WT8623 Audio Amplifier IC
35W Class‑D · 5.7–17V · 92% Efficiency · 4‑Level Gain · ESOP16
The WT8623 is a high‑power mono Class‑D audio amplifier designed for premium home audio and multimedia systems. It delivers 35W into a 3Ω load at 15V (THD+N ≤ 10%) and offers 4‑level adjustable gain (20dB to 37dB) for flexible system integration. With 92% efficiency, it eliminates the need for heatsinks in most applications. The device operates over a wide 5.7–17V supply range and features advanced EMI suppression, allowing cost‑effective ferrite bead filters for EMC compliance. Comprehensive over‑current, short‑circuit, and thermal protection with auto‑recovery ensure robust operation. Housed in a thermally‑enhanced ESOP16 package, the WT8623 is ideal for LCD TVs, multimedia speakers, and home theater systems.
- 35W output @ 15V, 3Ω (THD+N ≤ 10%)
- 4‑level gain – 20/26/32/37dB
- 92% efficiency – no heatsink required
- 5.7–17V wide supply range
- Filter‑free – ferrite bead sufficient
- ESOP16 package with thermal pad
WT8623 Key Features
Electrical Specifications (TA = 25°C)
| Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | — | 5.7 | — | 17 | V |
| Quiescent Current | VCC=12V, no load | — | 6.5 | 9 | mA |
| Shutdown Current | SD=0V | — | 20 | 50 | µA |
| Output Power (Single‑side PCB) | RL=2Ω, VCC=9V, THD+N≤10% | — | 18.35 | — | W |
| Output Power (Double‑side PCB) | RL=4Ω, VCC=15V, THD+N≤10% | — | 30.0 | — | W |
| Output Power (Double‑side PCB) | RL=3Ω, VCC=15V, THD+N≤10% | — | 35.0 | — | W |
| Output Power (Double‑side PCB) | RL=4Ω, VCC=16V, THD+N≤10% | — | 32.0 | — | W |
| THD+N | VCC=14V, 8Ω, 12W, f=1kHz | — | 0.1 | — | % |
| PSRR | 1kHz, 200mVPP ripple, Gain=20dB | — | 70 | — | dB |
| Efficiency | — | — | 92 | — | % |
| Oscillator Frequency | — | — | 330 | — | kHz |
| Thermal Shutdown | — | 150 | 170 | — | °C |
| Start‑up Time | — | — | 100 | — | ms |
Output power depends on PCB thermal design (single‑side vs. double‑side). Double‑side PCB with adequate copper area is recommended for full power output.
Pin Description – ESOP16
| Pin | Name | Function |
|---|---|---|
| 1 | SD | Shutdown (high = active, low = shutdown) |
| 2 | Gain0 | Gain configuration bit 0 (with Gain1) |
| 3 | Gain1 | Gain configuration bit 1 (with Gain0) |
| 4 | AVCC | Analog power supply |
| 5 | AGND | Analog ground (connect via 0Ω resistor to power ground) |
| 6 | GVDD | Gate drive voltage (bootstrap supply) |
| 7 | INN | Negative input |
| 8 | INP | Positive input |
| 9 | PVCC | Power supply (5.7–17V) |
| 10 | BSP | Positive bootstrap |
| 11 | OUTP | Positive output |
| 12 | BSP | Positive bootstrap |
| 13 | OUTN | Negative output |
| 14 | PGND | Power ground (connect to exposed pad) |
| 15 | OUTN | Negative output (duplicated for current capability) |
| 16 | BSN | Negative bootstrap |
| 0 (Pad) | E‑GND | Exposed thermal pad – must be soldered to PGND with large copper area |
Gain0 and Gain1 logic levels set the gain: 00=20dB, 01=26dB, 10=32dB, 11=37dB. (0 = ≤0.8V, 1 = ≥2V).
WT8623 Gain Configuration
| Gain1 | Gain0 | Gain (dB) | Typical Input Impedance |
|---|---|---|---|
| 0 | 0 | 20 | ~20kΩ |
| 0 | 1 | 26 | ~13kΩ |
| 1 | 0 | 32 | ~7.8kΩ |
| 1 | 1 | 37 | ~5.2kΩ |
Logic low = ≤0.8V, logic high = ≥2V. The gain setting also affects input impedance – refer to the datasheet for complete details.
Protection & Safety
- Over‑Current Protection (OCP): Shuts down output during short circuits or excessive current.
- Short‑Circuit Protection (SCP): Protects against output shorts to ground or supply.
- Thermal Shutdown (TSD): Disables output when temperature exceeds ~150–170°C (with ±15°C tolerance). Auto‑recovers after temperature drops by 20°C.
- Auto‑Recovery: The device restarts normal operation automatically after fault conditions are removed (110ms recovery time).
Start‑up & Shutdown Sequencing
To minimize pop‑and‑click noise, follow these timing guidelines:
- Power‑up: Ensure the host chip (audio source) is stable before enabling WT8623 (SD high).
- Power‑down: Pull SD low to disable WT8623 before the host chip power is removed.
- Enable timing: Wait for the host’s analog output bias to stabilize before setting SD high.
- Disable timing: Pull SD low before disabling the host’s analog output.
Proper sequencing is essential to eliminate audible pops during power transitions.
Design & Layout Recommendations
- Thermal management: The exposed pad must be soldered to a large ground plane with multiple vias. For full power output, use double‑side PCB with adequate copper area.
- Decoupling: Place 10µF and 0.1µF capacitors close to PVCC and AVCC pins.
- Input: For differential input, connect INP and INN to the source. For single‑ended, connect INN to ground via a capacitor and apply signal to INP.
- Output filter: A low‑cost ferrite bead filter is sufficient for most EMC requirements. For stricter EMC, use an LC filter (inductor ≥33µH, 3A).
- Bootstrap: Connect 100nF capacitors between bootstrap pins (BSP/BSN) and the corresponding output pins.
- Layout: Keep audio traces away from interference sources, use ground‑surround routing, and make output traces ≥1mm wide.
For EMC compliance, add an LC π‑filter (10–22µH, 3A) on the supply line and separate analog/digital grounds with a 0Ω resistor or ferrite bead.
WT8623 Applications
Why Choose WT8623
FAQs
What is the WT8623?
A high‑power mono Class‑D amplifier delivering up to 35W with 92% efficiency and 4‑level gain, designed for LCD TVs and multimedia audio.
What is the WT8623 supply voltage range?
5.7V to 17V, supporting both lower‑voltage and higher‑voltage systems.
How do I set the gain?
Using the Gain0 and Gain1 pins – four combinations offer 20, 26, 32, and 37dB gain.
What is the maximum output power?
35W into 3Ω at 15V (THD+N ≤ 10%) with double‑side PCB layout.
Does WT8623 need a heatsink?
No – its 92% efficiency and low thermal resistance allow operation without a heatsink in most applications.
What output filter is required?
A simple ferrite bead filter is sufficient; an LC filter is recommended for stricter EMC certification.
What is the package type?
ESOP16 with an exposed thermal pad for heat dissipation.
What is the difference between single‑side and double‑side PCB?
Double‑side PCB with larger copper area allows higher power output (up to 35W) by improving heat dissipation.
Note: The exposed pad (PGND) must be soldered to a large ground plane for proper thermal performance. For maximum output power, use a double‑side PCB with adequate copper area and thermal vias. The gain settings also change input impedance – ensure your source can drive the selected impedance. Refer to the datasheet for complete application schematics, characteristic curves, and PCB layout guidelines.
