IS31AP4066D DUAL 1.3W STEREO AUDIO AMPLIFIER December 2011 GENERAL DESCRIPTION KEY SPECIFICATIONS The IS31AP4066D is a dual bridge-connected audio power amplifier which, when connected to a 5V supply, will deliver 1.3W to an 8Ω load. The IS31AP4066D features a low-power consumption shutdown mode and thermal shutdown protection. It also utilizes circuitry to reduce “click-and-pop” during device turn-on. PO at RL = 8Ω, VDD = 5V THD+N = 1% ---------------------- 1.3W (Typ.) THD+N = 10% --------------------- 1.6W (Typ.) PO at RL = 8Ω, VDD = 4V THD+N = 1% ----------------------- 0.81W (Typ.) Shutdown current ------------------- 0.3μA (Typ.) Supply voltage range --------------- 2.7V ~ 5.5V QFN-16 (3mm × 3mm) package APPLICATIONS FEATURES Cell phones, PDA, MP4,PMP Portable and desktop computers Desktops audio system Multimedia monitors Suppress “click-and-pop” Thermal shutdown protection circuitry Micro power shutdown mode TYPICAL APPLICATION CIRCUIT R2 20K VCC VCC C3 SHUTDOWN WORKING 1uF INA BNC 15 SHUTDOWN 2,11 VDD C1 0.22uF R1 4 INA - -OUTA 3 20K + +OUTA 1 + 8 BYPASS C4 + 1uF +OUTB 12 INB BNC C2 0.22uF + R3 9 INB -OUTB 10 - 20K GND 5,6,7,13,14,16 R4 20K Figure 1 Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 Typical Application Circuit 1 IS31AP4066D PIN CONFIGURATION GND 13 14 GND 15 SHUTDOWN Pin Configuration (Top View) 16 GND Package 10 -OUTB INA 4 9 8 3 BYPASS -OUTA 7 11 VDD GND 2 6 VDD QFN-16 GND 12 +OUTB 5 1 GND +OUTA INB PIN DESCRIPTION No. Pin Description 1 +OUTA Left channel +output. 2,11 VDD Supply voltage. 3 -OUTA Left channel –output. 4 INA Left channel Input. 5~7,13,14,16 GND GND. 8 BYPASS Bypass capacitor which provides the common mode voltage. 9 INB Right channel input. 10 -OUTB Right channel –output. 12 +OUTB Right channel +output. 15 ———————————— SHUTDOWN Shutdown control, hold low for shutdown mode. Thermal Pad Connect to GND. Copyright © 2011 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 2 IS31AP4066D ORDERING INFORMATION Industrial Range: -40°C to +85°C Order Part No. Package QTY/Reel IS31AP4066D-QFLS2-TR QFN-16, Lead-free 2500 Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 3 IS31AP4066D ABSOLUTE MAXIMUM RATINGS Supply voltage, VDD Voltage at any input pin Junction temperature, TJMAX Storage temperature range, Tstg Operating temperature ratings Solder information, Vapor Phase (60s) Infrared (15s) -0.3V ~ +6.0V -0.3V ~ VDD+0.3V -40°C ~ +150°C -65°C ~ +150°C −40°C ~ +85°C 215°C 220°C Note: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS The following specifications apply for VDD= 5V, unless otherwise noted. Limits apply for TA = 25°C. (Note 1 or specified) Symbol Parameter Condition Typ. Limit Unit 2.7 V(min) 5.5 V(max) VDD Supply voltage IDD Quiescent power supply current VIN = 0V, Io = 0A 3.9 10.0 mA(max) ISD Shutdown current GND applied to the shutdown pin 0.3 2.5 μA(max) VIH Shutdown input voltage high 1.4 V(min) VIL Shutdown input voltage low 0.4 V(max) TWU Turn on time 1μF bypass cap(C4) (Note 2) 120.0 ms ELECTRICAL CHARACTERISTICS OPERATION The following specifications apply for VDD= 5V, unless otherwise noted. Limits apply for TA = 25°C. (Note 2 or specified) Symbol Parameter Vos Output offset voltage Po Output power THD+N PSRR Total harmonic distortion +noise Power supply rejection ratio Condition Typ. Limit Unit VIN = 0V 5.0 25.0 mV(max) THD+N = 1%, f = 1kHz, RL= 8Ω 1.3 W(min) THD+N = 10%, f = 1kHz, RL = 8Ω 1.6 W(min) 1kHz, Avd = 2, R = 8Ω, Po = 1W 0.1 % Input floating, 217Hz, Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 80.0 dB Input floating 1kHz, Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 70.0 dB Input GND 217Hz, Vripple = 200mVp-p C4 = 1μF, RL =8Ω 60.0 dB Input GND 1kHz Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 60.0 dB -100.0 dB 7.0 μV Xtalk Channel separation f = 1kHz, C4 = 1μF VNO Output noise voltage 1kHz, A-weighted Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 4 IS31AP4066D ELECTRICAL CHARACTERISTICS