Generally, a Class D audio amplifier is a PWM amplifier or a switching amplifier. The amplifying devices in this amplifier, like transistors and generally MOSFETs, work as electronic switches but not as linear gain devices like in other amplifiers. So the switches in this type of amplifier are either completely ON or OFF to reduce the power losses within the output devices. They work by quickly switching backward and forward in between the supply rails with a PWM technique to generate a pulse train output. To attenuate their high-frequency content, a simple LPF is used to give analog output current & voltage. A small amount of energy can be dissipated within the amplifying transistors because they are either entirely on or off; thus, efficiency can go beyond 90%. This article elaborates on Class D audio amplifier IC – PAM8302 IC, pinout, specifications, and its applications.
What is PAM8302 IC?
The PAM8302 IC is a single-channel, 2.5-watt, low-cost, and filterless Class-D audio amplifier IC. This IC is originally manufactured by Diodes INC, and it provides higher-quality sound reproduction. This IC is available in SO-8, MSOP-8, and U-DFN3030-8 packages. So the filterless design of this amplifier removes the requirements of output filters by decreasing the external component count & overall cost.
PAM8302 IC operates with a single power supply that ranges from 1.8 volts to 5.5 volts, making it appropriate for utilization with different battery sources. This IC is mainly designed for battery-powered and portable audio applications because of its compact size, low power consumption, and high efficiency. The PAM8302 IC provides short-circuit protection and thermal shutdown.
This amplifier IC uses the PWM technique for high efficiency to change translates to less heat dissipation and longer battery life in battery-powered devices. The IC can deliver up to 2.5 watts of audio power into a 4-8 ohm speaker. It operates as a “filterless” amplifier, meaning it can drive speakers directly, eliminating the need for low-pass output filters and saving space and cost.
How does PAM8302 IC Work?
The PAM8302A is a Class-D 2.5W mono audio amplifier IC that amplifies audio signals for mono output. It is mainly designed for portable audio systems due to its efficiency & low power consumption to drive speakers directly without any output filters. This IC delivers up to 2.5 watts at 4Ω load or 1.5 Watts at 8Ω load using a 5.5V supply.
PAM8302 Class-D amplifier IC includes A+ and A- differential inputs, so it accepts both positive & negative audio signals. These are highly efficient ICs that exceed 90% efficiency whenever driving an 8-ohm speaker at over 1/2 watt power. This is quite a little IC, used in applications wherever space is narrow. Some breakout boards for this IC have a power shutdown pin that allows easy amplifier power status control.
PAM8302 IC Pin Configuration:
The PAM8302 IC pin configuration is shown below. So, this IC includes 8 pins, which are explained below.
PAM8302 IC Pin Configuration
- Pin-1 (SD): It is a shutdown control input pin of the amplifier IC. It is connected to logic low or ground to power down the amplifier. So, it allows for decreased power consumption whenever not in use.
- Pin-2 (NC): It is a no-connection pin of the amplifier IC.
- Pin-3 (IN+): It is a +ve differential audio input pin of IC.
- Pin-4 (IN-): It is a -ve differential audio input pin of IC.
- Pin-5 (VO+): It is a +ve differential audio o/p pin.
- Pin-6 (VDD): It is a power supply input pin of the IC.
- Pin-7 (GND): It is a ground pin of the amplifier IC.
- Pin-8 (VO-): It is a negative differential audio o/p pin of IC.
Features & Specifications:
The features & specifications of PAM8302 IC include the following.
- PAM8302 IC is a 2.5-watt class-D audio power amplifier IC.
- This IC includes 8 pins.
- These are available in SO-8, U-DFN3030-8, and MSOP-8 packages.
- Its operating voltage ranges from 2.5V to 5.5V.
- It provides 2.5Watts o/p at 10% THD with a 4ohm Load & 5Volts Power Supply
- This IC has low EMI & low quiescent current.
- THD + N is 0.1%.
- The signal-to-noise ratio is >95dB.
- Its shutdown current is <1uA
- It has up to 88% high efficiency.
- This IC has thermal shutdown, low noise, and short circuit protection.
- It saves space and less cost.
- Its operating temperature ranges from -40oC to +85oC.
Equivalents & Alternatives
Equivalent PAM8302 IC is TPA3125D2N IC. Alternative PAM8302 ICs are; TDS7294, LM386, PAM8610, TDA2030, TDA1554, TDA7294, TDA7279, TDA7265, TDA2005, LM3886, TDA2002, LA4440, etc.
