ICs for Audio Common Use AN5270 4.3 W × 1(8Ω) Power Amplifier with Volume Control and Tone Control ■ Overview 3.75±0.25 1.7±0.25 +0.1 0.45 –0.05 2.54 9 8 7 6 5 4 3 2 1 22.3±0.3 5.8±0.25 1.5±0.25 7.1 ±0.25 0.5 ±0.1 1.2 ±0.25 8.4±0.25 15.0 18.3±0.25 19.9±0.1 • DC volume control : 0 to 5 V • DC tone control : 0 to 5 V • 9-lead single-in-line plastic package with fin 0.1±0.05 ■ Features 6.3 ±0.3 φ3.3±0.1 φ2.65±0.1 Unit : mm The AN5720 is an integrated circuit designed for 4.3 W(8 Ω) power amplifier with volume control and tone control. 1.7 ±0.25 5.6±0.25 HSIP009-P-0000 ■ Block Diagram 9 VCC2 8 Out GND 7 6 RF 5 Tone control Tone-ctl. Vol-ctl. 3 LF 2 In 1 VCC1 4 Volume control Pre amp. ■ Pin Descriptions Pin No. Pin Name 1 VCC1 2 Sound input 3 Low frequency input 4 Volume control 5 Tone control 6 Ripple filter 7 Ground 8 Sound output 9 VCC2 Note) Pins 2 and 4 are weaker in protection against positive surge than the other pins. It is necessary to pay attention during application use. 1 AN5270 ICs for Audio Common Use ■ Absolute Maximum Ratings Parameter Supply voltage Circuit voltage Symbol Ratings Unit VCC1(V1-7) 14 V VCC2(V9-7) 26 V2-7 0 to V9-7 V3-7 0 to V9-7 V4-7 0 to V1-7 V5-7 0 to V1-7 ICC1 15 mA ICC2 2 A I8 −1.7 to +1.7 APP PD 1.6 W Topr −20 to +70 °C Tstg −55 to +150 °C Supply current Circuit current *3, 4 Power dissipation *2 Operating ambient temperature Storage temperature *1 *1 Note) Do not apply a current or voltage from the external to the terminals that are not described above. *1 : Ta = 25 °C, excluding parameters regarding ambient temperature and storage temperature. *2 : Ta = 70 °C, the IC is mounted on PCB, without external heat sink. *3 : For circuit currents, '+' denotes current flowing into the IC, and '−' denotes current flowing out of the IC. *4 : As the output Pin8 does not have over current protection circuit incorporated, therefore please take precaution not to short the output pin to either VCC or GND. ■ Recommended Operating Range Parameter Operating supply voltage range 2 Symbol Range Unit VCC1 11 to 13 V VCC2 15 to 24 ICs for Audio Common Use AN5270 ■ Electrical Caracteristics at VCC1 = 12 V, VCC2 = 18 V, f = 1 kHz, Ta = 25 °C, RL = 8 Ω, Vol. = max., Tone = max. Parameter Symbol Conditions Min Typ Max Unit Quiescent current 1 ITOT1 No input signal Measure VCC1 current 7 10 13 mA Quiescent current 2 ITOT2 No input signal Measure VCC2 current 20 28 48 mA Output DC bias VODC No input signal Measure Pin8 DC 7.2 8.3 9.4 V VO = 1 Vrms, GV = 20 log(VO / VIN) 28 30 32 dB VO = 1 Vrms, BPF : 400 Hz to 30 kHz 0.5 1.0 % Voltage gain GV Total harmonic distortion THD Max. output power Pomax THD = 10 %, PO = VO2 / RL 4.0 4.3 W Max. output attenuation Attmax VO = 1.0 Vrms, Vol. = max. → min. Attmax = 20 log [VO(vol. = max.) / VO(vol. = min.)] −69 −66 dB ∆GTC f = 10 kHz, fix VIN where VO(tone = max.) = 1 Vrms Tone = max. → min. ∆GTC = 20 log [VO(tone = max.) / VO(tone = min.)] 18 20 dB Tone variable range ■ Application Circuit Example AN78M12 12V 47µF External audio in 30kΩ 47µF 0.039 µF 9 VCC2 Out 8 GND 7 RF 6 3 LF Tone-ctl. 5 Ext TV 100kΩ AV 33µF SW SIF-IC Det. out 24kΩ 3.3µF 5.1kΩ Vol-ctl. 4 100Ω 33µF In 2 VCC1 1 AN5270 470 µF 2200µF 8Ω 18V Power supply GND AN78M05 33µF 5V 1kΩ 10kΩ VR 33µF 33kΩ 9kΩ 22µF 100µF 10kΩ VR Note) Design considerations for shock noise prevention. : In the application of the IC, please adopt the above power supply configuration whenever possible. Where this is not possible, then it is better to ensure that VCC1 should start up first before the onset of VCC2, in order to prevent power-on shock noise. Similarly, please ensure that VCC2 declines faster than VCC1, in order to prevent power-off shock noise. 