The following specifications apply for VDD= 3V, unless otherwise noted. Limits apply for TA = 25°C. (Note 1 or specified) Symbol Parameter power Condition supply Typ. Limit Unit VIN = 0V, IO = 0A 2.6 6.5 mA(max) GND applied to the shutdown pin 0.1 2.2 μA(max) IDD Quiescent current ISD Shutdown current VIH Shutdown input voltage high 1.1 V(min) VIL Shutdown input voltage low 0.4 V(max) TWU Turn on time 1μF bypass cap(C4) (Note 2) 110 ms ELECTRICAL CHARACTERISTICS OPERATION The following specifications apply for VDD= 3V, unless otherwise noted. Limits apply for TA = 25°C. (Note 2 or specified) Symbol Parameter Vos Output offset voltage Po Output power THD+N PSRR Total harmonic distortion+noise Power supply rejection ratio Condition Typ. Limit Unit VIN=0V 2.5 25.0 mV THD+N = 1%, f = 1kHz, RL= 8Ω 0.5 W THD+N = 10%, f = 1kHz, RL = 8Ω 0.6 W 1kHz, Avd = 2, RL = 8Ω, Po = 0.3W 0.1 % Input floating, 217Hz, Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 75.0 dB Input floating 1kHz, Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 70.0 dB Input GND 217Hz, Vripple = 200mVp-p C4 = 1μF, RL =8Ω 62.0 dB Input GND 1kHz Vripple = 200mVp-p C4 = 1μF, RL = 8Ω 62.0 dB -100.0 dB 7.0 uV Xtalk Channel separation f = 1kHz, C4 = 1μF VNO Output noise voltage 1kHz, A-weighted Note1: All parameters are production tested at 25°C, functional operation of the device and parameters specified over other temperature range, are guaranteed by design, characterization and process control. Note 2: Guaranteed by design. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 5 IS31AP4066D TYPICAL PERFORMANCE CHARACTERISTICS Vcc = 3V RL f = 1kHz Vcc = 5V RL f = 1kHz Figure 2 THD+N vs. Output Power Vcc = 5V RL Po = 1W Figure 4 THD+N vs. Output Power Vcc = 3V RL Po=300mW THD+N vs. Frequency Figure 5 THD+N vs. Frequency Vcc = 3V RL Input GND Vcc = 5V RL Input GND Figure 6 Figure 3 PSRR vs. Frequency Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 Figure 7 PSRR vs. Frequency 6 IS31AP4066D Vcc = 5V RL Vcc = 5V RL Input Floating Figure 8 PSRR vs. Frequency Vcc = 3V RL Input Floating Figure 10 Crosstalk vs. Frequency Vcc = 5V RL A-Weighting Figure 11 PSRR vs. Frequency Noise Floor Vcc = 3V RL Vcc = 5V RL Figure 12 Figure 9 Frequency Response Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 Figure 13 Frequency Response 7 IS31AP4066D Vcc = 3V RL Vcc = 3V RL A-Weighting Figure 14 Crosstalk vs. Frequency Figure 15 Noise Floor RL Top Side Bottom Side Vcc = 5V RL f = 1kHz Output Power (W) Figure 16 Dropout Voltage vs. Supply Voltage Figure 17 Power Dissipation vs. Output Power RL f = 1kHz THD+N = 10% THD+N = 1% Figure18 Output Power vs. Supply Voltage Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 8 IS31AP4066D APPLICATION INFORMATION EXPOSED-DAP PACKAGE PCB MOUNTING CONSIDERATIONS The IS31AP4066D’s QFN (die attach paddle) package provides a low thermal resistance between the die and the PCB to which the part is mounted and soldered. This allows rapid heat transfer from the die to the surrounding PCB copper traces, ground plane and, finally, surrounding air. The QFN package must have it’s DAP soldered to a copper pad on the PCB. The DAP’s PCB copper pad is connected to a large plane of continuous unbroken copper. This plane forms a thermal mass and heat sink and radiation area. Place the heat sink area on either outside plane in the case of a two-sided PCB, or on an inner layer of a board with more than two layers. BRIDGE CONFIGURATION EXPLANATION As shown in Figure 2, the IS31AP4066D consists of two pairs of operational amplifiers, forming a two-channel (channel A and channel B) stereo amplifier. External feedback resistors R2, R4 and input resistors R1 and R3 set the closed-loop gain of Amp A (-out) and Amp B (-out) whereas two internal 20kΩ resistors set Amp A’s (+out) and Amp B’s (+out) gain at 1. The IS31AP4066D drives a load, such speaker, connected between the two amplifier outputs, −OUTA and +OUTA. Figure 2 shows