Audio Amplifier Circuit with PAM8302 IC
The PAM8302 audio amplifier IC circuit, shown below, is designed mainly for audio amplification. This circuit’s required components mainly include the PAM8302 IC, capacitors 0.1 uF, 10 uF, and 1 uF, and a speaker.
The connections of this circuit are as follows;
- The speaker is connected to the +positive and –negative outputs.
- Connect the audio input signals to IN+ and IN-, which are completely ‘differential. ’ So, if your audio source does not contain differential outputs, then connect the audio input to GND.
- The Vcc input voltage is connected to the Vin & GND connections.
- The gain is adjusted with the onboard potentiometer. So, if the volume is very low or distorted, then amplify the gain by rotating the potentiometer clockwise.
- Pull the input of SD low to mute the output. So here, the output is “Bridge Tied which means the output pins are directly connected to the connections of speakers without connection to GND.
- The right and left channel negative connections should not be mutually fixed. The output of the amplifier should not be attached to more amplifiers; then, it must drive the speakers directly.
Audio Amplifier Circuit with PAM8302 IC
Working
The PAM8302 IC works with a voltage supply that ranges from 1.8 volts to 5.5 volts. So this circuit has two decoupling capacitors, 10µF & 1µF, which are connected in parallel among VDD & GND. So, these capacitors assist in filtering and steadying the power supply. Thus, audio input signals are simply connected to IN+ (pin-3) and IN- (pin-4). So, every input pin includes a 0.1µF capacitor within the series.
So, these capacitors block any DC component within the input signal by allowing the audio signal only to be allowed throughout the amplifier. Here, pin-1 (SD) is the shutdown control pin. Whenever this pin is pulled low, the amplifier is switched off, decreasing power consumption. Whenever it is pulled high, the amplifier normally works. Here, the output audio signal is received from pins-5 like VO+ & pin-8 (VO-). So, these pins are connected directly to the speaker that gets the amplified audio signal.
Advantages & Disadvantages
The advantages of PAM8302 IC include the following.
- The PAM8302A Class-D audio amplifier IC has high efficiency, is compact, and drives speakers directly by removing the need for output filters.
- This IC provides low noise, short-circuit protection, and low THD+N, which makes it suitable for battery-powered and portable applications.
- It boasts up to 88% high efficiency because it optimizes battery life.
- Its filterless architecture simply allows straight speaker driving by saving space on PCB & component prices because fixed output filters are not necessary.
- This IC has low THD+N and low noise, which results in high-quality audio reproduction.
- It has low EMI & low quiescent current.
- These are cost-effective and compact.
- It is available in a variety of packages.
- These are simple to use.
- These are used in a wide range of applications.
The disadvantages of PAM8302 IC include the following.
- This amplifier IC doesn’t have a particular switch. So the whole product quality will fall short if the fixed power transistor & other electronic components are not properly matched.
- The potential close to the GND of the power transistor will change in the initial connection & amplifier’s final shutdown process will cause an increase in noise.
- This amplifier’s output circuit may include a dead zone.
- These amplifier’s speakers may emerge distorted due to some reason.
Applications
The applications of PAM8302 IC include the following.
- PAM8302 IC is used wherever compact size & high efficiency are significant, like PMP/MP4 players, portable speakers, walkie-talkies, GPS devices, cellular phones, speaker phones, hands-free phones, etc.
- These are used in portable audio devices like audio outputs within portable devices, powering speakers, etc.
- This IC is used in audio amplification for little projects & hobbyists.
- These are used in portable speakers because of their compact size & efficiency.
- It is used in personal audio gadgets like headphones, MP3 players, earphones, etc.
- This IC is used in MP3/MP4 players mainly for audio playback.
- It is used in GPS systems to power audio alerts & instructions.
- These are used in Walkie-Talkies to provide audio amplification.
- It is used in speakerphones and hands-free phones as an amplifier.
- This IC is used in cellular phones to drive the audio speaker.
- These ICs are used in DIY audio projects.
Please refer to this link for the PAM8302 IC Datasheet.
Thus, this is an overview of PAM8302 IC, pin-out, features, specifications, circuit, working, pros, cons & its uses. So this mono, filter-free, and 2.5Watts class D audio power amplifier has a differential input that uses the PWM technique for power efficiency. This IC uses a 250 kHz PWM o/p with an H-bridge o/p driver to drive a tiny speaker within tables and cell phones. Thus, here is a question for you: What is LM386 IC?