WT8002 Audio Amplifier IC
2W (4Ω) / 3W (3Ω) · AB Class · 2.2–5.5V · 1µA Shutdown · SOP8
The WT8002 is a high‑power AB‑class mono bridge‑tied‑load (BTL) audio amplifier designed for portable and USB‑powered audio applications. It delivers 2W into a 4Ω load or 3W into a 3Ω load at 5V with less than 10% THD+N. The device features an ultra‑low < 1µA shutdown current, wide supply voltage range (2.2–5.5V), and external gain adjustability for flexible system design. Its BTL architecture eliminates the need for output coupling capacitors, while built‑in pop‑and‑click suppression ensures clean audio playback. Housed in a compact SOP8 package, the WT8002 is ideal for USB multimedia speakers, portable electronics, and toy applications.
- 2W @ 4Ω / 3W @ 3Ω (5V, THD+N < 10%)
- 1W @ 8Ω (THD+N < 1%)
- < 1µA shutdown current
- 2.2–5.5V wide supply range
- External gain adjustable via resistors
- SOP8 package – easy to integrate
Key Features
Electrical Specifications (VDD = 5V, RL = 8Ω, TA = 25°C)
| Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | — | 2.2 | 5.0 | 5.5 | V |
| Quiescent Current | No load | — | 10 | — | mA |
| Shutdown Current | VSD high | — | — | 1.0 | µA |
| Output Power (8Ω) | THD+N ≤ 1%, f=1kHz | — | 1.1 | — | W |
| Output Power (8Ω) | THD+N ≤ 10%, f=1kHz | — | 1.6 | — | W |
| Output Power (4Ω) | THD+N ≤ 1%, f=1kHz | — | 1.6 | — | W |
| Output Power (4Ω) | THD+N ≤ 10%, f=1kHz | — | 2.4 | — | W |
| Output Power (3Ω) | THD+N ≤ 10%, f=1kHz | — | 3.0 | — | W |
| THD+N | 20Hz–20kHz, PO=1W, 8Ω | — | 0.1 | — | % |
| Output Offset Voltage | — | — | 10 | — | mV |
| Output Resistance | — | 7 | 8.5 | 10 | kΩ |
For 3Ω load performance: 3W @ THD+N ≤ 10%. Refer to the datasheet for detailed characteristic curves.
Pin Description – SOP8
| Pin | Name | Function |
|---|---|---|
| 1 | SD | Shutdown (high = shutdown, low = active) |
| 2 | BYP | Bypass capacitor for internal reference (VDD/2) |
| 3 | +IN | Non‑inverting input |
| 4 | −IN | Inverting input |
| 5 | VO1 | Negative output (BTL) |
| 6 | VDD | Power supply (2.2–5.5V) |
| 7 | GND | Ground |
| 8 | VO2 | Positive output (BTL) |
The device uses a bridge‑tied load (BTL) configuration. Outputs are differential and connect directly to the speaker without coupling capacitors.
Typical Application & Design Notes
Key design recommendations:
- Gain setting: AVD = 2 × (RF / RI). Typical RF = 20kΩ, RI = 10kΩ for gain = 2.
- Input coupling: Use CI = 0.1–0.39µF with RI to form a high‑pass filter.
- Bypass capacitor: Use 1µF on the BYP pin for optimal PSRR.
- Power decoupling: Place 10µF and 0.1µF capacitors as close as possible to the VDD pin.
- SD pin: The WT8002 has no internal pull‑up resistor. Do not leave the SD pin floating – drive it low for active operation or high for shutdown.
- Layout: Keep audio traces away from high‑frequency signals, use ground‑surround routing, and make output traces ≥1mm wide.
For EMC compliance, add an LC π‑filter (10–22µH, 1.2A) on the supply line and use 0Ω resistors or ferrite beads for analog/digital ground separation.
Applications
Why Choose WT8002
FAQs
What is the WT8002?
A high‑power AB‑class mono BTL audio amplifier delivering up to 3W, with low shutdown current and wide supply range.
What is the supply voltage range?
2.2V to 5.5V, suitable for battery and USB‑powered devices.
How much current does it draw in shutdown?
Less than 1µA typical.
What is the maximum output power?
3W into 3Ω at 5V (THD+N < 10%), 2W into 4Ω, or 1.5W into 8Ω.
Does it require output coupling capacitors?
No – the BTL output eliminates the need for DC‑blocking capacitors.
How do I control shutdown?
Drive the SD pin high (>2.0V) to shut down, or low (<0.8V) for normal operation.
Can I adjust the gain?
Yes, gain is set by the ratio of feedback resistor (RF) to input resistor (RI): AVD = 2 × (RF / RI).
What is the package type?
SOP8, a standard surface‑mount package with 8 leads.
Note: The WT8002 has no internal pull‑up resistor on the SD pin – it must be externally driven. For optimal performance, place decoupling capacitors close to the IC, keep input traces away from noise sources, and ensure proper grounding. The device operates reliably across the full temperature range (–40°C to +85°C). Refer to the datasheet for detailed application guidelines, characteristic curves, and PCB layout recommendations.