that Amp A’s (-out) output serves as Amp A’s (+out) input. This results in both amplifiers producing signals identical in magnitude, but 180° out of phase. Taking advantage of this phase difference, a load is placed between −OUTA and +OUTA and driven differentially (commonly referred to as “bridge mode”). This results in a differential gain of AVD = 2×(Rf/Ri) (1) or AVD = 2×(R2/R1) Bridge mode amplifiers are different from single-ended amplifiers that drive loads connected between a single amplifier’s output and ground. For a given supply voltage, bridge mode has a distinct advantage over the single-ended configuration: its differential output doubles the voltage swing across the load. This produces four times the output power when compared to a single-ended amplifier under the same conditions. This increase in attainable output power assumes that the amplifier is not current limited Another advantage of the differential bridge output is no net DC voltage across the load. This is accomplished by biasing channel A’s and channel B’s outputs at half-supply. This eliminates the coupling capacitor that single supply, single ended amplifiers require. Eliminating an output coupling capacitor in a single-ended configuration forces a single-supply Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 amplifier’s half-supply bias voltage across the load. This increases internal IC power dissipation and may permanently damage loads such as speakers. POWER DISSIPATION Power dissipation is a major concern when designing a successful single-ended or bridged amplifier. Equation (2) states the maximum power dissipation point for a single ended amplifier operating at a given supply voltage and driving a specified output load. PDMAX = (VDD)2/(2π2RL) Single-Ended (2) However, a direct consequence of the increased power delivered to the load by a bridge amplifier is higher internal power dissipation for the same conditions. The IS31AP4066D has two operational amplifiers per channel. The maximum internal power dissipation per channel operating in the bridge mode is four times that of a single-ended amplifier. From Equation (3), assuming a 5V power supply and an 8Ω load, the maximum single channel power dissipation is 0.63W or 1.26W for stereo operation. PDMAX = 4×(VDD)2/(2π2RL) Bridge Mode (3) The IS31AP4066D’s power dissipation is twice that given by Equation (2) or Equation (3) when operating in the single-ended mode or bridge mode, respectively. Twice the maximum power dissipation point given by Equation (3) must not exceed the power dissipation given by Equation (4): PDMAX' = (TJMAX − TA)/θJA (4) The IS31AP4066D’s TJMAX = 150°C. In the QFN package soldered to a DAP pad that expands to a copper area of 5in2 on a PCB, the IS31AP4066D’s θJA is 23°C/W. At any given ambient temperature TA, use Equation (4) to find the maximum internal power dissipation supported by the IC packaging. Rearranging Equation (4) and substituting PDMAX for PDMAX' results in Equation (5). This equation gives the maximum ambient temperature that still allows maximum stereo power dissipation without violating the IS31AP4066D’s maximum junction temperature. TA = TJMAX – 2×PDMAX θJA (5) For a typical application with a 5V power supply and an 8Ω load, the maximum ambient temperature that allows maximum stereo power dissipation without exceeding the maximum junction temperature is approximately 85°C for the QFN package. TJMAX = PDMAX θJA + TA (6) Equation (6) gives the maximum junction temperature TJMAX. If the result violates the IS31AP4066D’s 150°C, reduce the maximum junction temperature by reducing the power supply voltage or increasing the load resistance. Further allowance should be made for 9 IS31AP4066D increased ambient temperatures. SELECTING PROPER EXTERNAL COMPONENTS The above examples assume that a device is a surface mount part operating around the maximum power dissipation point. Since internal power dissipation is a function of output power, higher ambient temperatures are allowed as output power or duty cycle decreases. Optimizing the IS31AP4066D’s performance requires properly selecting external components. Though the IS31AP4066D operates well when using external components with wide tolerances, best performance is achieved by optimizing component values. 