3 AN5270 ICs for Audio Common Use ■ Technical Information • Characteristic curve chart PD Ta 11 10.4 10 4 Pmax < Area of safe operation Tjmax − Ta Rth 9 1 8 0.5 7 6.65 IC (A) Power dissipation PD (W) 10 ms single pulse, free air 2 1.7 6 5 4.14 4 3.36 3 2.5 2 3 25 °C 70 °C 0.1 2 2.63 0.05 1 2.15 0.02 1.6 1 0.01 0 0 20 40 60 1 80 100 120 140 160 5 10 26 50 100 VCE (V) Ambient temperature Ta (°C) 1 No heat sink 2 5.5 × 5.0 cm2 Al board (t = 1 mm) 3 7.5 × 7.5 cm2 Al board (t = 1 mm) 4 Infinity heat sink • Structure of pre-amp. stage Power stage Pre-amp. stage Tone-control Volume-control Output 8 GF 2.8 kΩ Point1 GL1 Ci G 47 kΩ Point2 GL2 2.8 kΩ C2 VIN 5.6 kΩ 1 kΩ Input 2 33 pF GB LF input 3 GT GP (25 dB) C1 R1 Fig. Simplified structure of AN5270 pre-amp. stage Explanation of gain notations : GT : Gain of tone-amp. (treble-amp.) GF GB : Gain of flat-response amp. : Gain of bass-amp. GL1 : Gain at point 1 with respect to VIN. GL2 : Gain at point 2 with respect to VIN. GP : Gain of power stage. Gpre : Gain of pre-amp. stage. 4 ICs for Audio Common Use AN5270 ■ Technical Information (continued) • Structure of pre-amp. stage (continued) GF amp., the flat-amp., amplifies the signal equally for all frequencies in the range of 20 Hz to 70 kHz. GT amp., the treble or tone-amp., has an internal LPF connected to its inverting input. The non-inverting input of GT amp. is connected to the input signal. Thus, the output of GT passes only the upper range of frequencies (cut-off frequency = 2.5 kHz). GB amp., the bass-amp., amplifies the lower range of frequencies. Its cut-off frequency is determined by R1· C1. If LF pin is left open, then GB amp. has no effect on the overall frequency response. • Gain calculation General formula for gain of pre-amp. is (when vol. = max., tone = max.) : Gpre = GL1 · (GF + GT) − GB · GL2 By vector analysis as shown in fig. Vector diagram of Gpre, GV [dB] = Gpre + GP GV [dB] = 20 log √[GL1 · (GF + GT) − GB · GL2 · cosθ]2 + (GB · GL2 · sinθ)2 + GP where GL1 = 0.5 GF = 1.3 Gpre GB = 5.4 0 for (100 Hz) GT = 1.3 for (1 kHz) 2.5 for (10 kHz) θ GP = 25 dB Z3 · 0.848 GB ≈ Z3 + R1 6600 Z3 = √1 + (2πf · C1 · 6600)2 θ = −tan−1 (2πf · C1 · 6600) GL1 · (GF + GT) GB · GL2 Fig. Vector diagram of Gpre GV G1 : Gain at 100 Hz G2 : Gain at 1 kHz G3 : Gain at 10 kHz f1 : High frequency cut-off when Pin3 is open. f2 : Low frequency cut-off G1 −3 dB G2 G3 −3 dB *1 Tone = max. Tone = min. 100 Hz f2 1 kHz f1 10 kHz f Fig. Frequency response of AN5270 Note) *1 : This is the response if LF pin is open (i.e. R1 open). 5 AN5270 ICs for Audio Common Use ■ Technical Information (continued) • Cut-off frequencies f1 = 1 = 2.5 kHz 2π · G · Ci · Ri where G = 40 times, Ci = 33 pF, R1 = 47 kΩ f2 = 1 = 530 Hz 2π · R1 · C1 if R1 = 3 kΩ, C2 = 0.1 µF • Summary of frequency characteristics for typical values of R1 and C1 Actual Gain(dB)* R1(Ω) C1(F) 2.2 k 5.1k f2(Hz) ∆GTC(dB) 31.0 31.0 1.8 k 800 10.0 21.0 27.5 25.0 26.0 30.0 30.0 30.0 408 204 21.0 18.0 14.0 36.0 34.0 33.0 35.0 32.0 31.0 30.0 30.0 30.0 1.6 k 723 530 10.0 19.0 21.0 31.0 26.0 18.0 29.0 27.0 26.0 30.0 30.0 30.0 312 159 80 19.0 17.0 16.0 G1(100 Hz) G2(1 kHz) G3(10 kHz) 0.039 µ 0.039 µ 35.0 31.0 34.0 31.0 10 k 20 k ∞ 0.039 µ 0.039 µ 26.0 17.5 24.0 1k 2.2 k 3k 0.1 µ 0.1 µ 0.1 µ 5.1 k 10 k 20 k 0.1 µ 0.1 µ 0.1 µ Note) * : Tone = max. Table. Tabulated summary of frequency characteristics of AN5270. • Volume control The volume control range is 0 to 5 V. This range is adopted so as to simplify the pull-up of typical PWM output from micro-computer IC. The following simplified PWM output configuration is suggested : The high input impedance of the volume control pin makes the input current extremely small, so that it is not necessary to have an external