WT8302A Audio Amplifier IC
2.5W Class‑D · AERC Ultra‑Low EMI · 2.5–5.5V · 40ms Startup · SOP8
The WT8302A is a high‑efficiency, ultra‑low EMI mono Class‑D audio amplifier designed for portable and battery‑powered devices. It delivers 2.5W into a 4Ω load at 5V with 88% efficiency. The proprietary AERC (Adaptive Edge Rate Control) technology provides exceptional full‑bandwidth EMI suppression, achieving over 20dB margin under FCC Part 15 Class B standards without additional filtering. The device features an ultra‑low < 1µA shutdown current, 40ms fast startup, wide supply voltage range (2.5–5.5V), and integrated pop‑and‑click suppression. Built‑in over‑current, short‑circuit, and thermal protection with auto‑recovery ensure reliable operation. Housed in a compact SOP8 package, the WT8302A is ideal for USB speakers, portable media players, and other low‑voltage audio systems.
- 2.5W output @ 5V, 4Ω
- AERC ultra‑low EMI technology
- 88% efficiency
- < 1µA shutdown current
- 40ms fast startup time
- SOP8 package
Key Features
Electrical Specifications (TA = 25°C)
| Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | — | 2.5 | 5.0 | 5.5 | V |
| Quiescent Current | VDD=5.2V, no load | — | 4 | 8 | mA |
| Quiescent Current | VDD=3.6V, no load | — | 3 | — | mA |
| Shutdown Current | VSD=0V | — | — | 1.0 | µA |
| Output Power | RL=4Ω, THD+N≤10%, f=1kHz | — | 2.5 | — | W |
| Output Power | RL=8Ω, THD+N≤10%, f=1kHz | — | — | — | W |
| On‑Resistance | VDD=5V | — | 260 | — | mΩ |
| PSRR | f=1kHz, VPP=200mV | 45 | 50 | — | dB |
| CMRR | — | — | –70 | — | dB |
| Oscillator Frequency | — | — | 250 | — | kHz |
| Start‑up Time | — | — | 40 | — | ms |
| Output Offset Voltage | VIN=0V | — | 5 | 25 | mV |
AERC technology provides exceptional EMI suppression. The BYPASS capacitor (pin 2) is optional but recommended for high‑noise environments.
Pin Description – SOP8
| Pin | Name | Function |
|---|---|---|
| 1 | SD | Shutdown (high = active, low = shutdown) |
| 2 | NC/BYP | Not connected / Bypass capacitor (optional, for high‑noise environments) |
| 3 | +IN | Non‑inverting input |
| 4 | −IN | Inverting input |
| 5 | VO+ | Positive output (BTL) |
| 6 | VDD | Power supply (2.5–5.5V) |
| 7 | GND | Ground |
| 8 | VO− | Negative output (BTL) |
Pin 2 (BYP) is not required for normal operation. However, adding a capacitor to ground on this pin can improve PSRR in high‑noise environments.
AERC EMI Technology
The WT8302A features proprietary AERC (Adaptive Edge Rate Control) technology, which significantly reduces EMI emissions across the entire audio bandwidth. With a 60cm audio cable, the device achieves over 20dB margin under FCC Part 15 Class B standards – without any additional filtering components. This makes the WT8302A particularly suitable for EMI‑sensitive applications such as:
- FM radios and CMMB receivers
- Mobile phone analog TV
- Devices with integrated antennas
- Compact portable systems with limited shielding
This advanced technology eliminates the need for expensive EMI filtering components, reducing both BOM cost and PCB area.
Protection & Safety
- Over‑Current Protection (OCP): Shuts down during excessive output current.
- Short‑Circuit Protection (SCP): Protects against output short to ground or supply.
- Thermal Shutdown (TSD): Disables output when junction temperature exceeds safe limits.
- Under‑Voltage Protection (UVP): Prevents operation below safe voltage levels.
- Auto‑Recovery: Automatically resumes normal operation after fault conditions are removed.
Design & Layout Recommendations
Key design guidelines:
- Decoupling: Place a 1µF ceramic capacitor as close as possible to the VDD pin. For better low‑frequency filtering, add a 10µF or larger capacitor.
- Gain setting: Gain = 150kΩ / (10kΩ + RIN) [V/V]. Use 1% tolerance resistors for optimal performance.
- Input filtering: The input capacitor forms a high‑pass filter: fC = 1 / (2π × (10k + RIN) × CIN). Choose values to reject 217Hz noise.
- Output filter: The device operates without output filters. For EMC compliance in sensitive applications, use a ferrite bead or LC filter (10–22µH, 1A).
- Layout: Keep audio traces away from interference sources, use ground‑surround routing, and make output traces ≥1mm wide.
For EMC certification, add an LC π‑filter (10–22µH, 1A) on the supply line and separate analog/digital grounds with a 0Ω resistor or ferrite bead.
Applications
Why Choose WT8302A
FAQs
What is the WT8302A?
A high‑efficiency, ultra‑low EMI mono Class‑D amplifier delivering 2.5W at 5V/4Ω, featuring AERC EMI suppression technology.
What is AERC technology?
Adaptive Edge Rate Control – a proprietary technology that reduces EMI across the full audio bandwidth, achieving >20dB FCC margin without output filters.
What is the supply voltage range?
2.5V to 5.5V, suitable for both battery and USB‑powered devices.
How much current does it draw in shutdown?
Less than 1µA, maximizing battery life in standby.
How fast does it start up?
40ms typical, allowing for quick response to playback triggers.
Does it require an output filter?
No – the filter‑free design eliminates the need for external filtering components.
What is the package type?
SOP8, a standard surface‑mount package.
What protection features does it have?
Over‑current, short‑circuit, thermal shutdown, and under‑voltage protection with auto‑recovery.
Note: For optimal performance, place decoupling capacitors close to the IC and keep input traces away from noise sources. The bypass capacitor on pin 2 is optional but recommended for high‑noise environments. The device can operate with or without an output filter – ferrite beads are recommended for EMC compliance in sensitive applications. Refer to the datasheet for complete application guidelines and PCB layout recommendations.
