristics (Continued) 10 VDD=2.6V RL=8 Av=6dB BW < 80kHz 10 VDD=2.6V RL=16 Av=6dB BW < 80kHz 1 1 THD + N (%) THD + N (%) f = 20KHz f = 20KHz 0.1 f = 1KHz 0.1 f = 1KHz f = 20Hz f = 20Hz 0.01 10m 50m 100m 500m 1 0.01 10m 50m 100m 500m 1 Output Power (W) Output Power (W) Figure 7. THD+N vs. Output Power Figure 8. THD+N vs. Output Power 10 VDD=2.6V RL=32 Av=6dB BW < 80kHz 10 VDD=5V RL=8 Po=500mW BW < 80kHz THD + N (%) f = 20KHz THD + N (%) 0.1 0.01 20 1 1 0.1 f = 20Hz f = 1KHz 0.01 10m 50m 100m 500m 1 50 100 200 500 1k 2k 5k 10k 20k Output Power (W) Frequency (Hz) Figure 9. THD+N vs. Output Power Figure 10. THD+N vs. Frequency 10 VDD=5V RL=16 Po=250mW BW < 80kHz 10 VDD=5V RL=32 Po=200mW BW < 80kHz 1 1 THD + N (%) 0.1 THD + N (%) 0.1 0.01 20 50 100 200 500 1k 2k 5k 10k 20k 0.01 20 50 100 200 500 1k 2k 5k 10k 20k Frequency (Hz) Frequency (Hz) Figure 11. THD+N vs. Frequency Figure 12. THD+N vs. Frequency 7 FAN7024 Performance Characteristics (Continued) 10 VDD=3.3V RL=8 Po=250mW BW < 80kHz 10 VDD=3.3V RL=16 Po=200mW BW < 80kHz 1 1 THD + N (%) 0.1 THD + N (%) 0.1 0.01 20 50 100 200 500 1k 2k 5k 10k 20k 0.01 20 50 100 200 500 1k 2k 5k 10k 20k Frequency (Hz) Frequency (Hz) Figure 13. THD+N vs. Frequency Figure 14. THD+N vs. Frequency 10 VDD=3.3V RL=32 Po=100mW BW < 80kHz 10 VDD=2.6V RL=8 Po=125mW BW < 80kHz 1 1 THD + N (%) 0.1 THD + N (%) 0.1 0.01 20 0.01 20 50 100 200 500 1k 2k 5k 10k 20k 50 100 200 500 1k 2k 5k 10k 20k Frequency (Hz) Frequency (Hz) Figure 15. THD+N vs. Frequency Figure 16. THD+N vs. Frequency 10 VDD=2.6V RL=16 Po=100mW BW < 80kHz 10 VDD=2.6V RL=32 Po=75mW BW < 80kHz 1 1 THD + N (%) 0.1 THD + N (%) 0.1 0.01 20 50 100 200 500 1k 2k 5k 10k 20k 0.01 20 50 100 200 500 1k 2k 5k 10k 20k Frequency (Hz) Frequency (Hz) Figure 17. THD+N vs. Frequency Figure 18. THD+N vs. Frequency 8 FAN7024 Performance Characteristics (Continued) 0 -10 -20 -30 -40 VDD = 5V Vripple = 250mV RL = 8 Vin = 0V (Input Open) 0 -10 -20 -30 VDD = 5V Vripple = 250mV RL = 8 Vin = 0V (Input Grounded) Av = 6dB PSRR (dB) -50 -60 -70 -80 -90 -100 -110 -120 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k CB = 1.0uF PSRR (dB) -40 -50 -60 -70 -80 -90 -100 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k CB = 1.0uF Frequency (Hz) Frequency (Hz) Figure 19. Power Supply Rejection Ratio Figure 20. Power Supply Rejection Ratio 0 -10 -20 -30 -40 VDD = 3.3V Vripple = 250mV RL = 8 Vin = 0V (Input Open) 0 -10 -20 -30 VDD = 3.3V Vripple = 250mV RL = 8 Vin = 0V (Input Grounded) Av = 6dB PSRR (dB) PSRR (dB) -50 -60 -70 -80 -90 -100 -110 -120 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k CB = 1.0uF -40 -50 -60 -70 -80 -90 -100 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k CB = 1.0uF Frequency (Hz) Frequency (Hz) Figure 21. Power Supply Rejection Ratio Figure 22. Power Supply Rejection Ratio 1m 500u 100u 50u 3.5 VDD = 5V RL = 8 Av = 6dB Vin = 0V 3.0 Temp. = 25C Supply Current(mA) 2.5 2.0 1.5 1.0 0.5 0.0 0 Noise Floor (dB) 10u 5u 1u 50n 10n 5n 1n 20 VO1+VO2 50 100 200 500 1k 2k 5k 10k 20k 1 2 3 4 5 Frequency (Hz) Supply Voltage(V) Figure 23. Noise Floor Figure 24. Supply Current vs. Supply Voltage 9 FAN7024 Performance Characteristics (Continued) 2.5 Vin = 0V VDD=5V Temp. = 25C 0.7 0.6 2.0 Supply Current(mA) Power Dissipation (W) 0.5 0.4 0.3 0.2 0.1 RL=8 RL=16 1.5 1.0 RL=32 0.5 f=1KHz THD+N<1% BW<80kHz VDD=5V 0.0 0 1 2 3 4 5 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Shutdown Voltage(V) Output Power (W) Figure 25. Supply Current vs. Shutdown Voltage Figure 26. Power Dissipation vs. Output Power 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2.0 f=1KHz RL=8 BW<80kHz 1.0 0.9 0.8 f=1KHz RL=16 BW<80kHz Output Power(W) Output Power(W) 10% THD+N 0.7 0.6 0.5 0.4 0.3 0.2 0.1 10% THD+N 1% THD+N 1% THD+N 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Supply Voltage(V) Supply Voltage(V) Figure 27. Output Power vs. Supply Voltage Figure 28. Output Power vs. Supply Voltage 0.6 3.0 0.5 0.4 10% THD+N Ambient Temperature [C] f=1KHz RL=32 BW<80kHz 10MLP(Multi-La ye r) : 2.5W m a x 2.5 Output Power(W) 2.0 0.3 1.5 0.2 1.0 10MLP(Single -La ye r) : 753mW m a x 1% THD+N 0.1 0.5 8MSOP : 657m W ma x 0.0 0.0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 25 50 75 100 125 150 Supply Voltage(V) Power Dissipation [W] Figure 29. Output Power vs. Supply Voltage Figure 30. Power Derating Curve 10 FAN7024 Application Informations Power Supply Bypassing Proper power supply bypassing is critical for low noise and high power supply rejection. A larger capacitor may help to increase immunity to the supply noise. However, considering economical design, attaching 10uF electrolytic capacitor or tantalum capacitor with 0.1uF ceramic capacitor to the VDD pin as close as possible is enough to get a good supply noise rejection. The capacitor location on both the bypass pin and power supply pin should be as close to the device as possible. Connecting a 1uF capacitor, CB, between the bypass pin and ground improves the internal bias voltage's stability and improves the amplifier's PSRR. The PSRR improvements increase