buffer at the PWM output. Configuration A : 5V Volume control 4 R4 300 Ω Treble control R5 12 kΩ PWM output 18 kΩ C4 2.2 µF 5 300 Ω Fig. Volume control interface circuit for AN5270 6 Microcomputer IC ICs for Audio Common Use AN5270 ■ Technical Information (continued) • Volume control (continued) Alternative responses of volume control may be obtained by addition of a diode across the resistor R4. Configuration B : Volume attenuation R4 18 kΩ Config. B 12 kΩ 2.2 µF A C Configuration C : R4 18 kΩ 0 0.6 V Volume DC Pin4 (V) 5V 12 kΩ 2.2 µF 10 kΩ Fig. Volume characteristics of AN5270 • Tone control The tone cotrol range is 0 to 5 V. Please adopt the same PWM configration as suggested for the volume control. The variable range of tone control is about 20 dB, depending on the values of R1 · C1 components that are connected to Pin3. Internally, there is a LPF formed by Ri = 47 kΩ and a Miller capacitor which is formed by Ci = 33 pF and the gain amplifier G = 40. The cut-off frequency is thus : 1 = 2.5 kHz 2π · G · Ci · Ri To achieve a rich deep-bass effect, the tone control should be adjusted to minimum (0 V). To achieve a bright treble effect, the tone control should be adjusted to maximum. • VCC requirement VCC1 should be fixed at 12 V. Achieve best performance by obtaining this supply from a 12 V voltage regulator output. 7 AN5270 ICs for Audio Common Use ■ Technical Information (continued) • Power-on/off pop-noise elimination In most TV applications, it is observed that there is a short period of delay from power-on to the onset of sound. The purpose of power-on mute is to eliminate any unpleasant 'pop' noise (caused by transients) by effectively muting the power amplifier. In this IC, an internal mute is incorporated at the instant of power-on and power-off. The length of mute time depends on the value of the ripple filter condenser at Pin6. In the following diagram, the value of the condenser connected to RF pin (Pin6) is 47 µF. 18 V VCC2 Pin9 12 V VCC1 Pin1 270 ms Internal mute-pulse 170 ms 1.2 s 5V Volume Pin4 Output Pin8 470 ms 220 ms Fig. Power on/off typical timing characteristics of AN5270 (The above timing diagram is based on the evaluation circuit that is given in the product specification. Actual chasis performance may differ due to differences in power supply and external components.) The internal mute pulse will force the volume to minimum by grounding Pin4 momentarily. In most chasis, it is also common to implement externally the audio defeat feature by forcing Pin4 to ground momentarily, for the purpose of power-on/off as well as during channel switching. Should the internal mute be insufficient, it is recommended that the external audio defeat be used. 8 ICs for Audio Common Use AN5270 ■ Technical Information (continued) • Power-off pop-noise countermeaasure (for study consideration only) To prevent power-off shock noise, please ensure that VCC2 (18 V) declines faster than VCC1 (12 V). In addition, to ensure that VCC1 variation will not cause any 'pop' , one suggested countermeasure is to connect a condenser between Pin6 and Pin9 (e.g. 47 µF, use non-polarity type if possible). RF 6 C6 47 µF VCC2 9 Cpop 47 µF NP 2200 µF Fig. One suggested counter-measure against power-off 'pop' for AN5270. This effect of Cpop is to discharge C6 gradually as soon as power is switched off. However, it must be noted that the necessity of this countermeasure is dependent upon the set design and other timing considerations. • THD improvement (for study consideration only) 1 47 µF 6 C6 Fig. THD improvement circuit. Instead of connecting the negative terminal of C6 to ground, when that terminal is connected to Pin1, it is noticed that THD is improved considerably. 9