XL386

XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 1 Features 3 Description • • • The 386 are power amplifiers designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200. 1 • • • • • • Battery Operation Minimum External Parts Wide Supply Voltage Range: 4 V–12 V or 5 V–18 V Low Quiescent Current Drain: 4 mA Voltage Gains from 20 to 200 Ground-Referenced Input Self-Centering Output Quiescent Voltage Low Distortion: 0.2% (AV = 20, VS = 6 V, RL = 8 Ω, PO = 125 mW, f = 1 kHz) Available in 8-Pin MSOP Package The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 mW when operating from a 6-V supply, making the 386 ideal for battery operation. 2 Applications • • • • • • • • AM-FM Radio Amplifiers Portable Tape Player Amplifiers Intercoms TV Sound Systems Line Drivers Ultrasonic Drivers Small Servo Drivers Power Converters 4 Schematic 6 VS 15 k 7 BYPASS 15 k GAIN 8 GAIN 1 15 k 5 VOUT 150 2 1.35 k 3 - INPUT + INPUT 50 k 50 k 4 GND 1 1 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 5 Pin Configuration and Functions D Package 8-Pin MSOP Top View GAIN - INPUT + INPUT GND 1 8 2 7 3 6 4 5 GAIN BYPASS VS VOUT Pin Functions PIN TYPE DESCRIPTION NAME NO. GAIN 1 – Gain setting pin –INPUT 2 I Inverting input +INPUT 3 I Noninverting input GND 4 P Ground reference VOUT 5 O Output VS 6 P Power supply voltage BYPASS 7 O Bypass decoupling path GAIN 8 – Gain setting pin 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN Supply Voltage, VCC XD386-1.XL386 15 22 XD386 Package Dissipation MAX UNIT V 1.25 XL386 0.73 XL386-MS 0.595 W Input Voltage, VI –0.4 0.4 V Storage temperature, Tstg –65 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±1000 Charged-device model (CDM), per JEDEC specification JESD22C101 (2) ±1000 2 UNIT V XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT Supply Voltage 4 12 386 5 18 Speaker Impedance 4 VI Analog input voltage –0.4 0.4 V TA Operating free-air temperature 0 70 °C VCC V V Ω 6.4 Thermal Information XL386 THERMAL METRIC (1) XL386 XD386 D (MSOP) DGK (SOP) P (DIP) 8 8 8 UNIT RθJA Junction-to-ambient thermal resistance 115.7 169.3 53.4 °C/W RθJC(top) Junction-to-case (top) thermal resistance 59.7 73.1 42.1 °C/W RθJB Junction-to-board thermal resistance 56.2 100.2 30.6 °C/W ψJT Junction-to-top characterization parameter 12.4 9.2 19.0 °C/W ψJB Junction-to-board characterization parameter 55.6 99.1 50.5 °C/W 6.5 Electrical Characteristics over operating free-air temperature range (unless otherwise noted) PARAMETER VS Operating Supply Voltage IQ Quiescent Current TEST CONDITIONS Output Power TYP MAX 4 12 XD386 5 18 VS = 6 V, VIN = 0 4 VS = 6 V, RL = 8 Ω, THD = 10% XD386 XL386 XL386-MS POUT MIN XD386 XL386 XL386-MS 250 325 VS = 9 V, RL = 8 Ω, THD = 10% 500 700 VS = 16 V, RL = 32 Ω, THD = 10% 700 100 VS = 6 V, f = 1 kHz 26 10 µF from Pin 1 to 8 46 AV Voltage Gain BW Bandwidth VS = 6 V, Pins 1 and 8 Open THD Total Harmonic Distortion VS = 6 V, RL = 8 Ω, POUT = 125 mW f = 1 kHz, Pins 1 and 8 Open PSRR Power Supply Rejection Ratio VS = 6 V, f = 1 kHz, CBYPASS = 10 μF Pins 1 and 8 Open, Referred to Output RIN Input Resistance IBIAS Input Bias Current VS = 6 V, Pins 2 and 3 Open 3 300 8 UNIT V mA mW dB kHz 0.2% 50 dB 50 kΩ 250 nA XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 6.6 Typical Characteristics Supply Current vs Supply Voltage Power Supply Rejection vs Frequency Output Voltage vs Supply Voltage Voltage Gain vs Frequency Total Harmonic Distortion vs Frequency Total Harmonic Distortion vs Power Out 4 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 Typical Characteristics (continued) Device Dissipation vs Output Power Device Dissipation vs Output Power Device Dissipation vs Output Power 5 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 7 Detailed Description 7.1 Overview The 386 is a mono low voltage amplifier that can be used in a variety of applications. It can drive loads from 4 Ω to 32 Ω. The gain is internally set to 20 but it can be modified from 20 to 200 by placing a resistor and capacitor between pins 1 and 8. This device comes in three different 8-pin packages as PDIP, SOIC and VSSOP to fit in different applications. 