SGM4918.pdf
No.11220
● SGM4918A: External Feedback Gain Network
SGM4918B: 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
● 80mW into 32Ω Load from 5V Power Supply at THD+N = 0.1%
(TYP, per Channel)
● Low 0.03% THD+N
● High PSRR (-78dB at 217Hz)
● Integrated Click-and-Pop Suppression
● 2.7V to 5.2V Single Supply Operation
● Low Quiescent Current (5.8mA at VDD = 5V)
● Shutdown Control
● Short-Circuit and Thermal-Overload Protections
● Undervoltage Lockout Function
● -40℃ to +85℃ Operating Temperature Range
● Available in Green TDFN-3×3-10L Package
The SGM4918 stereo headphone amplifier is designed for portable equipment where board space is at a premium. The SGM4918 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 SGM4918B, the gain is set internally (-2V/V), further reducing component count. For SGM4918A, the gain can be adjusted by external feedback resistors.
The SGM4918 delivers up to 80mW per channel into a 32Ω load and has low 0.03% 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.