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. If these measures are insufficient, a heat sink can be added to reduce θJA. The heat sink can be created using additional copper area around the package, with connections to the ground pin(s), supply pin and amplifier output pins. The θJA is the sum of θJC, θCS, and θSA. (θJC is the junction-to-case thermal impedance, θCS is the case-to-sink thermal impedance, and θSA is the sink-to-ambient thermal impedance.) The IS31AP4066D is unity-gain stable, giving a designer maximum design flexibility. The gain should be set to no more than a given application requires. This allows the amplifier to achieve minimum THD+N and maximum signal-to-noise ratio. These parameters are compromised as the closed-loop gain increases. However, low gain demands input signals with greater voltage swings to achieve maximum output power. Fortunately, many signal sources such as audio CODECs have outputs of 1VRMS (2.83VP-P). Please refer to the Audio Power Amplifier Design section for more information on selecting the proper gain. POWER SUPPLY BYPASSING As with any power amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection. Applications that employ a 5V regulator typically use a 10μF in parallel with a 0.1μF filter capacitor to stabilize the regulator’s output, reduce noise on the supply line, and improve the supply’s transient response. However, their presence does not eliminate the need for a local 1.0μF tantalum bypass capacitance connected between the IS31AP4066D’s supply pins and ground. Keep the length of leads and traces that connect capacitors between the IS31AP4066D’s power supply pin and ground as short as possible. MICRO-POWER SHUTDOWN The voltage applied to the SHUTDOWN pin controls the IS31AP4066D’s shutdown function. Activate micro-power shutdown by applying GND to the SHUTDOWN pin. When active, the IS31AP4066D’s micro-power shutdown feature turns off the amplifier’s bias circuitry, reducing the supply current. The low 0.3μA typical shutdown current is achieved by applying a voltage that is as near as GND as possible to the SHUTDOWN pin. There are a few ways to control the micro-power shutdown. These include using a single-pole, single-throw switch, a microprocessor, or a microcontroller. When use a switch, connect an external 100k resistor between the SHUTDOWN pin and GND. Select normal amplifier operation by closing the switch. Opening the switch sets the SHUTDOWN pin to ground through the 100k resistor, which activates the micropower shutdown. The switch and resistor guarantee that the SHUTDOWN pin will not float. This prevents unwanted state changes. In a system with a microprocessor or a microcontroller, use a digital output to apply the control voltage to the SHUTDOWN pin. Driving the SHUTDOWN pin with active circuitry eliminates the pull up resistor. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 INPUT CAPACITOR VALUE SELECTION Amplifying the lowest audio frequencies requires high value input coupling capacitors (C1 and C2) in Figure 2. A high value capacitor can be expensive and may compromise space efficiency in portable designs. In many cases, however, the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 150 Hz. Applications using speakers with this limited frequency response reap little improvement by using large input capacitor. Besides effecting system cost and size, C1 and C2 have an effect on the IS31AP4066D’s click and pop performance. When the supply voltage is first applied, a transient (pop) is created as the charge on the input capacitor changes from zero to a quiescent state. The