7.2 Functional Block Diagram Gain Circuitry + Bias Circuitry Bypass 7.3 Feature Description There is an internal 1.35-KΩ resistor that sets the gain of this device to 20. The gain can be modified from 20 to 200. Detailed information about gain setting can be found in the Detailed Design Procedure section. 7.4 Device Functional Modes As this is an Op Amp it can be used in different configurations to fit in several applications. The internal gain setting resistor allows the 386 to be used in a very low part count system. In addition a series resistor can be placed between pins 1 and 5 to modify the gain and frequency response for specific applications. 6 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 8 Application and Implementation 8.1 Application Information Below are shown different setups that show how the 386 can be implemented in a variety of applications. 8.2 Typical Application 8.2.1 386 with Gain = 20 Figure 10 shows the minimum part count application that can be implemented using 386. Its gain is internally set to 20. 2 6 - 1 250 µF + 8 386 VIN 3 10 k 5 7 0.05 µF + 4 10 386 with Gain = 20 8.2.1.1 Design Requirements Table 1. Design Parameters DESIGN PARAMETER EXAMPLE VALUE Load Impedance 4 Ω to 32 Ω Supply Voltage 5 V to 12 V 8.2.1.2 Detailed Design Procedure 8.2.1.2.1 Gain Control To make the 386 a more versatile amplifier, two pins (1 and 8) are provided for gain control. With pins 1 and 8 open the 1.35-kΩ resistor sets the gain at 20 (26 dB). If a capacitor is put from pin 1 to 8, bypassing the 1.35-kΩ resistor, the gain will go up to 200 (46 dB). If a resistor is placed in series with the capacitor, the gain can be set to any value from 20 to 200. Gain control can also be done by capacitively coupling a resistor (or FET) from pin 1 to ground. Additional external components can be placed in parallel with the internal feedback resistors to tailor the gain and frequency response for individual applications. For example, we can compensate poor speaker bass response by frequency shaping the feedback path. This is done with a series RC from pin 1 to 5 (paralleling the internal 15-kΩ resistor). For 6 dB effective bass boost: R ~= 15 kΩ, the lowest value for good stable operation is R = 10 kΩ if pin 8 is open. If pins 1 and 8 are bypassed then R as low as 2 kΩ can be used. This restriction is because the amplifier is only compensated for closed-loop gains greater than 9. 7 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 8.2.1.2.2 Input Biasing The schematic shows that both inputs are biased to ground with a 50 kΩ resistor. The base current of the input transistors is about 250 nA, so the inputs are at about 12.5 mV when left open. If the dc source resistance driving the 386 is higher than 250 kΩ it will contribute very little additional offset (about 2.5 mV at the input, 50 mV at the output). If the dc source resistance is less than 10 kΩ, then shorting the unused input to ground will keep the offset low (about 2.5 mV at the input, 50 mV at the output). For dc source resistances between these values we can eliminate excess offset by putting a resistor from the unused input to ground, equal in value to the dc source resistance. Of course all offset problems are eliminated if the input is capacitively coupled. When using the 386 with higher gains (bypassing the 1.35 kΩ resistor between pins 1 and 8) it is necessary to bypass the unused input, preventing degradation of gain and possible instabilities. This is done with a 0.1 μF capacitor or a short to ground depending on the dc source resistance on the driven input. 8.2.1.3 Application Curve Supply Current vs Supply Voltage 8 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 DIP 89 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 SOP 10 8 XL386 SOP8/XD386-1 DIP8/XL386-MS MSOP-8 MSOP-8 811