The LM48820 is a ground-referenced, fixed-gain audio power amplifier capable of delivering 95mW of continuous average power into a 16Ω single-ended load, with less than 1% THD +N from a 3V power supply. It features a new circuit technology that utilizes a charge pump to generate a negative reference voltage, eliminating the need for output-coupling capacitors typically used with normal single-ended loads. The LM48820 does not require output coupling capacitors or bootstrap capacitors, making it ideally suited for mobile phone and other portable applications.
The LM48820 is a ground‑referenced, fixed‑gain audio power amplifier designed for portable devices such as mobile phones, MP3 players, and PDAs. It delivers up to 95 mW continuous average power into a 160 Ω load while maintaining less than 1 % THD+N from a 3 V supply. The device uses a charge‑pump to generate a negative reference voltage, eliminating the need for output‑coupling capacitors.
Key features include an ultra‑low‑current shutdown mode (0.05 pA typical), soft‑start to reduce inrush current, internal thermal shutdown protection, and pop‑and‑click suppression circuitry. The amplifier is offered in a 0.4 mm pitch micro‑SMD package and requires no external gain‑setting resistors.
The datasheet provides pin descriptions, absolute maximum ratings, electrical characteristics, typical application circuits, and performance graphs covering THD+N versus frequency and output power.
| Output Power (typical) | 95 mW into 160 Ω |
|---|---|
| Fixed Gain | 1.5 V/V |
| Shutdown Current (typical) | 0.05 pA |
| Operating Voltage Range | 1.6 V to 4.5 V |
| Power Supply Rejection Ratio (217 Hz) | 80 dB (typ) |
The LM48820 has an internal fixed gain of 1.5 V/V.
The shutdown current is typically 0.05 pA per channel.
It operates from 1.6 V up to 4.5 V.
Typical output power is 95 mW into a 160 Ω load.