as the bypass pin capacitor value increases. The selection of bypass capacitors, especially CB, depends on desired PSRR requirements, click and pop performance as explained in the section, Proper Selection of External Components, system cost, and size constraints. Shutdown Function In order to reduce power consumption while not in use, the FAN7024 contains a shutdown function(pin 1) to externally turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when a logic high is placed on the shutdown pin. The trigger point between a logic low and high level is typically half supply. It is best to switch between ground and supply to provide maximum device performance. By switching the shutdown pin to the VDD, the supply current of the FAN7024 will be minimized in the shutdown mode. While the device isdisabled with shutdown pin voltages less than VDD, the shutdown current may be greater than the typical value of 0.1uA. In either case, the shutdown pin should be tied to a definite voltage because leaving the pin floating may result in an unwanted state change. In many applications, a microcontroller or microprocessor output is used to control the shutdown circuitry which provides a quick, smooth transition into shutdown. Another solution is to use a single-pole, single-throw switch in conjunction with an external pull-up resistor. When the switch is closed, the shutdown pin is connected to ground and the device is enabled. If the switch is open, the FAN7024 will be disabled through the external pull-up resistor. This scheme guarantees that the shutdown pin will not float. This prevents unwanted state changes. Bridge Configuration Explantion As shown in typical appliction circuit, the FAN7024 has two operational amplifiers internally, allowing for a few different amplifier configurations. The first amplifier's gain is externally configurable, while the second amplifier is internally fixed in a unity-gain, inverting configuration. The close-loop gain of the first amplifier is set by selecting the ratio of RF to RI while the second amplifier's gain is fixed by two internal 20k resistors. In the typical application circuit, the output of the first amplifier serves as the input of the second amplifier which results in both amplifiers producing signals indentical in magnitude, but out of phase 180. Consequently the differential gain of the device is RF A VD = 2 -----RI (1) By driving the load differentially through outputs VO1 and VO2, an amplifier configuration commonly referred to as "bridged mode" is established. Bridged mode operation is different from the classical single-ended amplifier configuration where one side of its load is connected to ground. A bridge amplfier design has a few distinct advantages over the single-ended configuration, as it provides differential drive to the load, thus doubling output swing for a specified supply voltage. Four times the output power is possible as compared to a single-ended amplifier under the same conditions. This increase in attainable output power assumes that the amplifier is not current limited or clipped. A bridgge configuration , such as the one used in FAN7024, also creates a second advantage over single-ended amplifiers. Since the differential outputs, VO1 and VO2, are biased at half-suppy, no net DC voltage exists across the load. This eliminates the need for an output coupling capacitor which is required in a single supply, single-ended amplifier configuration. If an output coupling capacitor is not used in a single-ended configuration, the half-supply bias across the load would result in both increased internal IC power dissipation as well as permanant loudspeaker damage. Adaptive Q-current Control Circuit Among the several kinds of the analog amplifiers, a class-AB amplifier satisfies moderate total harmonic distortion(THD) and the efficiency. In general, the output distortion is proportional to the quiescent-current(Q-current) of the output stage, but power efficiency is inversely propotional to that. To satisfy both needs, an adaptive Q-current control(AQC) technique is proposed. The AQC circuit controls the Q-current with respect to the amount of the output distortion, whereas it is not activated when no input signals are applied or no output distortion is sensed. 11 FAN7024 Power Dissipation Power dissipation is a major concern when designing any power amplifier and must be thoroughly uderstood to ensure a successful design. Equation (2) states the maximum power dissipation point for a bridged amplifier operating at a given supply voltage and driving a specified output load. P DMAX V DD = 4 ---------------2 2 R L 2 (2) Since the FAN7024 is driving a bridged amplifier, the internal maximum power dissipation point of the FAN7024 results from equation (2). Even with the large internal power dissipation, the FAN7024 does not require heat sinking over a wide range of ambient temperature. From equation (2), assuming a 5V power supply and an 8 load, the maximum power dissipation point is 633mW. The maximum power dissipation point