General Description
The APA2178 is a stereo, fixed gain, Cap-Free headphone driver which is available in a WLCSP2x2-16 package.
The APA2178 is a ground-reference output, and doesn’t need the output capacitors for DC blocking. The advantages of eliminating the output capacitor are saving the cost, PCB’s space, and component height.
The built-in gain setting can minimize the external component counts and save the PCB space. High PSRR provides increased immunity to noise and RF rectification. In addition to these features, a fast startup time and small package size make the APA2178 an ideal choice for portable multimedia device.

Features
• No Output Capacitor Required
• Operating Voltage: 1.8V~4.5V
• Supply Current
    – IDD=5mA at VDD=3.3V
• Low Shutdown Current
    – IDD=1mA at VDD=3.3V
• Meeting VISTA Requirements
• Output Power at 1% THD+N
    – 70mW, at VDD=3.3V, RL = 16W at 10% THD+N
    – 100mW, at VDD=3.3V, RL = 16W
• Less External Components Required
• High PSRR: 78dB at 217Hz
• Short-Circuit and Thermal Protection
• ± 8KV ESD Performance
• Surface-Mount Packaging
    – WLCSP2x2-16
• Lead Free and Green Devices Available (RoHS Compliant)

Applications
• Handsets
• PDAs
• Portable multimedia devices
• Notebooks