GENERAL DESCRIPTION The SGM4917 stereo headphone amplifier is designed for portable equipment where board space is at a premium. The SGM4917 uses capless architecture to produce a ground-referenced output from a single power supply, eliminating the need for large DC-blocking capacitors for output, saving cost, board space, and component height. Additionally, for SGM4917B, the gain is set internally (-2V/V), further reducing component count. For SGM4917A, the gain can be adjusted by external feedback resistors. The SGM4917 delivers up to 80mW per channel into a 32Ω load and has low 0.02% THD+N. A -78dB power supply rejection ratio (PSRR) at 217Hz allows this device to operate from noisy digital supplies without an additional linear regulator. Comprehensive click-and-pop circuitry suppresses audible clicks and pops on startup and shutdown. The SGM4917 operates from a single 2.7V to 5.5V supply, consumes only 2.7mA supply current, and is specified over the extended -40°C to +85°C temperature range. The SGM4917 is available in a Green TQFN-3×3-16L package. FEATURES  SGM4917A: External Feedback Gain Network SGM4917B: Fixed -2V/V Gain  No Bulky DC-Blocking Capacitors Required  Ground-Referenced Outputs Eliminate DC-Bias Voltage on Headphone Ground Pin  No Degradation of Low-Frequency Response Due to Output Capacitors  Differential Inputs for Enhanced Noise Cancellation  80mW into 32Ω Load from 5V Power Supply at THD+N = 0.1% (TYP, per Channel)  Low 0.02% THD+N  High PSRR (-78dB at 217Hz)  Integrated Click-and-Pop Suppression  2.7V to 5.5V Single Supply Operation  Low Quiescent Current (2.7mA at VDD = 5V)  Shutdown Control  Undervoltage Lockout Function  -40℃ to +85℃ Operating Temperature Range  Available in Green TQFN-3×3-16L Package