obtained from equation (2) must not be greater than the power dissipation that results from equation (3) : ( T JMAX - T A ) P DMAX = --------------------------------R thja (3) For package 8MSOP(FAN7024MU), Rthja=190C/W, TJMAX=150C for the FAN7024. Depending on the ambient temperature, TA, of the system surroundings, equation (3) can be used to find the maximum internal power dissipation supported by the IC packaging. If the result of equation (2) is greater than that of equation (3), then decrease the supply voltage, increase the load impedance, or reduce the ambient temperature, TA. If these measures are insufficient, a heat sink can be added to reduce TA. For the typical application of a 5V power supply, with 8 load, the maximum ambient temperature possible without violating the maximum junction temperature is approximately 30C provided that device operation is around the power dissipation point. Internal power dissipation is a function of output power and thus, if typical operation is not around the maximum power dissipation point, the ambient temperature can be increased. Refer to the Performance Characteristics curves for power dissipation information for lower output powers. Proper Selection of External Components Selection of external components in applications using integrated power amplifiers is critical to optimize device and system performance. While the FAN7024 is tolerant of external component combinations, consideration to component values must be used to maximize overall system quality. The FAN7024 is unity-gain stable and this gives a designer maximum system flexibility. The FAN7024 should be used in low gain configurations to minimize THD+N values and maximize the signal-to-noise ratio. Low gain configurations require large input signals to obtain a given output power. Besides gain, one of the major considerations is the closed-loop bandwidth of the amplifier. The input coupling capacitor, CI, forms a first order high pass filter which limits low frequency response. This value should be chosen based on needed frequency response for a few distinct reasons. Selection of Capacitor Size In the typical application, an input capacitor, CI, is required to allow the amplifier to bias the input signal to the proper DC level for optimum operation. In this case, CI and RI form a high-pass filter with the corner frequency 1f c = -----------------2R I C I (4) The value of CI is important to consider, as it directly affects the bass(low frequency) performance of the circuit. Clearly a certain sized capacitor is needed to couple in low frequencies without severe attenuation. But in many cases the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 150Hz. Thus using large input capacitor may not increase systme performance. In addition to systme cost and size, click and pop performance is affected by the size of the input coupling capacitor, CI. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage(normally VDD/2). This charge comes from the output via feedback and is apt to create pops upon device enable. Thus, by minimizing the capacitor size based on necessary low frequency response, turn-on pops can be minimized. Besides minimizing the input capacitor sizes, careful consideration should be paid to the bypass capacitor value. Bypass capacitor, CB, is the most critical component to minimize turn-on pops since it determines how fast the FAN7024 turns on. The slower the FAN7024's outputs ramp to their quiescent DC voltage(normally VDD/2), the smaller the turn-on pop. Thus choosing CB equal to 1.0uF along with a small value of CI(in the range of 0.1uF to 0.39uF), should produce a clickless and popless shutdown function. While the device will function properly, (no oscillations or motorboating), with CB equal to 0.1uF, the device will be much more susceptible to turn-on clicks and pops. Thus, a value of CB equal to 1uF or larger is recom- 12 FAN7024 mended in all but the most cost sensitive designs. Pop Noise Reduction The FAN7024 contains circuitry to minimize turn-on and shutdown transients or 'clicks and pop'. For this discussion, turn-on refers to either applying the power supply voltage or when the shutdown mode is deactivated. To reduce the pop noise, the FAN7024 has some delay. During that delay, the input capacitor is precharged and the normal operation is prepared. Such delay time can be controlled by choosing CB. The delay time is expressed as CB t delay = 2.5V ------------- + 20ms 40uA (5) 13 FAN7024 Mechanical Dimensions Package Dimensions in millimeters 8MSOP 14 FAN7024 Mechanical Dimensions Package Dimensions in millimeters 10MLP BOTTOM VIEW 15 FAN7024 Ordering Information Device FAN7024MU FAN7024MUX FAN7024MPX Package 8MSOP 10MLP Operating Temperature -40C ~ +85C Packing Tube Tape& Reel Tape& Reel DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. www.fairchildsemi.com 8/28/03 0.0m 001 Stock#DSxxxxxxxx 2003 Fairchild Semiconductor Corporation 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. |
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