■ Overview
YDA144 (D-4N) is a digital audio power amplifier IC with maximum output of 2.1W (RL=4Ω)×2ch. YDA144 has a “Pure Pulse Direct Speaker Drive Circuit” which directly drives speakers while reducing distortion of pulse output signal and reducing noise on the signal, and realizes the highest standard low distortion rate characteristics and low noise characteristics among digital amplifier ICs for mobile use.
In addition, circuit design with fewer external parts can be made depend on the condition of use because corresponds to filter less.
The YDA144 features Yamaha original non-clip output control function which detects output signal clip due to the over level input signal and suppress the output signal clip automatically. Also the non-clip output control function can adapt the output clip caused by power supply voltage down with battery. This is the difference from the traditional AGC (Auto Gain Control) or ALC (Auto Level Control) circuit. Attack time and release time can be freely set by external resistances or capacitances.

■ Features
• Maximum output
   2.1 W×2ch (VDDP=VDDA=5.0V, RL=4Ω, THD+N=10%)
   0.75 W×2ch (VDDP=VDDA=3.6V, RL=8Ω, THD+N=10%)
• Distortion Rate (THD+N)
   0.03 % (VDDP=VDDA=3.6V, RL=8Ω, Po=0.4W, 1kHz)
• Residual Noise
   40µVrms (VDDP=VDDA=3.6V, Av=12dB)
• Efficiency
   84 % (VDDP=VDDA=3.6V, RL=8Ω, Po=600mW)
   78 % (VDDP=VDDA=3.6V, RL=8Ω, Po=100mW)
• S/N Ratio
   95dB (VDDP=VDDA=3.6V, Av=12dB)
• Channel separation
   95dB (VDDP=VDDA=3.6V, RL=8Ω, Av=18dB, 1kHz)
• Over-current Protection function
• Thermal Protection function
• Low voltage Malfunction Prevention function
• 2ch independent power-down control function
• Power-down High speed Recovery function
• Package
   Lead-free 16-ball WLCSP (YDA144-WZ)
   Lead-free 20-pin QFN (YDA144-QZ)