magnitude of the pop is directly proportional to the input capacitor’s size. Higher value capacitors need more time to reach a quiescent DC voltage (usually VDD/2) when charged with a fixed current. The amplifier’s output charges the input capacitor through the feedback resistors, R2 and R4. Thus, pops can be minimized by selecting an input capacitor value that is no higher than necessary to meet the desired −3dB frequency. A shown in Figure 2, the input resistors (R1 and R3) and the input capacitors (C1 and C2) produce a −3dB high pass filter cutoff frequency that is found using Equation (7). f-3dB= 1/2πRinCin= 1/2π R1C1 (7) As an example when using a speaker with a low frequency limit of 150Hz, C1, using Equation (7) is 0.053μF. The 0.33μF C1 shown in Figure 2 allows the IS31AP4066D to drive high efficiency, full range speaker whose response extends below 30Hz. 10 IS31AP4066D BYPASS CAPACITOR VALUE SELECTION Besides minimizing the input capacitor size, careful consideration should be paid to value of C4, the capacitor connected to the BYPASS pin. Since C4 determines how fast the IS31AP4066D settles to quiescent operation, its value is critical when minimizing turn-on pops. The slower the IS31AP4066D’s outputs ramp to their quiescent DC voltage (nominally 1/2 VDD), the smaller the turn-on pop. Choosing C4 equal to 1.0μF along with a small value of C1 (in the range of 0.1μF to 0.39μF), produces a click-less and pop-less shutdown function. As discussed above, choosing C1 no larger than necessary for the desired bandwith helps minimize clicks and pops. Connecting a 1μF capacitor, C4, between the BYPASS pin and ground improves the internal bias voltage’s stability and improves the amplifier’s PSRR. OPTIMIZING CLICK AND POP REDUCTION PERFORMANCE The IS31AP4066D contains circuitry that minimizes 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. When the part is turned on, an internal current source changes the voltage of the BYPASS pin in a controlled, linear manner. Ideally, the input and outputs track the voltage applied to the BYPASS pin. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 The gain of the internal amplifiers remains unity until the voltage on the bypass pin reaches 1/2 VDD. As soon as the voltage on the bypass pin is stable, the device becomes fully operational. Although the BYPASS pin current cannot be modified, changing the size of C4 alters the device’s turn-on time and the magnitude of “clicks and pops”. Increasing the value of C4 reduces the magnitude of turn-on pops. However, this presents a tradeoff: as the size of C4 increases, the turn-on time increases. There is a linear relationship between the size of C4 and the turn-on time. Here are some typical turn-on times for various values of C4 (all tested at VDD=5V): C4 TON 0.01μF 13ms 0.1μF 26ms 0.22μF 44ms 0.47μF 68ms 1.0μF 120 ms In order eliminate “clicks and pops”; all capacitors must be discharged before turn-on. Rapidly switching VDD on and off may not allow the capacitors to fully discharge, which may cause “clicks and pops”. 11 IS31AP4066D CLASSIFICATION REFLOW PROFILES Profile Feature Pb-Free Assembly Preheat & Soak Temperature min (Tsmin) Temperature max (Tsmax) Time (Tsmin to Tsmax) (ts) 150°C 200°C 60-120 seconds Average ramp-up rate (Tsmax to Tp) 3°C/second max. Liquidous temperature (TL) Time at liquidous (tL) 217°C 60-150 seconds Peak package body temperature (Tp)* Max 260°C Time (tp)** within 5°C of the specified classification temperature (Tc) Max 30 seconds Average ramp-down rate (Tp to Tsmax) 6°C/second max. Time 25°C to peak temperature 8 minutes max. Figure 19 Classification Profile Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 12 IS31AP4066D TAPE AND REEL INFORMATION Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 13 IS31AP4066D PACKAGE INFORMATION QFN-16 Note: All dimensions in millimeters unless otherwise stated. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 11/29/2011 14