The APA2051 is a monolithic integrated circuit, whichcombine

　　Features
Operating Voltage
– HVDD= 3.0~3.6V
– VDD= 4.5~5.5V
No Output Capacitor at Headphone Amplifier
Required
Meeting VISTA Requirement
Low Distortion
AMP Mode
– THD+N=56dB, at VDD = 5V, RL = 4Ω, PO=1.5W
– THD+N=64dB, at VDD = 5V, RL = 8Ω, PO=0.9W
HP Mode
– THD+N=73dB, at HVDD=3.3V, RL=16Ω
PO=125mW
– THD+N=77dB, at HVDD=3.3V, RL=32Ω,
PO=88mW
– THD+N=85dB, at HVDD=3.3V, RL=10kΩ,
VO=1.7Vrms
Output Power at 1% THD+N
– 1.9W, at VDD = 5V, AMP Mode, RL = 4Ω
– 1.2W, at VDD = 5V, AMP Mode, RL = 8Ω
at 10% THD+N
–2.4W at VDD = 5V, AMP Mode, RL = 4Ω
–1.5W at VDD = 5V, AMP Mode, RL = 8Ω
Depop Circuitry Integrated
Internal 19-Steps Gain Setting for Flexible Appli
cation
Thermal Shutdown Protection and Over-Current

General Description

The APA2051 is a monolithic integrated circuit, which
combines a stereo power amplifier and a stereo output
capacitor-less headphone amplifier. The stereo power
amplifier provides 19-steps gain setting for flexible
application. The headphone amplifier is ground-refer-
ence output, and no need the output capacitors for DC
blocking. The advantages of eliminating the output ca-
pacitor are saving cost, PCB’s space, and component
height.
Both the de-pop circuitry and the thermal shutdown pro-
tection circuitry are integrated in the APA2051, which re-
duces pops and clicks noise during power on/off and in
shutdown mode. Thermal shutdown protects the chip
from being destroyed by over-temperature failure. To sim-
plify the audio system design in notebook computer
applications, the APA2051 provides the internal gain
setting, and these features can minimize components
and PCB area.
The APA2051 is available in TQFN4x4-28 package. This
package is characterized by space saving and thermal
efficiency.